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

A spectroscopic study of

We are planning a 10ΞLi production experiment using the 10B(K−,K+)X reaction at the J-PARC, K1.8 beamline. We perform spectroscopy of missing masses using the S − 2S spectrometer, which can achieve high resolution. Since the cross section of Ξ-hypernuclei is very small, we would like to use a thick target. To ensure the missing mass resolution, we propose a semiinclusive method using a tracking device to detect the decay particles from Ξ-hypernuclei

光子エネルギー1.5-2.4 GeVにおけるd(γ, K+π-)X 反応を用いたK-pp束縛状態の探索

京都大学0048新制・課程博士博士(理学)甲第18072号理博第3950号新制||理||1569(附属図書館)30930京都大学大学院理学研究科物理学・宇宙物理学専攻(主査)教授 永江 知文, 准教授 成木 恵, 教授 鶴 剛学位規則第4条第1項該当Doctor of ScienceKyoto UniversityDGA

A scintillator pixel array for real-time spectroscopy of GeV-scale and multi-species ions produced in laser-plasma experiments

After the development of chirped pulse amplification by G. Mouro, laser ion acceleration has attracted a lot of interest for various fields of research, such as high energy density physics, nuclear physics, and fast ignition scheme in inertial confinement fusion. Recent theoretical and numerical investigations predict generation of sub-GeV to GeV energy ions. However, it is difficult to discriminate GeV-scale ions into different mass and energies using conventional diagnostic instruments (e.g. Thomson parabola spectrometer, solid state nuclear track detector).We have developed a novel diagnostic system based on particle counting analysis (PCA), which is generally used in nuclear physics experiments. The diagnosis provides a mass-dependent ion spectrum based on time-of-flight and pulse-height analysis of single particle events. With a novel arrangement of multiple scintillators with different ion stopping powers, PCA offers potential advantages over commonly used diagnostics in terms of coverage solid angle, detection efficiency, and real-time analysis for GeV-scale ions. The basic detector setup was tested using the Heavy Ion Medical Accelerator in Chiba (HIMAC) in Japan. Our system shows its ability to resolve protons, B^5+, C^6+, and O^8+ ion beams with energy range of 60-430 MeV/u. We also discuss an advanced detector design using multi-layered scintillator pixel array coupled with avalanche photodiodes, which allows angularly-resolved analysis and makes PCA more practical diagnostic technique in laser-driven particle acceleration experiments.High Temperature Plasma Diagnostics Conference 202

J-PARC E27 Experiment to Search for a K−pp Bound State

We have carried out an experimental search for the simplest kaonic nucleus, $K^{ - }pp$, by using the $d(\pi ^{ + },K^{ + })$ reaction at $p_{\pi ^{ + }}$ = 1.69 GeV/$c$. The differential cross section of this reaction with covering a wide missing-mass range from the $\Lambda$ production threshold to the $\Lambda (1405)/\Sigma (1385)$ region has been measured for the first time. The inclusive missing-mass shape of the $\Lambda$ and $\Sigma$ production region was understood with a simple quasi-free picture except for an enhancement at 2.13 GeV/$c^{2}$ due to a $\Sigma N$ cusp. An obtained peak attributed to $Y^{*}$ production was significantly shifted to the low mass side compared with the simulation by $- 22.4$ MeV/$c^{2}$

J-PARC E19 Experiment: Pentaquark Θ+ Search in Hadronic Reaction at J-PARC

A search for the Θ^+ pentaquark in the $\pi ^{ - }p \to K^{ - }X$ reaction was performed at the J-PARC Hadron Facility. Two data samples were collected in 2010 and 2012 at π beam momenta of 1.92 and 2.0 GeV/c, respectively. No peak structure was observed in the missing mass spectra obtained from either data set. The upper limit for the production cross section averaged over the scattering-angle range of 2° to 15° in the laboratory frame was found to be 0.28 µb/sr. The decay width of the Θ^+ can be directly connected to the production cross section through a theoretical calculation using an effective Lagrangian. The estimated upper limits of the width were 0.41 and 2.8 MeV for the spin-parities of 1/2^+ and 1/2^−, respectively

Strangeness physics programs by S-2S at J-PARC

In the K1.8 beam-line at Hadron Experimental Facility of J-PARC, a new magnetic spectrometer S-2S is being installed. S-2S was designed to achieve a high momentum resolution of Δp/p = 6 × 10−4 in FWHM. Several strangeness-physics programs which require the high resolution will be realized by S-2S. The present article introduces J-PARC E70 (missing-mass spectroscopy of Ξ12Be) and E94 (missing-mass spectroscopy of Λ7Li, Λ10B, and Λ12C) experiments