Fundamental Physics with Cold Neutrons at J-PARC
M. Kitaguchi1#, Y. Arimoto2, H. Funahashi3, N. Higashi4, M. Hino5, K. Hirota6, S. Imajo7,
T. Ino2, Y. Iwashita8, R. Katayama4, K. Mishima9, H. Oide10, H. Otono11, Y. Seki12, T. Shima13,
H. M. Shimizu6, K. Taketani2, T. Yamada4, S. Yamashita9, and T. Yoshioka11
1

Center for Experimental Studies, KMI, Nagoya University, Nagoya 464-8602, Japan,High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0802, Japan,
3
Institute for Liberal Arts and Science, Kyoto University, Yoshida, Kyoto 606-8501, Japan,
4
Department of Physics, University of Tokyo, Bunkyo, Tokyo 113-0033, Japan,
5Research Reactor Institute, Kyoto University, Kumatori, Osaka Kyoto 590-0494, Japan,
6
Department of Physics, Nagoya University, Nagoya 464-8602, Japan,
7
Department of Physics, Kyoto University, Kyoto 606-8502, Japan,
8Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan,
9International Center for Elementary Particle Physics, University of Tokyo, Bunkyo, Tokyo 113-0033, Japan,
10
CERN, CH-1211, Genevé 23, Switzerland,
11
Research Center for Advanced Particle Physics,Kyushu University, Fukuoka 812-8581, Japan.
12RIKEN, Wako, Saitama 351-0198, Japan
13
Research Center for Nuclear Physics, Osaka University, Ibaraki, Osaka 567-0047, Japan,2# a corresponding author: E-mail kitaguchi@phi.phys.nagoya-u.ac.jp
Neutron is a chargeless massive particle with the lifetime in the macroscopic range,
which consequently is suitable for the precision measurement of the small influence of newphysics beyond the standard model of elementary particles. Combination of theinstantaneousely luminous cold neutrons and the advanced neutron optical devices enables usto perform new types of high precision measurements. A neutron beamline “Neutron Opticsand Physics (NOP)” has been constructed at the beam port BL05 of the Materials and Life
science Facility (MLF) of the J-PARC. Three beam branches divided by supermirror bender
are utilized for various physics experiments [1].
The recent values of neutron lifetime deviate far beyond the systematic errors claimed in
the past and require the further improvement for the consistency with the primordial Big Bang
nucleosynthesis. Neutron lifetime measurement with pulsed beam is continuing at thepolarized beam branch. The well-defined bunches is injected into time projection chamber(TPC). The TPC detects both of the electrons from neutron beta decay and the nuclear
reaction by 3He in order to estimate the flux at the same time. New data acquisition system
was installed and the commissioning of TPC has been started. The precise analysis of the data
including Monte-Calro simulation is also in progress.
The ultracold neutrons (UCNs) are utilized for various precision measurements. In orderto develop and test the neutron optical devices, a Doppler shifter was installed to provideUCNs on the unpolarized beam branch. Some UCN optical devices for the search for neutron
electric dipole moment (EDM) are developed and demonstrated [2].
We will report the current status of the NOP beamline.
References[1] K. Mishima, et. al., Nucl. Instr. and Meth. A600 (2009) 342.
[2] Y. Arimoto, et. al., Prog. Theor. Exp. Phys. (2012) 02B007.