27 research outputs found
Search for Tetraneutron by Pion Double Charge Exchange Reaction at J-PARC
Tetraneutron () has come back in the limelight, because of recent
observation of a candidate resonant state at RIBF. We propose to investigate
the pion double charge exchange (DCX) reaction, i.e. , as an alternative way to populate tetraneutron. An intense
beam with the kinetic energy of ~850 MeV, much higher than that in past
experiments at LAMPF and TRIUMF, will open up a possibility to improve the
experimental sensitivity of the formation cross section, which will be much
smaller than hitherto known DCX cross sections such as .Comment: 4 pages, 1 figure; proceedings of the 14th International Conference
on Meson-Nucleon Physics and the Structure of the Nucleon (MENU2016), Kyoto,
Japan, 25-30 July 201
Fundamental physics activities with pulsed neutron at J-PARC(BL05)
"Neutron Optics and Physics (NOP/ BL05)" at MLF in J-PARC is a beamline for
studies of fundamental physics. The beamline is divided into three branches so
that different experiments can be performed in parallel. These beam branches
are being used to develop a variety of new projects. We are developing an
experimental project to measure the neutron lifetime with total uncertainty of
1 s (0.1%). The neutron lifetime is an important parameter in elementary
particle and astrophysics. Thus far, the neutron lifetime has been measured by
several groups; however, different values are obtained from different
measurement methods. This experiment is using a method with different sources
of systematic uncertainty than measurements conducted to date. We are also
developing a source of pulsed ultra-cold neutrons (UCNs) produced from a
Doppler shifter are available at the unpolarized beam branch. We are developing
a time focusing device for UCNs, a so called "rebuncher", which can increase
UCN density from a pulsed UCN source. At the low divergence beam branch, an
experiment to search an unknown intermediate force with nanometer range is
performed by measuring the angular dependence of neutron scattering by noble
gases. Finally the beamline is also used for the research and development of
optical elements and detectors. For example, a position sensitive neutron
detector that uses emulsion to achieve sub-micrometer resolution is currently
under development. We have succeeded in detecting cold and ultra-cold neutrons
using the emulsion detector.Comment: 9 pages, 5 figures, Proceedings of International Conference on
Neutron Optics (NOP2017
Search For A Ξ Bound State In The 12C(K-,K+)X Reaction At 1.8 Gev/c
The 26th International Nuclear Physics Conference, 11-16 September, 2016, Adelaide, Australia
Beam and SKS spectrometers at the K1.8 beam line
High-resolution spectrometers for both incident beams and scattered particles have been constructed at the K1.8 beam line of the Hadron Experimental Facility at J-PARC. A point-to-point optics is realized between the entrance and exit of QQDQQ magnets for the beam spectrometer. Fine-pitch wire chamber trackers and hodoscope counters are installed in the beam spectrometer to accept a high rate beam up to 107 Hz. The superconducting kaon spectrometer for scattered particles was transferred from KEK with modifications to the cryogenic system and detectors. A missing-mass resolution of 1.9 ± 0.1 MeV/c2 (FWHM) was achieved for the ∑ peaks of (π±, K+) reactions on a proton target in the first physics run of E19 in 2010
Experimental searches for antikaonic clusters
The existence of antikaonic nuclear clusters, quasi-bound systems composed of an antikaon and a nucleus, is an important issue both theoretically and experimentally. By using all available experimental data, which are rather old and poor in statistics, a qualitative theoretical consensus is that antikaon nucleus interaction is attractive and strongly absorptive. However, there remain large uncertainties in quantitative estimates on these strengths, which prevents from drawing a definite conclusion. In the experimental side, new data are recently accumulated. Here I summarize the present experimental status on the antikaonic clusters mainly obtained in stopped K− reactions
Strangeness Nuclear Physics at J-PARC
After the big earthquake in the east part of Japan on March 11, 2011, the beams in the hadron experimental hall at J-PARC have been successfully recovered in February, 2012. The experimental program using pion beams is now on-going with the primary proton beam power of ~5 kW. Before a long summer shutdown scheduled in 2013, several experiments in strangeness nuclear physics are going to take data. In this period, we anticipate the beam power would exceed 10 kW and the experiments to use K[-] beams will start. The experimental program is explained briefly