arXiv subjects

A. Umeya

Publications and source records attributed to A. Umeya.

3 recordsLinked to original sources

arXiv2024

Mini-Proceedings of the "Fourth International Workshop on the Extension Project for the J-PARC Hadron Experimental Facility (HEF-ex 2024)"

The mini proceedings of the "Fourth International Workshop on the Extension Project for the J-PARC Hadron Experimental Facility (HEF-ex 2024) [https://kds.kek.jp/event/46965]" held at J-PARC, February 19-21, 2024, are presented. The workshop was devoted to discussing the physics case that connects both the present and the future Hadron Experimental Facility at J-PARC, covering a wide range of topics in flavor, hadron, and nuclear physics related to both experimental and theoretical activities being conducted at the facility.

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arXiv2009

The $Λ$-$Σ$ coupling effect in the neutron-rich $Λ$-hypernucleus $_Λ^{10}$Li by microscopic shell model

We investigate the structure of the neutron-rich $Λ$-hypernucleus $_Λ^{10}$Li by using microscopic shell-model calculations considering a $Λ$-$Σ$ coupling effect. The calculated $Σ$-mixing probability in the $_Λ^{10}$Li ground state is found to be about 0.34 % which is coherently enhanced by the $Λ$-$Σ$ coupling configurations, leading to the energy shift 0.28 MeV which is about 3 times larger than that in $_Λ^{7}$Li. The importance of the $Σ$ configuration obtained by the $ΣN$ interaction and the potentiality of the neutron-rich environment are discussed.

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arXiv2008

Feasibility of extracting a $Σ^-$ admixture probability in the neutron-rich $^{10}_Λ$Li hypernucleus

We examine theoretically production of the neutron-rich $^{10}_Λ$Li hypernucleus by a double-charge exchange ($π^-$, $K^+$) reaction on a $^{10}$B target with distorted-wave impulse approximation calculations. The result shows that the magnitude and shape of the calculated spectrum at 1.20 GeV/c by a one-step mechanism $π^-p \to K^+ Σ^-$ via $Σ^-$ doorways caused by a $Σ^-p \leftrightarrow Λn$ coupling can explain the recent experimental data, and the $Σ^-$ admixture probability in $^{10}_Λ$Li is found to be the order of 10$^{-1}$ %. The ($π^-$, $K^+$) reaction provides a capability of extracting properties of wave functions with $Λ$-$Σ$ coupling effects in neutron-rich nuclei, together with the reaction mechanism.

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