Search

In the last decade, heavy-ion based experiments (HypHI, STAR and ALICEi ) announced surprisingly short lifetime for 3 ΛH mesonic weak decay (MWD), which is difficult to interpret given the fact that 3 ΛH is a very loosely bound system. It will be very interesting to study this issue with a different experimental approach. We propose a direct measurement for 3 ΛH hypernucleus MWD lifetime with ∼10% precision as J-PARC E73 experiment; 4 ΛH hypernucleus lifetime will also be measured as a feasibility test for our experimental approach. In this proceeding, we will introduce the experimental method and the current status of E73 experiment.

We have measured the 3d→2p transition x rays of kaonic ^{3}He and ^{4}He atoms using superconducting transition-edge-sensor microcalorimeters with an energy resolution better than 6 eV (FWHM). We determined the energies to be 6224.5±0.4(stat)±0.2(syst) eV and 6463.7±0.3(stat)±0.1(syst) eV, and widths to be 2.5±1.0(stat)±0.4(syst) eV and 1.0±0.6(stat)±0.3(stat) eV, for kaonic ^{3}He and ^{4}He, respectively. These values are nearly 10 times more precise than in previous measurements. Our results exclude the large strong-interaction shifts and widths that are suggested by a coupled-channel approach and agree with calculations based on optical-potential models.

$\bar K$-nuclear bound systems, kaonic nuclei, have been widely discussed as products of the strongly attractive $\bar K N$ interaction in $I = 0$ channels. Recently, we demonstrated that kaonic nuclei can be produced via in-flight $(K^-,N)$ reactions using the low-momentum DC kaon beam at the J-PARC E15 experiment. We observed the simplest kaonic nuclei, $K^-pp$, having a much deeper binding energy than normal nuclei. For further studies, we have proposed a series of experimental programs for the systematic investigation of light kaonic nuclei, from $\bar K N$ ($\Lambda(1405)$) to $\bar K NNNN$. In the new experiment approved as J-PARC E80, we will measure the $\bar K NNN$ ($A=3$) system as a first step toward a comprehensive study., Comment: 10 pages, 5 figures, proceedings of the 8th Asia-Pacific Conference on Few-Body Problems in Physics (APFB2020), accepted for publication in Fwe-Body Systems

The K¯NN bound system, symbolically denoted as “K−pp”, is the simplest K¯-nuclear bound system which has been widely discussed as a consequence of the strongly attractive K¯N interaction in I = 0 channels. Many theoretical works have pointed out the existence of the “K−pp” bound system, but the calculated properties such as the binding energy and the width spread out due to the uncertainty of the K¯N interaction below the K¯+N mass threshold. Experimentally, there are several reports on observation of a “K−pp” candidate with the binding energy of around 100 MeV, however, no definitive evidence was available so far. At J-PARC, we conducted a experimental search for the “K−pp” bound system using K− + 3He reaction at 1.0 GeV/c where the “K−pp” is expected to be directly produced via the (K−, n) reaction. We finally observed a bound state below the K− +p+p mass threshold in the Λpn final state, which can be interpreted as the “K− pp” bound state. The possible existence of the “K− pp” state is discussed from both aspects of production and decay.

A di-quark correlation has been proposed to describe the internal structure of hadrons, especially those of exotic ones. Nevertheless it lacks a conclusive experimental evidence. The J-PARC E50 experiment performs charmed baryon spectroscopy at J-PARC high-momentum beam line to investigate the role of di-quark correlations in baryons. The energy levels of the excited sates are measured by a missing-mass technique for the first time, and the production rates and decay branching ratios are also measured.

The structure of the Λ(1405) hyperon is an important and long-standing issue related to the K-nucleus interaction. The J-PARC E31 experiment has been performed to investigate the Λ(1405) spectrum shape. Because it is hard to form the Λ(1405) directly by a KN scattering in free space, E31 uses the d(K-, n) reaction with an incident kaon momentum of 1 GeV/c. We will identify three final states - ς-π+, ς+π-, ς0π0-so that the isospin structure of hyperon resonance states produced can be decomposed. The first physics run of the E31 experiment was performed in 2016. To enhance the statistics of the data set, we have performed the second physics run in the beginning of 2018. During the second run of E31, around 3.9×1010 kaons impacted on the deuteron target.

The antikaon-nucleon interaction close to threshold provides crucial information on the interplay between spontaneous and explicit chiral symmetry breaking in low-energy QCD. In this context the importance of kaonic deuterium X-ray spectroscopy has been well recognized, but no experimental results have yet been obtained due to the difficulty of the measurement. We propose to measure the shift and width of the kaonic deuterium 1s state with an accuracy of 60 eV and 140 eV respectively at J-PARC. These results together with the kaonic hydrogen data (KpX at KEK, DEAR and SIDDHARTA at DAFNE) will then permit the determination of values of both the isospin I=0 and I=1 antikaon-nucleon scattering lengths and will provide the most stringent constraints on the antikaon-nucleon interaction, promising a breakthrough. Refined Monte Carlo studies were performed, including the investigation of background suppression factors for the described setup. These studies have demonstrated the feasibility of determining the shift and width of the kaonic deuterium atom 1s state with the desired accuracy of 60 eV and 140 eV., 12 pages, 9 figures

We have searched for the simplest kaonic nuclear state, KNN, using the in-flight 3He (K-, n) reaction at the J-PARC hadron experimental facility. In the semi-inclusive neutron missing-mass spectrum at θnlab=0°, an excess of yield was observed just below the K- pp mass-threshold, which cannot be explained by any elementary reactions [PTEP 2015, 061D01]. To understand the missing-mass spectrum of 3He (K-, n) X, we investigated the elementary (K-, n) reactions using hydrogen and deuterium targets. The p (K-, n) X missing-mass spectrum was well described by the charge-exchange reaction. However, in the d (K-, n) X spectrum, we observed an excess of yield just below the K- p mass-threshold, which was similar to that in the 3He (K-, n) X spectrum. (Less)

We have proposed an experiment for studying charmed baryons via the p ( π − , D ⁎ − ) reaction at the J-PARC high-momentum beam line. Charmed baryons will be measured by a missing mass method. Scattered D ⁎ − will be reconstructed by detecting its decay chain of D ⁎ − → D ¯ 0 π − → K + π − π − . We designed a Ring Imaging Cherenkov (RICH) counter with two radiators, aerogel and C 4 F 10 of refractive indices 1.04 and 1.00137, respectively, in order to identify pions and kaons in a wide momentum range from 2 to 16 GeV/ c . Spherical mirrors will be used to focus Cherenkov photons to the photon sensor alloys. The performance of the designed RICH counter is evaluated by a Monte-Carlo simulation based on GEANT4. Detection efficiency for scattered particles averaged over π and K is found to be 99%. Wrong particle identification ratios of pions and protons to kaons are 0.1% and 0.14%, respectively. The background level in the inclusive p ( π − , D ⁎ − ) spectrum increases only 5% due to the wrong identifications.

The heavy quark baryon spectroscopy is an essential ways to understand the hadron structure. In the case of the charmed baryon, two light quarks are isolated and form the diquark correlation due to the small color-magnetic interaction between the charm and lighter quarks. The excitation modes from the diquark correlation are reflected to the structure of the excited spectrum and the decay modes of excited states. In addition, by measuring the ratio of the cross section between the ground state Λc + and excited states, the information of the inside structure such as the configuration of the diquark correlation and the spin/isospin of excited states can be obtained [1]. From the systematic study of charmed baryons, the diquark correlation which is expectedly a degree of freedom to describe hadrons can be revealed. We propose a spectroscopy experiment [2] to investigate excited states of charmed baryons at the J-PARC high-momentum beam line. The high-intensity secondary pion beams of more than 10 7 per pulse are used with a momentum of 20 GeV/c. The beam momentum can be measured with the resolution of 0.1% by using the momentum-dispersive optics. The excitation energy, width and production cross section are measured by the missing mass technique. The charmed baryons are produced via the π − + p -> Yc* + + D* − reaction. The decay particles of the D* − meson are detected by the forward magnetic spectrometer system which has a large acceptance and a high-momentum resolution. Due to the forward large acceptance of the spectrometer, the decay measurements of the produced charmed baryons can also be performed for determining the absolute decay branching ratio and the spin/parity of the excited states. The systematic measurement of the excitation energy, production rate and decay properties of charmed baryons are performed at J-PARC.

To investigate the relationship of dental status to food diversity among older Japanese.A community-based cross-sectional study conducted in the town of Tosa, Kochi Prefecture, Japan.The study participants were 252 Japanese (84 men and 168 women, average age 81.2 years) and dentate participants were classified into three groups: 1-9 teeth, 10-19 teeth and 20 or more teeth. Food diversity was assessed as a validated measure of dietary quality using the 11-item Food Diversity Score Kyoto (FDSK-11), which evaluates frequency of consumption of 11 main food groups. Multivariable analysis of the differences in FDSK-11 score ranging from 0 to 11, with a higher score indicating greater food diversity, among the three dental status groups was conducted using general linear models. All the performed analyses were stratified by gender.There was no association between dental status and food diversity score in models for men. In contrast, women with ≤ 9 teeth and with 10-19 teeth had significantly lower FDSK-11 scores than women with ≥ 20 teeth after adjusting for confounders (p0.001 and p = 0.009, respectively). Additionally, there was a trend toward lower scores for FDSK-11 with fewer teeth (p = 0.001).A less varied diet, as indicated by low FDSK-11 score, was observed in female participants with fewer teeth. Tooth loss was associated with poor diet quality among older Japanese women.

An experiment to search for the $K^-pp$ bound state was performed via the in-flight $^3$He($K^-,n)$ reaction using 5.3 $\times$ $10^9$ kaons at 1 GeV/$c$ at the J-PARC hadron experimental facility. In the semi-inclusive neutron missing-mass spectrum at $\theta_{n}^{lab}=0^\circ$, no significant peak was observed in the region corresponding to $K^-pp$ binding energy larger than 80 MeV, where a bump structure has been reported in the $\Lambda p$ final state in different reactions. Assuming the state to be isotropically decaying into $\Lambda p$, mass-dependent upper limits on the production cross section were determined to be 30--180, 70--250, and 100--270 $\mu$b/sr, for the natural widths of 20, 60, and 100 MeV, respectively, at 95\% confidence level., Comment: 12 pages, 6 figures

Objective: The purpose of this report is to document the presence of dimethyl sulfide in mouth air as the predominant volatile sulfur compound (VSC) in an asthmatic patient who was regularly taking suplatast tosilate. Study design: The patient was a 33-year-old woman who complained of bad breath. She had been diagnosed as having asthma and was receiving periodical medical examinations once a month. VSC in her mouth air were measured with a gas chromatograph. Oral physiotherapy was also carried out to remove any oral malodor of which the source was intraoral. Results: With the improvement in oral hygiene and periodontal conditions, the level of VSC was reduced but dimethyl sulfide still remained as the predominant VSC. Conclusions: Dimethyl sulfide metabolized from suplatast tosilate may be a potential cause of halitosis.

We have collected the first physics data of an experimental search for the simplest kaonic nuclear bound state, “ K − pp”, by the 3He( K − n) reaction at J-PARC. We confirmed that our spectrometer system works as designed and observed clear peak structure composed of the quasi-elastic K − “ n ” → K − n and the charge-exchange K − “ p ” → ¯ K 0 n reactions in the forward neutron spectrum.

In the J-PARC E15 experiment, a K − pp search was performed via the 3 He(K − , n ) reaction at 1.0 GeV/c . A forward-going neutron is detected by a neutron counter with 15 m flight length, and decay particles from K − pp are simultaneously measured by a cylindrical detector system that surrounds a liquid 3 He target system. In March and May, 2013, we carried out the first physics data-taking with 5×109 incident kaons on the 3 He target, and we have obtained a preliminary exclusive analysis result of 3 He(K − , Λp )n reaction.

Previously gelatins have been shown to reduce copper(II) bis(bipyridine) [CBB(II)] and that only sugars of the reducing substances, which are known to be gelatin impurities, reduced CBB(II). Even u...

To search for an S= -1 di-baryonic state which decays to $\Lambda p$, the $ {\rm{}^3He}(K^-,\Lambda p)n_{missing}$ reaction was studied at 1.0 GeV/$c$. Unobserved neutrons were kinematically identified from the missing mass $M_X$ of the $ {\rm{}^3He}(K^-,\Lambda p)X$ reaction in order to have a large acceptance for the $\Lambda pn$ final state. The observed $\Lambda p n$ events, distributed widely over the kinematically allowed region of the Dalitz plot, establish that the major component comes from a three nucleon absorption process. A concentration of events at a specific neutron kinetic energy was observed in a region of low momentum transfer to the $\Lambda p$. To account for the observed peak structure, the simplest S-wave pole was assumed to exist in the reaction channel, having Breit-Wigner form in energy and with a Gaussian form-factor. A minimum $\chi^2$ method was applied to deduce its mass $M_X\ =$ 2355 $ ^{+ 6}_{ - 8}$ (stat.) $ \pm 12$ (syst.) MeV/c$^2$, and decay-width $\Gamma_X\ = $ 110 $ ^{+ 19}_{ - 17}$ (stat.) $ \pm 27$ (syst.) MeV/c$^2$, respectively. The form factor parameter $Q_X \sim$ 400 MeV/$c$ implies that the range of interaction is about 0.5

Result and problems were studied in 12 patients who received percutaneous cardiopulmonary support (PCPS) after cardiac or aortic surgery. Causative diseases included acute myocardial infarction in 7 cases, rupture of the left ventricular septum after infarction, acute mitral valve regurgitation after infarction, rupture of the left ventricular free wall, a stuck valve, and an aortic aneurysm in the thoracicoabdominal region in each 1 case. The time of postoperative PCPS ranged from 2 to 361 hours, and the mean supply flow volume was 1.78 +/- 0.45 l/min/m2. Seven patients could be taken off the treatment or discharged from the hospital (58.3%). The comparison between surviving and non-surviving cases showed a significantly longer assisted circulation time in the latter. An increase of bleeding after surgery was found in all 8 patients who received PCPS for a long period postoperatively. This was assumed to be due to the thrombocytic activation by heparin.

The heavy quark baryon spectroscopy is a key way to understand what the building block of hadrons is. The diquark correlation which is expectedly an essential degree of freedom to describe the hadron structure can be investigated from the spectroscopy of charmed baryons. An experiment to observe and investigate the charmed baryons was proposed at the J-PARC high- momentum beam line. The missing mass spectroscopy experiment via the π− p → Y*+c D*− reaction at 20 GeV/c will be performed for the systematic measurement of the excitation energy, the production rates and the decay products of charmed baryons. In addition, the properties of the strange baryons can also be measured systematically by using the same experimental setup. From the systematic study of both charmed baryons and hyperons, the diquark correlation can be revealed which is expectedly an essential degree of freedom to describe the hadron structure.

The J-PARC E15 experiment searches for the simplest kaonic nuclear bound state, K−pp, via the 3He(K−,n) reaction at the K1.8BR beam-line in the J-PARC hadron experimental facility. We performed the first data-taking in May, 2013, with 5 × 109 incident kaons on the 3He target. The preliminary results are reported focusing on the forward-neutron spectrum, which shows a clear peak structure composed of the quasi-elastic K−"n" → K−n and the charge-exchange K−"p" → 0n reactions as expected.

Objective The purpose of this study was to examine the usefulness of methyl mercaptan concentration ratio on mass screening for periodontal disease in an elderly population. Methods One hundred and twenty-two individuals (73 males and 49 females) aged 75 years who had at least 20 teeth in 2003 were chosen from participants of the Niigata Elderly Study (longitudinal study since 1998). Volatile sulfur compounds (VSC) in their mouth such as hydrogen sulfide (H2S), methyl mercaptan (CH3SH) and dimethyl sulfide ((CH3)2S) were measured, using portable gas chromatography (Oral Chroma®, Abilit Co Ltd, Osaka, Japan). The subjects were divided into periodontitis/no periodontitis groups based on having at least one site of pocket depth with more than 6 mm (PD 6+ mm). A CH3SH concentration ratio was defined as CH3SH/(CH3SH + H2S). The receiver operating characteristic curve was plotted to decide the best cut off point of the CH3SH concentration ratio for screening of subjects with PD 6+ mm. Results and discussion The best cut-off point of the CH3SH concentration ratio was 0.35, and the sensitivity and specificity of this cut-off point were 58.7 and 68.4%, respectively. The percentage of subjects with PD 6+ mm in the group of CH3SH concentration ratio ≥0.35 was 52.9 % (27 of 51) and that in the

summary Four commercial visible light (VL)-cured composite resin veneering materials with a dentine shade were examined for their Knoop hardness and fracture toughness. Composite specimens were classified into three groups. The first group was cured by VL only, the second group was cured by VL and postcured by VL and the third group was cured by VL and post-cured by heat. It became evident that one composite containing four-functional urethane monomer had both hardness and fracture toughness greater than those of the other three composites containing two-functional urethane monomer. The filler content (vol%) in the composite tended to be linearly proportional to both hardness and fracture toughness. Post-curing by VL and heat were proven to effectively increase both hardness and fracture toughness of once light-cured composites. These results suggest that the clinical performance (e.g. wear resistance and colour stability) of VL-cured composite resin veneering materials might be improved with the aid of post-curing.

A 51-year-old woman admitted to our hospital. Chest X-ray film showed infiltrations in left S4 region, which had been pointed out since two years before. On exploratory thoracotomy, lingual segmentectomy was performed because no metastatic lesions were found in the mediastinal and hilar lymph nodes. Pathological and immunohistological examinations revealed findings corresponding to pulmonary malignant lymphoma (diffuse, small cell type, B cell) with amyloid plaque. The patient is doing well 20 months after operation without any signs of recurrence. The clinical and histological findings of this case may suggest a close relationship between malignant lymphoma and production of amyloid.

A 70-year-old female was referred to our hospital because of swelling at her frontal neck and an abnormal shadow on a chest X-ray film. CT scan and MRI showed a 11.0 x 7.5 cm well-demarcated tumor in the upper mediastinum. Thyroidal scintigraphy revealed an slight accumulation, leading to a diagnosis of intrathoracic goiter. During operation the mass was found to be composed of two tumors. The upper tumor was attached with fibrous adhesion to the right lobe of cervical thyroid but no connection. Histological examination showed follicular but not malignant adenoma of the thyroid.

It was examined whether the tannin-fluoride preparation (HY preparation), which might have a caries-reductive, plaque inhibiting and astringent action, could reduce the incidence of gingival inflammation around abutment teeth. Zinc oxide eugenol cement mixed with the HY preparation was packed in the cavity prepared in the resin base facing the abutment tooth. Gingival crevicular fluid (Periotron units:GCF), gingival index (GI), plaque index (PlI) and probing depth around the abutment teeth were measured over a 3 month period. The following results were obtained: 1. GCF decreased at month 1 and showed low values at months 2 and 3. 2. GI showed a decreasing tendency. 3. PlI and probing depth did not show obvious changes. These results indicate that the tannin-fluoride preparation reduces gingival inflammation around abutment teeth.

A new sectional partial denture utilizing lock mechanism (lock denture) has been developed. Utilizing the lock mechanism, two parts of sectional partial denture are locked together easily and tightly. A lock denture has been constructed for an upper removable partial denture, has been worn for over three months and has clinically been proven to obtain good function and esthetics.

A case of left ventricular-right atrial (LV-RA) communication associated with a false aneurysm of membranous septum is presented. The patient was a 51-year-old woman. Using a left ventriculography this case was diagnosed preoperatively as LV-RA communication. We found that the right atrium was directly communicated with the left ventricle through a fibrous membranous aneurysm adhering to the septal leaflet of the tricuspid valve. It was suggested that a false aneurysm, made by jet lesion from the left ventricle, perforated to the right atrium. So the current case was considered an acquired infravaluvular type LV-RA communication formed in the course of the natural closure of the membranous ventricular septal defect.

The rotational path of insertion differs substantially from the conventional path or perpendicular path of insertion. With a rotational path, one segment of the partial denture is seated first, then the remainder of it is rotated into position. One segment of this system is the rigid retentive component with a long occlusal rest and the other is the conventional clasp. This study examined the influence of mesio-distal distance of the edentulous space, the point of the displacing force, the undercut of rigid retentive component and the inclination of the abutment tooth on the retention of this system. The following results were obtained: 1) Retention of the denture was the lowest when a displacing force was applied at the conventional clasp part under the conditions of mesio-distal distances with edentulous spaces of 10, 20 and 30 mm, respectively. 3) Retention showed a tendency to decrease progressively as the proximal undercut on the rigid retentive component was changed to 2.0, 1.5, 1.0 and 0.5 mm, respectively. The values of the decreasing ratio of retentive forces were almost the same regardless of the mesio-distal distance of the edentulous space. 4) Retention of the denture was improved when a tilted tooth was used as an abutment tooth on the rigid retentive component side.

We reported three cases of spontaneous rupture which were surgically treated with direct suture method. One patient was operated on within eight hours after rupture with good results. In two patients diagnoses were made more than two days after rupture. One had esophageal fistula, but completely recovered after cervical oesophageal fistula, and another died of multiple organ failure. In this syndrome, early diagnosis and surgical treatment are essential for acceptable results. For early diagnosis, we emphasized on the presence of roentgenologic mediastinal and cervical emphysema. In patients for whom diagnosis was delayed and post-operative leakage at the oesophageal suture line occurred, temporarily fistulation of the cervical oesophagus proved to be effective in exclusion and diversion of the ruptured segment.