|
T2K Collaboration(Abe, K. et al), Cervera-Villanueva, A., Escudero, L., Izmaylov, A., Sorel, M., & Stamoulis, P. (2015). Neutrino oscillation physics potential of the T2K experiment. Prog. Theor. Exp. Phys., (4), 043C01–36pp.
Abstract: The observation of the recent electron neutrino appearance in a muon neutrino beam and the high-precision measurement of the mixing angle theta(13) 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 sin(2) 2 theta(23), the octant of theta(23), and the mass hierarchy, in addition to the measurements of delta CP, sin(2) theta(23), and Delta m(32)(2), for various combinations of nu-mode and (nu) over bar -mode data-taking. With an exposure of 7.8 x 10(21) protons-on-target, T2K can achieve 1 sigma resolution of 0.050 (0.054) on sin(2) theta(23) and 0.040 (0.045) x 10(-3) eV(2) on Delta m(32)(2) for 100% (50%) neutrino beam mode running assuming sin(2) theta(23) = 0.5 and Delta m(32)(2) = 2.4 x 10(-3) eV(2). T2K will have sensitivity to the CP-violating phase delta(CP) at 90% C.L. or better over a significant range. For example, if sin(2) 2 theta(23) is maximal (i.e.theta(23) = 45 degrees) the range is -115 degrees < delta(CP) < -60 degrees for normal hierarchy and +50 degrees < delta(CP) < + 130 degrees for inverted hierarchy. When T2K data is combined with data from the NO nu A experiment, the region of oscillation parameter space where there is sensitivity to observe a non-zero delta CP is substantially increased compared to if each experiment is analyzed alone.
|
|
|
T2K Collaboration(Abe, K. et al), Cervera-Villanueva, A., Escudero, L., Izmaylov, A., Sorel, M., & Stamoulis, P. (2015). Measurement of the electron neutrino charged-current interaction rate on water with the T2K ND280 pi(0) detector. Phys. Rev. D, 91(11), 112010–11pp.
Abstract: 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 pi(0) detector. The predominant portion of the v(e) flux (similar to 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.
|
|
|
T2K Collaboration(Abe, K. et al), Cervera-Villanueva, A., Escudero, L., Izmaylov, A., Sorel, M., & Stamoulis, P. (2015). Measurement of the nu(mu) charged-current quasielastic cross section on carbon with the ND280 detector at T2K. Phys. Rev. D, 92(11), 112003–14pp.
Abstract: This paper reports a measurement by the T2K experiment of the nu(mu) charged current quasielastic (CCQE) cross section on a carbon target with the off-axis detector based on the observed distribution of muon momentum (rho(mu)) and angle with respect to the incident neutrino beam (theta(mu)). The flux-integrated CCQE cross section was measured to be <sigma > = (0.83 +/- 0.12) x 10(-38) cm(2). The energy dependence of the CCQE cross section is also reported. The axial mass, M-A(QE), 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) rho(mu)-cos theta(mu) distribution, the effective M-A(QE) parameter was measured to be 1.26(-0.18)(+0.21) GeV/c(2) (1.43(-0.22)(+0.28) GeV/c(2)).
|
|
|
T2K Collaboration(Abe, K. et al), Cervera-Villanueva, A., Escudero, L., Izmaylov, A., Sorel, M., & Stamoulis, P. (2016). Upper bound on neutrino mass based on T2K neutrino timing measurements. Phys. Rev. D, 93(1), 012006–15pp.
Abstract: 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/c(2) 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 m(v)(2) < 5.6 MeV2/c(4).
|
|
|
T2K Collaboration(Abe, K. et al), Cervera-Villanueva, A., Izmaylov, A., Sorel, M., & Stamoulis, P. (2016). Measurement of the muon neutrino inclusive charged-current cross section in the energy range of 1-3 GeV with the T2K INGRID detector. Phys. Rev. D, 93(7), 072002–23pp.
Abstract: We report a measurement of the nu(mu)-nucleus inclusive charged-current cross section (= sigma(cc)) 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 degrees to 1.1 degrees. 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 sigma(cc) (1.1 GeV) = 1.10 +/- 0.15 (10(-38) cm(2)/nucleon), sigma(cc) (2.0 GeV) = 2.07 +/- 0.27 (10(-38) cm(2)/nucleon), and sigma(cc) (3.3 GeV) = 2.29 +/- 0.45 (10(-38) cm(2)/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.
|
|