Re-evaluation of the T2KK physics potential with simulations including backgrounds

2009/01/12 by Kaoru Hagiwara, Naotoshi Okamura · 2 citations
Physics and Astronomy · #Neutrino Physics Research #Particle physics theoretical and experimental studies #Radioactive Decay and Measurement Techniques #hep-ph

paper · pdf · doi:10.1088/1126-6708/2009/07/031

published as JHEP 0907:031,2009 · 46 pages, 13 figures

arxiv created 2009/01/12 · openalex publication_date 2009/07/09 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28

Abstract

The Tokai-to-Kamioka-and-Korea (T2KK) neutrino oscillation experiment under examination can have a high sensitivity to determine the neutrino mass hierarchy for a combination of relatively large (∼ 3.0^circ) off-axis angle beam at Super-Kamiokande (SK) and small (∼ 0.5^circ) off-axis angle at L ∼ 1,000km in Korea. We elaborate previous studies by taking into account smearing of reconstructed neutrino energy due to finite resolution of electron or muon energies, nuclear Fermi motion and resonance production, as well as the neutral current π⁰ production background to the nu_mu to nu_e oscillation signal. It is found that the mass hierarchy pattern can still be determined at 3sigma level if sin²2thata_rct \quiv 4|U_e3|²(1-|U_e3|²) \gsim 0.08(0.09) when the hierarchy is normal (inverted) with 5 ×10²¹ POT exposure, or 5 years of the T2K experiment, if a 100kton water cherenkov detector is placed in Korea. The π⁰ backgrounds deteriorate the capability of the mass hierarchy determination, whereas the events from nuclear resonance productions contribute positively to the hierarchy discrimination power. We also find that the π⁰ backgrounds seriously affect the CP phase measurement. Although δ_mns can still be constrained with an accuracy of ∼ ± 45^circ (± 60^circ) at 1sigma level for the normal (inverted) hierarchy with the above exposure if sin²2theta_rct \gsim 0.04, CP violation can no longer be established at 3sigma level even for delta_mns=± 90^circ and sin²2theta_rct=0.1. About four times higher exposure will be needed to measure delta_mns with ± 30^circ accuracy.

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