The rate of neutrino-electron elastic scattering interactions from 862 keV Be7 solar neutrinos in Borexino is determined to be 46.0±1.5(stat)+1.5−1.6(syst) counts/(day⋅100 ton). This corresponds to a νe-equivalent Be7 solar neutrino flux of (3.10±0.15)×10+9 cm−2 s−1 and, under the assumption of νe transition to other active neutrino flavours, yields an electron neutrino survival probability of 0.51±0.07 at 862 keV. The no flavor change hypothesis is ruled out at 5.0 σ. A global solar neutrino analysis with free fluxes determines Φpp=6.06+0.02−0.06×1010 cm−2 s−1 and ΦCNO<1.3×10+9 cm−2 s−1 (95% C.L.). These results significantly improve the precision with which the Mikheyev-Smirnov-Wolfenstein large mixing angle neutrino oscillation model is experimentally tested at low energy.
Precision measurement of the 7Be solar neutrino interaction rate in Borexino
ORTICA, Fausto;ROMANI, Aldo;
2011
Abstract
The rate of neutrino-electron elastic scattering interactions from 862 keV Be7 solar neutrinos in Borexino is determined to be 46.0±1.5(stat)+1.5−1.6(syst) counts/(day⋅100 ton). This corresponds to a νe-equivalent Be7 solar neutrino flux of (3.10±0.15)×10+9 cm−2 s−1 and, under the assumption of νe transition to other active neutrino flavours, yields an electron neutrino survival probability of 0.51±0.07 at 862 keV. The no flavor change hypothesis is ruled out at 5.0 σ. A global solar neutrino analysis with free fluxes determines Φpp=6.06+0.02−0.06×1010 cm−2 s−1 and ΦCNO<1.3×10+9 cm−2 s−1 (95% C.L.). These results significantly improve the precision with which the Mikheyev-Smirnov-Wolfenstein large mixing angle neutrino oscillation model is experimentally tested at low energy.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
