Publications
152 results found
Abe K, Amey J, Andreopoulos C, et al., 2017, Search for Lorentz and CPT violation using sidereal time dependence of neutrino flavor transitions over a short baseline, Physical Review D, Vol: 95, ISSN: 2470-0010
A class of extensions of the Standard Model allows Lorentz and CPT violations, which can be identified by the observation of sidereal modulations in the neutrino interaction rate. A search for such modulations was performed using the T2K on-axis near detector. Two complementary methods were used in this study, both of which resulted in no evidence of a signal. Limits on associated Lorentz and CPT-violating terms from the Standard Model extension have been derived by taking into account their correlations in this model for the first time. These results imply such symmetry violations are suppressed by a factor of more than 1020 at the GeV scale.
Abe K, Amey J, Andreopoulos C, et al., 2017, Combined analysis of neutrino and antineutrino oscillations at T2K, Physical Review Letters, Vol: 118, ISSN: 0031-9007
T2K reports its first results in the search for CP violation in neutrino oscillations using appearance and disappearance channels for neutrino- and antineutrino-mode beams. The data include all runs from January 2010 to May 2016 and comprise 7.482×1020 protons on target in neutrino mode, which yielded in the far detector 32 e-like and 135 μ-like events, and 7.471×1020 protons on target in antineutrino mode, which yielded 4 e-like and 66 μ-like events. Reactor measurements of sin22θ13 have been used as an additional constraint. The one-dimensional confidence interval at 90% for the phase δCP spans the range (−3.13, −0.39) for normal mass ordering. The CP conservation hypothesis (δCP=0, π) is excluded at 90% C.L.
Abe K, Andreopoulos C, Antonova M, et al., 2017, First measurement of the muon neutrino charged current single pion production cross section on water with the T2K near detector, Physical Review D, Vol: 95, ISSN: 2470-0010
The T2K off-axis near detector, ND280, is used to make the first differential cross section measurements of muon neutrino charged current single positive pion production on a water target at energies ∼0.8 GeV. The differential measurements are presented as a function of the muon and pion kinematics, in the restricted phase space defined by pπ+>200 MeV/c, pμ>200 MeV/c, cos(θπ+)>0.3 and cos(θμ)>0.3. The total flux integrated νμ charged current single positive pion production cross section on water in the restricted phase space is measured to be ⟨σ⟩ϕ=4.25±0.48(stat)±1.56(syst)×10−40 cm2/nucleon. The total cross section is consistent with the NEUT prediction (5.03×10−40 cm2/nucleon) and 2σ lower than the GENIE prediction (7.68×10−40 cm2/nucleon). The differential cross sections are in good agreement with the NEUT generator. The GENIE simulation reproduces well the shapes of the distributions, but overestimates the overall cross section normalization.
Stowell P, Wret C, Wilkinson C, et al., 2017, NUISANCE: a neutrino cross-section generator tuning and comparison framework, Journal of Instrumentation, Vol: 12, ISSN: 1748-0221
NUISANCE is an open source C++ framework which facilitates detailed studies of neutrino interaction cross-section models implemented in Monte Carlo neutrino event generators. It provides a host of automated methods to perform comparisons of multiple generators to published cross-section measurements and each other. External reweighting libraries are used to allow the end-user to evaluate the impact of model parameters variations in the generators with data, or to tune the generator predictions to arbitrary dataset combinations. The design is modular and focusses on ease-of-use to allow new datasets and more generators to be added without requiring detailed understanding of the entire NUISANCE package. We discuss the motivation for the NUISANCE framework and suggested usage cases, alongside a description of its core structure.
Abe K, Andreopoulos C, Antonova M, et al., 2016, Measurement of coherent pi(+) production in low energy neutrino-carbon scattering, Physical Review Letters, Vol: 117, ISSN: 1079-7114
We report the first measurement of the flux-averaged cross section for charged current coherent π+production on carbon for neutrino energies less than 1.5 GeV, and with a restriction on the final state phase space volume in the T2K near detector, ND280. Comparisons are made with predictions from the Rein-Sehgal coherent production model and the model by Alvarez-Ruso et al., the latter representing the first implementation of an instance of the new class of microscopic coherent models in a neutrino interaction Monte Carlo event generator. We observe a clear event excess above background, disagreeing with the null results reported by K2K and SciBooNE in a similar neutrino energy region. The measured flux-averaged cross sections are below those predicted by both the Rein-Sehgal and Alvarez-Ruso et al. models.
Patrignani C, Agashe K, Aielli G, et al., 2016, Review of Particle Physics, Chinese Physics C, Vol: 40, ISSN: 1674-1137
The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 3,062 new measurements from 721 papers, we list, evaluate, and average measured properties of gauge bosons and the recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as Higgs Boson Physics, Supersymmetry, Grand Unified Theories, Neutrino Mixing, Dark Energy, Dark Matter, Cosmology, Particle Detectors, Colliders, Probability and Statistics. Among the 117 reviews are many that are new or heavily revised, including those on Pentaquarks and Inflation.The complete Review is published online in a journal and on the website of the Particle Data Group (http://pdg.lbl.gov). The printed PDG Book contains the Summary Tables and all review articles but no longer includes the detailed tables from the Particle Listings. A Booklet with the Summary Tables and abbreviated versions of some of the review articles is also available.
Lu XG, Pickering L, Dolan S, et al., 2016, Measurement of nuclear effects in neutrino interactions with minimal dependence on neutrino energy, Physical Review C, Vol: 94, ISSN: 1089-490X
We present a phenomenological study of nuclear effects in neutrino charged-current interactions, using transverse kinematic imbalances in exclusive measurements. Novel observables with minimal dependence on neutrino energy are proposed to study quasielastic scattering and especially resonance production. They should be able to provide direct constraints on nuclear effects in neutrino- and antineutrino-nucleus interactions.
Abe K, Andreopoulos C, Antonova M, et al., 2016, Measurement of double-differential muon neutrino charged-current interactions on C8H8 without pions in the final state using the T2K off-axis beam, Physcial Review D, Vol: 93, ISSN: 2470-0010
We show a practical implementation of a pulse characterization method for sub-cycle pulse measurements in the infrared spectral range based on spectral shearing interferometry. We employ spatially-encoded arrangement filter-based spectral phase interferometry for direct electric field reconstruction with external ancila pulses (X-SEA-F-SPIDER). We show merits and limitations of the setup and an in-depth comparison to another widely used temporal characterization technique - Second-Harmonic Generation Frequency Resolved Optical Gating (SHG-FROG). The X-SEA-F-SPIDER implementation presented in this paper allows measurement of sub-cycle pulses with over one octave wide spectrum spanning the 900–2400 nm range without adding any extra dispersion due to the pulse characterization apparatus.
Abe K, Andreopoulos C, Antonova M, et al., 2016, Measurement of Muon Antineutrino Oscillations with an Accelerator-Produced Off-Axis Beam, Physical Review Letters, Vol: 116, ISSN: 1079-7114
T2K reports its first measurements of the parameters governing the disappearance of ν¯μ in an off-axis beam due to flavor change induced by neutrino oscillations. The quasimonochromatic ν¯μ beam, produced with a peak energy of 0.6 GeV at J-PARC, is observed at the far detector Super-Kamiokande, 295 km away, where the ν¯μ survival probability is expected to be minimal. Using a data set corresponding to 4.01×1020 protons on target, 34 fully contained μ-like events were observed. The best-fit oscillation parameters are sin2(θ¯23)=0.45 and |Δm¯232|=2.51×10−3 eV2 with 68% confidence intervals of 0.38–0.64 and 2.26–2.80×10−3 eV2, respectively. These results are in agreement with existing antineutrino parameter measurements and also with the νμ disappearance parameters measured by T2K.
Wilkinson C, Terri R, Andreopoulos C, et al., 2016, Testing charged current quasi-elastic and multinucleon interaction models in the NEUT neutrino interaction generator with published datasets from the MiniBooNE and MINER nu A experiments, Physical Review D, Vol: 93, ISSN: 1550-7998
There has been a great deal of theoretical work on sophisticated charged current quasi-elastic (CCQE) neutrino interaction models in recent years, prompted by a number of experimental results that measured unexpectedly large CCQE cross sections on nuclear targets. As the dominant interaction mode at T2K energies, and the signal process in oscillation analyses, it is important for the T2K experiment to include realistic CCQE cross section uncertainties in T2K analyses. To this end, T2K’s Neutrino Interaction Working Group has implemented a number of recent models in NEUT, T2K’s primary neutrino interaction event generator. In this paper, we give an overview of the models implemented and present fits to published νμ and ν¯μ CCQE cross section measurements from the MiniBooNE and MINERνA experiments. The results of the fits are used to select a default cross section model for future T2K analyses and to constrain the cross section uncertainties of the model. We find strong tension between datasets for all models investigated. Among the evaluated models, the combination of a modified relativistic Fermi gas with multinucleon CCQE-like interactions gives the most consistent description of the available data.
Abe K, Andreopoulos C, Antonova M, et al., 2016, Measurement of the muon neutrino inclusive charged-current cross section in the energy range of 1–3 GeV with the T2K INGRID detector, Physical Review D, Vol: 93, ISSN: 1550-7998
We report a measurement of the νμ-nucleus inclusive charged-current cross section (=σcc) on iron using data from the INGRID detector exposed to the J-PARC neutrino beam. The detector consists of 14 modules in total, which are spread over a range of off-axis angles from 0° to 1.1°. The variation in the neutrino energy spectrum as a function of the off-axis angle, combined with event topology information, is used to calculate this cross section as a function of neutrino energy. The cross section is measured to be σcc(1.1 GeV)=1.10±0.15 (10−38 cm2/nucleon), σcc(2.0 GeV)=2.07±0.27 (10−38 cm2/nucleon), and σcc(3.3 GeV)=2.29±0.45 (10−38 cm2/nucleon), at energies of 1.1, 2.0, and 3.3 GeV, respectively. These results are consistent with the cross section calculated by the neutrino interaction generators currently used by T2K. More importantly, the method described here opens up a new way to determine the energy dependence of neutrino-nucleus cross sections.
Abe K, Adam J, Aihara H, et al., 2016, Upper bound on neutrino mass based on T2K neutrino timing measurements, Physical Review D, Vol: 93, ISSN: 1550-7998
The Tokai to Kamioka (T2K) long-baseline neutrino experiment consists of a muon neutrino beam, produced at the J-PARC accelerator, a near detector complex and a large 295-km-distant far detector. The present work utilizes the T2K event timing measurements at the near and far detectors to study neutrino time of flight as a function of derived neutrino energy. Under the assumption of a relativistic relation between energy and time of flight, constraints on the neutrino rest mass can be derived. The sub-GeV neutrino beam in conjunction with timing precision of order tens of ns provide sensitivity to neutrino mass in the few MeV/c2 range. We study the distribution of relative arrival times of muon and electron neutrino candidate events at the T2K far detector as a function of neutrino energy. The 90% C.L. upper limit on the mixture of neutrino mass eigenstates represented in the data sample is found to be m2ν<5.6 MeV2/c4.
Abe K, Adam J, Aihara H, et al., 2015, Measurement of the nu(mu) charged-current quasielastic cross section on carbon with the ND280 detector at T2K, Physical Review D, Vol: 92, ISSN: 1550-7998
This paper reports a measurement by the T2K experiment of the νμ charged current quasielastic (CCQE) cross section on a carbon target with the off-axis detector based on the observed distribution of muon momentum (pμ) and angle with respect to the incident neutrino beam (θμ). The flux-integrated CCQE cross section was measured to be ⟨σ⟩=(0.83±0.12)×10−38 cm2. The energy dependence of the CCQE cross section is also reported. The axial mass, MQEA, of the dipole axial form factor was extracted assuming the Smith-Moniz CCQE model with a relativistic Fermi gas nuclear model. Using the absolute (shape-only) pμ−cosθμ distribution, the effective MQEA parameter was measured to be 1.26+0.21−0.18 GeV/c2 (1.43+0.28−0.22 GeV/c2).
Abe K, Adam J, Aihara H, et al., 2015, Measurement of the electron neutrino charged-current interaction rate on water with the T2K ND280 pi(0) detector, Physical Review D, Vol: 91, ISSN: 1550-7998
This paper presents a measurement of the charged current interaction rate of the electron neutrino beam component of the beam above 1.5 GeV using the large fiducial mass of the T2K π0 detector. The predominant portion of the νe flux (∼85%) at these energies comes from kaon decays. The measured ratio of the observed beam interaction rate to the predicted rate in the detector with water targets filled is 0.89±0.08(stat)±0.11(sys), and with the water targets emptied is 0.90±0.09(stat)±0.13 (sys). The ratio obtained for the interactions on water only from an event subtraction method is 0.87±0.33(stat)±0.21(sys). This is the first measurement of the interaction rate of electron neutrinos on water, which is particularly of interest to experiments with water Cherenkov detectors.
Abe K, Adam J, Aihara H, et al., 2015, Measurement of the nu(mu) charged current quasielastic cross section on carbon with the T2K on-axis neutrino beam, Physical Review D, Vol: 91, ISSN: 1550-7998
We report a measurement of the νμ charged current quasielastic cross-sections on carbon in the T2K on-axis neutrino beam. The measured charged current quasielastic cross-sections on carbon at mean neutrino energies of 1.94 GeV and 0.93 GeV are (11.95±0.19(stat)+1.82−1.47(syst))×10−39 cm2/neutron, and (10.64±0.37(stat)+2.03−1.65(syst))×10−39 cm2/neutron, respectively. These results agree well with the predictions of neutrino interaction models. In addition, we investigated the effects of the nuclear model and the multi-nucleon interaction.
Abe K, Aihara H, Andreopoulos C, et al., 2015, Physics potential of a long-baseline neutrino oscillation experiment using a J-PARC neutrino beam and Hyper-Kamiokande, Progress of Theoretical and Experimental Physics, Vol: 2015, ISSN: 2050-3911
Hyper-Kamiokande will be a next-generation underground water Cherenkov detector with a total (fiducial) mass of 0.99 (0.56) million metric tons, approximately 20 (25) times larger than that of Super-Kamiokande. One of the main goals of Hyper-Kamiokande is the study of CPCP asymmetry in the lepton sector using accelerator neutrino and anti-neutrino beams. In this paper, the physics potential of a long-baseline neutrino experiment using the Hyper-Kamiokande detector and a neutrino beam from the J-PARC proton synchrotron is presented. The analysis uses the framework and systematic uncertainties derived from the ongoing T2K experiment. With a total exposure of 7.5 MW ×107×107s integrated proton beam power (corresponding to 1.56×10221.56×1022 protons on target with a 30 GeV proton beam) to a 2.5∘2.5∘ off-axis neutrino beam, it is expected that the leptonic CPCP phase δCPδCP can be determined to better than 19 degrees for all possible values of δCPδCP, and CPCP violation can be established with a statistical significance of more than 3σ3σ (5σ5σ) for 76%76% (58%58%) of the δCPδCP parameter space. Using both νeνe appearance and νμνμ disappearance data, the expected 1σσ uncertainty of sin2θ23sin2θ23 is 0.015(0.006) for sin2θ23=0.5(0.45)sin2θ23=0.5(0.45).
Collaboration T, Abe K, Adam J, et al., 2015, Measurements of neutrino oscillation in appearance and disappearance channels by the T2K experiment with 6.6E20 protons on target, Physical Review D, Vol: 91, ISSN: 1550-7998
We report on measurements of neutrino oscillation using data from the T2Klong-baseline neutrino experiment collected between 2010 and 2013. In ananalysis of muon neutrino disappearance alone, we find the following estimatesand 68% confidence intervals for the two possible mass hierarchies: Normal Hierarchy: $\sin^2\theta_{23}=0.514^{+0.055}_{-0.056}$ and $\Deltam^2_{32}=(2.51\pm0.10)\times 10^{-3}$ eV$^2$/c$^4$ Inverted Hierarchy: $\sin^2\theta_{23}=0.511\pm0.055$ and $\Deltam^2_{13}=(2.48\pm0.10)\times 10^{-3}$ eV$^2$/c$^4$ The analysis accounts for multi-nucleon mechanisms in neutrino interactionswhich were found to introduce negligible bias. We describe our first analyses that combine measurements of muon neutrinodisappearance and electron neutrino appearance to estimate four oscillationparameters and the mass hierarchy. Frequentist and Bayesian intervals arepresented for combinations of these parameters, with and without includingrecent reactor measurements. At 90% confidence level and including reactormeasurements, we exclude the region: $\delta_{CP}=[0.15,0.83]\pi$ for normal hierarchy and$\delta_{CP}=[-0.08,1.09]\pi$ for inverted hierarchy. The T2K and reactor data weakly favor the normal hierarchy with a BayesFactor of 2.2. The most probable values and 68% 1D credible intervals for theother oscillation parameters, when reactor data are included, are: $\sin^2\theta_{23}=0.528^{+0.055}_{-0.038}$ and $|\Deltam^2_{32}|=(2.51\pm0.11)\times 10^{-3}$ eV$^2$/c$^4$.
Abe K, Adam J, Aihara H, et al., 2015, Neutrino oscillation physics potential of the T2K experiment, Progress of Theoretical and Experimental Physics, Vol: 2015, ISSN: 2050-3911
The observation of the recent electron neutrino appearance in a muon neutrino beam and the high-precision measurement of the mixing angle θ13 have led to a re-evaluation of the physics potential of the T2K long-baseline neutrino oscillation experiment. Sensitivities are explored for CP violation in neutrinos, non-maximal sin22θ23, the octant of θ23, and the mass hierarchy, in addition to the measurements of δCP, sin2θ23, and Δm232, for various combinations of ν-mode and ν¯-mode data-taking.With an exposure of 7.8×1021protons-on-target, T2K can achieve 1σ resolution of 0.050 (0.054) on sin2θ23 and 0.040 (0.045)×10−3eV2 on Δm232 for 100% (50%) neutrino beam mode running assuming sin2θ23=0.5 and Δm232=2.4×10−3eV2. T2K will have sensitivity to the CP-violating phase δCP at 90% C.L. or better over a significant range. For example, if sin22θ23 is maximal (i.e. θ23=45∘) the range is −115∘<δCP<−60∘ for normal hierarchy and +50∘<δCP<+130∘ for inverted hierarchy. When T2K data is combined with data from the NOνA experiment, the region of oscillation parameter space where there is sensitivity to observe a non-zero δCP is substantially increased compared to if each experiment is analyzed alone.
Abe K, Adam J, Aihara H, et al., 2015, Search for short baseline nu(e) disappearance with the T2K near detector, Physical Review D - Particles, Fields, Gravitation and Cosmology, Vol: 91, ISSN: 1550-2368
The T2K experiment has performed a search for νe disappearance due to sterile neutrinos using 5.9×1020 protons on target for a baseline of 280 m in a neutrino beam peaked at about 500 MeV. A sample of νe CC interactions in the off-axis near detector has been selected with a purity of 63% and an efficiency of 26%. The p-value for the null hypothesis is 0.085 and the excluded region at 95% C.L. is approximately sin22θee>0.3 for Δm2eff>7 eV2/c4.
Aguilar-Arevalo AA, Brown BC, Bugel L, et al., 2015, Measurement of the antineutrino neutral-current elastic differential cross section, Physical Review D - Particles, Fields, Gravitation and Cosmology, Vol: 91, ISSN: 1550-2368
We report the measurement of the flux-averaged antineutrino neutral current elastic scattering cross section (dσ¯νN→¯νN/dQ2) on CH2 by the MiniBooNE experiment using the largest sample of antineutrino neutral current elastic candidate events ever collected. The ratio of the antineutrino to neutrino neutral current elastic scattering cross sections and a ratio of the antineutrino neutral current elastic to antineutrino charged current quasielastic cross sections are also presented.
Abe K, Adam J, Aihara H, et al., 2014, Measurement of the Inclusive Electron Neutrino Charged Current Cross Section on Carbon with the T2K Near Detector, PHYSICAL REVIEW LETTERS, Vol: 113, ISSN: 0031-9007
- Author Web Link
- Open Access Link
- Cite
- Citations: 40
Abe K, Adam J, Aihara H, et al., 2014, Measurement of the neutrino-oxygen neutral-current interaction cross section by observing nuclear deexcitation gamma rays, Physical Review D - Particles, Fields, Gravitation and Cosmology, Vol: 90, ISSN: 1550-2368
We report the first measurement of the neutrino-oxygen neutral-current quasielastic (NCQE) cross section. It is obtained by observing nuclear deexcitation γ rays which follow neutrino-oxygen interactions at the Super-Kamiokande water Cherenkov detector. We use T2K data corresponding to 3.01×1020 protons on target. By selecting only events during the T2K beam window and with well-reconstructed vertices in the fiducial volume, the large background rate from natural radioactivity is dramatically reduced. We observe 43 events in the 4–30 MeV reconstructed energy window, compared with an expectation of 51.0, which includes an estimated 16.2 background events. The background is primarily nonquasielastic neutral-current interactions and has only 1.2 events from natural radioactivity. The flux-averaged NCQE cross section we measure is 1.55×10−38 cm2 with a 68% confidence interval of (1.22,2.20)×10−38 cm2 at a median neutrino energy of 630 MeV, compared with the theoretical prediction of 2.01×10−38 cm2.
Abe K, Adam J, Aihara H, et al., 2014, Measurement of the inclusive nu(mu) charged current cross section on iron and hydrocarbon in the T2K on-axis neutrino beam, Physical Review D - Particles, Fields, Gravitation and Cosmology, Vol: 90, ISSN: 1550-2368
We report a measurement of the νμ inclusive charged current cross sections on iron and hydrocarbon in the Tokai-to-Kamioka (T2K) on-axis neutrino beam. The measured inclusive charged current cross sections on iron and hydrocarbon averaged over the T2K on-axis flux with a mean neutrino energy of 1.51 GeV are (1.444±0.002(stat)+0.189−0.157(syst))×10−38 cm2/nucleon and (1.379±0.009(stat)+0.178−0.147(syst))×10−38 cm2/nucleon, respectively, and their cross-section ratio is 1.047±0.007(stat)±0.035(syst). These results agree well with the predictions of the neutrino interaction model, and thus we checked the correct treatment of the nuclear effect for iron and hydrocarbon targets in the model within the measurement precisions.
Abe K, Adam J, Aihara H, et al., 2014, Precise measurement of the neutrino mixing parameter theta(23) from muon neutrino disappearance in an off-axis beam, Physical Review Letters, Vol: 112, ISSN: 0031-9007
New data from the T2K neutrino oscillation experiment produce the most precise measurement of the neutrino mixing parameter θ23. Using an off-axis neutrino beam with a peak energy of 0.6 GeV and a data set corresponding to 6.57×10 20 protons on target, T2K has fit the energy-dependent νμ oscillation probability to determine oscillation parameters. The 68% confidence limit on sin 2(θ23) is 0.514+0.055−0.056 (0.511±0.055), assuming normal (inverted) mass hierarchy. The best-fit mass-squared splitting for normal hierarchy is Δm2 32= (2.51±0.10)×10−3eV2/c4 (inverted hierarchy: Δm2 13= (2.48±0.10)×10−3eV2/c4). Adding a model of multinucleon interactions that affect neutrino energy reconstruction is found to produce only small biases in neutrino oscillation parameter extraction at current levels of statistical uncertainty.
Abe K, Adam J, Aihara H, et al., 2014, Measurement of the intrinsic electron neutrino component in the T2K neutrino beam with the ND280 detector, PHYSICAL REVIEW D, Vol: 89, ISSN: 1550-7998
- Author Web Link
- Cite
- Citations: 22
Adey D, Agarwalla SK, Ankenbrandt CM, et al., 2014, Light sterile neutrino sensitivity at the nuSTORM facility, Physical Review D: Particles, Fields, Gravitation and Cosmology, Vol: 89, ISSN: 1550-7998
A facility that can deliver beams of electron and muon neutrinos from the decay of a stored muon beam has the potential to unambiguously resolve the issue of the evidence for light sterile neutrinos that arises in short-baseline neutrino oscillation experiments and from estimates of the effective number of neutrino flavors from fits to cosmological data. In this paper, we show that the nuSTORM facility, with stored muons of 3.8 GeV/c ± 10%, will be able to carry out a conclusive muon neutrino appearance search for sterile neutrinos and test the LSND and MiniBooNE experimental signals with 10σ sensitivity, even assuming conservative estimates for the systematic uncertainties. This experiment would add greatly to our knowledge of the contribution of light sterile neutrinos to the number of effective neutrino flavors from the abundance of primordial helium production and from constraints on neutrino energy density from the cosmic microwave background. The appearance search is complemented by a simultaneous muon neutrino disappearance analysis that will facilitate tests of various sterile neutrino models.
Abe K, Adam J, Aihara H, et al., 2014, Observation of electron neutrino appearance in a muon neutrino beam, Physical Review Letters, Vol: 112, ISSN: 0031-9007
The T2K experiment has observed electron neutrino appearance in a muon neutrino beam produced 295 km from the Super-Kamiokande detector with a peak energy of 0.6 GeV. A total of 28 electron neutrino events were detected with an energy distribution consistent with an appearance signal, corresponding to a significance of 7.3σ when compared to 4.92±0.55 expected background events. In the Pontecorvo-Maki-Nakagawa-Sakata mixing model, the electron neutrino appearance signal depends on several parameters including three mixing angles θ12, θ23, θ13, a mass difference Δm232 and a CP violating phase δCP. In this neutrino oscillation scenario, assuming |Δm232|=2.4×10−3 eV2, sin2θ23=0.5, and Δm232>0 (Δm232<0), a best-fit value of sin22θ13=0.140+0.038−0.032 (0.170+0.045−0.037) is obtained at δCP=0. When combining the result with the current best knowledge of oscillation parameters including the world average value of θ13 from reactor experiments, some values of δCP are disfavored at the 90% C.L
Uchida Y, 2013, Measurement of neutrino oscillation parameters from muon neutrino disappearance with an off-axis beam, Physical Review Letters, Vol: 111, ISSN: 0031-9007
Allan D, Andreopoulos C, Angelsen C, et al., 2013, The electromagnetic calorimeter for the T2K near detector ND280, JOURNAL OF INSTRUMENTATION, Vol: 8, ISSN: 1748-0221
- Author Web Link
- Cite
- Citations: 49
Abe K, Abgrall N, Aihara H, et al., 2013, Evidence of electron neutrino appearance in a muon neutrino beam, PHYSICAL REVIEW D, Vol: 88, ISSN: 1550-7998
- Author Web Link
- Open Access Link
- Cite
- Citations: 133
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.