Future Long-Baseline Neutrino Facilities and Detectors

Table 8

Physics targets and expected sensitivities of the hyper-Kamiokande experiment updated from [2]. 𝜎_SD is the WIMP-proton spin-dependent cross-section.

Physics target	Sensitivity	Conditions
Neutrino study w/J-PARC 𝜈
(i) CP phase precision	<20°	at 𝑠^22𝜃13(≡sin^22𝜃13)>0.03 and
		mass hierarchy (MH) is known
(ii) CPV 3𝜎 discovery coverage	74%	at 𝑠^22𝜃13=0.1, 7.5 MW⋅yrs
		MH known
	54%	at 𝑠^22𝜃13=0.1, 7.5 MW⋅yrs
		MH unknown
	69%	at 𝑠^22𝜃13=0.1, 3.75 MW⋅yrs
		MH known
	42%	at 𝑠^22𝜃13=0.1, 3.75 MW⋅yrs
		MH unknown
Atmospheric neutrino study		10-year observation
(i) MH determination	>3𝜎 CL	at 0.4<𝑠^2𝜃23 and 0.04<𝑠^22𝜃13
(ii) 𝜃23 octant determination	>90% CL	at 𝑠^22𝜃23<0.99 and 0.04<𝑠^22𝜃13
Nucleon decay searches		10 years data
(i) 𝑝→𝑒^++𝜋^0	1.3×10^35 yrs (90% CL)
	5.7×10^34 yrs (3𝜎 CL)
(ii) 𝑝→𝜈+𝐾^+	2.5×10^34 yrs (90% CL)
	1.0×10^34 yrs (3𝜎 CL)
Solar neutrinos
(i) 8B 𝜈 from Sun	200 𝜈’s/day	7.0 MeV threshold (total energy)
(ii) 8B 𝜈 day/night accuracy	<1%	5 years, only stat. error
Astrophysical objects
(i) Supernova burst 𝜈	170,000–260,000 𝜈’s	at Galactic center (10 kpc)
	30–50 𝜈’s	at M31 (Andromeda galaxy)
(ii) Supernova relic 𝜈	300 𝜈’s/10 years	>20 MeV
(iii) WIMP annihilation at Sun		5-year observation
	𝜎SD=10^−39 cm^2	at 𝑀WIMP=10 GeV
		𝜒𝜒→𝑏𝑏 dominant
	𝜎SD=10^−40 cm^2	at 𝑀WIMP=100 GeV
		𝜒𝜒→𝑊^+𝑊^− dominant