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新山 雅之 所属 京都産業大学 理学部 物理科学科 職種 教授 |
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| 発行・発表の年月 | 2013/10 |
| 形態種別 | その他 |
| 標題 | Proposal: A Search for Sterile Neutrino at J-PARC Materials and Life Science Experimental Facility |
| 執筆形態 | その他 |
| 著者・共著者 | M. Harada,S. Hasegawa,Y. Kasugai,S. Meigo,K. Sakai,S. Sakamoto,K. Suzuya,E. Iwai,T. Maruyama,K. Nishikawa,R. Ohta,M. Niiyama,S. Ajimura,T. Hiraiwa,T. Nakano,M. Nomachi,T. Shima,T. J. C. Bezerra,E. Chauveau,T. Enomoto,H. Furuta,H. Sakai,F. Suekane,M. Yeh,G. T. Garvey,W. C. Louis,G. B. Mills,R. Van de Water |
| 概要 | We propose a definite search for sterile neutrinos at the J-PARC Materials
and Life Science Experimental Facility (MLF). With the 3 GeV Rapid Cycling Synchrotron (RCS) and spallation neutron target, an intense neutrino beam from muon decay at rest (DAR) is available. Neutrinos come from \mu+ decay, and the oscillation to be searched for is (anti \nu \mu -> anti \nu e) which is detected by the inverse \beta decay interaction (anti \nu e + p -> e+ + n), followed by a gamma from neutron capture. The unique features of the proposed experiment, compared with the LSND and experiments using horn focused beams, are; (1) The pulsed beam with about 600 ns spill width from J-PARC RCS and muon long lifetime allow us to select neutrinos from \mu DAR only. (2) Due to nuclear absorption of \pi- and \mu-, neutrinos from \mu- decay are suppressed to about the $10^{-3}$ level. (3) Neutrino cross sections are well known. The inverse \beta decay cross section is known to be a few percent accuracy. (4) The neutrino energy can be calculated from positron energy by adding ~1.8 MeV. (5) The anti \nu \mu and \nu e fluxes have different and well defined spectra. This allows us to separate oscillated signals from those due to \mu- decay contamination. We propose to proceed with the oscillation search in steps since the region of \Delta m^2 to be searched can be anywhere between sub-eV^2 to several tens of eV^2. We start to examine the large \Delta m^2 region, which can be done with short baseline at first. At close distance to the MLF target gives a high neutrino flux, and allows us to use relatively small detector. If no definitive positive signal is found, a future option exists to cover small \Delta m^2 region. This needs a relatively long baseline and requires a large detector to compensate for the reduced neutrino flux. |
| PermalinkURL | http://arxiv.org/abs/1310.1437v1 |
| researchmap用URL | http://arxiv.org/pdf/1310.1437v1 |