検索対象:     
報告書番号:
※ 半角英数字
 年 ~ 
 年
検索結果: 4 件中 1件目~4件目を表示
  • 1

発表形式

Initialising ...

選択項目を絞り込む

掲載資料名

Initialising ...

発表会議名

Initialising ...

筆頭著者名

Initialising ...

キーワード

Initialising ...

使用言語

Initialising ...

発行年

Initialising ...

開催年

Initialising ...

選択した検索結果をダウンロード

論文

Observation of a $$bar{K}NN$$ bound state in the $$^{3}$$He $$(K^-, Lambda p)n$$ reaction

山我 拓巳*; 橋本 直; 谷田 聖; 他66名*

Physical Review C, 102(4), p.044002_1 - 044002_14, 2020/10

 被引用回数:4 パーセンタイル:57.67(Physics, Nuclear)

We have performed an exclusive measurement of the $$K^{-}+! ~^{3}{rm He} to Lambda pn$$ reaction at an incident kaon momentum of $$1 {rm GeV}/c$$. In the $$Lambda p$$ invariant mass spectrum, a clear peak was observed below the mass threshold of $$bar{K}+N+N$$, as a signal of the kaonic nuclear bound state, $$bar{K}NN$$. The binding energy, decay width, and $$S$$-wave Gaussian reaction form-factor of this state were observed to be $$B_{K} = 42pm3({rm stat.})^{+3}_{-4}({rm syst.}) {rm MeV}$$, $$Gamma_{K} = 100pm7({rm stat.})^{+19}_{-9}({rm syst.}) {rm MeV}$$, and $$Q_{K} = 383pm11({rm stat.})^{+4}_{-1}({rm syst.}) {rm MeV}/c$$, respectively. The total production cross-section of $$bar{K}NN$$, determined by its $$Lambda p$$ decay mode, was $$sigma^{tot}_{K} cdot BR_{Lambda p} = 9.3pm0.8({rm stat.})^{+1.4}_{-1.0}({rm syst.}) mu{rm b}$$. We estimated the branching ratio of the $$bar{K}NN$$ state to the $$Lambda p$$ and $$Sigma^{0}p$$ decay modes as $$BR_{Lambda p}/BR_{Sigma ^{0}p} sim 1.7$$, by assuming that the physical processes leading to the $$Sigma N!N$$ final states are analogous to those of $$Lambda pn$$.

論文

Results of $$bar{K}NN$$ search via the $$(K^-, n)$$ reaction at J-PARC

山我 拓巳*; 橋本 直; 谷田 聖; 他66名*

JPS Conference Proceedings (Internet), 26, p.023008_1 - 023008_6, 2019/11

There is a long-standing argument of the existence of kaonic nucleus, which is a bound state of anti-kaon and nucleus. Theoretically, its existence is strongly supported, however its binding energy and width have not been established yet. It is strongly desired to have an experiment to investigate the simplest kaonic nucleus, so-called $$K^-pp$$ bound state. We performed an experiment to search for $$K^-pp$$ via the in-flight $$(K^-, n)$$ reaction at J-PARC. By studying $$Lambda p$$ invariant mass spectrum in the $$Lambda pn$$ final state and its dependence on momentum transfer of $$K^{-}N to bar{K}N$$, we observed a resonant state located below $$M_{K^{-}pp}$$. The mass and width of this resonant state are $$2324 pm 3(textit{stat}.)_{-3}^{+6}(textit{syst}.)$$ MeV/$$c^2$$, and $$115 pm 7(textit{stat}.)_{-20}^{+10}(textit{syst}.)$$ MeV, respectively, which can be naturally interpreted as a theoretically predicted $$K^-pp$$ bound state.

論文

Study of the elementary $$(K^-,n)$$ reactions to search for the $$bar{K}NN$$ bound state via the $$^3$$He$$(K^-,n)$$ reaction at J-PARC

山我 拓巳*; 谷田 聖; 他74名*

AIP Conference Proceedings 1735, p.040007_1 - 040007_6, 2016/05

 被引用回数:0 パーセンタイル:0.41

We have searched for the simplest kaonic nuclear state, $$bar{K}NN$$, using the in-flight $$^3$$He$$(K^-,n)$$ reaction at the J-PARC hadron experimental facility. In the semi-inclusive neutron missing-mass spectrum at $$theta_{n}^{rm lab}=0^{circ}$$, 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 $$^3$$He$$(K^-,n)X$$, 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 $$^3$$He$$(K^-,n)X$$ spectrum.

論文

Spectroscopic study of hyperon resonances below $$bar{K}N$$ threshold via the $$(K^-,n)$$ reaction on deuteron

山我 拓巳*; 谷田 聖; J-PARC E31 Collaboration*; 他70名*

JPS Conference Proceedings (Internet), 8, p.021016_1 - 021016_5, 2015/09

We are planning to carry out an experimental study of hyperon resonance via the $$d(K^-,n)$$ reaction using kaon beam which has momentum of 1 GeV/$$c$$ at the J-PARC hadron experimental facility. In the presented reaction, $$Lambda(1405)$$ can be produced dynamically from meson-baryon resonant state. The performance of the counters was tested at the previous beam time of the J-PARC. The counters worked as expected. The preparation of experimental setup had been done.

4 件中 1件目~4件目を表示
  • 1