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Title: Search for atmospheric neutrino oscillations with the Soudan 2 detector

Abstract

Underground proton decay detectors record a sizeable number of atmospheric neutrino-induced events. These neutrinos come primarily from the decay of pions and muons produced in cosmic ray showers in the earth's atmosphere. The expected flux ratio of muon neutrinos to electron neutrinos traversing an underground detector, {nu}{mu}/{nu}{sub e}, is about 2. The combined effects of detector systematics and nuclear cross section differences between {nu}{sub mu} and {nu}{sub e} interactions typically reduce the measured {nu}{sub mu}/{nu}{sub 3} event ratio to about 1. Over the last decade, both the Kamioka detector in Japan and the IMB detector in the United States have made high-statistics measurements of the atmospheric neutrino event ratio. Both groups have presented strong experimental evidence that the underground {nu}{sub mu}/{nu}{sub e} event ratio is substantially smaller than predicted. In both cases, a statistically significant deficit of muon neutrino-induced events is measured. One possible explanation of the muon neutrino deficit is that these neutrinos are undergoing flavor oscillations between their production points in the atmosphere and their interaction points in underground detectors. An MSW effect interpretation of solar neutrino experiments implies a {nu}{sub e} {yields} {nu}{sub mu} oscillation region in {delta}m{sup 2}-sin{sup 2}(2{theta}) space at least two orders of magnitudemore » lower in {delta}m{sup 2} than the best fit point of the Kamioka result. It is therefore usually assumed that the relevant flavor oscillation for atmospheric muon neutrinos would be {nu}{sub mu} {yields} {nu}{sub r}. The Soudan 2 nucleon decay detector is now approaching completion and collecting data. It will be able to make low-background measurements of atmospheric neutrinos in the next few years to check the possibility that atmospheric neutrinos undergo detectable flavor oscillations.« less

Authors:
 [1]
  1. Minnesota Univ., Minneapolis, MN (United States)
Publication Date:
Research Org.:
Argonne National Lab., IL (United States). High Energy Physics Div.
Sponsoring Org.:
USDOE; USDOE, Washington, DC (United States)
OSTI Identifier:
5748596
Report Number(s):
ANL-HEP-CP-92-03; CONF-9111141-3
ON: DE92007397
DOE Contract Number:  
W-31109-ENG-38
Resource Type:
Conference
Resource Relation:
Conference: Workshop on long-baseline neutrino oscillations, Batavia, IL (United States), 17-20 Nov 1991
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; NEUTRINO OSCILLATION; NEUTRINO DETECTION; NEUTRINOS; MONTE CARLO METHOD; SHOWER COUNTERS; DETECTION; ELEMENTARY PARTICLES; FERMIONS; LEPTONS; MASSLESS PARTICLES; MEASURING INSTRUMENTS; RADIATION DETECTION; RADIATION DETECTORS; 662320* - Neutrino Interactions- (1992-); 440104 - Radiation Instrumentation- High Energy Physics Instrumentation

Citation Formats

Roback, D M. Search for atmospheric neutrino oscillations with the Soudan 2 detector. United States: N. p., 1992. Web.
Roback, D M. Search for atmospheric neutrino oscillations with the Soudan 2 detector. United States.
Roback, D M. 1992. "Search for atmospheric neutrino oscillations with the Soudan 2 detector". United States. https://www.osti.gov/servlets/purl/5748596.
@article{osti_5748596,
title = {Search for atmospheric neutrino oscillations with the Soudan 2 detector},
author = {Roback, D M},
abstractNote = {Underground proton decay detectors record a sizeable number of atmospheric neutrino-induced events. These neutrinos come primarily from the decay of pions and muons produced in cosmic ray showers in the earth's atmosphere. The expected flux ratio of muon neutrinos to electron neutrinos traversing an underground detector, {nu}{mu}/{nu}{sub e}, is about 2. The combined effects of detector systematics and nuclear cross section differences between {nu}{sub mu} and {nu}{sub e} interactions typically reduce the measured {nu}{sub mu}/{nu}{sub 3} event ratio to about 1. Over the last decade, both the Kamioka detector in Japan and the IMB detector in the United States have made high-statistics measurements of the atmospheric neutrino event ratio. Both groups have presented strong experimental evidence that the underground {nu}{sub mu}/{nu}{sub e} event ratio is substantially smaller than predicted. In both cases, a statistically significant deficit of muon neutrino-induced events is measured. One possible explanation of the muon neutrino deficit is that these neutrinos are undergoing flavor oscillations between their production points in the atmosphere and their interaction points in underground detectors. An MSW effect interpretation of solar neutrino experiments implies a {nu}{sub e} {yields} {nu}{sub mu} oscillation region in {delta}m{sup 2}-sin{sup 2}(2{theta}) space at least two orders of magnitude lower in {delta}m{sup 2} than the best fit point of the Kamioka result. It is therefore usually assumed that the relevant flavor oscillation for atmospheric muon neutrinos would be {nu}{sub mu} {yields} {nu}{sub r}. The Soudan 2 nucleon decay detector is now approaching completion and collecting data. It will be able to make low-background measurements of atmospheric neutrinos in the next few years to check the possibility that atmospheric neutrinos undergo detectable flavor oscillations.},
doi = {},
url = {https://www.osti.gov/biblio/5748596}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jan 20 00:00:00 EST 1992},
month = {Mon Jan 20 00:00:00 EST 1992}
}

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