skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Improved Search for {nu}{sub {mu}}{yields}{nu}{sub e} Oscillation in a Long-Baseline Accelerator Experiment

Abstract

We performed an improved search for {nu}{sub {mu}}{yields}{nu}{sub e} oscillation with the KEK to Kamioka (K2K) long-baseline neutrino oscillation experiment, using the full data sample of 9.2x10{sup 19} protons on target. No evidence for a {nu}{sub e} appearance signal was found, and we set bounds on the {nu}{sub {mu}}{yields}{nu}{sub e} oscillation parameters. At {delta}m{sup 2}=2.8x10{sup -3} eV{sup 2}, the best-fit value of the K2K {nu}{sub {mu}} disappearance analysis, we set an upper limit of sin{sup 2}2{theta}{sub {mu}}{sub e}<0.13 at a 90% confidence level.

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ;  [1];  [2]; ; ; ;  [3]
  1. Department of Physics, Kyoto University, Kyoto 606-8502 (Japan)
  2. A. Soltan Institute for Nuclear Studies, 00-681 Warsaw (Poland)
  3. Institut de Fisica d'Altes Energies, Universitat Autonoma de Barcelona, E-08193 Bellaterra, Barcelona (Spain) (and others)
Publication Date:
OSTI Identifier:
20775235
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 96; Journal Issue: 18; Other Information: DOI: 10.1103/PhysRevLett.96.181801; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ACCELERATORS; ELECTRON NEUTRINOS; MUON NEUTRINOS; NEUTRINO OSCILLATION; PROTONS

Citation Formats

Yamamoto, S., Hasegawa, M., Hayashi, K., Hiraide, K., Inagaki, T., Kubota, J., Kurimoto, Y., Maesaka, H., Morita, T., Nakaya, T., Nishikawa, K., Sasaki, T., Sato, H., Ueda, S., Yokoyama, M., Zalipska, J., Aliu, E., Andringa, S., Espinal, X., and Fernandez, E. Improved Search for {nu}{sub {mu}}{yields}{nu}{sub e} Oscillation in a Long-Baseline Accelerator Experiment. United States: N. p., 2006. Web. doi:10.1103/PhysRevLett.96.181801.
Yamamoto, S., Hasegawa, M., Hayashi, K., Hiraide, K., Inagaki, T., Kubota, J., Kurimoto, Y., Maesaka, H., Morita, T., Nakaya, T., Nishikawa, K., Sasaki, T., Sato, H., Ueda, S., Yokoyama, M., Zalipska, J., Aliu, E., Andringa, S., Espinal, X., & Fernandez, E. Improved Search for {nu}{sub {mu}}{yields}{nu}{sub e} Oscillation in a Long-Baseline Accelerator Experiment. United States. doi:10.1103/PhysRevLett.96.181801.
Yamamoto, S., Hasegawa, M., Hayashi, K., Hiraide, K., Inagaki, T., Kubota, J., Kurimoto, Y., Maesaka, H., Morita, T., Nakaya, T., Nishikawa, K., Sasaki, T., Sato, H., Ueda, S., Yokoyama, M., Zalipska, J., Aliu, E., Andringa, S., Espinal, X., and Fernandez, E. Fri . "Improved Search for {nu}{sub {mu}}{yields}{nu}{sub e} Oscillation in a Long-Baseline Accelerator Experiment". United States. doi:10.1103/PhysRevLett.96.181801.
@article{osti_20775235,
title = {Improved Search for {nu}{sub {mu}}{yields}{nu}{sub e} Oscillation in a Long-Baseline Accelerator Experiment},
author = {Yamamoto, S. and Hasegawa, M. and Hayashi, K. and Hiraide, K. and Inagaki, T. and Kubota, J. and Kurimoto, Y. and Maesaka, H. and Morita, T. and Nakaya, T. and Nishikawa, K. and Sasaki, T. and Sato, H. and Ueda, S. and Yokoyama, M. and Zalipska, J. and Aliu, E. and Andringa, S. and Espinal, X. and Fernandez, E.},
abstractNote = {We performed an improved search for {nu}{sub {mu}}{yields}{nu}{sub e} oscillation with the KEK to Kamioka (K2K) long-baseline neutrino oscillation experiment, using the full data sample of 9.2x10{sup 19} protons on target. No evidence for a {nu}{sub e} appearance signal was found, and we set bounds on the {nu}{sub {mu}}{yields}{nu}{sub e} oscillation parameters. At {delta}m{sup 2}=2.8x10{sup -3} eV{sup 2}, the best-fit value of the K2K {nu}{sub {mu}} disappearance analysis, we set an upper limit of sin{sup 2}2{theta}{sub {mu}}{sub e}<0.13 at a 90% confidence level.},
doi = {10.1103/PhysRevLett.96.181801},
journal = {Physical Review Letters},
number = 18,
volume = 96,
place = {United States},
year = {Fri May 12 00:00:00 EDT 2006},
month = {Fri May 12 00:00:00 EDT 2006}
}
  • There is a growing interest in very long baseline neutrino oscillation experimentation using an accelerator produced neutrino beam as a machinery to probe the last three unmeasured neutrino oscillation parameters: the mixing angle {theta}{sub 13}, the possible CP violating phase {delta}{sub CP} and the mass hierarchy, namely, the sign of {Delta}m{sub 32}{sup 2}. Water Cherenkov detectors such as IMB, Kamiokande and Super-Kamiokande have shown to be very successful at detecting neutrino interactions. Scaling up this technology may continue to provide the required performance for the next generation of experiments. This report presents the latest effort to demonstrate that a nextmore » generation (>100 kton) water Cherenkov detector can be used effectively for the rather difficult task of detecting {nu}{sub e}s from the neutrino oscillation {nu}{sub {mu}{yields}{nu}e} despite the large expected potential background resulting from {pi}{sup 0}s produced via neutral current interactions.« less
  • The results of the search for {nu}{sub {mu}} {yields} {nu}{sub e} oscillations in the NOMAD experiment at CERN are presented. The experiment looked for the appearance of {nu}{sub e} in a predominantly {nu}{sub {mu}} wideband neutrino beam at the CERN SPS. No evidence for oscillations was found. The 90% confidence limits obtained are {delta}m{sup 2} < 0.4 eV{sup 2} for maximal mixing and sin{sup 2}(2{theta}) < 1.4 x 10{sup -3} for large {delta}m{sup 2}. This result excludes the LSND allowed region of oscillation parameters with {delta}m{sup 2} > or approx. 10 eV{sup 2}.
  • We are searching for {nu}{sub {mu}} to {nu}{sub {tau}} oscillation via the observation of the decay of the tau lepton generated in charged current interactions of {nu}{sub {tau}}. The beam exposure started in May 1994 and will finish in Nov. 1997. A partial sample of neutrino interactions reconstructed by the electronic detector have been located in the emulsion target and analyzed to search for tau decays. No candidate has been observed. This result translates in an upper limit on the oscillation parameter sin{sup 2} 2{theta}=4.5x10{sup -3}. Within 2 years, a sensitivity to sin{sup 2} 2{theta}=2x10{sup -4} will be reached.
  • This analysis of data from the Liquid Scintillator Neutrino Detector (LSND) at the Los Alamos Meson Physics Facility (LAMPF) sets bounds on neutrino oscillations in the appearance channel {bar {nu}}{sub {mu}}{r_arrow}{bar {nu}}{sub {ital e}} by searching for the signature of the reaction {bar {nu}}{sub {ital e}}{ital p}{r_arrow}{ital e}{sup +}{ital n}: an {ital e}{sup +} followed by a 2.2 MeV {gamma} ray from neutron capture. Five {ital e}{sup {plus_minus}}-{gamma} coincidences are observed in time with the LAMPF beam, with an estimated background of 6.2 events. The 90% confidence limits obtained in this analysis are {Delta}{ital m}{sup 2}{lt}0.07 eV{sup 2} for sin{supmore » 2}2{theta}=1, and sin{sup 2}2{theta}{lt}6{times}10{sup {minus}3} for {Delta}{ital m}{sup 2}{approx_gt}20 eV{sup 2}. The possible signal at the edge of the detector`s sensitivity is mentioned.« less
  • Using the {bar {nu}}{sub {mu}} from the {mu}{sup +} decay-at-rest in the LAMPF A6 beam stop, a {bar {nu}}{sub {mu}}{r_arrow}{bar {nu}}{sub {ital e}} oscillation search is currently under investigation with the Liquid Scintillator Neutrino Detector (LSND). The {bar {nu}}{sub {ital e}} appearance is detected via the charged-current reaction {bar {nu}}{sub {ital e}}{ital p}{r_arrow}{ital e}{sup +}{ital n} in coincidence with a 2.2 MeV {gamma} from the subsequent neutron capture on a free proton, {ital np}{r_arrow}{ital d}{gamma}. After an initial month and a half run in 1993 the experiment observes 8 events consistent with the above signature. The total estimated background ismore » 0.9{plus_minus}0.2 events. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.« less