Acquiring information about neutrino parameters by detecting supernova neutrinos

Abstract

We consider the supernova shock effects, the Mikheyev-Smirnov-Wolfenstein effects, the collective effects, and the Earth matter effects in the detection of type II supernova neutrinos on the Earth. It is found that the event number of supernova neutrinos depends on the neutrino mass hierarchy, the neutrino mixing angle 13 , and neutrino masses. Therefore, we propose possible methods to identify the mass hierarchy and acquire information about 13 and neutrino masses by detecting supernova neutrinos. We apply these methods to some current neutrino experiments.

Detection of supernova neutrinos at spallation neutron sources

“…2 shows the path of SN neutrinos reaching the detector on the Earth. When all effects, including the SN shock effects, the MSW effects, the neutrino collective effects, and the Earth matter effects, are taken into account, the SN neutrino fluxes at the detector can be written as [26]…”

“…In Eqs. ( 2) and (3), P 2e ( P2e ) is the probability that a (anti)neutrino mass eigenstate ν 2 (ν 2 ) enters the surface of the Earth and arrives at the detector as an electron (anti)neutrino ν e (ν e ), P νν ( Pνν ) is the probability that the (anti)neutrino ν(ν) remains as ν(ν) after the collective effects, and P H ( PH ) is the crossing probability for (anti)neutrinos to jump from one eigenstate to another at the high resonance layer [26]. We assume a "standard" SN explosion at a distance D = 10 kpc from the Earth, releasing a total energy E B = 3 × 10 53 erg (similar to SN1987A [4,5]).…”

“…1(a). While considering the SN shock effects [12][13][14][15], the Mikheyev-Smirnov-Wolfenstein (MSW) effects [16][17][18][19], the neutrino collective effects [20][21][22], and the Earth matter effects [23][24][25], the detection of SN neutrinos on the Earth was studied [26]. Then, the energy spectra of SN neutrinos can be calculated, as shown in Fig.…”

Detection of Supernova Neutrinos on the Earth for Large θ 13

“…A summary for neutrino flavor conversions due to the neutrino shock wave effects and the MSW effects in various density regions is given in Table II [10].…”

“…In addition, the shock wave effects may change the density distribution of SN and the position of the high resonance. The expression of P H for large θ 13 needs to be developed [10][19] [25]. When studying the Earth matter effects, the realistic density distribution of the Earth needs to be considered [26][27].…”