Proposal: A Search for Sterile Neutrino at J-PARC Materials and Life Science Experimental Facility
Proposal: A Search for Sterile Neutrino at J-PARC Materials and Life Science Experimental Facility
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提案：在 J-PARC 材料与生命科学实验设施寻找惰性中微子
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
K. Sakai
中科院分区：
文献类型：
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作者：
M. Harada;G. Mills;E. Iwai;F. Suekane;S. Meigo;M. Yeh;Y. Kasugai;M. Nomachi;H. Furuta;M. Niiyama;S. Hasegawa;T. Enomoto;T. Shima;R. D. Water;T. Maruyama;H. Sakai;W. Louis;K. Nishikawa;S. Ajimura;E. Chauveau;R. Ohta;T. Hiraiwa;S. Sakamoto;T. Nakano;T. Bezerra;G. Garvey;K. Suzuya;K. Sakai
我们建议在J-PARC材料和生命科学实验设施（MLF）中明确寻找无菌中微子。利用3GeV的快速循环同步加速器（RCS）和散斑中子靶，可以获得来自μ子静止衰变（DAR）的强中微子束。中微子来自mu+衰变，要搜索的振荡是（反
u mu -> anti
u e），其由逆检测 η衰变相互作用（反
u e + p -> e+ + n），随后是来自中子俘获的γ。与LSND和喇叭聚焦束实验相比，该实验的独特之处在于：（1）J-PARC RCS产生的脉冲束具有约600 ns的溢出宽度和μ子的长寿命，使我们能够仅从μ DAR中选择中微子。(2)由于π-和μ-的核吸收，来自μ-衰变的中微子被抑制到大约10 ^{-3}$的水平。(3)中微子的横截面是众所周知的。逆 已知η衰变截面的精确度为百分之几。(4)中微子的能量可以从正电子的能量加上~1.8 MeV计算出来。(5)反
你和
Ue通量具有不同的和明确定义的光谱。这使我们能够将振荡信号从μ衰变污染中分离出来.我们建议逐步进行振荡搜索，因为要搜索的Δ m^2的区域可以在亚电子伏^2到几十电子伏^2之间的任何地方。我们开始检查大的Delta m^2区域，这可以首先用短基线来完成。在近距离的MLF目标给出了一个高中微子通量，并允许我们使用相对较小的探测器。如果未发现明确的阳性信号，则未来可选择覆盖较小的Delta m^2区域。这需要一个相对较长的基线，并需要一个大的探测器来补偿减少的中微子通量。
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
u mu -> anti
u e) which is detected by the inverse eta decay interaction (anti
u 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 eta 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
u mu and
u 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.