Search for anomalous single top quark production in association with a photon in pp collisions at $$ \sqrt{s}=8 $$ TeV

Journal of High Energy Physics, Apr 2016

The CMS collaboration, V. Khachatryan, A. M. Sirunyan, A. Tumasyan, W. Adam, E. Asilar, T. Bergauer, J. Brandstetter, E. Brondolin, M. Dragicevic, et al.

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Search for anomalous single top quark production in association with a photon in pp collisions at $$ \sqrt{s}=8 $$ TeV

B(t ! c ) < 8 TeV Search for anomalous single top quark production in association with a photon in pp collisions at The result of a search for avor changing neutral currents (FCNC) through single top quark production in association with a photon is presented. The study is based on proton-proton collisions at a center-of-mass energy of 8 TeV using data collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 19.8 fb 1. The search for t events where t ! Wb and W ! a photon, at least one hadronic jet with at most one being consistent with originating from a bottom quark, and missing transverse momentum. No evidence of single top quark production in association with a photon through a FCNC is observed. Upper limits at the 95% con dence level are set on the tu and tc anomalous couplings and translated into upper limits on the branching fraction of the FCNC top quark decays: B(t ! u ) < . Upper limits are also set on the cross section of associated t production in a restricted phase-space region. These are the most stringent limits currently available. Flavour Changing Neutral Currents; Hadron-Hadron scattering (experi- - The CMS collaboration 1 Introduction 2 The CMS detector 3 Data and simulation samples 4 Event selection and reconstruction of signal 5 Background estimation 6 Signal extraction 7 Systematic uncertainties 8 Upper limits on anomalous couplings 9 Upper limits on the FCNC cross sections for a restricted phase space 10 Summary The CMS collaboration 1 Introduction predicted branching fraction (B) for t ! u and t ! c decays are approximately 10 14 [ 2 ]. However, an enhancement of several orders of magnitude is predicted in some extensions of the SM, resulting in branching fractions observable at the LHC in some cases [ 3, 4 ]. Therefore, observation of these rare top quark decay modes would be indicative of physics beyond the SM. Searches for FCNC tu and tc interactions have been carried out by several experiments, with as yet no indication of a signal. The measured upper limits at the 95% con dence level (CL) on the branching fraction of t ! q , with q representing an up or charm quark, through single top quark production are 4.1% (L3) [5], 0.29% (ZEUS) [6], and 0.64% (H1) [7] . The 95% CL limit set by the CDF experiment through top quark pair production is B(t ! q ) < 3:2% [8]. { 1 { The most general e ective Lagrangian up to dimension-six operators, Le , used to describe the FCNC tq vertex has the following form [9]: eQt q ( tLq PL + tRq PR)tA + h.c.; (1.1) where e and Qt are the electric charges of the electron and top quark, respectively, q is the four-momentum of the photon, is an e ective cuto , which conventionally is taken as the top quark mass, [ ; ], and PL and PR re ect, respectively, the leftand right-handed projection operators. The strengths of the anomalous couplings are denoted by tLq;R. No speci c chirality is assumed for the FCNC interaction of tq , i.e., L R tq = tq = tq . In the SM, the values of tu and tc vanish at the lowest tree level. A fully gauge-invariant e ective-Lagrangian approach for parametrizing the top quark FCNC interactions has been studied in ref. [10]. The FCNC e ective Lagrangian can be used to calculate both the branching fractions of the t ! q decays and the cross sections for the production of a top quark in association with a photon. The top quark FCNC processes can be probed through either top quark production or decay. In this paper, we examine the associated production of a single top quark and a photon, which is sensitive to the anomalous tq FCNC coupling. The di erence between quarks and antiquarks in the parton distribution functions (PDF) of the proton in the presence of a nite tu coupling leads to an asymmetry between top and anti-top quark production rates. No asymmetry is expected for tc , because of the similar charm and anti-charm quark contents in the proton. This would allow a distinction between the tu and tc signal scenarios if these processes were observed [ 11 ]. Better sensitivity to the tu coupling is expected because the up quark PDF in the proton is larger than that of the charm quark. Within the SM, top quarks can also be produced in association with a photon. This proceeds through the radiation of a photon from the initial- or nal-state particles in tchannel, s-channel, and W-associated production of single top quarks. These processes are treated as backgrounds in this analysis. We search for FCNC interactions at the tu and tc vertices by looking for events with a single top quark and a photon in the nal state, where the top quark decays into a W boson and a bottom quark, followed by the decay of the W boson to a muon and a ! neutrino. The nal state includes W events in which the lepton decays to . We focus on this particular leptonic decay because it has a very clean signature. Figure 1 illustrates the lowest-order diagram for this t process including the muonic decay of the W boson from the top quark decay. The FCNC vertex is identi ed by a lled circle. One of the distinctive signatures of the signal is the presence of a high transverse momentum (pT) photon in the nal state. The photon is expected to have large transverse momentum, owing to its recoil from the heavy top quark. The analysis is performed using events with a muon, a photon, at least one hadronic jet, with at most one being consistent with originating from a bottom quark, and missing transverse momentum. The results are compared with leading-order (LO) and next-to-leading-order (NLO) calculations of the FCNC signal production cross section based on perturbative quantum chromodynamics (QCD) [12]. HJEP04(216)35 the event rate from about 100 kHz to less than 1 kHz, before data storage. A more detailed description of the CMS detector, together with a de nition of the coordinate system and kinematic variables used in this analysis, can be found in ref. [13]. 3 Data and simulation samples The analysis is based on a data sample of proton-proton collisions at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.8 fb 1, collected with the CMS detector at the CERN LHC. Monte Carlo (MC) simulated signal samples of pp ! t ! W b ! ` `b , with ` representing e, , or leptons, are generated with the PROTOS 2.0 generator [14], with a minimum pT requirement of 30 GeV for the associated photon. PROTOS is a LO generator for single top quark and tt production that includes anomalous top quark couplings. To study the response of the analysis to the signal and to processes with potentially similar nal-state signatures, simulated event samples of t+ , tt, tt+ , W +jets, Z +jets, { 3 { Drell-Yan, W+jets, and WW + jets events are generated using the LO MadGraph 5 generator [15]. Diboson samples (WW, WZ, and ZZ) are generated using pythia 6 [16]. Single top quark events from tq-, tb-, and tW-channel are generated with the NLO powheg 1.0 [17{20] event generator. The NLO predictions for the main irreducible W + jets background and the Z + jets process are calculated using the BAUR generator [21]. For all simulated samples, showering and hadronization are implemented with pythia 6, and lepton decays with the tauola 2.7 program [22]. The CTEQ6L [23] PDFs are used to model the proton PDFs for the LO generators, while CT10 [24] is used for the NLO generators. The top quark mass is set to 172.5 GeV. The response of the CMS detector is simulated with Geant4 [25], and all simulated events are reconstructed and analyzed using the standard CMS software. The MC simulated events are weighted to reproduce the trigger and reconstruction e ciencies measured in data. The pythia 6 generator is used to simulate the presence of additional protonproton interactions in the same or nearby proton bunch crossings (pileup). The distribution of the number of pileup events in the simulation is weighted to match that in data. 4 Event selection and reconstruction of signal The signal events are generally characterized by the presence of an isolated energetic photon, a muon, signi cant missing transverse momentum, and one b quark jet (b jet). The presence of an isolated muon and an isolated photon provides a clean signature for the signal. Events are initially selected with a single-muon trigger, requiring a muon with a minimum pT of 24 GeV within the pseudorapidity range j j < 2:1. Events are also required to have at least one well reconstructed pp interaction vertex candidate [26]. When more than one interaction vertex is found in an event, the one with the highest P p 2T of its asso ciated charged-particle tracks is called the primary vertex and selected for further analysis. The track associated with the muon candidate is required to be consistent with a particle coming from the primary vertex. size where R = p ( and A particle- ow algorithm (PF) is used to reconstruct single-particle candidates, combining information from all subdetectors [27, 28]. The muon candidates are reconstructed by matching the information for tracks in the silicon tracker and the muon system. The muon candidates are required to have pT > 26 GeV and j j < 2:1. An accepted muon is required to have a relative isolation Irel < 0:12, where Irel is de ned as the sum of the scalar pT of all charged (except the muon candidate) and neutral PF candidates inside a cone of )2 + ( )2 < 0:4 around the muon direction, divided by the muon pT, are the di erences in the pseudorapidity and azimuthal angle between the directions of the PF candidate and the muon. To remove the contribution from pileup, the charged particles included in the calculation of Irel are required to originate from the same vertex as the muon. Based on the average deposited energy density of neutral particles from pileup, a correction is applied to the neutral component in the isolation cone. One muon candidate is required in each event, and events with additional muon candidates with pT > 10 GeV, j j < 2:5, and Irel < 0.2 are discarded. { 4 { HJEP04(216)35 Photon candidates with signi cant energy deposition in the ECAL are required to have a pT > 50 GeV, with j j < 2:5, but be outside of the transition region between the ECAL barrel and endcaps, 1:44 < j j < 1:56. The isolation of photon candidates is de ned using the following criteria: the ratio of the hadronic energy H to the total electromagnetic energy E (H=E) inside a cone of size R < 0:15 around the crystal containing the largest energy is required to be less than 0.05; the second moment of the electromagnetic shower in ( ) [29] is required to be less than 0.011 (0.031) in the barrel (endcaps). Separate charged- and neutral-hadron isolation criteria, de ned as the scalar sum of the pT of all charged- or neutral-hadron PF candidates inside a cone of size R < 0:3 around the photon candidate, are applied. For the barrel, charged- and neutral-hadron isolation values are required to be less than 0.7 GeV and 0:4 + 0:04 pT, while for the endcaps they are required to be less than 0.5 GeV and 1:5 + 0:04 pT GeV, respectively, where pT is the transverse momentum of the photon candidate. The isolation criteria are corrected for additional interactions in the same bunch crossing [30]. A pixel detector track veto is employed to minimize the misidenti cation of an electron as a photon. Events with exactly one photon candidate are selected for further analysis. Events with one or more electron candidates that pass loose selection requirements of pT > 20 GeV, j j < 2:5, and Irel < 0:15 are rejected. The electron Irel is de ned in a manner similar to that for muons, using an isolation cone size of R < 0:3. Jets are clustered from the reconstructed PF candidates, using the infrared- and collinear-safe anti-kT algorithm with a distance parameter of 0.5 [31]. The charged hadrons originating from pileup interactions are excluded from the clustered PF candidates, and the remaining contributions from neutral particles are taken into account using a jet-areabased correction [30]. The momentum of a jet is de ned as the vector sum of the momenta of all particles in the jet, and corrections to the jet energy are applied as a function of the jet pT and [32]. Only jets with pT > 30 GeV and j j < 2:5 are considered in the analysis. The combined secondary vertex (CSV) algorithm [33, 34] is used to identify jets originating from the hadronization of b quarks. The algorithm combines the information from the secondary vertex and track impact parameters into a likelihood discriminant, whose output distinguishes between b jets and light- avor jets. The chosen cuto on the value of the discriminant corresponds to a b tagging e ciency of about 70%, while the misidenti cation probability is 18% for c jets, and 1.5% for other jets [33, 34]. To reduce the background from tt and tt + processes, events with more than one identi ed b jet are rejected. In events with no b-tagged jet, the jet with the largest value of T the b tag discriminant is chosen as the b jet candidate. The missing transverse momentum vector, p~miss, is de ned as the negative vectorial sum of the momentum in the transverse plane of all PF objects. Its magnitude, pTmiss, is required to be greater than 30 GeV. The direction of the photon candidate is required to be separated from the directions of the muon and b jet candidates by R( ; ) > 0:7 and R(b jet; ) > 0:7. The top quark kinematic properties are reconstructed using the muon and b jet fourmomenta and p~miss. The pT of the undetected neutrino is assumed to be equal to the T magnitude of p~miss, while its longitudinal component is obtained by constraining the inT { 5 { variant mass of the neutrino and muon to the world-average value of the W boson mass [35]. When the resulting quadratic equation has two real solutions, the one with the smaller absolute value of the longitudinal component of the neutrino momentum is taken [36]. When the solution is complex, the real part is considered as the longitudinal z component of the neutrino momentum. The top quark candidate is reconstructed by combining the reconstructed W boson and the b jet candidate. Events with a reconstructed top quark invariant mass m b within 130 to 220 GeV are selected for further analysis. After all the selection criteria, signal e ciencies of 1.8% and 2.4% are achieved from simulation for tu and tc signal events, respectively. 5 Background estimation The main background contributions arise from W +jets and W + jets events, where the W + jets background can mimic the signal when a jet is misidenti ed as a photon. The W +jets and W + jets backgrounds are estimated from data, while estimates for the backgrounds from single top quark (tq-, tb-, and tW-channel), t + , tt, tt + , Z+ +jets, Drell-Yan, WW + jets, and diboson backgrounds are calculated from the numbers of simulated events passing the event selection, scaled to their theoretical cross sections. The contributions from the W+jets and W +jets backgrounds are estimated from data using a neural network (NN) discriminant formed from a combination of several variables: the pT of the photon and jet candidates, the cosine of the angle between the momenta of the W boson and photon candidate, the azimuthal angle between the momentum of the photon candidate and the missing transverse momentum, and H=E. The NN is trained to distinguish these two sources of background and its output is parametrized as: F (xNN) = cWjSWj(xNN) + cW jSW j(xNN) + bB(xNN); (5.1) where xNN is the neural network output, SWj(xNN), SW j(xNN), and B(xNN) are, respectively, the normalized distributions for W + jets, W + jets, and the sum of all other backgrounds, and cWj, cW j, and b are the corresponding fractions of each distribution. From previous limits, it is known that any signal contribution will be small and is not included in eq. (5.1). The e ect of its possible presence is accounted for as a systematic uncertainty. The parametrization in eq. (5.1) is t to the data, leaving the W + jets and W + jets normalizations as free parameters. Both the normalization and the distribution in the sum of all other backgrounds, i.e., the b and B(xNN) terms, are obtained from simulation. The distribution for W + jets, SWj(xNN), is obtained from data in a control region de ned by requiring photons with wide electromagnetic showers ( > 0:011 for the barrel and > 0:031 for the endcap), and no b-tagged jets, while keeping all other selection criteria the same as in the signal region. The requirement of no b-tagged jets ensures a high content of W + jets, suppressing thereby the tt and single top quark contribution. The distribution for W + jets, SW j(xNN), is obtained from simulation. The numbers of W + jets and W + jets events are determined from the t to the NN output distribution. The t results are taken as central values for the analysis, and are assigned uncertainties that re ect the di erences obtained when varying the control region de nition. Addition{ 6 { HJEP04(216)35 ally, an uncertainty is assigned accounting for the limited knowledge of the contaminations from other SM backgrounds in the control sample, estimated through a comparison with the results after subtracting their expectations from simulation. To take into account the uncertainties coming from the theoretical predictions of the cross sections for the simulated backgrounds, the individual cross sections are each varied by 30% [37{39] and the di erences in the tted results with respect to the nominal t are added in quadrature. A total of 1794 events are selected in data and, assuming no contribution from FCNC, 1805 80 events are expected, where the uncertainty is statistical. The expected amount of SM background is dominated by the W + jets process, amounting to 57% of the total. The contributions of W + jets, tt, and Z + jets events are 16%, 8%, and 7% of the total background events, respectively. The remaining background events originate from t+ , tt + , single top quark (tq+tb+tW), WW + jets, and diboson production. 6 Signal extraction Several discriminant variables are used to distinguish the signal from the SM backgrounds. To achieve the best discriminating power, a multivariate classi cation, based on boosted decision trees (BDT) [ 40, 41 ], is used. One BDT is used for the tu channel and another for the tc channel to take advantage of the slight di erences in their production. For the tu signal, the asymmetry between the top and anti-top quark rates translates into a lepton charge asymmetry. The lepton charge is therefore used as an input in training the BDT for the tu signal. Eight variables are chosen to construct the two BDTs. The BDT input variables are: (i) pT of the photon candidate, (ii) b tagging discriminant, (iii) pT of the b jet, (iv) pT of the muon (only for tc ), (v) cos(p~t; p~ ), the cosine of the angle between the direction of the reconstructed top quark and photon, (vi) R(b jet; ), (vii) R( ; ), (viii) lepton charge (only for tu ), and (ix) jet multiplicity. The pT of the photon candidate is the most important variable for separating signal from background. The pT of the muon does not contribute signi cantly to the discrimination of the tu signal, and is therefore not used in this case. Each BDT is trained using simulated signal (either tu or tc ) and W + jets, tt, and diboson background events. The distributions used as input to the BDT are obtained from data for W + jets and W + jets and from simulation for the remaining background contributions. The W + jets distributions are obtained from the same control region as used for the NN inputs. Events with a reconstructed top quark mass in the sideband region de ned as m b > 220 GeV or m b < 130 GeV are used to obtain the W + jets distributions. The sideband region is enriched in W + jets, with about 35% contamination from other background sources. This contamination is subtracted using an estimate from data for the W + jets contribution and MC predictions for the remaining background sources. and SM background. Figure 3 shows the BDT output distributions for data, the estimated background, and the tu and tc signals. As described above, the W + jets and W + jets distributions and their normalizations are estimated from data, while the remaining background contributions are obtained from simulation. The signal shapes are normalized { 7 { V700 CMS e E250 200 150 100 50 1 /0350 CMS . (c) Data estimated background combined in quadrature. to a cross section of 1 pb for showing the expected signal distributions in the gures. The vertical bars indicate the statistical uncertainty. The hatched band shows the contribution of the statistical and systematic uncertainties added in quadrature, with the dominant source being the statistical uncertainty in the estimation of the number of W + jets and W 7 + jets events in data. Systematic uncertainties The e ect on the signal and SM background expectations from di erent systematic sources is discussed below. Instrumental uncertainties: the uncertainties in the trigger e ciency [42], photon [43] and lepton [44] selection e ciencies, jet energy scale and resolution, missing transverse momentum [32], and the modeling of pileup are propagated to the uncertainties in the signal and SM background expectations. The uncertainty in modeling the pileup is estimated by changing the total inelastic proton-proton cross section by 5% [45]. The uncertainty coming from the photon energy scale is estimated by changing the photon energy in simulation by 1% in the ECAL barrel and 3% in the endcaps [43]. The pT- and -dependent uncertainties in the b jet identi ca{ 8 { 1 /01000 CMS . are normalized to a cross section of 1 pb. The vertical bars on the points give the statistical uncertainties. The hatched band shows the sum of the statistical and systematic uncertainties in the predicted background distributions combined in quadrature. The lower plots show the ratio of the data to the SM prediction. HJEP04(216)35 tion e ciencies and misidenti cation (mistag) rates are implemented as in ref. [33]. The systematic uncertainty in the measured integrated luminosity is estimated to be 2.6% [46]. Among the instrumental uncertainties, the luminosity uncertainty only a ects the normalization, while the uncertainties from the trigger, lepton and photon selection e ciencies, b tagging, jet energy scale and resolution, and pileup also a ect the BDT discriminant output distributions for signal and background. Theoretical uncertainties: the uncertainty from the choice of PDF is determined according to the PDF4LHC prescription [47, 48] using the MSTW2008 [49] and NNPDF [50] PDFs. The uncertainty from the factorization and renormalization scales is evaluated by comparing simulated samples, produced using factorization and renormalization scales multiplied and divided by a factor of two relative to their standard values (top quark mass). A conservative estimate of the uncertainty owing to the top quark mass used in the simulation is obtained by producing simulated samples with the top quark mass shifted by 2 GeV. The uncertainties in the PDF, renormalization and factorization scales, and top quark mass a ect both the predicted BDT distributions and the normalizations. An uncertainty of 5% in the signal rate is estimated from the NLO QCD corrections [12]. This uncertainty is assumed not to a ect the signal distributions. Normalization of the background: the uncertainties described in section 5 for the estimated W + jets and W + jets backgrounds are found to be 17% and 23%, respectively. The uncertainties in the normalization of all other backgrounds are found to be 30% [37{39]. 8 Upper limits on anomalous couplings No evidence is observed for anomalous single top quark production in association with a photon in the BDT output distributions shown in gure 3. These results are used to set { 9 { Exp. limit (LO) 1 (exp. limit) 2 (exp. limit) Obs. limit (LO) 2:7 2:5 corresponding branching fractions B(t ! u ) and B(t ! c ) at LO and NLO are given. The one and two standard deviation ( ) ranges on the LO and NLO expected limits are also presented. an upper limit on this process, as well as on the anomalous couplings tu and tc . The limits are calculated using the modi ed frequentist approach [51, 52] that is implemented in the Theta package [53]. In this approach, a binned maximum-likelihood method is used for the BDT output distribution, which includes all systematic uncertainties described in the previous section as nuisance parameters. The NLO QCD corrections to the production of a single top quark plus a photon through FCNC processes are sizable and depend on the photon pT requirement [12]. Upper limits on the cross sections are presented both with and without NLO QCD corrections. We use a k factor k = NLO= LO = 1:375 to go from LO to NLO, corresponding to a minimum photon pT of 50 GeV [12]. The 95% CL upper limits on the number of events observed are 9.1 and 16.0 for the tu and tc signals, respectively. The 95% CL upper limits on the product of the LO signal cross sections and the leptonic branching fraction of the W boson are tu B(t ! Wb ! b` `) < 25 fb and tc B(t ! Wb ! b` `) < 34 fb. The corresponding upper limits for the NLO calculations are tu B(t ! Wb ! b` `) < 26 fb and tc B(t ! Wb ! b` `) < 37 fb. The expected limits and the one and two standard deviation limits on tu B(t ! Wb ! b` `) and tc B(t ! Wb ! b` `) at LO and NLO are presented in table 1. These results can be translated into upper limits on the anomalous couplings tu and tc and on the branching fractions B(t ! u + ) and B(t ! c + ) using the theoretical expectations [54]. The 95% CL upper bounds on the anomalous couplings and branching fractions with and without including the NLO QCD corrections to the signal cross section are presented in table 1, along with the expected limits. The one and two standard deviation ranges of the LO and ZEUS (q=u) mt=172 GeV mt=175 GeV mt=175 GeV mt=175 GeV mt=172.5 GeV mt=172.5 GeV CMS (q=mut=)172.5 GeV (q=c) 10-4 10-3 95% CL excluded region H1 (q=u) mt=175 GeV 10-2 10-1 B(t → qγ) 1 ZEUS [6], H1 [7], D0 [55], CDF [8, 56], ATLAS [57], and CMS experiments [58]. The two vertical dashed lines show the results of this analysis. NLO expected limits on the anomalous couplings and branching fractions are also shown in table 1. The measured 95% CL upper limits on B(t ! qZ) versus B(t ! q ) from the L3 [5], ZEUS [6], H1 [7], D0 [55], CDF [56], ATLAS [57], and CMS [58] experiments, as well as the results of this analysis, are presented in gure 4. limits on the signal cross sections. These are calculated as the ratio of the di erence of the shifted expected limit coming from the related systematic source and the nominal expected limit. 9 Upper limits on the FCNC cross sections for a restricted phase space Upper limits on the signal cross sections are also determined for a restricted phase-space region in which the detector is fully e cient. This removes the need to extrapolate to phasespace regions where the analysis has little or no sensitivity. The results are especially useful for comparing with theoretical models that predict enhancements in a particular phasespace region [10]. The measurement uses a simpler event-counting procedure instead of a t to the BDT distribution. We de ne the ducial cross section, d, in a volume de ned for stable particles at the generator level before any interaction with the detector. This can be related to the total cross section, , through d = A, where A is the acceptance in the ducial volume. Stable particles are characterized as particles with mean lifetimes exceeding 30 ps. The upper limit on d is obtained from the limit on A , where accounts for detector resolution, trigger e ciencies, and identi cation and isolation requirements applied in the analysis. The leptons at the particle level are the electrons or muons originating from the decay of W bosons. The charged leptons from hadron decays are discarded, while electrons or muons from direct decays of leptons are included. HJEP04(216)35 Type Rate Rate+Shape b tagging and mistag e ciency Source Integrated luminosity Background normalization (W + jets) Background normalization (W + jets) Other background normalizations Trigger e ciency Pileup e ects Lepton identi cation and isolation Photon identi cation and isolation Photon energy scale Jet energy scale Jet energy resolution PDF Scale Top quark mass 1:8 5:6 2:5 <1 2:2 7 <1 1:9 <1 1:1 2:9 2:1 3:1 1 2:5 tu (%) tc (%) 4 3 1 1:1 0:4 2:3 4:4 4:5 3:1 4 2:2 3:4 <1 2:4 1 expected upper limits on the tu cross sections. The values are given as a percentage of the expected upper limits. The sources are broken up into those that only a ect the overall rate of signal events and those that a ect both the rate and the shape of the BDT distributions. Stable particles, except muons, electrons, photons and neutrinos, are used to reconstruct particle-level jets in the simulation. Jet reconstruction at the particle level is based on the anti-kT algorithm [31] with a distance parameter of 0.5. When a reconstructed jet contains a B hadron, the jet is tagged as a b jet. In events without a matched b jet, the jet with the largest pT is used to reconstruct the decayed top quark. The pT of the neutrinos is calculated as the magnitude of the vector sum of the pT of each neutrino in the event, except those originating from hadron decays. From these objects, the top quark mass is calculated in order to make kinematical cuts used in the de nition of the ducial region. The ducial region is introduced at particle level, similar to the event selection requirements, and is summarized in table 3. The e ciency is found to be 16% and 19% from simulation for the respective tu and tc events in the ducial region. An additional ducial region is de ned by also requiring exactly one b-tagged jet in the event. The values of are thereby reduced to 11% and 14% for the two signals, respectively. Table 4 shows the 95% CL upper limits on the signal cross sections in the two ducial regions for the tu processes. These are calculated from the total number of selected events in data (Nobs), the SM expectation (NSM), both at detector level, and the e ciency for a signal event in the ducial region to be reconstructed at detector level. The uncertainties in the SM expectation include statistical and systematic uncertainties. HJEP04(216)35 Object Single muon Electron veto Single photon Veto for additional muons At least one jet (Nb jet < 2) Missing pT Muon, jets, and photons Reconstructed top quark mass pT > 50 GeV, j j < 2:5 (1:44 < j j < 1:56 excluded) Requirement pT > 26 GeV, j j < 2:1 pT > 10 GeV, j j < 2:5 pT > 20 GeV, j j < 2:5 pT > 30 GeV, j j < 2:5 T pmiss > 30 GeV R( ; ) and R(jet; ) > 0:7 SM expectations (NSM), the e ciencies ( ), and the upper limits on the cross sections d at the 95% CL in the ducial region for the two signal channels, without and with a requirement on the presence of a single accompanying b jet. The total number of observed events is decreased by a factor of approximately 6.5 after requiring exactly one identi ed b jet in an event, while the expected number of SM events decreases by a factor of 7. The combined relative uncertainty in the number of expected SM events increases from 12% to 19% when this b jet requirement is included. The upper limits are calculated including a total systematic uncertainty in the signal selection e ciencies of 10%, estimated using a method similar to that described in section 7. These are the rst limits set on the anomalous t production within a restricted phasespace region. 10 Summary B(t ! c ) < 1:7 The result of a search for avor changing neutral currents (FCNC) through single top quark production in association with a photon has been presented. The search is performed using proton-proton collisions at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.8 fb 1, collected by the CMS detector at the LHC. The number of observed events is consistent with the SM prediction. Upper limits are set at 95% CL on the anomalous FCNC couplings of tu < 0:025 and tc < 0:091 using NLO QCD calculations. The corresponding upper limits on the branching fractions are B(t ! u ) < 1:3 10 4 and 10 3, which are the most restrictive bounds to date. Observed upper HJEP04(216)35 limits on the cross section in a restricted phase space are found to be 47 fb and 39 fb at 95% CL for tu and tc production, respectively, when exactly one identi ed b jet is required in the data. These are the rst results on anomalous t production within a restricted phase-space region. Acknowledgments We congratulate our colleagues in the CERN accelerator departments for the excellent performance of the LHC and thank the technical and administrative sta s at CERN and at other CMS institutes for their contributions to the success of the CMS e ort. In addition, we gratefully acknowledge the computing centers and personnel of the Worldwide LHC Computing Grid for delivering so e ectively the computing infrastructure essential to our analyses. Finally, we acknowledge the enduring support for the construction and operation of the LHC and the CMS detector provided by the following funding agencies: BMWFW and FWF (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIENCIAS (Colombia); MSES and CSF (Croatia); RPF (Cyprus); MoER, ERC IUT and ERDF (Estonia); Academy of Finland, MEC, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NIH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); MSIP and NRF (Republic of Korea); LAS (Lithuania); MOE and UM (Malaysia); CINVESTAV, CONACYT, SEP, and UASLP-FAI (Mexico); MBIE (New Zealand); PAEC (Pakistan); MSHE and NSC (Poland); FCT (Portugal); JINR (Dubna); MON, RosAtom, RAS and RFBR (Russia); MESTD (Serbia); SEIDI and CPAN (Spain); Swiss Funding Agencies (Switzerland); MST (Taipei); ThEPCenter, IPST, STAR and NSTDA (Thailand); TUBITAK and TAEK (Turkey); NASU and SFFR (Ukraine); STFC (United Kingdom); DOE and NSF (U.S.A.). Individuals have received support from the Marie-Curie program and the European Research Council and EPLANET (European Union); the Leventis Foundation; the A. P. Sloan Foundation; the Alexander von Humboldt Foundation; the Belgian Federal Science Policy O ce; the Fonds pour la Formation a la Recherche dans l'Industrie et dans l'Agriculture (FRIA-Belgium); the Agentschap voor Innovatie door Wetenschap en Technologie (IWTBelgium); the Ministry of Education, Youth and Sports (MEYS) of the Czech Republic; the Council of Science and Industrial Research, India; the HOMING PLUS program of the Foundation for Polish Science, co nanced from European Union, Regional Development Fund; the OPUS program of the National Science Center (Poland); the Compagnia di San Paolo (Torino); MIUR project 20108T4XTM (Italy); the Thalis and Aristeia programs co nanced by EU-ESF and the Greek NSRF; the National Priorities Research Program by Qatar National Research Fund; the Rachadapisek Sompot Fund for Postdoctoral Fellowship, Chulalongkorn University (Thailand); and the Welch Foundation, contract C-1845. Open Access. 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Plestina9, F. Romeo, S.M. Shaheen, J. Tao, C. Wang, Z. Wang, H. Zhang State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing, China J.C. Sanabria C. Asawatangtrakuldee, Y. Ban, Q. Li, S. Liu, Y. Mao, S.J. Qian, D. Wang, Z. Xu Universidad de Los Andes, Bogota, Colombia C. Avila, A. Cabrera, L.F. Chaparro Sierra, C. Florez, J.P. Gomez, B. Gomez Moreno, University of Split, Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture, Split, Croatia N. Godinovic, D. Lelas, I. Puljak, P.M. Ribeiro Cipriano University of Split, Faculty of Science, Split, Croatia Z. Antunovic, M. Kovac Institute Rudjer Boskovic, Zagreb, Croatia V. Brigljevic, K. Kadija, J. Luetic, S. Micanovic, L. Sudic University of Cyprus, Nicosia, Cyprus H. Rykaczewski Charles University, Prague, Czech Republic M. Bodlak, M. Finger10, M. Finger Jr.10 A. Attikis, G. Mavromanolakis, J. Mousa, C. Nicolaou, F. Ptochos, P.A. Razis, Academy of Scienti c Research and Technology of the Arab Republic of Egypt, Egyptian Network of High Energy Physics, Cairo, Egypt M. El Sawy11;12, E. El-khateeb13;13, T. Elkafrawy13, A. Mohamed14, E. Salama12;13 National Institute of Chemical Physics and Biophysics, Tallinn, Estonia B. Calpas, M. Kadastik, M. Murumaa, M. Raidal, A. Tiko, C. Veelken Department of Physics, University of Helsinki, Helsinki, Finland P. Eerola, J. Pekkanen, M. Voutilainen Helsinki Institute of Physics, Helsinki, Finland J. Harkonen, V. Karimaki, R. Kinnunen, T. Lampen, K. Lassila-Perini, S. Lehti, T. Linden, P. Luukka, T. Maenpaa, T. Peltola, E. Tuominen, J. Tuominiemi, E. Tuovinen, L. Wendland J. Talvitie, T. Tuuva Lappeenranta University of Technology, Lappeenranta, Finland DSM/IRFU, CEA/Saclay, Gif-sur-Yvette, France M. Besancon, F. Couderc, M. Dejardin, D. Denegri, B. Fabbro, J.L. Faure, C. Favaro, F. Ferri, S. Ganjour, A. Givernaud, P. Gras, G. Hamel de Monchenault, P. Jarry, E. Locci, M. 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Van Hove Centre de Calcul de l'Institut National de Physique Nucleaire et de Physique des Particules, CNRS/IN2P3, Villeurbanne, France S. Gadrat Universite de Lyon, Universite Claude Bernard Lyon 1, CNRS-IN2P3, Institut de Physique Nucleaire de Lyon, Villeurbanne, France S. Beauceron, C. Bernet, G. Boudoul, E. Bouvier, C.A. Carrillo Montoya, R. Chierici, D. Contardo, B. Courbon, P. Depasse, H. El Mamouni, J. Fan, J. Fay, S. Gascon, M. Gouzevitch, B. Ille, F. Lagarde, I.B. Laktineh, M. Lethuillier, L. Mirabito, A.L. Pequegnot, S. Perries, J.D. Ruiz Alvarez, D. Sabes, L. Sgandurra, V. Sordini, M. Vander Donckt, P. Verdier, S. Viret HJEP04(216)35 Georgian Technical University, Tbilisi, Georgia T. Toriashvili16 D. Lomidze Tbilisi State University, Tbilisi, Georgia RWTH Aachen University, I. Physikalisches Institut, Aachen, Germany C. Autermann, S. Beranek, M. Edelho , L. Feld, A. Heister, M.K. Kiesel, K. Klein, M. Lipinski, A. Ostapchuk, M. Preuten, F. Raupach, S. Schael, J.F. Schulte, T. 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Loukas, A. Agapitos, S. Kesisoglou, A. Panagiotou, N. Saoulidou, E. Tziaferi University of Ioannina, Ioannina, Greece I. Evangelou, G. Flouris, C. Foudas, P. Kokkas, N. Loukas, N. Manthos, I. Papadopoulos, E. Paradas, J. Strologas Wigner Research Centre for Physics, Budapest, Hungary G. Bencze, C. Hajdu, A. Hazi, P. Hidas, D. Horvath20, F. Sikler, V. Veszpremi, G. Vesztergombi21, A.J. Zsigmond Institute of Nuclear Research ATOMKI, Debrecen, Hungary N. Beni, S. Czellar, J. Karancsi22, J. Molnar, Z. Szillasi University of Debrecen, Debrecen, Hungary M. Bartok23, A. Makovec, P. Raics, Z.L. Trocsanyi, B. Ujvari National Institute of Science Education and Research, Bhubaneswar, India P. Mal, K. Mandal, D.K. Sahoo, N. Sahoo, S.K. Swain Panjab University, Chandigarh, India S. Bansal, S.B. Beri, V. Bhatnagar, R. Chawla, R. Gupta, U.Bhawandeep, A.K. Kalsi, A. Kaur, M. Kaur, R. Kumar, A. Mehta, M. Mittal, J.B. Singh, G. Walia University of Delhi, Delhi, India Ashok Kumar, A. Bhardwaj, B.C. Choudhary, R.B. Garg, A. Kumar, S. Malhotra, M. Naimuddin, N. Nishu, K. Ranjan, R. Sharma, V. Sharma Saha Institute of Nuclear Physics, Kolkata, India S. Bhattacharya, K. Chatterjee, S. Dey, S. Dutta, Sa. Jain, N. Majumdar, A. Modak, K. Mondal, S. Mukherjee, S. Mukhopadhyay, A. Roy, D. Roy, S. Roy Chowdhury, S. Sarkar, M. Sharan P. Shukla, A. Topkar Bhabha Atomic Research Centre, Mumbai, India A. Abdulsalam, R. Chudasama, D. Dutta, V. Jha, V. Kumar, A.K. Mohanty2, L.M. Pant, Tata Institute of Fundamental Research, Mumbai, India T. Aziz, S. Banerjee, S. Bhowmik24, R.M. Chatterjee, R.K. Dewanjee, S. Dugad, S. Ganguly, S. Ghosh, M. Guchait, A. Gurtu25, G. Kole, S. Kumar, B. Mahakud, M. Maity24, B. Sutar, N. Wickramage26 Indian Institute of Science Education and Research (IISER), Pune, India S. Chauhan, S. Dube, S. Sharma Institute for Research in Fundamental Sciences (IPM), Tehran, Iran H. Bakhshiansohi, H. Behnamian, S.M. Etesami27, A. Fahim28, R. Goldouzian, M. Khakzad, M. Mohammadi Najafabadi, M. Naseri, S. Paktinat Mehdiabadi, F. Rezaei Hosseinabadi, B. Safarzadeh29, M. Zeinali University College Dublin, Dublin, Ireland M. Felcini, M. Grunewald C. Tuvea;b L. Viliania;b INFN Sezione di Bari a, Universita di Bari b, Politecnico di Bari c, Bari, Italy M. Abbresciaa;b, C. Calabriaa;b, C. Caputoa;b, A. Colaleoa, D. Creanzaa;c, L. Cristellaa;b, N. De Filippisa;c, M. De Palmaa;b, L. Fiorea, G. Iasellia;c, G. Maggia;c, M. Maggia, G. Minielloa;b, S. Mya;c, S. Nuzzoa;b, A. Pompilia;b, G. Pugliesea;c, R. Radognaa;b, A. Ranieria, G. Selvaggia;b, L. Silvestrisa;2, R. Vendittia;b, P. Verwilligena INFN Sezione di Bologna a, Universita di Bologna b, Bologna, Italy G. Abbiendia, C. Battilana2, A.C. Benvenutia, D. Bonacorsia;b, S. Braibant-Giacomellia;b, L. Brigliadoria;b, R. Campaninia;b, P. Capiluppia;b, A. Castroa;b, F.R. Cavalloa, S.S. Chhibraa;b, G. Codispotia;b, M. Cu ania;b, G.M. Dallavallea, F. Fabbria, A. Fanfania;b, D. Fasanellaa;b, P. Giacomellia, C. Grandia, L. Guiduccia;b, S. Marcellinia, G. Masettia, A. Montanaria, F.L. Navarriaa;b, A. Perrottaa, A.M. Rossia;b, T. Rovellia;b, G.P. Sirolia;b, N. Tosia;b, R. Travaglinia;b INFN Sezione di Catania a, Universita di Catania b, Catania, Italy G. Cappelloa, M. Chiorbolia;b, S. Costaa;b, F. Giordanoa;b, R. Potenzaa;b, A. Tricomia;b, INFN Sezione di Firenze a, Universita di Firenze b, Firenze, Italy G. Barbaglia, V. Ciullia;b, C. Civininia, R. D'Alessandroa;b, E. Focardia;b, S. Gonzia;b, V. Goria;b, P. Lenzia;b, M. Meschinia, S. Paolettia, G. Sguazzonia, A. Tropianoa;b, INFN Laboratori Nazionali di Frascati, Frascati, Italy L. Benussi, S. Bianco, F. Fabbri, D. Piccolo, F. Primavera INFN Sezione di Genova a, Universita di Genova b, Genova, Italy V. Calvellia;b, F. Ferroa, M. Lo Veterea;b, M.R. Mongea;b, E. Robuttia, S. Tosia;b INFN Sezione di Milano-Bicocca a, Universita di Milano-Bicocca b, Milano, Italy L. Brianza, M.E. Dinardoa;b, S. Fiorendia;b, S. Gennaia, R. Gerosaa;b, A. Ghezzia;b, P. Govonia;b, S. Malvezzia, R.A. Manzonia;b, B. Marzocchia;b;2, D. Menascea, L. Moronia, M. Paganonia;b, D. Pedrinia, S. Ragazzia;b, N. Redaellia, T. Tabarelli de Fatisa;b INFN Sezione di Napoli a, Universita di Napoli 'Federico II' b, Napoli, Italy, Universita della Basilicata c, Potenza, Italy, Universita G. Marconi d, Roma, S. Buontempoa, N. Cavalloa;c, S. Di Guidaa;d;2, M. Espositoa;b, F. Fabozzia;c, A.O.M. Iorioa;b, G. Lanzaa, L. Listaa, S. Meolaa;d;2, M. Merolaa, P. Paoluccia;2, C. Sciaccaa;b, F. Thyssen Trento c, Trento, Italy INFN Sezione di Padova a, Universita di Padova b, Padova, Italy, Universita di P. Azzia;2, N. Bacchettaa, L. Benatoa;b, D. Biselloa;b, A. Bolettia;b, A. Brancaa;b, R. Carlina;b, P. Checchiaa, M. Dall'Ossoa;b;2, T. Dorigoa, U. Dossellia, F. Gasparinia;b, U. Gasparinia;b, A. Gozzelinoa, S. Lacapraraa, M. Margonia;b, A.T. Meneguzzoa;b, M. Passaseoa, J. Pazzinia;b, M. Pegoraroa, N. Pozzobona;b, P. Ronchesea;b, F. Simonettoa;b, E. Torassaa, M. Tosia;b, M. Zanetti, P. Zottoa;b, A. Zucchettaa;b;2, G. Zumerlea;b INFN Sezione di Pavia a, Universita di Pavia b, Pavia, Italy A. Braghieria, A. Magnania, P. Montagnaa;b, S.P. Rattia;b, V. Rea, C. Riccardia;b, P. Salvinia, I. Vaia, P. Vituloa;b INFN Sezione di Perugia a, Universita di Perugia b, Perugia, Italy L. Alunni Solestizia;b, M. Biasinia;b, G.M. Bileia, D. Ciangottinia;b;2, L. Fanoa;b, P. Laricciaa;b, G. Mantovania;b, M. Menichellia, A. Sahaa, A. Santocchiaa;b, A. Spieziaa;b INFN Sezione di Pisa a, Universita di Pisa b, Scuola Normale Superiore di Pisa c, Pisa, Italy K. Androsova;30, P. Azzurria, G. Bagliesia, J. Bernardinia, T. Boccalia, G. Broccoloa;c, R. Castaldia, M.A. Cioccia;30, R. Dell'Orsoa, S. Donatoa;c;2, G. Fedi, L. Foaa;cy, A. Giassia, M.T. Grippoa;30, F. Ligabuea;c, T. Lomtadzea, L. Martinia;b, A. Messineoa;b, F. Pallaa, A. Rizzia;b, A. Savoy-Navarroa;31, A.T. Serbana, P. Spagnoloa, P. Squillaciotia;30, R. Tenchinia, G. Tonellia;b, A. Venturia, P.G. Verdinia INFN Sezione di Roma a, Universita di Roma b, Roma, Italy L. Baronea;b, F. Cavallaria, G. D'imperioa;b;2, D. Del Rea;b, M. Diemoza, S. Gellia;b, C. Jordaa, E. Longoa;b, F. Margarolia;b, P. Meridiania, G. Organtinia;b, R. Paramattia, F. Preiatoa;b, S. Rahatloua;b, C. Rovellia, F. Santanastasioa;b, P. Traczyka;b;2 INFN Sezione di Torino a, Universita di Torino b, Torino, Italy, Universita del Piemonte Orientale c, Novara, Italy N. Amapanea;b, R. Arcidiaconoa;c;2, S. Argiroa;b, M. Arneodoa;c, R. Bellana;b, C. Biinoa, N. Cartigliaa, M. Costaa;b, R. Covarellia;b, A. Deganoa;b, N. Demariaa, L. Fincoa;b;2, B. Kiania;b, C. Mariottia, S. Masellia, E. Migliorea;b, V. Monacoa;b, E. Monteila;b, M. Musicha, M.M. Obertinoa;b, L. Pachera;b, N. Pastronea, M. Pelliccionia, G.L. Pinna Angionia;b, F. Raveraa;b, A. Romeroa;b, M. Ruspaa;c, R. Sacchia;b, A. Solanoa;b, A. Staianoa, U. Tamponia HJEP04(216)35 S. Belfortea, V. Candelisea;b;2, M. Casarsaa, F. Cossuttia, G. Della Riccaa;b, B. Gobboa, C. La Licataa;b, M. Maronea;b, A. Schizzia;b, A. Zanettia Kangwon National University, Chunchon, Korea A. Kropivnitskaya, S.K. Nam Kyungpook National University, Daegu, Korea D.H. Kim, G.N. Kim, M.S. Kim, D.J. Kong, S. Lee, Y.D. Oh, A. Sakharov, D.C. Son Chonbuk National University, Jeonju, Korea J.A. Brochero Cifuentes, H. Kim, T.J. Kim Chonnam National University, Institute for Universe and Elementary Particles, S. Choi, Y. Go, D. Gyun, B. Hong, M. Jo, H. Kim, Y. Kim, B. Lee, K. Lee, K.S. Lee, Kwangju, Korea S. Song Korea University, Seoul, Korea S. Lee, S.K. Park, Y. Roh Seoul National University, Seoul, Korea H.D. Yoo University of Seoul, Seoul, Korea Sungkyunkwan University, Suwon, Korea Y. Choi, J. Goh, D. Kim, E. Kwon, J. Lee, I. Yu Vilnius University, Vilnius, Lithuania A. Juodagalvis, J. Vaitkus M. Choi, H. Kim, J.H. Kim, J.S.H. Lee, I.C. Park, G. Ryu, M.S. Ryu National Centre for Particle Physics, Universiti Malaya, Kuala Lumpur, Malaysia I. Ahmed, Z.A. Ibrahim, J.R. Komaragiri, M.A.B. Md Ali32, F. Mohamad Idris33, W.A.T. Wan Abdullah, M.N. Yusli Centro de Investigacion y de Estudios Avanzados del IPN, Mexico City, Mexico E. Casimiro Linares, H. Castilla-Valdez, E. De La Cruz-Burelo, I. Heredia-De La Cruz34, A. Hernandez-Almada, R. Lopez-Fernandez, A. Sanchez-Hernandez Universidad Iberoamericana, Mexico City, Mexico S. Carrillo Moreno, F. Vazquez Valencia Benemerita Universidad Autonoma de Puebla, Puebla, Mexico I. Pedraza, H.A. Salazar Ibarguen Universidad Autonoma de San Luis Potos , San Luis Potos , Mexico A. Morelos Pineda University of Auckland, Auckland, New Zealand D. Krofcheck P.H. Butler University of Canterbury, Christchurch, New Zealand National Centre for Physics, Quaid-I-Azam University, Islamabad, Pakistan A. Ahmad, M. Ahmad, Q. Hassan, H.R. Hoorani, W.A. Khan, T. Khurshid, M. Shoaib National Centre for Nuclear Research, Swierk, Poland H. Bialkowska, M. Bluj, B. Boimska, T. Frueboes, M. Gorski, M. Kazana, K. Nawrocki, K. Romanowska-Rybinska, M. Szleper, P. Zalewski Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Warsaw, Poland G. Brona, K. Bunkowski, A. Byszuk35, K. Doroba, A. Kalinowski, M. Konecki, J. Krolikowski, M. Misiura, M. Olszewski, M. Walczak Laboratorio de Instrumentac~ao e F sica Experimental de Part culas, Lisboa, Portugal P. Bargassa, C. Beir~ao Da Cruz E Silva, A. Di Francesco, P. Faccioli, P.G. Ferreira Parracho, M. Gallinaro, N. Leonardo, L. Lloret Iglesias, F. Nguyen, J. Rodrigues Antunes, J. Seixas, O. Toldaiev, D. Vadruccio, J. Varela, P. Vischia Joint Institute for Nuclear Research, Dubna, Russia S. Afanasiev, P. Bunin, M. Gavrilenko, I. Golutvin, I. Gorbunov, A. Kamenev, V. Karjavin, V. Konoplyanikov, A. Lanev, A. Malakhov, V. Matveev36, P. Moisenz, V. Palichik, V. Perelygin, S. Shmatov, S. Shulha, N. Skatchkov, V. Smirnov, A. Zarubin Petersburg Nuclear Physics Institute, Gatchina (St. Petersburg), Russia V. Golovtsov, Y. Ivanov, V. Kim37, E. Kuznetsova, P. Levchenko, V. Murzin, V. Oreshkin, I. Smirnov, V. Sulimov, L. Uvarov, S. Vavilov, A. Vorobyev Institute for Nuclear Research, Moscow, Russia Yu. Andreev, A. Dermenev, S. Gninenko, N. Golubev, A. Karneyeu, M. Kirsanov, N. Krasnikov, A. Pashenkov, D. Tlisov, A. Toropin Institute for Theoretical and Experimental Physics, Moscow, Russia V. Epshteyn, V. Gavrilov, N. Lychkovskaya, V. Popov, I. Pozdnyakov, G. Safronov, A. Spiridonov, E. Vlasov, A. Zhokin National Research Nuclear University 'Moscow Engineering Physics InstiA. Bylinkin P.N. Lebedev Physical Institute, Moscow, Russia V. Andreev, M. Azarkin38, I. Dremin38, M. Kirakosyan, A. Leonidov38, G. Mesyats, S.V. Rusakov Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow, Russia V. Savrin A. Baskakov, A. Belyaev, E. Boos, V. Bunichev, M. Dubinin39, L. Dudko, A. Ershov, A. Gribushin, V. Klyukhin, N. Korneeva, I. Lokhtin, I. Myagkov, S. Obraztsov, M. Per lov, State Research Center of Russian Federation, Institute for High Energy Physics, Protvino, Russia I. Azhgirey, I. Bayshev, S. Bitioukov, V. Kachanov, A. Kalinin, D. Konstantinov, V. Krychkine, V. Petrov, R. Ryutin, A. Sobol, L. Tourtchanovitch, S. Troshin, N. Tyurin, Sciences, Belgrade, Serbia P. Adzic40, J. Milosevic, V. Rekovic University of Belgrade, Faculty of Physics and Vinca Institute of Nuclear Centro de Investigaciones Energeticas Medioambientales y Tecnologicas (CIEMAT), Madrid, Spain J. Alcaraz Maestre, E. Calvo, M. Cerrada, M. Chamizo Llatas, N. Colino, B. De La Cruz, A. Delgado Peris, D. Dom nguez Vazquez, A. Escalante Del Valle, C. Fernandez Bedoya, J.P. Fernandez Ramos, J. Flix, M.C. Fouz, P. Garcia-Abia, O. Gonzalez Lopez, S. Goy Lopez, J.M. Hernandez, M.I. Josa, E. Navarro De Martino, A. Perez-Calero Yzquierdo, J. Puerta Pelayo, A. Quintario Olmeda, I. Redondo, L. Romero, J. Santaolalla, M.S. Soares Universidad Autonoma de Madrid, Madrid, Spain C. Albajar, J.F. de Troconiz, M. Missiroli, D. Moran Universidad de Oviedo, Oviedo, Spain J. Cuevas, J. Fernandez Menendez, S. Folgueras, I. Gonzalez Caballero, E. Palencia Cortezon, J.M. Vizan Garcia Santander, Spain Instituto de F sica de Cantabria (IFCA), CSIC-Universidad de Cantabria, I.J. Cabrillo, A. Calderon, J.R. Castin~eiras De Saa, P. De Castro Manzano, J. Duarte Campderros, M. Fernandez, J. Garcia-Ferrero, G. Gomez, A. Lopez Virto, J. Marco, R. Marco, C. Martinez Rivero, F. Matorras, F.J. Munoz Sanchez, J. Piedra Gomez, T. Rodrigo, A.Y. Rodr guez-Marrero, A. Ruiz-Jimeno, L. Scodellaro, I. Vila, R. Vilar Cortabitarte CERN, European Organization for Nuclear Research, Geneva, Switzerland D. Abbaneo, E. Au ray, G. Auzinger, M. Bachtis, P. Baillon, A.H. Ball, D. Barney, A. Benaglia, J. Bendavid, L. Benhabib, J.F. Benitez, G.M. Berruti, P. Bloch, A. Bocci, A. Bonato, C. Botta, H. Breuker, T. Camporesi, R. Castello, G. Cerminara, M. D'Alfonso, D. d'Enterria, A. Dabrowski, V. Daponte, A. David, M. De Gruttola, F. De Guio, A. De Roeck, S. De Visscher, E. Di Marco, M. Dobson, M. Dordevic, B. Dorney, T. du Pree, M. Dunser, N. Dupont, A. Elliott-Peisert, G. Franzoni, W. Funk, D. Gigi, K. Gill, D. Giordano, M. Girone, F. Glege, R. Guida, S. Gundacker, M. Gutho , J. Hammer, P. Harris, J. Hegeman, V. Innocente, P. Janot, H. Kirschenmann, M.J. Kortelainen, K. Kousouris, K. Krajczar, P. Lecoq, C. Lourenco, M.T. Lucchini, N. Magini, L. Malgeri, M. Mannelli, A. Martelli, L. Masetti, F. Meijers, S. Mersi, E. Meschi, F. Moortgat, S. Morovic, M. Mulders, M.V. Nemallapudi, H. Neugebauer, S. Orfanelli41, L. Orsini, L. Pape, E. Perez, M. Peruzzi, A. Petrilli, G. Petrucciani, A. Pfei er, D. Piparo, A. Racz, G. Rolandi42, M. Rovere, M. Ruan, H. Sakulin, C. Schafer, C. Schwick, A. Sharma, P. Silva, M. Simon, P. Sphicas43, D. Spiga, J. Steggemann, B. Stieger, M. Stoye, Y. Takahashi, D. Treille, A. Triossi, A. Tsirou, G.I. Veres21, N. Wardle, H.K. Wohri, A. Zagozdzinska35, W.D. Zeuner Paul Scherrer Institut, Villigen, Switzerland W. Bertl, K. Deiters, W. Erdmann, R. Horisberger, Q. Ingram, H.C. Kaestli, D. Kotlinski, U. Langenegger, D. Renker, T. Rohe Institute for Particle Physics, ETH Zurich, Zurich, Switzerland F. Bachmair, L. Bani, L. Bianchini, M.A. Buchmann, B. Casal, G. Dissertori, M. Dittmar, M. Donega, P. Eller, C. Grab, C. Heidegger, D. Hits, J. Hoss, G. Kasieczka, W. Lustermann, B. Mangano, M. Marionneau, P. Martinez Ruiz del Arbol, M. Masciovecchio, D. Meister, F. Micheli, P. Musella, F. Nessi-Tedaldi, F. Pandol , J. Pata, F. Pauss, L. Perrozzi, M. Quittnat, M. Rossini, A. Starodumov44, M. Takahashi, V.R. Tavolaro, K. Theo latos, R. Wallny Universitat Zurich, Zurich, Switzerland T.K. Aarrestad, C. Amsler45, L. Caminada, M.F. Canelli, V. Chiochia, A. De Cosa, C. Galloni, A. Hinzmann, T. Hreus, B. Kilminster, C. Lange, J. Ngadiuba, D. Pinna, P. Robmann, F.J. Ronga, D. Salerno, Y. Yang National Central University, Chung-Li, Taiwan M. Cardaci, K.H. Chen, T.H. Doan, Sh. Jain, R. Khurana, M. Konyushikhin, C.M. Kuo, W. Lin, Y.J. Lu, S.S. Yu National Taiwan University (NTU), Taipei, Taiwan Arun Kumar, R. Bartek, P. Chang, Y.H. Chang, Y.W. Chang, Y. Chao, K.F. Chen, P.H. Chen, C. Dietz, F. Fiori, U. Grundler, W.-S. Hou, Y. Hsiung, Y.F. Liu, R.-S. Lu, M. Min~ano Moya, E. Petrakou, J.f. Tsai, Y.M. Tzeng Chulalongkorn University, Faculty of Science, Department of Physics, Bangkok, Thailand B. Asavapibhop, K. Kovitanggoon, G. Singh, N. Srimanobhas, N. Suwonjandee Cukurova University, Adana, Turkey A. Adiguzel, S. Cerci46, Z.S. Demiroglu, C. Dozen, I. Dumanoglu, S. Girgis, G. Gokbulut, Y. Guler, E. Gurpinar, I. Hos, E.E. Kangal47, A. Kayis Topaksu, G. Onengut48, K. Ozdemir49, S. Ozturk50, B. Tali46, H. Topakli50, M. Vergili, C. Zorbilmez Middle East Technical University, Physics Department, Ankara, Turkey I.V. Akin, B. Bilin, S. Bilmis, B. Isildak51, G. Karapinar52, M. Yalvac, M. Zeyrek Bogazici University, Istanbul, Turkey E.A. Albayrak53, E. Gulmez, M. Kaya54, O. Kaya55, T. Yetkin56 Istanbul Technical University, Istanbul, Turkey K. Cankocak, S. Sen57, F.I. Vardarl Institute for Scintillation Materials of National Academy of Science of Ukraine, Kharkov, Ukraine B. Grynyov Kharkov, Ukraine L. Levchuk, P. Sorokin National Scienti c Center, Kharkov Institute of Physics and Technology, University of Bristol, Bristol, United Kingdom R. Aggleton, F. Ball, L. Beck, J.J. Brooke, E. Clement, D. Cussans, H. Flacher, J. Goldstein, M. Grimes, G.P. Heath, H.F. Heath, J. Jacob, L. Kreczko, C. Lucas, Z. Meng, D.M. Newbold58, S. Paramesvaran, A. Poll, T. Sakuma, S. Seif El Nasr-storey, S. Senkin, D. Smith, V.J. Smith Rutherford Appleton Laboratory, Didcot, United Kingdom K.W. Bell, A. Belyaev59, C. Brew, R.M. Brown, D. Cieri, D.J.A. Cockerill, J.A. Coughlan, K. Harder, S. Harper, E. Olaiya, D. Petyt, C.H. Shepherd-Themistocleous, A. Thea, I.R. Tomalin, T. Williams, W.J. Womersley, S.D. Worm Imperial College, London, United Kingdom M. Baber, R. Bainbridge, O. Buchmuller, A. Bundock, D. Burton, S. Casasso, M. Citron, D. Colling, L. Corpe, N. Cripps, P. Dauncey, G. Davies, A. De Wit, M. Della Negra, P. Dunne, A. Elwood, W. Ferguson, J. Fulcher, D. Futyan, G. Hall, G. Iles, M. Kenzie, R. Lane, R. Lucas58, L. Lyons, A.-M. Magnan, S. Malik, J. Nash, A. Nikitenko44, J. Pela, M. Pesaresi, K. Petridis, D.M. Raymond, A. Richards, A. Rose, C. Seez, A. Tapper, K. Uchida, M. Vazquez Acosta60, T. Virdee, S.C. Zenz Brunel University, Uxbridge, United Kingdom J.E. Cole, P.R. Hobson, A. Khan, P. Kyberd, D. Leggat, D. Leslie, I.D. Reid, P. Symonds, L. Teodorescu, M. Turner Baylor University, Waco, U.S.A. A. Borzou, K. Call, J. Dittmann, K. Hatakeyama, A. Kasmi, H. Liu, N. Pastika The University of Alabama, Tuscaloosa, U.S.A. O. Charaf, S.I. Cooper, C. Henderson, P. Rumerio Boston University, Boston, U.S.A. A. Avetisyan, T. Bose, C. Fantasia, D. Gastler, P. Lawson, D. Rankin, C. Richardson, J. Rohlf, J. St. John, L. Sulak, D. Zou Brown University, Providence, U.S.A. J. Alimena, E. Berry, S. Bhattacharya, D. Cutts, N. Dhingra, A. Ferapontov, A. Garabedian, J. Hakala, U. Heintz, E. Laird, G. Landsberg, Z. Mao, M. Narain, S. Piperov, S. Sagir, T. Sinthuprasith, R. Syarif University of California, Davis, Davis, U.S.A. R. Breedon, G. Breto, M. Calderon De La Barca Sanchez, S. Chauhan, M. Chertok, J. Conway, R. Conway, P.T. Cox, R. Erbacher, M. Gardner, W. Ko, R. Lander, M. Mulhearn, D. Pellett, J. Pilot, F. Ricci-Tam, S. Shalhout, J. Smith, M. Squires, D. Stolp, M. Tripathi, S. Wilbur, R. Yohay University of California, Los Angeles, U.S.A. R. Cousins, P. Everaerts, C. Farrell, J. Hauser, M. Ignatenko, D. Saltzberg, E. Takasugi, V. Valuev, M. Weber University of California, Riverside, Riverside, U.S.A. K. Burt, R. Clare, J. Ellison, J.W. Gary, G. Hanson, J. Heilman, M. Ivova PANEVA, P. Jandir, E. Kennedy, F. Lacroix, O.R. Long, A. Luthra, M. Malberti, M. Olmedo Negrete, A. Shrinivas, H. Wei, S. Wimpenny, B. R. Yates University of California, San Diego, La Jolla, U.S.A. J.G. Branson, G.B. Cerati, S. Cittolin, R.T. D'Agnolo, A. Holzner, R. Kelley, D. Klein, J. Letts, I. Macneill, D. Olivito, S. Padhi, M. Pieri, M. Sani, V. Sharma, S. Simon, M. Tadel, A. Vartak, S. Wasserbaech61, C. Welke, F. Wurthwein, A. Yagil, G. Zevi Della Porta University of California, Santa Barbara, Santa Barbara, U.S.A. D. Barge, J. Bradmiller-Feld, C. Campagnari, A. Dishaw, V. Dutta, K. Flowers, M. Franco Sevilla, P. Ge ert, C. George, F. Golf, L. Gouskos, J. Gran, J. Incandela, C. Justus, N. Mccoll, S.D. Mullin, J. Richman, D. Stuart, I. Suarez, W. To, C. West, J. Yoo California Institute of Technology, Pasadena, U.S.A. D. Anderson, A. Apresyan, A. Bornheim, J. Bunn, Y. Chen, J. Duarte, A. Mott, H.B. Newman, C. Pena, M. Pierini, M. Spiropulu, J.R. Vlimant, S. Xie, R.Y. Zhu Carnegie Mellon University, Pittsburgh, U.S.A. M.B. Andrews, V. Azzolini, A. Calamba, B. Carlson, T. Ferguson, M. Paulini, J. Russ, M. Sun, H. Vogel, I. Vorobiev University of Colorado Boulder, Boulder, U.S.A. J.P. Cumalat, W.T. Ford, A. Gaz, F. Jensen, A. Johnson, M. Krohn, T. Mulholland, U. Nauenberg, K. Stenson, S.R. Wagner Cornell University, Ithaca, U.S.A. J. Alexander, A. Chatterjee, J. Chaves, J. Chu, S. Dittmer, N. Eggert, N. Mirman, G. Nicolas Kaufman, J.R. Patterson, A. Rinkevicius, A. Ryd, L. Skinnari, L. So , W. Sun, S.M. Tan, W.D. Teo, J. Thom, J. Thompson, J. Tucker, Y. Weng, P. Wittich Fermi National Accelerator Laboratory, Batavia, U.S.A. S. Abdullin, M. Albrow, J. Anderson, G. Apollinari, S. Banerjee, L.A.T. Bauerdick, A. Beretvas, J. Berryhill, P.C. Bhat, G. Bolla, K. Burkett, J.N. Butler, H.W.K. Cheung, F. Chlebana, S. Cihangir, V.D. Elvira, I. Fisk, J. Freeman, E. Gottschalk, L. Gray, D. Green, S. Grunendahl, O. Gutsche, J. Hanlon, D. Hare, R.M. Harris, S. Hasegawa, J. Hirschauer, Z. Hu, S. Jindariani, M. Johnson, U. Joshi, A.W. Jung, B. Klima, B. Kreis, S. Kwany, S. Lammel, J. Linacre, D. Lincoln, R. Lipton, T. Liu, R. Lopes De Sa, J. Lykken, K. Maeshima, J.M. Marra no, V.I. Martinez Outschoorn, S. Maruyama, D. Mason, P. McBride, P. Merkel, K. Mishra, S. Mrenna, S. Nahn, C. Newman-Holmes, V. O'Dell, K. Pedro, O. Prokofyev, G. Rakness, E. Sexton-Kennedy, A. Soha, W.J. Spalding, L. Spiegel, L. Taylor, S. Tkaczyk, N.V. Tran, L. Uplegger, E.W. Vaandering, C. Vernieri, M. Verzocchi, R. Vidal, H.A. Weber, A. Whitbeck, F. Yang University of Florida, Gainesville, U.S.A. D. Acosta, P. Avery, P. Bortignon, D. Bourilkov, A. Carnes, M. Carver, D. Curry, S. Das, G.P. Di Giovanni, R.D. Field, I.K. Furic, J. Hugon, J. Konigsberg, A. Korytov, J.F. Low, P. Ma, K. Matchev, H. Mei, P. Milenovic62, G. Mitselmakher, D. Rank, R. Rossin, L. Shchutska, M. Snowball, D. Sperka, N. Terentyev, L. Thomas, J. Wang, S. Wang, J. Yelton Florida International University, Miami, U.S.A. S. Hewamanage, S. Linn, P. Markowitz, G. Martinez, J.L. Rodriguez Florida State University, Tallahassee, U.S.A. A. Ackert, J.R. Adams, T. Adams, A. Askew, J. Bochenek, B. Diamond, J. Haas, S. Hagopian, V. Hagopian, K.F. Johnson, A. Khatiwada, H. Prosper, M. Weinberg Florida Institute of Technology, Melbourne, U.S.A. M.M. Baarmand, V. Bhopatkar, S. Colafranceschi63, M. Hohlmann, H. Kalakhety, D. Noonan, T. Roy, F. Yumiceva University of Illinois at Chicago (UIC), Chicago, U.S.A. M.R. Adams, L. Apanasevich, D. Berry, R.R. Betts, I. Bucinskaite, R. Cavanaugh, O. Evdokimov, L. Gauthier, C.E. Gerber, D.J. Hofman, P. Kurt, C. O'Brien, I.D. Sandoval Gonzalez, C. Silkworth, P. Turner, N. Varelas, Z. Wu, M. Zakaria The University of Iowa, Iowa City, U.S.A. B. Bilki64, W. Clarida, K. Dilsiz, S. Durgut, R.P. Gandrajula, M. Haytmyradov, V. Khristenko, J.-P. Merlo, H. Mermerkaya65, A. Mestvirishvili, A. Moeller, J. Nachtman, H. Ogul, Y. Onel, F. Ozok66, A. Penzo, C. Snyder, P. Tan, E. Tiras, J. Wetzel, K. Yi Johns Hopkins University, Baltimore, U.S.A. I. Anderson, B.A. Barnett, B. Blumenfeld, N. Eminizer, D. Fehling, L. Feng, A.V. Gritsan, P. Maksimovic, C. Martin, M. Osherson, J. Roskes, A. Sady, U. Sarica, M. Swartz, M. Xiao, Y. Xin, C. You The University of Kansas, Lawrence, U.S.A. P. Baringer, A. Bean, G. Benelli, C. Bruner, R.P. Kenny III, D. Majumder, M. Malek, M. Murray, S. Sanders, R. Stringer, Q. Wang Kansas State University, Manhattan, U.S.A. A. Ivanov, K. Kaadze, S. Khalil, M. Makouski, Y. Maravin, A. Mohammadi, L.K. Saini, N. Skhirtladze, S. Toda Lawrence Livermore National Laboratory, Livermore, U.S.A. D. Lange, F. Rebassoo, D. Wright University of Maryland, College Park, U.S.A. C. Anelli, A. Baden, O. Baron, A. Belloni, B. Calvert, S.C. Eno, C. Ferraioli, J.A. Gomez, N.J. Hadley, S. Jabeen, R.G. Kellogg, T. Kolberg, J. Kunkle, Y. Lu, A.C. Mignerey, Y.H. Shin, A. Skuja, M.B. Tonjes, S.C. Tonwar Massachusetts Institute of Technology, Cambridge, U.S.A. A. Apyan, R. Barbieri, A. Baty, K. Bierwagen, S. Brandt, W. Busza, I.A. Cali, Z. Demiragli, L. Di Matteo, G. Gomez Ceballos, M. Goncharov, D. Gulhan, Y. Iiyama, G.M. Innocenti, M. Klute, D. Kovalskyi, Y.S. Lai, Y.-J. Lee, A. Levin, P.D. Luckey, A.C. Marini, C. Mcginn, C. Mironov, X. Niu, C. Paus, D. Ralph, C. Roland, G. Roland, J. Salfeld-Nebgen, G.S.F. Stephans, K. Sumorok, M. Varma, D. Velicanu, J. Veverka, J. Wang, T.W. Wang, B. Wyslouch, M. Yang, V. Zhukova University of Minnesota, Minneapolis, U.S.A. B. Dahmes, A. Evans, A. Finkel, A. Gude, P. Hansen, S. Kalafut, S.C. Kao, K. Klapoetke, Y. Kubota, Z. Lesko, J. Mans, S. Nourbakhsh, N. Ruckstuhl, R. Rusack, N. Tambe, J. Turkewitz University of Mississippi, Oxford, U.S.A. J.G. Acosta, S. Oliveros University of Nebraska-Lincoln, Lincoln, U.S.A. E. Avdeeva, K. Bloom, S. Bose, D.R. Claes, A. Dominguez, C. Fangmeier, R. Gonzalez Suarez, R. Kamalieddin, J. Keller, D. Knowlton, I. Kravchenko, J. Lazo-Flores, F. Meier, J. Monroy, F. Ratnikov, J.E. Siado, G.R. Snow State University of New York at Bu alo, Bu alo, U.S.A. M. Alyari, J. Dolen, J. George, A. Godshalk, C. Harrington, I. Iashvili, J. Kaisen, A. Kharchilava, A. Kumar, S. Rappoccio Northeastern University, Boston, U.S.A. G. Alverson, E. Barberis, D. Baumgartel, M. Chasco, A. Hortiangtham, A. Massironi, D.M. Morse, D. Nash, T. Orimoto, R. Teixeira De Lima, D. Trocino, R.-J. Wang, D. Wood, J. Zhang Northwestern University, Evanston, U.S.A. K.A. Hahn, A. Kubik, N. Mucia, N. Odell, B. Pollack, A. Pozdnyakov, M. Schmitt, S. Stoynev, K. Sung, M. Trovato, M. Velasco University of Notre Dame, Notre Dame, U.S.A. A. Brinkerho , N. Dev, M. Hildreth, C. Jessop, D.J. Karmgard, N. Kellams, K. Lannon, S. Lynch, N. Marinelli, F. Meng, C. Mueller, Y. Musienko36, T. Pearson, M. Planer, A. Reinsvold, R. Ruchti, G. Smith, S. Taroni, N. Valls, M. Wayne, M. Wolf, A. Woodard The Ohio State University, Columbus, U.S.A. L. Antonelli, J. Brinson, B. Bylsma, L.S. Durkin, S. Flowers, A. Hart, C. Hill, R. Hughes, W. Ji, K. Kotov, T.Y. Ling, B. Liu, W. Luo, D. Puigh, M. Rodenburg, B.L. Winer, H.W. Wulsin Princeton University, Princeton, U.S.A. O. Driga, P. Elmer, J. Hardenbrook, P. Hebda, S.A. Koay, P. Lujan, D. Marlow, T. Medvedeva, M. Mooney, J. Olsen, C. Palmer, P. Piroue, X. Quan, H. Saka, D. Stickland, C. Tully, J.S. Werner, A. Zuranski University of Puerto Rico, Mayaguez, U.S.A. S. Malik Purdue University, West Lafayette, U.S.A. V.E. Barnes, D. Benedetti, D. Bortoletto, L. Gutay, M.K. Jha, M. Jones, K. Jung, D.H. Miller, N. Neumeister, B.C. Radburn-Smith, X. Shi, I. Shipsey, D. Silvers, J. Sun, A. Svyatkovskiy, F. Wang, W. Xie, L. Xu Purdue University Calumet, Hammond, U.S.A. N. Parashar, J. Stupak Rice University, Houston, U.S.A. A. Adair, B. Akgun, Z. Chen, K.M. Ecklund, F.J.M. Geurts, M. Guilbaud, W. Li, B. Michlin, M. Northup, B.P. Padley, R. Redjimi, J. Roberts, J. Rorie, Z. Tu, J. Zabel University of Rochester, Rochester, U.S.A. B. Betchart, A. Bodek, P. de Barbaro, R. Demina, Y. Eshaq, T. Ferbel, M. Galanti, A. Garcia-Bellido, J. Han, A. Harel, O. Hindrichs, A. Khukhunaishvili, G. Petrillo, M. Verzetti Rutgers, The State University of New Jersey, Piscataway, U.S.A. S. Arora, A. Barker, J.P. Chou, C. Contreras-Campana, E. Contreras-Campana, D. Duggan, D. Ferencek, Y. Gershtein, R. Gray, E. Halkiadakis, D. Hidas, E. Hughes, S. Kaplan, R. Kunnawalkam Elayavalli, A. Lath, K. Nash, S. Panwalkar, M. Park, S. Salur, S. Schnetzer, D. She eld, S. Somalwar, R. Stone, S. Thomas, P. Thomassen, M. Walker University of Tennessee, Knoxville, U.S.A. M. Foerster, G. Riley, K. Rose, S. Spanier, A. York Texas A&M University, College Station, U.S.A. O. Bouhali67, A. Castaneda Hernandez67, M. Dalchenko, M. De Mattia, A. Delgado, S. Dildick, R. Eusebi, W. Flanagan, J. Gilmore, T. Kamon68, V. Krutelyov, R. Mueller, I. Osipenkov, Y. Pakhotin, R. Patel, A. Perlo , A. Rose, A. Safonov, A. Tatarinov, K.A. Ulmer2 Texas Tech University, Lubbock, U.S.A. N. Akchurin, C. Cowden, J. Damgov, C. Dragoiu, P.R. Dudero, J. Faulkner, S. Kunori, K. Lamichhane, S.W. Lee, T. Libeiro, S. Undleeb, I. Volobouev Vanderbilt University, Nashville, U.S.A. E. Appelt, A.G. Delannoy, S. Greene, A. Gurrola, R. Janjam, W. Johns, C. Maguire, Y. Mao, A. Melo, H. Ni, P. Sheldon, B. Snook, S. Tuo, J. Velkovska, Q. Xu University of Virginia, Charlottesville, U.S.A. M.W. Arenton, S. Boutle, B. Cox, B. Francis, J. Goodell, R. Hirosky, A. Ledovskoy, H. Li, C. Lin, C. Neu, X. Sun, Y. Wang, E. Wolfe, J. Wood, F. Xia Wayne State University, Detroit, U.S.A. C. Clarke, R. Harr, P.E. Karchin, C. Kottachchi Kankanamge Don, P. Lamichhane, J. Sturdy University of Wisconsin - Madison, Madison, WI, U.S.A. D.A. Belknap, D. Carlsmith, M. Cepeda, A. Christian, S. Dasu, L. Dodd, S. Duric, E. Friis, B. Gomber, M. Grothe, R. Hall-Wilton, M. Herndon, A. Herve, P. Klabbers, A. Lanaro, A. Levine, K. Long, R. Loveless, A. Mohapatra, I. Ojalvo, T. Perry, G.A. Pierro, G. Polese, T. Ruggles, T. Sarangi, A. Savin, A. Sharma, N. Smith, W.H. Smith, D. Taylor, N. Woods y: Deceased China 1: Also at Vienna University of Technology, Vienna, Austria 2: Also at CERN, European Organization for Nuclear Research, Geneva, Switzerland 3: Also at State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing, Moscow, Russia 4: Also at Institut Pluridisciplinaire Hubert Curien, Universite de Strasbourg, Universite de Haute Alsace Mulhouse, CNRS/IN2P3, Strasbourg, France 5: Also at National Institute of Chemical Physics and Biophysics, Tallinn, Estonia 6: Also at Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, 7: Also at Universidade Estadual de Campinas, Campinas, Brazil 8: Also at Centre National de la Recherche Scienti que (CNRS) - IN2P3, Paris, France 9: Also at Laboratoire Leprince-Ringuet, Ecole Polytechnique, IN2P3-CNRS, Palaiseau, France 10: Also at Joint Institute for Nuclear Research, Dubna, Russia 11: Also at Beni-Suef University, Bani Sweif, Egypt 12: Now at British University in Egypt, Cairo, Egypt 13: Also at Ain Shams University, Cairo, Egypt 14: Also at Zewail City of Science and Technology, Zewail, Egypt 15: Also at Universite de Haute Alsace, Mulhouse, France 16: Also at Tbilisi State University, Tbilisi, Georgia 17: Also at RWTH Aachen University, III. Physikalisches Institut A, Aachen, Germany 18: Also at University of Hamburg, Hamburg, Germany 19: Also at Brandenburg University of Technology, Cottbus, Germany 20: Also at Institute of Nuclear Research ATOMKI, Debrecen, Hungary 21: Also at Eotvos Lorand University, Budapest, Hungary 23: Also at Wigner Research Centre for Physics, Budapest, Hungary 24: Also at University of Visva-Bharati, Santiniketan, India 25: Now at King Abdulaziz University, Jeddah, Saudi Arabia 26: Also at University of Ruhuna, Matara, Sri Lanka 27: Also at Isfahan University of Technology, Isfahan, Iran 28: Also at University of Tehran, Department of Engineering Science, Tehran, Iran 29: Also at Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran, Iran 30: Also at Universita degli Studi di Siena, Siena, Italy 31: Also at Purdue University, West Lafayette, U.S.A. 32: Also at International Islamic University of Malaysia, Kuala Lumpur, Malaysia 33: Also at Malaysian Nuclear Agency, MOSTI, Kajang, Malaysia 34: Also at Consejo Nacional de Ciencia y Tecnolog a, Mexico city, Mexico 35: Also at Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland 36: Also at Institute for Nuclear Research, Moscow, Russia 37: Also at St. Petersburg State Polytechnical University, St. Petersburg, Russia 38: Also at National Research Nuclear University 'Moscow 39: Also at California Institute of Technology, Pasadena, U.S.A. 40: Also at Faculty of Physics, University of Belgrade, Belgrade, Serbia 41: Also at National Technical University of Athens, Athens, Greece 42: Also at Scuola Normale e Sezione dell'INFN, Pisa, Italy 43: Also at University of Athens, Athens, Greece 44: Also at Institute for Theoretical and Experimental Physics, Moscow, Russia 45: Also at Albert Einstein Center for Fundamental Physics, Bern, Switzerland 46: Also at Adiyaman University, Adiyaman, Turkey 47: Also at Mersin University, Mersin, Turkey 48: Also at Cag University, Mersin, Turkey 49: Also at Piri Reis University, Istanbul, Turkey 50: Also at Gaziosmanpasa University, Tokat, Turkey 51: Also at Ozyegin University, Istanbul, Turkey 52: Also at Izmir Institute of Technology, Izmir, Turkey 53: Also at Istanbul Bilgi University, Istanbul, Turkey 54: Also at Marmara University, Istanbul, Turkey 55: Also at Kafkas University, Kars, Turkey 56: Also at Yildiz Technical University, Istanbul, Turkey 57: Also at Hacettepe University, Ankara, Turkey Kingdom Belgrade, Serbia 58: Also at Rutherford Appleton Laboratory, Didcot, United Kingdom 59: Also at School of Physics and Astronomy, University of Southampton, Southampton, United 60: Also at Instituto de Astrof sica de Canarias, La Laguna, Spain 61: Also at Utah Valley University, Orem, U.S.A. 62: Also at University of Belgrade, Faculty of Physics and Vinca Institute of Nuclear Sciences, 63: Also at Facolta Ingegneria, Universita di Roma, Roma, Italy 64: Also at Argonne National Laboratory, Argonne, U.S.A. 65: Also at Erzincan University, Erzincan, Turkey 67: Also at Texas A&M University at Qatar, Doha, Qatar 68: Also at Kyungpook National University, Daegu, Korea [1] S.L. 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Raupach, S. Schael. Search for anomalous single top quark production in association with a photon in pp collisions at $$ \sqrt{s}=8 $$ TeV, Journal of High Energy Physics, 2016, 35, DOI: 10.1007/JHEP04(2016)035