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

J-PARCにおけるd(π+, K+)反応を用いたストレンジダイバリオン系の研究

京都大学0048新制・課程博士博士(理学)甲第18787号理博第4045号新制||理||1582(附属図書館)31738京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, 教授 谷森 達, 准教授 成木 恵学位規則第4条第1項該当Doctor of ScienceKyoto UniversityDGA

Electrical conductivity of ceria-based oxides/alkali carbonate eutectic nanocomposites

Differential thermal analysis (DTA) and electrical conductivity calculated from AC impedance measurements are discussed for binary and ternary eutectics: (Li0.52Na0.48)2CO3 (LN) and (Li0.435Na0.315K0.25)2 CO3 (LNK), coexisting with nanosized CeO2 and ceria-based oxides such as CeO2:Sm3+(samarium doped ceria: SDC) particles prepared by the Pechini method. The influence of the surface properties of oxides with smooth surfaces, narrow particle size distributions, and large specific surface areas near the eutectic point is presented. The obtained DTA spectra indicate that the melting enthalpy disappeared in systems with a melt containing less than 30 vol% and 45 vol% LN and LNK eutectics, respectively. Sm3+ doping contributes to an increase in the electrical conductivity of the composites below the eutectic points of molten carbonate. The temperature dependence of the electrical conductivity for both binary and ternary eutectic carbonates coexisting with CeO2 and SDC at melt contents less than ca. 15 vol% does not indicate a remarkable change in conductivity in the temperature range near each eutectic point of molten carbonate. The low-temperature characteristics are significantly improved using nanosized ceria-based oxides because of non-frozen eutectics with a low molar enthalpy of fusion and limited solid-phase influence on ionic conduction

Status of J-PARC E07: Systematic study of double strangeness nuclei with hybrid emulsion method

© 2019 Author(s). J-PARC E07 is the most complex emulsion experiment to date investigating double hypernuclei with a hybrid emulsion method. This experiment aims to detect 104 Ξ- stop events, ten times more events than the past experiments. Thus, an unequivocal identification of several new double hypernuclei is expected. The beam exposure has been completed at the K1.8 beam line of the J-PARC hadron facility in June 2017. The photographic development of all emulsion sheets has also been completed in February 2018. The emulsion sheets are presently being analyzed with dedicated optical microscopes. Current statistics is comparable to that of E373 and so far 10 events of 3-vertices topology have been detected. A typical event of double Λ hypernucleus and a twin Λ hypernucleus are introduced. We plan to complete the main part of the emulsion scanning within a year

High resolution spectroscopy of the “Σ

We present a new proposal, J-PARC E90, to measure a missing-mass spectrum near the ΣN threshold for the d(K−, π−) reactions at 1.4 GeV/c. While many previous experiments support apparent enhancement near the ΣN thresh-old, the dynamical origin of this so-called “ΣN cusp” remains yet unsolved. The enhancement suggests either a cusp structure or a weakly bound state. One of the keys to making it clear is improving the missing-mass resolution and statistics. Our new experiment can achieve the missing-mass resolution of 0.4 MeV in σ using the K1.8 beam line and S-2S spectrometers at J-PARC. Further-more, we can suppress quasi-free background processes with the time projection chamber (HypTPC), which operated nicely for the H-dibaryon search experi-ment (J-PARC E42). The J-PARC E90 aims to extract the scattering length of the ΣN system with isospin T = 1/2 and spin-triplet channels