Probing non-standard interactions at Daya Bay

Journal of High Energy Physics, Jul 2015

In this article we consider the presence of neutrino non-standard interactions (NSI) in the production and detection processes of reactor antineutrinos at the Daya Bay experiment. We report for the first time, the new constraints on the flavor non-universal and flavor universal charged-current NSI parameters, estimated using the currently released 621 days of Daya Bay data. New limits are placed assuming that the new physics effects are just inverse of each other in the production and detection processes. With this special choice of the NSI parameters, we observe a shift in the oscillation amplitude without distorting the L/E pattern of the oscillation probability. This shift in the depth of the oscillation dip can be caused by the NSI parameters as well as by θ 13, making it quite difficult to disentangle the NSI effects from the standard oscillations. We explore the correlations between the NSI parameters and θ 13 that may lead to significant deviations in the reported value of the reactor mixing angle with the help of iso-probability surface plots. Finally, we present the limits on electron, muon/tau, and flavor universal (FU) NSI couplings with and without considering the uncertainty in the normalization of the total event rates. Assuming a perfect knowledge of the event rates normalization, we find strong upper bounds ∼ 0.1% for the electron and FU cases improving the present limits by one order of magnitude. However, for a conservative error of 5% in the total normalization, these constraints are relaxed by almost one order of magnitude.

A PDF file should load here. If you do not see its contents the file may be temporarily unavailable at the journal website or you do not have a PDF plug-in installed and enabled in your browser.

Alternatively, you can download the file locally and open with any standalone PDF reader:

https://link.springer.com/content/pdf/10.1007%2FJHEP07%282015%29060.pdf

Probing non-standard interactions at Daya Bay

Received: December Probing non-standard interactions at Daya Bay Sanjib Kumar Agarwalla 0 1 2 4 5 Partha Bagchi 0 1 2 4 5 David V. Forero 0 1 2 3 5 Mariam T´ortola 0 1 2 5 0 We explore the 1 Parc Cientific de Paterna, C/ Catedratico Jos ́e Beltr ́an , 2 E-46980 Paterna (Val`encia) , Spain 2 Sainik School Post , Bhubaneswar 751005 , India 3 Center for Neutrino Physics , Virginia Tech 4 Institute of Physics , Sachivalaya Marg 5 Open Access , c The Authors bAHEP Group, Institut de F´ısica Corpuscular - C.S.I.C./Universitat de Val`encia, (NSI) in the production and detection processes of reactor antineutrinos at the Daya Bay experiment. We report for the first time, the new constraints on the flavor non-universal and flavor universal charged-current NSI parameters, estimated using the currently released 621 days of Daya Bay data. New limits are placed assuming that the new physics effects are just inverse of each other in the production and detection processes. With this special choice of the NSI parameters, we observe a shift in the oscillation amplitude without distorting the L/E pattern of the oscillation probability. This shift in the depth of the oscillation dip can be caused by the NSI parameters as well as by θ13, making it quite difficult to disentangle the NSI effects from the standard oscillations. correlations between the NSI parameters and θ13 that may lead to significant deviations in the reported value of the reactor mixing angle with the help of iso-probability surface plots. Finally, we present the limits on electron, muon/tau, and flavor universal (FU) NSI couplings with and without considering the uncertainty in the normalization of the total event rates. Assuming a perfect knowledge of the event rates normalization, we find strong upper bounds ∼ 0.1% for the electron and FU cases improving the present limits by one order of magnitude. However, for a conservative error of 5% in the total normalization, these constraints are relaxed by almost one order of magnitude. ArXiv ePrint: 1412.1064 Neutrino Physics; Beyond Standard Model - Data analysis of modern reactor experiments Bounds on NSI from Daya Bay without normalization error Constraints on electron-NSI couplings Constraints on muon/tau-NSI couplings Constraints for the flavor-universal NSI case Bounds on NSI from Daya Bay with 5% normalization error Comparing NSI constraints from 217 and 621 days of Daya Bay run Summary and conclusions A Effective survival probability with the NSI parameters: εseγ 6= εγd∗e A.1 Presence of the NSI parameters only at the production stage A.2 NSI at the source and detector with the same magnitude and different phases 27 1 Introduction 3 4 5 2 Implementing NSI in modern reactor experiments Effective antineutrino survival probability in reactor experiments 2.3 Impact of the NSI parameters on the effective probability tineutrino experiments Daya Bay [1–3] and RENO [4] has firmly established the three-flavor neutrino paradigm [5–7] and signifies an important development towards our understanding of the structure of the neutrino mass matrix, whose precise reconstruction would shed light on the underlying new physics that gives rise to neutrino mass and mixing [8–10]. Another reactor electron antineutrino disappearance experiment: Double Chooz [11, 12], and the two accelerator electron (anti-)neutrino appearance experiments: MINOS [13] (completed) and T2K [14, 15] (presently running) have also confirmed the non-zero and moderately to see that with 621 days of data taking and using the merit of identical multi-detector Undoubtedly, this high precision measurement of the 1-3 mixing angle has speeded up the search for the neutrino mass ordering and the possible presence of a CP-violating phase in current and future neutrino oscillation experiments [16–20]. To explain the presence of small neutrino masses and relatively large neutrino mixings as indicated by neutrino oscillation data, various neutrino mass models have been proposed. These neutrino mass models come in various categories such as the cases where neutrinos acquire mass via the popular seesaw mechanism [21–31]. We find also models where neutrinos get mass radiatively due to the presence of extra Higgs bosons [32–34] or low energy supersymmetric hybrid models with spontaneous or bilinear breaking of R-parity [35, 36]. The structure of the standard electroweak neutral and charged currents gets affected by the presence of these mechanisms responsible for the neutrino mass generation [25]. In most of the cases, in the low energy regime, these effects are known as non-standard interactions (NSI). Various extensions of the Standard Model (SM), such as left-right symmetric models and supersymmetric models with R-parity violation, predict NSI of neutrinos with other fermions [37–45]. The NSI in these models are usually generated via the exchange of new massive particles at low energies. Neutrino NSI may be of charged-current (CC) or neutral-current (NC) type, and they can be classified in two main categories: flavor-changing NSI, when the flavor of the leptonic current involved in the process is changed, or flavor-conserving non-universal NSI, when the lepton flavor is not changed in the process but the strength of the interaction depends on it, violating the weak universality. In the low energy regime, these new interactions may be parameterized in the form of effective four-fermion Lagrangians: LCC−NSI = LNC−NSI = NC-NSI couplings generally affecting the neutrino propagation in matter (m). Note that in eqs. (1.1) and (1.2) we have assumed for the new interactions the same Lorentz structure as for the SM weak interactions, (V±A). Even though more general expressions are possible within a generic structure of operators, as shown in ref. [46], these are the dominant contributions for reactor experiments, where we will focus our attention in this work. NSI effects may appear at three different stages in a given neutrino experiment, namely neutrino production, neutrino propagation from the source to the detector, and neutrino detection. In a short-baseline reactor experiment, the effects on the neutrino propagation are negligible since it happens mainly in vacuum. Therefore, the new generation of shortbaseline reactor experiments, such as Daya Bay, offers an excellent scenario to probe the presence of NSI at the neutrino production and detection, free of any degeneracy with NSI propagation effects. Actually, some work has already been done in the context of NSI at short-baseline reactor experiments. In particular, forecasts for the sensitivity of Daya Bay to NSI have been published, for instance, in ref. [47]. More recently, another article presented constraints on neutrino NSI using the previous Daya Bay data set [48]. The results derived there are in general agreement with some of the cases we discuss in section 4. Nevertheless, our paper also studies the phenomenology of some other interesting cases not considered in ref. [48], and provides a detailed description of the effect of NSI in the neutrino survival probability. Finally, we also discuss the fragility of the bounds on the NSI couplings derived using Daya Bay data against the presence of an uncertainty on the total event rate normalization in the statistical analysis of reactor data. Given the production and detection neutrino processes involved in short-baseline reC.L. bounds on these parameters [49]: coming from unitarity constraints on the CKM matrix as well as from the non-observation of neutrino oscillations in the NOMAD experiment. Here the couplings with different = εfαfβ0,L + εfαfβ0,R. Other constraints on neutrino NSI couplings using solar and reactor neutrinos have been given in [50–55]. On the other hand, NSI have also been studied in the context of laboratory experiments with accelerators in refs. [53, 56–58], while bounds from atmospheric neutrino data have been presented in refs. [59, 60]. Recently a forecast for the sensitivity to NSI of the future PINGU detector has been presented in [61]. Future medium-baseline reactor experiments like JUNO can also serve as test bed to look for NSI [62]. This paper is organized as follows. In section 2, we describe the procedure for implementing the NSI effect in the modern reactor experiments. There, we derive the effective antineutrino survival probability expressions which we use later to analyze the Daya Bay data. We also give plots to discuss in detail the impact of the NSI parameters on the plots. Section 3 describes the numerical methods adopted to analyze the reactor data. Apart from this, a brief description of the Daya Bay experiment and the important features of its present data set which are relevant for the fit are also given in this section. Section 4 presents the constraints on the NSI parameters imposed by the current Daya Bay data assuming a perfect knowledge of the event rates normalization. Next we derive the bounds on the NSI parameters taking into account the uncertainty in the normalization of event rates with a prior of 5% in section 5. In section 6, we compare the constraints on 1The NSI parameters probed in our analysis get contributions from the (V±A) operators in eq. (1.1) we have dropped the chirality indices all over the paper. while the redefinition of the antineutrino flavor states is given by: the NSI parameters obtained with the current 621 days of Daya Bay data with the limits derived using the previously released 217 days of Daya Bay data. Finally, we summarize and draw our conclusions in section 7. In appendix A, we give the effective antineutrino Implementing NSI in modern reactor experiments According to the usual procedure followed in the non-standard analyses of reactor data [47, 63], we start by re-defining the neutrino flavour states in the presence of NSI in the source and detection processes. For the initial (at source) and final (at detector) neutrino flavor states, we have [64–67]: The normalization factors required to obtain an orthonormal basis can be expressed as: and the neutrino mixing between flavor and mass eigenstates is given by the usual expres The correct normalization of the neutrino states in presence of NSI is a very important point, required to obtain a total neutrino transition probability normalized to 1. However, one has to consider that when dealing with a non-orthonormal neutrino basis, the normalization of neutrino states will affect not only the neutrino survival probability but also the calculation of the produced neutrino fluxes and detection cross sections. In this while convoluting the neutrino oscillation probabilities, cross sections, and neutrino fluxes to estimate the number of events in a given experiment such as Daya Bay. This is due to the fact that the SM cross sections and neutrino fluxes used in our simulation have been theoretically derived assuming an orthonormal neutrino basis and therefore they need to be corrected. Then, from here we can consider the following effective redefinition of neutrino and antineutrino states: |ν¯αieff = |ν¯αi + X εα∗γ |ν¯γ i, s s where we have dropped the normalization factors that will cancel in the Monte Carlo simulation of Daya Bay data. From these effective neutrino states we will calculate an effective neutrino oscillation probability, that will be used all along our analysis. Note that when we will discuss the features of the probability prior to the simulation of a particular experiment, we will always refer to the effective probability, that might be greater than one. Effective antineutrino survival probability in reactor experiments tance L from source to detector is defined as: Pν¯αs→ν¯βd = |hν¯βd| exp (−i H L)|ν¯αi| . s 2 In terms of the neutrino mass differences and mixing angles, this transition probability in vacuum may be written as: where Δmj2k = mj2 − m2k. In the case of standard oscillations, Yαjβ is defined as: In presence of NSI, however, according to the definition of neutrino states in eq. (2.2), this expression is modified as follows [63]: Yαβ ≡ Uβ∗j Uαj + X εsα∗γ Uβ∗j Uγj + X εηd∗βUη∗j Uαj + X εsα∗γ εηd∗βUη∗j Uγj . j is produced at the source and a positron is detected inside the detector, one has to replace by splitting the new couplings into its absolute value and its phase: Now expanding the various terms of the general transition probability as given in eq. (2.8) Pν¯es→ν¯ed = Pν¯SeM→ν¯e + PnNoSnI-osc + PoNscS-Iatm + PoNscS-Isolar where the Standard Model (SM) contribution is given by Pν¯SeM→ν¯e = 1 − sin2 2θ13 c122 sin2 Δ31 + s122 sin2 Δ32 − c143 sin2 2θ12 sin2 Δ21, effective survival probability in eq. (2.12) can be written as: + |εede|2 + |εsee|2 + 2|εede||εee| cos(φede − φsee) (2.14) s +2|εede||εee| cos(φede +φsee)+2|εseμ||εμe| cos(φseμ +φdμe)+2|εseτ ||ετe| cos(φseτ +φτde), s d d PoNscS-Iatm = 2 ns13s23 h|εseμ| sin(δ − φseμ) − |εdμe| sin(δ + φdμe)i + s13c23 |εeτ | sin(δ − φseτ ) − |ετe| sin(δ + φτde)i h s d − s23c23 |εeμ||ετe| sin(φseμ + φτde) + |εeτ ||εμe| sin(φseτ + φdμe)i h s d s d − c223|εeτ ||ετe| sin(φseτ + φτde) − s223|εeμ||εμe| sin(φseμ + φdμe)o sin (2Δ31) s d s d −4 ns13s23 h|εseμ| cos(δ − φseμ) + |εdμe| cos(δ + φdμe)i + s13c23 |εeτ | cos(δ − φseτ ) + |ετe| cos(δ + φτde)i h s d + s23c23 |εeμ||ετe| cos(φseμ + φτde) + |εeτ ||εμe| cos(φseτ + φdμe)i h s d s d + c223|εeτ ||ετe| cos(φseτ + φτde) + s223|εeμ||εμe| cos(φseμ + φdμe)o sin2 (Δ31) , (2.15) s d s d −c23(|εeμ| sin φseμ + |εμe| sin φdμe) s d as given in ref. [46], with a good agreement between the calculated probabilities here and there. However, as it can be seen in the expressions above, here we also include new corrections will be discussed later in the paper. In eq. (2.15), note the presence of a term can affect the L/E dependence of the probability in the presence of neutrino NSI. In this work2 we assume that, likewise the mechanisms responsible for production (via each other, this is also true for the associated NSI [46, 47]. This assumption allows us to write εsγ = εd∗ ≡ |εγ |eiφγ where we drop the universal e index for simplicity. With these γ assumptions, eq. (2.12) takes the form (keeping the terms up-to the second order in small 2In the appendix, we have given the effective probability expressions for the physical situations where also modify the L/E pattern of the oscillation probability due to the shift in its energy. A detailed analysis of the Daya Bay data under such scenarios will be performed in [69]. non−oscillat{ozry NSI terms −4{s23|εμ|2 + c223|ετ |2 + 2s23c23|εμ||ετ |cos(φμ − φτ )} sin2 Δ31 2 −4{2s13[s23|εμ| cos (δ − φμ) + c23|ετ | cos(δ − φτ )]} sin2 Δ31. Pν¯es→ν¯ed ' 1 − sin2 2θ13 c122 sin2 Δ31 + s122 sin2 Δ32 − c143 sin2 2θ12 sin2 Δ21 For this special case of NSI parameters, there is no linear sine-dependent term in eq. (2.17) and two striking features are emerging from the effective probability expression which are responsible for a change in the oscillation amplitude. First we can see the presence of some non-oscillatory NSI terms which are independent of L and E and are given by and, second, there is a shift in the effective 1-3 mixing angle due to oscillatory NSI terms which can be written as s13 → s123 + s223|εμ|2 + c223|ετ |2 + 2s23c23|εμ||ετ | cos(φμ − φτ ) 2 These two features, which are brought about by the NSI parameters, are responsible for a shift in the oscillation amplitude without distorting the L/E pattern of the oscillation probability as can be clearly seen from figure 1 and figure 2 that we will discuss in the next section. Eq. (2.19) suggests that it will be quite challenging to discriminate the effect of note that there are some CP conserving terms in eq. (2.19) which come into the picture due to the presence of NSI parameters. One of the most important consequences of the new non-oscillatory NSI terms (see eq. (2.18)) is that they can cause a flavor transition at is known as “zero-distance” effect [46, 70]. In modern reactor experiments, this effect can be probed using the near detectors which are placed quite close to the source. For definiteness, in this work we have restricted our analysis to the following choices of the NSI parameters: • Lepton number conserving non-universal NSI parameters which depend on the flavor characterizing the violation of weak universality. Under this category, we study the following two cases: 1. Considering only the NSI parameters |εe| and φe which are associated with ν¯e. In the presence of these flavor conserving NSI parameters, eq. (2.17) takes the form: new non-oscillatory NSI terms appearing at the survival probability produce a This expression will be very useful to discuss the behavior of the effective prob 2. Considering only the NSI parameters |εμ| and φμ which are associated with ν¯μ. In the presence of these flavor violating NSI parameters, eq. (2.17) takes the e →ν¯ed ' Pν¯SeM→ν¯e + 2|εμ|2 − 4{s23|εμ|2 + 2s13s23|εμ| cos(δ − φμ)} sin2 Δ31. (2.22) 2 the effective survival probability will be exactly the same as eq. (2.22) with the in the neutrino transition probability may be interpreted as a global redefinition • Lepton number conserving universal NSI parameters which do not depend on flavor. in eq. (2.17) takes the form: −4{|ε|2 + 2s23c23|ε|2 + 2s13|ε| cos(δ − φ)(s23 + c23)} sin2 Δ31. (2.24) In this case, the effective mixing angle in the presence of oscillatory and nonoscillatory NSI terms will be given by: As stated above, the expressions given in this subsection to illustrate the shift in the effective reactor angle in the presence of NSI, eqs. (2.21), (2.23) and (2.25), contain only first order corrections in the NSI couplings. Note, however, that terms of second order will briefly discuss the relevance of second order corrections in our analysis. Clearly, these corrections to the effective neutrino probability are only significant in the cases where first 7.6 × 10−5 2.55 × 10−3 the right panel. In both the panels, the solid black lines depict the probability without new physics involved (SM case). it is straightforward to evaluate the size of the second order terms for the three cases under study. Taking into account the baselines and neutrino energies probed at the Daya Bay experiment, we find that second order corrections (for vahishing first order corrections) are one order of magnitude smaller than for the two other cases, comes from the smallness of the coefficient responsible for second order corrections in the expression of the effective 1 2 2 sin2 Δ31 − s23 , very close to zero for the energies and baselines studied in Daya Bay. This result can be observed in the correlation plots in figures 3 and 4 (see dashed blue line) in section 2.4. There, one sees that second order corrections are small but visible for electron-NSI and flavour-universal case, while they are almost negligible for the muon/tau-NSI case. The impact of the second order corrections over the results presented in this work is discussed in section 7. Impact of the NSI parameters on the effective probability Now we will study the possible impact of the NSI parameters at the effective probability level. Table 1 depicts the benchmark values of the various oscillation parameters that are considered to generate the oscillation probability plots. These choices of the oscillation parameters are in close agreement with the best-fit values that have been obtained in the recent global fits of the world neutrino oscillation data [5–7]. Here we would like to mention and the NSI-modified three-flavor oscillation effective probability as a function of the electron antineutrino energy with a source-detector distance of 1.58 km. In the left panel of eq. (2.20)). The solid black line shows the standard oscillation probability without the NSI terms (see eq. (2.13)). The other four lines have been drawn considering particular choices probability is less compared to the standard value because the contribution from the nonthen the oscillation probability is above the standard value because the contribution from most of the energies of interest. This is the sign of the non-unitarity effects [68, 72–75], caused by the presence of neutrino NSI at the source and detector of reactor experiments. In the right panel of figure 1, the band shows the changes in the effective probability after the NSI terms have a non-trivial L/E dependency. The standard oscillation probability without the NSI terms is shown by the solid black line and the other four lines have been (more) compared to the standard value for almost all the choices of neutrino energy as light grey region. In figure 2, the solid black line depicts the standard probability without Energy [MeV] km for the flavor-universal NSI case (see section 2.2 for details). The dark salmon region shows the without new physics involved (SM case). considering the NSI parameters. The other four lines in this plot display the effective oscilin the figure legends. It is quite clear from eq. (2.24) that the non-oscillatory terms dominate over the oscillatory terms in the flavor-universal NSI case. Therefore, the dark salmon region of figure 2 closely resembles the left panel of figure 1 where we consider the NSI to draw the iso-probability surface plots. Left panel of figure 3 shows the iso-probability oscillation probability without considering the NSI parameters as given by eq. (2.13). Now increase the overall probability (see eq. (2.20)). Then, we need to increase the value of for (δ − φμ,τ ) = 90◦ or -90◦ in the right panel of figure 3. case with the help of iso-probability surface contours. In the left panel, we consider four are the same for 90◦ and -90◦ choices of phases (see the dashed blue lines) because the phases and the baseline L = 1.58 km. it enhances the overall oscillation probability to a great extent even for a small value of reduce the contribution coming from the standard survival oscillation probability. Right flavor-universal NSI case, the contribution from the non-oscillatory NSI terms dominates features emerging from the extreme right panel of figure 7 (see later in section 4) where give a negative contribution to the neutrino survival probability that, to be compensated, requires an enhancement of the standard survival probability by reducing the value of Data analysis of modern reactor experiments Reactor antineutrinos are produced by the fission of the isotopes 235U, 239Pu, 241Pu and 238U contributing to the neutrino flux with a certain fission fraction fk. Reactor antineuis a delayed coincidence between two gamma rays: one coming from the positron (prompt signal) and the other coming from the neutron capture in the innermost part of the antineutrino detector (AD), containing gadolinium-doped liquid scintillator. The light created is collected by the photo-multipliers (PMTs) located in the outermost mineral oil-region. The The expected number of IBD events at the d-th detector, Td, can be estimated summing up the contributions of all reactors to the detector: Td = X Trd = Z ∞ where Np is the number of protons in the target volume, Ptrh is the reactor thermal power, d denotes the efficiency of the detector and hEki is the energy release per fission for a given isotope k taken from ref. [76]. The neutrino survival probability Pee depends also on the we use the parameterization given in ref. [77] as well as the new normalization for reactor taken from ref. [79]. Daya Bay experiment Daya Bay is a reactor neutrino experiment with several antineutrino detectors (ADs), arranged in three experimental halls (EHs). Electron antineutrinos are generated in six in the EHs. The effective baselines are 512 m and 561 m for the near halls EH1 and EH2 and 1579 m for the far hall EH3 [2]. With this near-far technology Daya Bay has minimized the systematic errors coming from the ADs and thus provided until now the most precise determination of the reactor mixing angle. In the last Neutrino conference, Daya Bay has reported its preliminary results considering 621 days of data taking combining their results for two different experimental setups [3]: one with six ADs as it was published in ref. [2] and the other after the installation of two more detectors, eight ADs in total. This new combined data set has four times more statistics in comparison with the previous Daya Bay results. Thus, the precision in the determination of the reactor mixing angle has been improved, and it is now of the order of 6%. In this work we will consider the most recent data release by the Daya Bay Collaboration described above and we will concentrate on the total observed rates at each detector, Md − Td 1 + anorm + Pr ωrdαr + ξd + βd r=1 r Here Td corresponds to the theoretical prediction in eq. (3.1), Md is the measured number contribution of the r-th reactor to the d-th AD number of events, determined by the baselines Lrd and the total thermal power of each reactor. The pull parameters, used to the reactor, detector and background uncertainties with the corresponding set of errors the quadratic sum of the background uncertainties taken from ref. [3]. Finally, we also consider an absolute normalization factor anorm to account for the uncertainty in the total in the normalization of reactor antineutrino fluxes. In our analysis we will follow two different approaches concerning this parameter. In section 4 we will take it equal to zero, assuming perfect knowledge of the events normalization. This hypothesis will be relaxed in section 5, where we will allow for a non-zero normalization factor in the statistical analysis, being determined from the fit to the Daya Bay data. As we will see, the results obtained in our analysis are strongly correlated with the treatment of the total normalization of reactor neutrino events in the statistical analysis of Daya Bay data and therefore it is of crucial importance to do a proper treatment of this factor. Bounds on NSI from Daya Bay without normalization error In this section we will present the bounds on the NSI couplings we have obtained using current Daya Bay reactor data. In all the results, we have assumed maximal 2-3 mixing and we have marginalized over atmospheric splitting with a prior of 3%. For definiteness will discuss the bounds arising from Daya Bay data in comparison with existing bounds. We Constraints on electron-NSI couplings According to the expression in eq. (2.20), the effective survival probability in the case when only NSI with electron antineutrinos are considered is independent of the standard Our results are presented in figure 5. From the left panel in this figure, we can confirm the behaviors shown by the iso-probability curves in the section 2.4, namely, the presence regions correspond to 68% (black dashed line), 90% (green line) and 99% C.L. (red line) for 2 d.o.f. by one order of magnitude: no bound can be obtained from reactor data. Concerning the determination of the reactor mixing angle, the presence of the NSI The same interval is obtained for the two panels at figure 5 and it also coincides exactly with the allowed range in absence of NSI. In consequence, we can say that the reactor angle determination by Daya Bay is robust in this specific case. Constraints on muon/tau-NSI couplings In this subsection we present the results obtained considering only the NSI parameters associated with muon and tau neutrinos. As we have discussed in section 2.2, in this case, see eq. (2.22). Therefore, it is enough to consider in our calculations the effective phase The results corresponding to this particular case are shown in figure 6. Here again we can see how the regions presented in the left panel of the figure agree with the behavior 0.012 0.024 0.036 0.048 0.012 0.024 0.036 0.048 -180◦ and 180◦. The regions correspond to 68% (black dashed line), 90% (green line), and 99% C.L. (red line) for 2 d.o.f. shown in the iso-probability plots (right panel of figure 3) where there is an anticorrelacompensated by a shift of the preferred value of the reactor mixing angle toward smaller while the obtained bound for the NSI coupling is the following In this case reactor data can not improve the present constraints on the NSI couplings at eq. (1.3), and we get a limit of the same order of magnitude of the ones derived at ref. [49]. However, in both cases the limits have been derived using different data and assumptions, and therefore, they can be regarded as complementary bounds coming from different data is allowed to vary. In this case, a wider range in the reactor mixing angle is allowed: The reason is that, in addition to the anticorrelation shown in the left panel, a correlation is negative. Note, however, that both correlations are not symmetric, what results in conventions for the lines is the same as in figure 5 in the redefinition of the effective reactor angle in the presence of NSI given in eq. (2.23). Nevertheless, even though there is a wider allowed region in the reactor angle, the bound is set to zero, namely: Constraints for the flavor-universal NSI case Here we present the results obtained under the hypothesis of flavor-universal NSI, that is, we assume all NSI couplings are present and they take the same value. Therefore, we entering in the calculations. In this case, the effective survival probability is given by the have considered four different cases in our analysis: one with all the phases set to zero, two cases varying only one of the phases with the other set to zero and a last case varying the two phases simultaneously. Our results are presented at figure 7. The left panel in figure 7 shows the tight constraint obtained for the magnitude of the The same behavior is also present in the middle panel of figure 7, where the Dirac phase by the non-oscillatory term in eq. (2.25). Under this assumption, we obtain the following bound on the magnitude of the flavor-universal coupling: the one obtained in the standard case, and therefore the Daya Bay determination is barely different values, a completely different behavior results, as it is shown in the right panel of therefore the first order expression in eq. (2.25) can not satisfactory explain the degeneracy As commented above, the presence of flavor universal NSI implies that the reactor mixing angle may be compatible with zero. Nevertheless, the degeneracy between the mixing angle with accelerator long-baseline neutrino experiments. A global analysis of neutrino data assuming the simultaneous presence of NSI in reactor and accelerator neutrino data would be very useful for this purpose. Besides solving the degeneracy, the combined analysis might provide further constraints on the NSI couplings as well as improve the agreement in ref. [80–82]. However, since the production, detection and propagation of neutrinos is quite different in both kind of experiments, a global analysis would require a very detailed study with many new physics parameters involved, besides the consideration of a specific model for NSI. In any case, this point is out of the scope of the present analysis and it will be considered elsewhere. Finally, let us comment that we have also considered the case of flavor-universal NSI with all the phases different from zero. However, we have not presented the results obtained therefore no information on any of the parameters can be extracted from the analysis of Daya Bay data. All the results obtained in this section are summarized in table 2. Needless table, we have marginalized over the NSI couplings over a wide range. Similarly, to place electron-type NSI coupling muon or tau-type NSI couplings universal NSI couplings without considering any uncertainty in the normalization of reactor event rates in the statistical analysis (anorm = 0). Bounds on NSI from Daya Bay with 5% normalization error In the previous section, we have not considered any normalization error in the statistical analysis of Daya Bay reactor data. This means that we have assumed a perfect knowledge of the event normalization at the experiment, disregarding the presence of uncertainties in the flux reactor normalization or in the detection cross section, among others. This procedure has been followed in most of the previous phenomenological analyses of Daya Bay data in presence of NSI, see for instance ref. [47]. In the more recent work at ref. [48], the authors have considered small uncertainties in the reactor flux and in the detector properties, although they did not take into account an uncertainty in the overall normalization of the event rates. Needless to say that a more detailed analysis of reactor data can not ignore the of Daya Bay data using the expression defined at eq. (3.2), where a free normalization factor is considered in order to account for the uncertainties in the total event number normalization. This point is very relevant in the study of NSI with reactor experiments, since the uncertainty in the event normalization presents a degeneracy with the zerodistance effect due to NSI. In consequence, the far over near technique exploited by Daya Bay in order to reduce the dependence upon total normalization does not work equally fine in the presence of NSI, where the non-oscillatory zero-distance effect, simultaneously present at near and far detectors, does not totally cancel. Actually, in the standard model case without NSI, the number of events expected at the near detector is given by: NNSMD ' N (1 + anorm)PeSeM(L = 0) = N (1 + anorm) , while, in the presence of NSI, the event number at the near detector is calculated as follows: NNNDSI ' N (1 + anorm)PeNeSI(L = 0) = N (1 + anorm)(1 + f (ε)) Here anorm controls the normalization of far and near detector events in the fit and, together to zero, we artificially increase the power of Daya Bay data to constrain the zero-distance effect due to NSI, getting non-realistic strong bounds on the NSI couplings. On the other hand, we can not leave the factor anorm totally free in our statistical analysis, as it is usually done in the standard Daya Bay analysis, where the factor is kept small thanks to the far over near technique. Actually, we have found that leaving the normalization factor totally free, and due to the degeneracy with the NSI couplings, it could achieve very large values, of the order of 10-20%. For this reason it is necessary the use of a prior on this magnitude. Recent reevaluations of the reactor antineutrino flux indicate an uncertainty on the total flux of about 3% [77, 83]. However, an independent analysis in ref. [84] claims that this uncertainty may have been underestimated due to the treatment of forbidden transitions in the antineutrino flux evaluation, and proposes a total uncertainty of 4%. Since the total normalization errors may also include uncertainties coming from other sources, we follow the conservative approach of taking a total uncertainty on the reactor event normalization To illustrate the differences with respect to the results obtained in the previous section, assuming no uncertainties in the event rate normalization, here we have considered only the cases where all phases are set to zero.3 The results obtained with these assumptions are presented in figure 8 and table 3. In the left panel of figure 8 we present the allowed this case, the range for the reactor mixing angle is rather similar to the one shown in the left panel of figure 5: still slightly better than the one at eq. (1.3)): the right panel of figure 8. In this case, the allowed range for the reactor mixing angle is a bit enlarged with respect to the previous one: due to the presence of NSI oscillation terms driven by the new physics couplings with muon and tau antineutrinos. As commented above, the loss of sensitivity to the NSI couplings is and, therefore, second order corrections are not relevant. assuming 5% uncertainty on the total event rate normalization of Daya Bay events. The conventions for the lines is the same as in figure 5. with a 5% uncertainty on the total event normalization. due to the degeneracy between the normalization uncertainty and the zero-distance terms induced by the presence of NSI. In this way, a larger value of the NSI parameters can be compensated with a non-zero normalization factor anorm, without spoiling the good agreement with experimental reactor data. Finally, the middle panel of figure 8 shows the results obtained when only NSI with muon or tau antineutrinos are considered. In this case, the cancellation between the norThe bound on the NSI coupling is given by: Comparing NSI constraints from 217 and 621 days of Daya Bay run The new high-precision data from Daya Bay with 621 days of running time [3] has improved the impact of the four time more statistics that the Daya Bay experiment has accumulated the new (old) 621 (217) days of Daya Bay data. Here all the phases are considered to be zero and with the help of eight ADs in comparison with the previously released Daya Bay data set with six ADs. Now it would be quite interesting to see how much we can further constrain the allowed ranges for these NSI parameters under consideration using the new 621 days of Daya Bay data in comparison with the old 217 days of Daya Bay run. In figure 9, we compare the performance of the current and the previous data sets of Daya Bay in constraining In both the panels, the solid (dashed) lines portray the results with the new (old) 621 (217) days of Daya Bay data. For the sake of illustration, we have only chosen the cases of NSI phases to be zero. In particular, we have focused on the situations which are presented in sections 4.1 and 4.2, where we do not consider the normalization uncertainty on the reactor the current data, the improvement in constraining the allowed parameter space between parameters using the previous (current) 217 (621) days of Daya Bay data. Here all the phases are considered to be zero. We do not consider the normalization uncertainty on the same while analyzing 621 days of Daya Bay data. This feature is also there in the case two when we consider the current 621 days of Daya Bay data compared to its previous compared to the old data set. These results suggest that the future data from the Daya Bay (621) days of Daya Bay data. Here all the phases are considered to be zero. We also do not consider Current (621 days) Previous (217 days) Current (621 days) Previous (217 days) electron-type NSI parameters muon or tau-type NSI parameters universal NSI parameters Current (621 days) Previous (217 days) Current (621 days) Previous (217 days) Current (621 days) Previous (217 days) Current (621 days) Previous (217 days) Current (621 days) Previous (217 days) (621) days of Daya Bay data. Here we allow the phases or their certain combinations to vary freely. experiment with more statistics is going to play an important role to further constrain the allowed parameter space for the NSI parameters. There are also marginal improvements parameters obtained using the old 217 days and new 621 days of Daya Bay data allowing the phases or their certain combinations to vary freely as we consider in table 2 in section 4. Like in table 4, here also we do not take into account the normalization uncertainty on even if we allow the phases to vary freely, we obtain better limits on the NSI parameters with the new data set as compared to the previous 217 days of Daya Bay data, except Summary and conclusions The success of the currently running Daya Bay, RENO, and Double Chooz reactor anaccuracy signifies an important advancement in the field of modern neutrino physics with nonzero mass and three-flavor mixing. With this remarkable discovery, the neutrino oscillation physics has entered into a high-precision era opening up the possibility of observing sub-dominant effects due to possible new physics beyond the Standard Model of particle physics. At present, undoubtedly the Daya Bay experiment in China is playing a leading and an important role in this direction. The recent high-precision and unprecedentedly copious data from the Daya Bay experiment has provided us an opportunity to probe the existence of the non-standard interaction effects which might crop up at the production point or at the detection stage of the reactor antineutrinos. In this paper for the first time, we have reported the new constraints on the flavor nonuniversal and also flavor universal NSI parameters obtained using the currently released 621 days of Daya Bay data. While placing the bounds on these NSI parameters, we have assumed that the new physics effects are just inverse of each other in the production and special case, we have discussed in detail the impact of the NSI parameters on the effective antineutrino survival probability expressions which we ultimately use to analyze the Daya Bay data. With this special choice of the NSI parameters, we have observed a shift in the oscillation amplitude without altering the L/E pattern of the oscillation probability. This shift in the depth of the oscillation dip can be caused due to the NSI parameters and as well Before presenting the final results, we have studied the correlations between the NSI paramquite useful to understand the final bounds on the NSI parameters that we have obtained from the fit. Since the shape of the oscillation probability is not distorted with the special choice of the NSI parameters considered in this paper, an analysis based on the total event rate at the Daya Bay experiment is sufficient to obtain the limits on the NSI parameters. As far as the flavor non-universal NSI parameters are concerned, first we have consida perfect knowledge of the normalization of the event rates, the current Daya Bay data freely in the fit. We have also observed that the determination of the 1-3 mixing angle is quite robust in this specific case and it is almost independent of the issue of uncertainty in coincides exactly with the allowed range in absence of NSI. Next we turn our attention to fect knowledge of the event rates normalization, the current Daya Bay data sets a limit of case when we do not consider any uncertainty in the normalization of event rates, the upper One of the novelties of this work is the inclusion of correction terms of second order in second order corrections at the effective probability level has been analyzed in section 2.2 as well as in the discussion of the probability and correlation plots in section 2.3 and relevant for the flavour-universal-NSI case, as commented in section 4.3. One of the interesting studies that we have performed in this paper is the comparison of the constraints on the NSI parameters placed with the current 621 days of Daya Bay data with the limits obtained using the previously released 217 days of Daya Bay run. In this analysis, all the phases are considered to be zero and the normalization of events is also kept data compared to its previous 217 days data. This comparative study reveals the merit of the huge statistics that Daya Bay has already accumulated. It also suggests that the future high-precision data from the Daya Bay experiment with enhanced statistics is inevitable to further probe the sub-leading effects in neutrino flavor conversion due to the presence of the possible NSI parameters beyond the standard three-flavor oscillation paradigm. S.K.A. acknowledges the support from DST/INSPIRE Research Grant [IFA-PH-12], Department of Science and Technology, India. The work of D.V.F. and M.T. was supported by the Spanish grants FPA2011-22975 and MULTIDARK CSD2009-00064 (MINECO) and PROMETEOII/2014/084 (Generalitat Valenciana). This work has also been supported by the U.S. Department of Energy under award number DE-SC0003915. In this appendix, we present the effective probability expressions for the physical scenarios depth of the first oscillation maximum but they also modify the L/E pattern of the probability due to the shift in its energy. We have already mentioned that a detailed analysis of the Daya Bay data considering such interesting physical cases will be performed in [69]. Presence of the NSI parameters only at the production stage Here we assume that the NSI parameters only affect the production mechanism of the antineutrinos in the reactor experiment. It allows us to write (dropping the universal With this assumption, we get the effective neutrino survival probability as follows: −4s13 [s23|εμ| cos(δ − φμ) + c23|ετ | cos(δ − φτ )] sin2 (Δ31) NSI at the source and detector with the same magnitude and different In this case, we assume that the magnitude of the NSI parameters is the same at the production and detection level, but the phases associated with the NSI parameters are different at the source and detector. Under this situation, we can write: Under this assumption, the effective neutrino survival probability takes the form: where the non-standard terms are given by: + |εe|2 h1 + cos(φed − φse) + cos(φed + φe) PoNscS-Ia-tImIb = 2 ns13s23|εμ| hsin(δ −φsμ)−sin(δ +φdμ)i+s13c23|ετ | hsin(δ −φτs )−sin(δ + φτ ) −s223|εμ|2 sin(φsμ + φμ) − c223|ετ |2 sin(φτs + φτ ) d d − c23s23|εμ||ετ | hsin(φτs + φdμ) + sin(φsμ + φτd)io −4ns13s23|εμ|hcos(δ −φsμ)+cos(δ +φdμ)i+c23s13|ετ |hcos(δ −φτs )+cos(δ +φτd)i This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited. [arXiv:1310.6732] [INSPIRE]. [arXiv:1204.0626] [INSPIRE]. (2014) 093006 [arXiv:1405.7540] [INSPIRE]. 89 (2014) 093018 [arXiv:1312.2878] [INSPIRE]. status of leptonic CP-violation, JHEP 11 (2014) 052 [arXiv:1409.5439] [INSPIRE]. Sci. 56 (2006) 569 [hep-ph/0603118] [INSPIRE]. Fortsch. Phys. 61 (2013) 466 [arXiv:1206.6678] [INSPIRE]. from theory to experiment, New J. Phys. 16 (2014) 045018 [arXiv:1402.4271] [INSPIRE]. [arXiv:1112.6353] [INSPIRE]. neutrino beam, Phys. Rev. Lett. 112 (2014) 061802 [arXiv:1311.4750] [INSPIRE]. neutrino beam, Phys. Rev. D 88 (2013) 032002 [arXiv:1304.0841] [INSPIRE]. Part. Nucl. Phys. 60 (2008) 338 [arXiv:0710.0554] [INSPIRE]. 2013 (2013) 503401 [INSPIRE]. superbeams using liquid argon detectors, JHEP 03 (2014) 087 [arXiv:1304.3251] [INSPIRE]. (2014) 457803 [arXiv:1401.4705] [INSPIRE]. Rev. Lett. 44 (1980) 912 [INSPIRE]. C 790927 (1979) 315 [arXiv:1306.4669] [INSPIRE]. (1980) 2227 [INSPIRE]. model, Nucl. Phys. B 181 (1981) 287 [INSPIRE]. superstring models, Phys. Rev. D 34 (1986) 1642 [INSPIRE]. NJLS approach, Phys. Lett. B 368 (1996) 270 [hep-ph/9507275] [INSPIRE]. breaking, Phys. Rev. D 53 (1996) 2752 [hep-ph/9509255] [INSPIRE]. non-unitarity effects, Phys. Rev. D 81 (2010) 013001 [arXiv:0910.3924] [INSPIRE]. Phys. B 524 (1998) 23 [hep-ph/9706315] [INSPIRE]. mixings from supersymmetry with bilinear R parity violation: a theory for solar and atmospheric neutrino oscillations, Phys. Rev. D 62 (2000) 113008 [Erratum ibid. D 65 (2002) 119901] [hep-ph/0004115] [INSPIRE]. no mixing in the vacuum, Phys. Lett. B 260 (1991) 154 [INSPIRE]. enhanced flavor changing neutral current scattering, Phys. Rev. D 44 (1991) 1629 [INSPIRE]. [arXiv:0807.1003] [INSPIRE]. neutrino interactions, Phys. Rev. D 79 (2009) 013007 [arXiv:0809.3451] [INSPIRE]. seesaw model, Phys. Rev. D 79 (2009) 011301 [arXiv:0811.3346] [INSPIRE]. model, Phys. Lett. B 681 (2009) 269 [arXiv:0909.0455] [INSPIRE]. superbeam experiments, Phys. Rev. D 77 (2008) 013007 [arXiv:0708.0152] [INSPIRE]. at Daya Bay, JHEP 12 (2011) 001 [arXiv:1105.5580] [INSPIRE]. Daya Bay data, Phys. Rev. D 90 (2014) 073011 [arXiv:1403.5507] [INSPIRE]. neutrino interactions, JHEP 08 (2009) 090 [arXiv:0907.0097] [INSPIRE]. non-standard neutrino-electron interactions with solar and reactor neutrinos, Phys. Rev. D neutrino-quark interactions with solar, reactor and accelerator data, Phys. Rev. D 80 (2009) 105009 [Erratum ibid. D 80 (2009) 129908] [arXiv:0907.2630] [INSPIRE]. nonstandard neutrino interactions, JHEP 03 (2003) 011 [hep-ph/0302093] [INSPIRE]. [58] D.V. Forero and M.M. Guzzo, Constraining nonstandard neutrino interactions with electrons, Phys. Rev. D 84 (2011) 013002 [INSPIRE]. [60] M.C. Gonzalez-Garcia and M. Maltoni, Determination of matter potential from global analysis of neutrino oscillation data, JHEP 09 (2013) 152 [arXiv:1307.3092] [INSPIRE]. experiments with non-standard interactions, Nucl. Phys. B 888 (2014) 137 [63] T. Ohlsson and H. Zhang, Non-standard interaction effects at reactor neutrino experiments, Phys. Lett. B 671 (2009) 99 [arXiv:0809.4835] [INSPIRE]. of the leptonic mixing matrix, JHEP 10 (2006) 084 [hep-ph/0607020] [INSPIRE]. oscillations and recent Daya Bay, T 2K experiments, Phys. Rev. D 86 (2012) 073010 [1] Daya Bay collaboration , F.P. An et al ., Improved measurement of electron antineutrino disappearance at Daya Bay, Chin . Phys . C 37 ( 2013 ) 011001 [arXiv:1210.6327] [INSPIRE]. [2] Daya Bay collaboration , F.P. An et al ., Spectral measurement of electron antineutrino oscillation amplitude and frequency at Daya Bay , Phys. Rev. Lett . 112 ( 2014 ) 061801 [3] Daya Bay collaboration , C. Zhang, Recent results from the Daya Bay experiment, talk given at the Neutrino 2014 Conference, Boston U.S.A. ( 2014 ) [arXiv:1501.04991] [INSPIRE]. [4] RENO collaboration , J.K. Ahn et al., Observation of reactor electron antineutrino disappearance in the RENO experiment , Phys. Rev. Lett . 108 ( 2012 ) 191802 [5] D.V. Forero , M. Tortola and J.W.F. Valle , Neutrino oscillations refitted , Phys. Rev. D 90 [6] F. Capozzi et al., Status of three-neutrino oscillation parameters , circa 2013 , Phys. Rev . D [7] M.C. Gonzalez-Garcia , M. Maltoni and T. Schwetz , Updated fit to three neutrino mixing: [8] R.N. Mohapatra and A.Y . Smirnov , Neutrino mass and new physics, Ann. Rev. Nucl. Part. [9] S. Morisi and J.W.F. Valle , Neutrino masses and mixing: a flavour symmetry roadmap , [10] S.F. King , A. Merle , S. Morisi , Y. Shimizu and M. Tanimoto , Neutrino mass and mixing: [11] Double Chooz collaboration , Y. Abe et al., Indication for the disappearance of reactor electron antineutrinos in the Double Chooz experiment , Phys. Rev. Lett . 108 ( 2012 ) 131801 [12] Double Chooz collaboration , Y. Abe et al., Reactor electron antineutrino disappearance in the Double Chooz experiment , Phys. Rev. D 86 ( 2012 ) 052008 [arXiv:1207.6632] [INSPIRE]. [13] MINOS collaboration, P. Adamson et al ., Electron neutrino and antineutrino appearance in the full MINOS data sample , Phys. Rev. Lett . 110 ( 2013 ) 171801 [arXiv:1301.4581] [14] T2K collaboration , K. Abe et al., Observation of electron neutrino appearance in a muon [15] T2K collaboration , K. Abe et al., Evidence of electron neutrino appearance in a muon [16] H. Nunokawa , S.J. Parke and J.W.F. Valle , CP violation and neutrino oscillations , Prog. [17] S. Pascoli and T. Schwetz , Prospects for neutrino oscillation physics, Adv. High Energy Phys. [18] S.K. Agarwalla , S. Prakash and S. Uma Sankar , Exploring the three flavor effects with future [19] S.K. Agarwalla , Physics potential of long-baseline experiments , Adv. High Energy Phys . 2014 [20] H. Minakata , Neutrino physics now and in the near future , arXiv:1403 .3276 [INSPIRE]. [21] P. Minkowski , μ → eγ at a rate of one out of 109 muon decays? , Phys. Lett . B 67 ( 1977 ) 421 [22] T. Yanagida , Horizontal symmetry and masses of neutrinos , Conf. Proc. C 7902131 ( 1979 ) [23] R.N. Mohapatra and G. Senjanovi ´c, Neutrino mass and spontaneous parity violation , Phys. [24] M. Gell-Mann , P. Ramond and R. Slansky , Complex spinors and unified theories , Conf. Proc. [25] J. Schechter and J.W.F. Valle , Neutrino masses in SU(2) × U(1) theories , Phys. Rev. D 22 [26] G. Lazarides , Q. Shafi and C. Wetterich , Proton lifetime and fermion masses in an SO(10) [27] R.N. Mohapatra and J.W.F. Valle , Neutrino mass and baryon number nonconservation in [28] E.K. Akhmedov , M. Lindner , E. Schnapka and J.W.F. Valle , Left-right symmetry breaking in [29] E.K. Akhmedov , M. Lindner , E. Schnapka and J.W.F. Valle , Dynamical left-right symmetry [30] P.S.B. Dev and R.N. Mohapatra , TeV scale inverse seesaw in SO(10) and leptonic [31] S.M. Boucenna , S. Morisi and J.W.F. Valle , The low-scale approach to neutrino masses , Adv. High Energy Phys . 2014 ( 2014 ) 831598 [arXiv:1404.3751] [INSPIRE]. [32] T.P. Cheng and L.-F. Li , Neutrino masses, mixings and oscillations in SU(2) × U(1) models of electroweak interactions , Phys. Rev. D 22 ( 1980 ) 2860 [INSPIRE]. [33] A. Zee , A theory of lepton number violation, neutrino Majorana mass and oscillation , Phys. Lett . B 93 ( 1980 ) 389 [Erratum ibid . B 95 ( 1980 ) 461] [INSPIRE]. [34] K.S. Babu , Model of 'calculable' Majorana neutrino masses , Phys. Lett . B 203 ( 1988 ) 132 [35] M.A. Diaz , J.C. Romao and J.W.F. Valle , Minimal supergravity with R-parity breaking , Nucl. [36] M. Hirsch , M.A. Diaz , W. Porod , J.C. Romao and J.W.F. Valle , Neutrino masses and [37] E. Roulet , MSW effect with flavor changing neutrino interactions , Phys. Rev. D 44 ( 1991 ) [38] M.M. Guzzo , A. Masiero and S.T. Petcov , On the MSW effect with massless neutrinos and [39] V.D. Barger , R.J.N. Phillips and K. Whisnant , Solar neutrino solutions with matter [40] S. Bergmann , Y. Grossman and D.M. Pierce , Can lepton flavor violating interactions explain the atmospheric neutrino problem? , Phys. Rev. D 61 ( 2000 ) 053005 [hep-ph/9909390] [41] Z. Berezhiani and A. Rossi , Limits on the nonstandard interactions of neutrinos from e+ecolliders , Phys. Lett . B 535 ( 2002 ) 207 [hep-ph/0111137] [INSPIRE]. [42] S. Antusch , J.P. Baumann and E. Fernandez-Martinez , Non-standard neutrino interactions with matter from physics beyond the standard model, Nucl . Phys . B 810 ( 2009 ) 369 [43] M.B. Gavela , D. Hernandez , T. Ota and W. Winter , Large gauge invariant non-standard [44] M. Malinsky , T. Ohlsson and H. Zhang , Non-standard neutrino interactions from a triplet [45] T. Ohlsson , T. Schwetz and H. Zhang , Non-standard neutrino interactions in the Zee -Babu [46] J. Kopp , M. Lindner , T. Ota and J. Sato , Non-standard neutrino interactions in reactor and [47] R. Leitner , M. Malinsky , B. Roskovec and H. Zhang , Non-standard antineutrino interactions [48] I. Girardi and D. Meloni , Constraining new physics scenarios in neutrino oscillations from [49] C. Biggio , M. Blennow and E. Fernandez-Martinez , General bounds on non-standard [50] Z. Berezhiani , R.S. Raghavan and A. Rossi , Probing nonstandard couplings of neutrinos at the Borexino detector, Nucl . Phys . B 638 ( 2002 ) 62 [hep-ph/0111138] [INSPIRE]. [51] O.G. Miranda , M.A. Tortola and J.W.F. Valle , Are solar neutrino oscillations robust? , JHEP [52] J. Barranco , O.G. Miranda , C.A. Moura and J.W.F. Valle , Constraining non-standard [53] J. Barranco , O.G. Miranda , C.A. Moura and J.W.F. Valle , Constraining non-standard neutrino-electron interactions , Phys. Rev. D 77 ( 2008 ) 093014 [arXiv:0711.0698] [INSPIRE]. [54] A. Bolanos , O.G. Miranda , A. Palazzo , M.A. Tortola and J.W.F. Valle , Probing [55] F.J. Escrihuela , O.G. Miranda , M.A. Tortola and J.W.F. Valle , Constraining nonstandard [56] S. Davidson , C. Pena-Garay , N. Rius and A. Santamaria , Present and future bounds on [57] F.J. Escrihuela , M. Tortola , J.W.F. Valle and O.G. Miranda , Global constraints on muon-neutrino non-standard interactions , Phys. Rev. D 83 (2011) 093002 [59] N. Fornengo , M. Maltoni , R. Tomas and J.W.F. Valle , Probing neutrino nonstandard interactions with atmospheric neutrino data , Phys. Rev. D 65 (2002) 013010 [61] S. Choubey and T. Ohlsson , Bounds on non-standard neutrino interactions using PINGU , [62] Y.-F. Li and Y.-L. Zhou , Shifts of neutrino oscillation parameters in reactor antineutrino [64] S.M. Bilenky and C. Giunti , Seesaw type mixing and νμ → ντ oscillations , Phys. Lett. B 300 [65] Y. Grossman , Nonstandard neutrino interactions and neutrino oscillation experiments , Phys. [66] M.C. Gonzalez-Garcia , Y. Grossman , A. Gusso and Y. Nir , New CP-violation in neutrino [67] D. Meloni , T. Ohlsson , W. Winter and H. Zhang , Non-standard interactions versus non-unitary lepton flavor mixing at a neutrino factory , JHEP 04 ( 2010 ) 041 [68] S. Antusch , C. Biggio , E. Fernandez-Martinez , M.B. Gavela and J. Lopez-Pavon , Unitarity [69] S.K. Agarwalla , D.V. Forero and M. T ´ortola, Spectral analysis of Daya Bay data to investigate non-standard interactions, work in progress , ( 2015 ). [70] P. Langacker and D. London , Lepton number violation and massless nonorthogonal neutrinos , Phys. Rev. D 38 ( 1988 ) 907 [INSPIRE]. [71] D.V. Forero , M. Tortola and J.W.F. Valle , Global status of neutrino oscillation parameters after Neutrino-2012 , Phys. Rev . D 86 ( 2012 ) 073012 [arXiv:1205.4018] [INSPIRE]. [72] E. Fernandez-Martinez , M.B. Gavela , J. Lopez-Pavon and O. Yasuda , CP-violation from non-unitary leptonic mixing , Phys. Lett . B 649 ( 2007 ) 427 [hep-ph/0703098] [INSPIRE]. [73] S. Goswami and T. Ota , Testing non-unitarity of neutrino mixing matrices at neutrino factories , Phys. Rev. D 78 ( 2008 ) 033012 [arXiv:0802.1434] [INSPIRE]. [74] S. Luo , Non-unitary deviation from the tri-bimaximal lepton mixing and its implications on neutrino oscillations , Phys. Rev. D 78 ( 2008 ) 016006 [arXiv:0804.4897] [INSPIRE]. [75] D.V. Forero , S. Morisi , M. Tortola and J.W.F. Valle , Lepton flavor violation and non-unitary lepton mixing in low-scale type-I seesaw , JHEP 09 ( 2011 ) 142 [arXiv:1107.6009] [INSPIRE]. [76] V. Kopeikin , L. Mikaelyan and V. Sinev , Reactor as a source of antineutrinos: thermal fission energy , Phys. Atom. Nucl . 67 ( 2004 ) 1892 [Yad . Fiz. 67 ( 2004 ) 1916] [77] T. Mueller et al., Improved predictions of reactor antineutrino spectra , Phys. Rev. C 83 [78] K.N. Abazajian et al., Light sterile neutrinos: a white paper , arXiv:1204 .5379 [INSPIRE]. [79] P. Vogel and J.F. Beacom , Angular distribution of neutron inverse beta decay , [80] R. Adhikari , S. Chakraborty , A. Dasgupta and S. Roy , Non-standard interaction in neutrino [81] I. Girardi , D. Meloni and S.T. Petcov , The Daya Bay and T 2K results on sin2 2θ13 and non-standard neutrino interactions, Nucl . Phys . B 886 ( 2014 ) 31 [arXiv:1405.0416] [82] A. Di Iura , I. Girardi and D. Meloni , Probing new physics scenarios in accelerator and reactor neutrino experiments , J. Phys. G 42 ( 2015 ) 065003 [arXiv:1411.5330] [INSPIRE]. [83] P. Huber , On the determination of anti-neutrino spectra from nuclear reactors , Phys. Rev. C 84 ( 2011 ) 024617 [Erratum ibid . C 85 ( 2012 ) 029901] [arXiv:1106.0687] [INSPIRE]. [84] A.C. Hayes , J.L. Friar , G.T. Garvey , G. Jungman and G. Jonkmans , Systematic uncertainties in the analysis of the reactor neutrino anomaly , Phys. Rev. Lett . 112 ( 2014 )


This is a preview of a remote PDF: https://link.springer.com/content/pdf/10.1007%2FJHEP07%282015%29060.pdf

Sanjib Kumar Agarwalla, Partha Bagchi, David V. Forero, Mariam Tórtola. Probing non-standard interactions at Daya Bay, Journal of High Energy Physics, 2015, 60, DOI: 10.1007/JHEP07(2015)060