Toward new frontiers : Encounter and synergy of state-of-the-art astronomical detectors and exotic quantum beams

Program D01-6	Development of a particle identification detector for measuring high-momentum hadron beam reactions
Principal Investigator	SHIROTORI, Kotaro (Osaka University)

At the J-PARC hadron experimental facility, hadron particle beams such as pions, kaons and anti-protons can be provided as secondary beams. The J-PARC high-momentum beam line which can provide 30-GeV proton beam had been constructed with a successful extraction of the primary proton beam in 2020. In addition, the J-PARC high-momentum beam line is also designed to provide secondary beams with up to 20 GeV/c by installing a production target at the extraction point. Hadron beams with up to 20 GeV/c which are not available in the world give us unique opportunities to effectively produce hadrons with a charm quark and multiple strange quarks. By using hadron beams with 2–20 GeV/c from the J-PARC high-momentum beam line, we can get new chances to perform various experiments of hadron and nuclear physics while precent beam lines in the J-PARC hadron experimental facility can only provide hadron beams with up to 2 GeV/c. Therefore, cutting edge studies of charm and multi-strangeness hadrons can be opened at the J-PARC facility. The main project at the J-PARC high-momentum beam line is the charmed baryon spectroscopy experiment. In the experiment, we aim to investigate motions and correlations of quarks in the internal structure of hadrons which cannot directly be observed due to the quark confinement. The light quark pair correlation called the diquark correlation which is expected to be a new effective degree of freedoms can be established by the spectroscopic studies of charmed baryons.

We are constructing a large acceptance spectrometer for the charmed baryon spectroscopy experiment. Specifications of the spectrometer are suitable for the general purpose so that various experimental ideas of hadron and hypernuclear physics were proposed. Thus, the spectrometer is being constructed not only for the experimental setup of the charmed baryon spectroscopy but also the general-purpose experimental platform at the J-PARC high-momentum beam line. One of the most important particle identification detectors of the general-purpose spectrometer is a Ring Image CHerenkov detector (RICH). The RICH is designed to be capable to identify scattered particles from hadron reactions with a momentum-range of 2–17 GeV/c. For measuring the wide-momentum range of scattered particles, we combine to use two Cherenkov radiations such as Silica aerogel and Freon gas. RICH is designed as Hybrid type one. Micro-Pixel Photon Counter (MPPC) is planned to be used as a light sensor due to the leakage of the magnetic field from the spectrometer magnet. For compensating a small size of MPPC, a light guide/condenser will be developed. Although MPPC is not familiar to be used for RICH due to a small size and a large dark current rate, we aim to introduce MPPC as a new detector element for the RICH detector. The goal of the project is to realize the RICH and its detection technique with MPPC for the general-purpose spectrometer to perform various hadron and hypernuclear experiments at the J-PARC high-momentum beam line.


Fig. 1. General-purpose spectrometry (left) and schematic view of Ring Image Cherenkov detector (right).

Members

Reference Materials

• H. Noumi et al., J-PARC E50 Proposal (2012).
• K. Shirotori et al., JPS Conf. Proc. 8, 022012 (2015).
• S. H. Kim, A. Hosaka, H. C. Kim, H. Noumi, K. Shirotori, Prog. Theor. Exp. Phys. 2014, 103D01 (2014).
• T. Yamaga et al., Nucl. Instrum. Methods Phys. Res. A 766, 36–38 (2014).
• T. Yamaga et al., ELPH Annual Report 2014 (Tohoku University), 83–88 (2014).