The European Physical Journal C

http://link.springer.com/journal/10052

List of Papers (Total 3,038)

Measurement of the virtual-photon asymmetry A 2 and the spin-structure function g 2 of the proton

A measurement of the virtual-photon asymmetry A 2(x,Q 2) and of the spin-structure function g 2(x,Q 2) of the proton are presented for the kinematic range 0.004<x<0.9 and 0.18 GeV2<Q 2<20 GeV2. The data were collected by the HERMES experiment at the HERA storage ring at DESY while studying inclusive deep-inelastic scattering of 27.6 GeV longitudinally polarized leptons off a ...

ExSample—a library for sampling Sudakov-type distributions

Sudakov-type distributions are at the heart of generating radiation in parton showers as well as contemporary NLO matching algorithms along the lines of the POWHEG algorithm. In this paper, the C++ library ExSample is introduced, which implements adaptive sampling of Sudakov-type distributions for splitting kernels which are in general only known numerically. Besides the evolution ...

Electron performance measurements with the ATLAS detector using the 2010 LHC proton-proton collision data

Detailed measurements of the electron performance of the ATLAS detector at the LHC are reported, using decays of the Z, W and J/ψ particles. Data collected in 2010 at \(\sqrt{s}=7\mbox{~TeV}\) are used, corresponding to an integrated luminosity of almost 40 pb−1. The inter-alignment of the inner detector and the electromagnetic calorimeter, the determination of the electron energy ...

Search for charge non-conserving processes in 127I by coincidence technique

New lifetime limits on the charge non-conserving (CNC) electron capture with excitation of the 417.9 keV nuclear level in the 127I are established by using the coincidence technique. The analysed exposure is 0.87 ton × yr, collected deep underground at the Gran Sasso National Laboratory of the INFN by the highly radiopure DAMA/LIBRA setup (≈250 kg of highly radiopure NaI(Tl)). The ...

Measurement of the azimuthal correlation between the most forward jet and the scattered positron in deep-inelastic scattering at HERA

Deep-inelastic positron-proton scattering events at low photon virtuality, Q 2, with a forward jet, produced at small angles with respect to the proton beam, are measured with the H1 detector at HERA. A subsample of events with an additional jet in the central region is also studied. For both samples, differential cross sections and normalised distributions are measured as a ...

Implementation of the type III seesaw model in FeynRules/MadGraph and prospects for discovery with early LHC data

We discuss the implementation of the “minimal” type III seesaw model, i.e. with one fermionic triplet, in FeynRules/MadGraph. This is the first step in order to realize a real study of LHC data recorded in the LHC detectors. With this goal in mind, we comment on the possibility of discovering this kind of new physics at the LHC running at 7 TeV with a luminosity of few fb−1.

Can we get deeper inside the pion at the LHC?

We propose a measurement of leading neutrons spectra at LHC in order to extract inclusive π + p and π + π + cross-sections with high p T jets production. The cross-sections for these processes are simulated with the use of parton distributions in hadrons. In this work we estimate the possibility to extract parton distributions in the pion from the data on these cross-sections and ...

Cross-sections of large-angle hadron production in proton– and pion–nucleus interactions VIII: aluminium nuclei and beam momenta from ±3 GeV/c to ±15 GeV/c

We report on double-differential inclusive cross-sections of the production of secondary protons, charged pions, and deuterons, in the interactions with a 5% λ int thick stationary aluminium target, of proton and pion beams with momentum from ±3 GeV/c to ±15 GeV/c. Results are given for secondary particles with production angles 20∘<θ<125∘. Cross-sections on aluminium nuclei are ...

Exclusive electroproduction of two pions at HERA

The exclusive electroproduction of two pions in the mass range 0.4<M ππ <2.5 GeV has been studied with the ZEUS detector at HERA using an integrated luminosity of 82 pb−1. The analysis was carried out in the kinematic range of 2<Q 2<80 GeV2, 32<W<180 GeV and |t|<0.6 GeV2, where Q 2 is the photon virtuality, W is the photon-proton centre-of-mass energy and t is the squared ...

Forward energy flow, central charged-particle multiplicities, and pseudorapidity gaps in W and Z boson events from pp collisions at \(\sqrt{s}= 7\) TeV

A study of forward energy flow and central charged-particle multiplicity in events with W and Z bosons decaying into leptons is presented. The analysis uses a sample of 7 TeV pp collisions, corresponding to an integrated luminosity of 36 pb−1, recorded by the CMS experiment at the LHC. The observed forward energy depositions, their correlations, and the central charged-particle ...

Simulation of sextet diquark production

We present a method for simulating the production and decay of particles in the sextet representation of SU(3) C including the simulation of QCD radiation. Results from the Monte Carlo simulation of sextet diquark production at the LHC including both resonant and pair production are presented. We include limits on resonant diquark production from recent ATLAS results and perform ...

Revealing Bell’s nonlocality for unstable systems in high energy physics

Entanglement and its consequences—in particular the violation of Bell inequalities, which defies our concepts of realism and locality—have been proven to play key roles in Nature by many experiments for various quantum systems. Entanglement can also be found in systems not consisting of ordinary matter and light, i.e. in massive meson–antimeson systems. Bell inequalities have been ...

Performance of missing transverse momentum reconstruction in proton-proton collisions at \(\sqrt{s} = 7~\mbox{TeV}\) with ATLAS

The measurement of missing transverse momentum in the ATLAS detector, described in this paper, makes use of the full event reconstruction and a calibration based on reconstructed physics objects. The performance of the missing transverse momentum reconstruction is evaluated using data collected in pp collisions at a centre-of-mass energy of 7 TeV in 2010. Minimum bias events and ...

Performance of the ATLAS Trigger System in 2010

Proton–proton collisions at \(\sqrt{s}=7\) TeV and heavy ion collisions at \(\sqrt{s_{NN}}=2.76\) TeV were produced by the LHC and recorded using the ATLAS experiment’s trigger system in 2010. The LHC is designed with a maximum bunch crossing rate of 40 MHz and the ATLAS trigger system is designed to record approximately 200 of these per second. The trigger system selects events by ...

Upgraded breaking of the HLS model: a full solution to the τ−e + e − and ϕ decay issues and its consequences on g−2 VMD estimates

The muon anomalous magnetic moment a μ and the hadronic vacuum polarization are examined using data analyzed within the framework of a suitably broken HLS model. The analysis relies on all available scan data samples and leaves provisionally aside the existing ISR data. Our HLS model based global fit approach allows for a better check of consistency between data sets and we ...

Transverse enhancement model and MiniBooNE charge current quasi-elastic neutrino scattering data

Recently proposed Transverse Enhancement Model of nuclear effects in Charge Current Quasi-Elastic neutrino scattering (A. Bodek, H.S. Budd, M.E. Christy, Eur. Phys. J. C 71:1726, 2011) is confronted with the MiniBooNE high statistics experimental data.

Superluminal neutrinos from Lorentz-violating dimension-5 operators

We consider Lorentz- and CPT-violating dimension-5 operators to address the issue of superluminal neutrinos recently pointed out in OPERA experiments. We assume these operators in the photon and neutrino sectors to be coupled to Lorentz-violating backgrounds in a preferred frame defined by a time-like direction. We show that such operators can produce a curve with OPERA’s slope ...

Measurement of the diffractive longitudinal structure function \(F_{L}^{D}\) at HERA

First measurements are presented of the diffractive cross section σ ep→eXY at centre-of-mass energies \(\sqrt{s}\) of 225 and \(252\mathrm {\;GeV}\), together with a precise new measurement at \(\sqrt{s}\) of \(319\mathrm {\;GeV}\), using data taken with the H1 detector in the years 2006 and 2007. Together with previous H1 data at \(\sqrt{s}\) of \(301\mathrm {\;GeV}\), the ...

Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at \(\sqrt{s}=7\mbox{~TeV}\) with the ATLAS detector

The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton–proton collisions at a centre-of-mass energy of \(\sqrt{s} = 7\mbox{~TeV}\), using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb−1. The b-jets are identified using either a lifetime-based method, where ...

Benchmark models, planes, lines and points for future SUSY searches at the LHC

We define benchmark models for SUSY searches at the LHC, including the CMSSM, NUHM, mGMSB, mAMSB, MM-AMSB and p19MSSM, as well as models with R-parity violation and the NMSSM. Within the parameter spaces of these models, we propose benchmark subspaces, including planes, lines and points along them. The planes may be useful for presenting results of the experimental searches in ...

Search for massive colored scalars in four-jet final states in \(\sqrt{s}=7~\mbox{TeV}\) proton–proton collisions with the ATLAS detector

A search for pair-produced scalar particles decaying to a four-jet final state is presented. The analysis is performed using an integrated luminosity of 34 pb−1 recorded by the ATLAS detector in 2010. No deviation from the Standard Model is observed. For a scalar mass of 100 GeV (190 GeV) the limit on the scalar gluon pair production cross section at 95% confidence level is 1 nb ...

Search for a heavy neutral particle decaying into an electron and a muon using 1 fb−1 of ATLAS data

A search is presented for a high mass neutral particle that decays directly to the e ± μ ∓ final state. The data sample was recorded by the ATLAS detector in \(\sqrt{s}=7\mbox{~TeV}\) pp collisions at the LHC from March to June 2011 and corresponds to an integrated luminosity of 1.07 fb−1. The data are found to be consistent with the Standard Model background. The high e ± μ ∓ mass ...

Measurement of the jet fragmentation function and transverse profile in proton–proton collisions at a center-of-mass energy of 7 TeV with the ATLAS detector

The jet fragmentation function and transverse profile for jets with 25 GeV<p T jet<500 GeV and |η jet|<1.2 produced in proton–proton collisions with a center-of-mass energy of 7 TeV are presented. The measurement is performed using data with an integrated luminosity of 36 pb−1. Jets are reconstructed and their momentum measured using calorimetric information. The momenta of the ...

Radon-induced surface contaminations in low background experiments

In low background experiments the reduction of all possible radioactive contaminants is a crucial point for detector construction. This is also true for the surface contaminants, either those introduced during the production of detector components or those introduced during handling, treatment or storage. One of the most critical issue in this field is the control of the ...