A Long Baseline Neutrino Oscillation Experiment Using J-PARC Neutrino Beam and Hyper-Kamiokande

Abstract

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 CP asymmetry in the lepton sector using accelerator neutrino and anti-neutrino beams.In this document, 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 has been updated from the previous Letter of Intent [K. Abe et al., arXiv:1109.3262 [hepex]], based on the experience gained from the ongoing T2K experiment. With a total exposure of 7.5 MW × 10 7 sec integrated proton beam power (corresponding to 1.56 × 10 22 protons on target with a 30 GeV proton beam) to a 2.5-degree off-axis neutrino beam produced by the J-PARC proton synchrotron, it is expected that the CP phase δCP can be determined to better than 19 degrees for all possible values of δCP , and CP violation can be established with a statistical significance of more than 3 σ (5 σ) for 76% (58%) of the δCP parameter space.

Effects of neutrino magnetic moment and charge radius constraints and medium modifications of the nucleon form factors on the neutrino mean free path in dense matter

“…Beside the evidence for neutrino magnetic moment (NMM), the square charge radius for electron neutrino has been reported by LAMPF (Los Alamos Meson Physics Facility) experiment with R 2 = (0.9 ± 2.7) × 10 −32 cm 2 = (22.5±67.5)×10 −12 MeV 2 [4], while the plasmon decay in the globular cluster star predicts the limit of e v ≤ 2×10 −14 e, where e is the electron charge [2]. Other recent experimental evidence are of the solar [5][6][7], atmospheric [8][9][10][11][12], and long baseline accelerator and reactor neutrinos of neutrino flavor oscillations [13][14][15][16] as well as Supernova SN 1987a Observations [17][18][19]. They clearly show that neutrinos are massive and have finite magnetic moments and charge radii and hence, the SM has to be extended to accommodate the neutrino mass generation.…”

A Return To Neutrino Normalcy

“…The poorest measured oscillation parameters are θ 23 and δ which govern essentially all of the remaining uncertainty in the normalcy conditions. DUNE and T2HK both expect to measure θ 23 with < ∼ 1 • resolution and δ should be measured with ∼ 10 − 15 • precision from each experiment alone [12,13]. It may be the case that some of these inequalities may be close enough together to make a determination on normalcy quite difficult.…”

“…In most cases where normalcy can be tested given currently available data, the data prefers the normal case over the non-normal case. Next generation oscillation experiments such as DUNE and T2HK [12,13] are necessary and should be sufficient to determine if all the normalcy conditions are simultaneously satisfied or not.…”

Magic neutrino mass model with broken $μ-τ$ symmetry and Leptogenesis

“…The answers to first three questions are(will be) investigated in present(future) neutrino oscillation experiments like India-Based Neutrino Observatory(INO) [10], Deep Underground Neutrino Experiment(DUNE) [11], T2HK [12] and NOνA [13] etc. whereas direct search neutrino-mass-experiments [14,15] and lepton number violating processes like 0νββ decay will probe the answers to remaining two questions.…”