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Title: To catch a solar neutrino, search at night

Abstract

No abstract prepared.

Authors:
Publication Date:
OSTI Identifier:
22257027
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics Today; Journal Volume: 67; Journal Issue: 4; Other Information: (c) 2014 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTRONOMY; ASTROPHYSICS; COSMOLOGY; PARTICLE PROPERTIES; SOLAR NEUTRINOS

Citation Formats

Blau, Steven K. To catch a solar neutrino, search at night. United States: N. p., 2014. Web. doi:10.1063/PT.3.2338.
Blau, Steven K. To catch a solar neutrino, search at night. United States. doi:10.1063/PT.3.2338.
Blau, Steven K. Tue . "To catch a solar neutrino, search at night". United States. doi:10.1063/PT.3.2338.
@article{osti_22257027,
title = {To catch a solar neutrino, search at night},
author = {Blau, Steven K.},
abstractNote = {No abstract prepared.},
doi = {10.1063/PT.3.2338},
journal = {Physics Today},
number = 4,
volume = 67,
place = {United States},
year = {Tue Apr 01 00:00:00 EDT 2014},
month = {Tue Apr 01 00:00:00 EDT 2014}
}
  • Searches for possible day-night and semiannual variations of the {sup 8}B solar neutrino flux are reported based on 1040 days of Kamiokande-II data. Within statistical error, no such short-time variations were observed. The limit on the day-night difference sets a constraint on neutrino-oscillation parameters. A region defined by sin{sup 2}2{theta}{gt}0.02 and 2{times}10{sup {minus}6}{approx lt}{Delta}{ital m}{sup 2}{approx lt}10{sup {minus}5} eV{sup 2} is excluded at 90% C.L. without any assumption on the absolute value of the expected solar neutrino flux.
  • Calculations are presented to show how large a day-night effect would be seen in appropriately modified radiochemical detectors for the [Delta][ital m][sup 2], sin[sup 2]2[theta] regions allowed by the present gallium, [sup 37]Cl, and Kamiokande solar neutrino results.
  • This is the first of two articles aimed at providing comprehensive predictions for the day-night (D-N) effect for the Super-Kamiokande detector in the case of the Mikheyev-Smirnov-Wolfenstein (MSW) {nu}{sub e}{r_arrow}{nu}{sub {mu}({tau})} transition solution of the solar neutrino problem. The one-year-averaged probability of survival of the solar {nu}{sub e} crossing the Earth{close_quote}s mantle, the core, the inner 2/3 of the core, and the (core+mantle) is calculated with high precision (better than 1{percent}) using the elliptical orbit approximation to describe the Earth{close_quote}s motion around the Sun. Results for the survival probability in the indicated cases are obtained for a large set ofmore » values of the MSW transition parameters {Delta}m{sup 2} and sin{sup 2}2{theta}{sub V} from the {open_quotes}conservative{close_quotes} regions of the MSW solution, derived by taking into account possible relatively large uncertainties in the values of the {sup 8}B and {sup 7}Be neutrino fluxes. Our results show that the one-year-averaged D-N asymmetry in the {nu}{sub e} survival probability for neutrinos crossing the Earth{close_quote}s core can be, in the case of sin{sup 2}2{theta}{sub V}{le}0.013, larger than the asymmetry in the probability for (only mantle crossing+core crossing) neutrinos by a factor of up to 6. The enhancement is larger in the case of neutrinos crossing the inner 2/3 of the core. This indicates that the Super-Kamiokande experiment might be able to test the sin{sup 2}2{theta}{sub V}{le}0.01 region of the MSW solution of the solar neutrino problem by performing selective D-N asymmetry measurements. {copyright} {ital 1997} {ital The American Physical Society}« less
  • If neutrino oscillations in the solar interior are responsible for the suppressed /sup 8/B solar-neutrino flux measured by the Homestake /sup 37/Cl detector, then for certain values of neutrino mass difference and mixing angle, distinct day-night differences in the counting rate are expected due to propagation effects in the Earth. We describe the plans to measure day-night variations with the /sup 37/Cl detector, and present the results of calculations of /sup 37/Cl detector sensitivity and expected results.
  • Results are reported from the complete salt phase of the Sudbury Neutrino Observatory experiment in which NaCl was dissolved in the {sup 2}H{sub 2}O (''D{sub 2}O'') target. The addition of salt enhanced the signal from neutron capture as compared to the pure D{sub 2}O detector. By making a statistical separation of charged-current events from other types based on event-isotropy criteria, the effective electron recoil energy spectrum has been extracted. In units of 10{sup 6}cm{sup -2}s{sup -1}, the total flux of active-flavor neutrinos from {sup 8}B decay in the Sun is found to be 4.94{sub -0.21}{sup +0.21}(stat){sub -0.34}{sup +0.38}(syst) and themore » integral flux of electron neutrinos for an undistorted {sup 8}B spectrum is 1.68{sub -0.06}{sup +0.06}(stat){sub -0.09}{sup +0.08}(syst); the signal from ({nu}{sub x},e) elastic scattering is equivalent to an electron-neutrino flux of 2.35{sub -0.22}{sup +0.22}(stat){sub -0.15}{sup +0.15}(syst). These results are consistent with those expected for neutrino oscillations with the so-called large mixing angle parameters and also with an undistorted spectrum. A search for matter-enhancement effects in the Earth through a possible day-night asymmetry in the charged-current integral rate is consistent with no asymmetry. Including results from other experiments, the best-fit values for two-neutrino mixing parameters are {delta}m{sup 2}=(8.0{sub -0.4}{sup +0.6})x10{sup -5} eV{sup 2} and {theta}=33.9{sub -2.2}{sup +2.4} degrees.« less