arXiv subjects

Khin Swe Myint

Publications and source records attributed to Khin Swe Myint.

6 recordsLinked to original sources

arXiv2012

Analysis of heavy hyperhydrogen 6^H_Lambda

We have revisited the possible existence and the binding mechanism of heavy hyperhydrogen 6^H_Lambda. This Lambda hypernucleus is enriched in information about Lambda hypernuclear dynamics which would shed a light on significant role of coherent Lambda-Sigma coupling effect in neutron-rich nuclear medium, discussed by the authors. Recently, reports on an experimental evidence of 6^H_Lambda with theoretical comparison have appeared, wherein the significance of the coherent coupling in 6^H_Lambda has been criticized. In this report, we are revising our previous work and give further theoretical analysis to confirm the influence of the Lambda N - Sigma N coupling effect in the binding mechanism of 6^H_Lambda.

nucl-th↗

arXiv2010

Feshbach Resonance due to Coherent Lambda-Sigma Coupling in Lambda_He^7

Coherent Lambda-Sigma coupling effect in Lambda_He^7 is analyzed within three-body framework of two coupled channels, Lambda-t-t and Sigma-tau-t, where tau represents trinucleon which is either H^3 or He^3. The hyperon-trinucleon (Y tau) and trinucleon-trinucleon (tau tau) interactions are derived by folding G-matrices of YN and NN interactions with trinucleon density distributions. It is found that the binding energy of Lambda_He^7 is 4.04 MeV below the Lambda+t+t threshold without Lambda-Sigma coupling and the binding energy is increased to 4.46 MeV when the coupling effect is included. This state is 7.85 MeV above the He^6+Lambda threshold and it may have a chance to be observed as a Feshbach resonance in Li^7 (e,e'K^+)Lambda_He^7 experiment done at Jefferson Lab.

nucl-th↗

arXiv2005

Full-coupled channel approach to S=-2 s-shell hypernuclear systems

We describe full-coupled-channel ab initio calculations among the octet baryons for S=-2 s-shell hypernuclei,_{LambdaLambda}^4H,_{LambdaLambda}^5H and_{LambdaLambda}^6He. The wave function includes Lambda Lambda, Lambda Sigma, N Xi, and Sigma Sigma channels. Minnesota NN, D2^\prime YN and Nijmegen model D simulated YY interactions are used. This is the first attempt to explore the few-body problem of the full-coupled channel scheme for A=4-6, S=-2 multistrangeness hypernuclear systems. Bound state solutions of the Lambda Lambda hypernuclei,_{LambdaLambda}^4H,_{LambdaLambda}^5H and _{LambdaLambda}^6He, are obtained.

nucl-th↗

arXiv2004

Full-Coupled Channel Approach to Doubly Strange $s$-Shell Hypernuclei

We describe {\it ab initio} calculations of doubly strange, $S=-2$, $s$-shell hypernuclei ($^4_{ΛΛ}$H, $^5_{ΛΛ}$H, $^5_{ΛΛ}$He and $^6_{ΛΛ}$He) as a first attempt to explore the few-body problem of the {\it full}-coupled channel scheme for these systems. The wave function includes $ΛΛ$, $ΛΣ$, $NΞ$ and $ΣΣ$ channels. Minnesota $NN$, D2$^\prime$ $YN$, and simulated $YY$ potentials based on the Nijmegen hard-core model, are used. Bound state solutions of these systems are obtained. We find that a set of phenomenological $B_8B_8$ interactions among the octet baryons in $S=0, -1$ and -2 sectors, which is consistent with all of the available experimental binding energies of $S=0, -1$ and -2 $s$-shell (hyper-)nuclei, can predict a particle stable bound state of $^4_{ΛΛ}$H. For $^5_{ΛΛ}$H and $^5_{ΛΛ}$He, $ΛN-ΣN$ and $ΞN-ΛΣ$ potentials enhance the net $ΛΛ-NΞ$ coupling, and a large $Ξ$ probability is obtained even for a weaker $ΛΛ-NΞ$ potential.

nucl-th↗

arXiv2003

Stochastic Variational Search for $^{4}_{ΛΛ}$H

A four-body calculation of the $pnΛΛ$ bound state, $^{\ 4}_{ΛΛ}$H, is performed using the stochastic variational method and phenomenological potentials. The $NN$, $ΛN$, and $ΛΛ$ potentials are taken from a recent Letter by Filikhin and Gal, PRL{\bf 89}, 172502 (2002). Although their Faddeev-Yakubovsky calculation found no bound-state solution over a wide range of $ΛΛ$ interaction strengths, the present variational calculation gives a bound-state energy, which is clearly lower than the $_Λ^3{H}+Λ$ threshold, even for a weak $ΛΛ$ interaction strength deduced from a recent experimental $B_{ΛΛ}(^{6}_{ΛΛ}{He})$ value. The binding energies obtained are close to, and slightly larger than, the values obtained from the three-body $dΛΛ$ model in the Letter.

nucl-th↗

arXiv2002

Lambda Lambda-XiN Coupling Effects in Light Hypernuclei

The significance of $ΛΛ$-$Ξ$N coupling in double-$Λ$ hypernuclei has been studied. The Pauli suppression effect due to this coupling in $^6_{ΛΛ}$He has been found to be 0.43 MeV for the coupling strength of the NSC97e potential. This indicates that the free-space $ΛΛ$ interaction is stronger by about $5^{\circ}$ phase shift than that deduced from the empirical data of $^6_{ΛΛ}$He without including the Pauli suppression effect. In $^5_{ΛΛ}$He and $^5_{ΛΛ}$H, an attractive term arising from $ΛΛ$-$Ξ$N conversion is enhanced by the formation of an alpha particle in intermediate $Ξ$ states. According to this enhancement, we have found that the $ΛΛ$ binding energy ($ΔB_{ΛΛ}$) of $^5_{ΛΛ}$He is about 0.27 MeV larger than that of $^6_{ΛΛ}$He for the NSC97e coupling strength. This finding deviates from a general picture that the heavier is the core nucleus, the larger is $ΔB_{ΛΛ}$.

nucl-th↗