Nuclear Theory·nucl-th

Friday·May 17, 2019

8 papers—4 primary·4 cross-listed

01
Quantitative description of the $^{20}$ Ne( $p$ , $p α$ ) $^{16}$ O cross section as a means of probing the surface $α$ amplitude
Kazuki Yoshida🇯🇵 · Yohei Chiba🇯🇵 · Masaaki Kimura🇯🇵 · Yasutaka Taniguchi🇯🇵 · Yoshiko Kanada-En'yo🇯🇵 · Kazuyuki Ogata🇯🇵
The proton-induced $α$ knockout reaction has been utilized for decades to investigate the $α$ cluster states of nuclei, of the ground state in particular. However, even in recent years, it is reported that the deduced $α$ spectroscopic factors from $α$ knockout experiments and reaction analyses with a phenomenological $α$ cluster wave function diverge depending on the kinematical condition of the reaction. In the present study we examine the theoretical description of the $^{20}$ Ne( $p$ , $p α$ ) $^{16}$ O cross section based on the antisymmetrized molecular dynamics and the distorted wave impulse approximation by comparing with existing experimental data. We also investigate the correspondence between the $α$ cluster wave function and the $α$ knockout cross section. The existing $^{20}$ Ne( $p$ , $p α$ ) $^{16}$ O data at 101.5 MeV is well reproduced by the present framework. Due to the peripherality of the reaction, the surface region of the cluster wave function is selectively reflected to the knockout cross section. A quantitatively reliable $α$ cluster wave function, $p$ - $α$ cross section, and distorting potentials between scattering particles, $α$ - $^{16}$ O in particular, are crucial for the quantitative description of the ( $p$ , $p α$ ) cross section. Due to the peripherality of the reaction, the ( $p$ , $p α$ ) cross section is a good probe for the surface $α$ amplitude.
nucl-thnucl-exPRC(2019)·28 citations
02
Disentangling the pair and quartet condensates
V.V. Baran · D.S. Delion
We study the nontrivial interplay of the well known \emph{pairing} and the more complex \emph{quarteting} correlations in the particular case of $N > Z$ atomic nuclei. Within the new Analytical Disentangled Condensate model, by implementing the notion of \emph{fractional degeneracy} we obtain the clear physical picture of a rather weakly interacting mixture of quartet and neutron pair condensates which mainly feel each other's influence through Pauli blocking. The basic idea of our approach may be generalized in order to scrutinize the extent to which similar manifestations are present in various many-body systems.
nucl-thPRC(2019)·6 citations
03
The onset of $ΛΛ$ hypernuclear binding
L. Contessi🇮🇱 · M. Schäfer🇨🇿 · N. Barnea🇮🇱 · A. Gal🇮🇱 · J. Mareš🇨🇿
Binding energies of light, $A \leq 6$ , $ΛΛ$ hypernuclei are calculated using the stochastic variational method in a pionless effective field theory (EFT) approach at leading order with the purpose of assessing critically the onset of binding in the strangeness S=-2 hadronic sector. The EFT input in this sector consists of (i) a $ΛΛ$ contact term constrained by the $ΛΛ$ scattering length $a_{ΛΛ}$ , using a range of values compatible with $ΛΛ$ correlations observed in relativistic heavy ion collisions, and (ii) a $ΛΛ N$ contact term constrained by the only available $A \leq 6$ $ΛΛ$ hypernucler binding energy datum of $_{ΛΛ}^{6}$ He. The recently debated neutral three-body and four-body systems $_{ΛΛ}^{3}$ n and $_{ΛΛ}^{4}$ n are found unbound by a wide margin. A relatively large value of $∣ a_{ΛΛ} ∣ ≳ 1.5$ fm is needed to bind $_{ΛΛ}^{4}$ H, thereby questioning its particle stability. In contrast, the particle stability of the $A = 5$ $ΛΛ$ hypernuclear isodoublet $_{ΛΛ}^{5}$ H-- $_{ΛΛ}^{5}$ He is robust, with $Λ$ separation energy of order 1 MeV.
nucl-thhep-phnucl-exPLB(2019)·31 citations
04
Effect of in-medium $π$ and $η$ propagators to charge symmetry breaking interaction
Subhrajyoti Biswas🇮🇳
We revisit the charge symmetry breaking $(C S B)$ in nucleon-nucleon $(N N)$ interaction caused by $π$ - $η$ mixing in nuclear matter $(N M)$ employing one boson exchange $(O B E)$ model. The medium effect on $C S B$ is incorporated through the in-medium $π$ and $η$ propagators. In addition, the medium modification to the nucleon mass is also taken into account to construct the $C S B$ class $I I I$ potential considering off-shell $π$ - $η$ mixing amplitude and large contribution of in-medium meson propagators to $C S B$ potential is found for the pseudoscalar $(P S)$ interaction compared to that of pseudovector $(P V)$ interaction.
nucl-th0 citations

Affiliations

first authorsco-authorsvia INSPIRE

Quantitative description of the 20Ne(p,pα)16O cross section as a means of probing the surface α amplitude

Disentangling the pair and quartet condensates

The onset of ΛΛ hypernuclear binding

Effect of in-medium π and η propagators to charge symmetry breaking interaction

Affiliations

Quantitative description of the $^{20}$ Ne( $p$ , $p α$ ) $^{16}$ O cross section as a means of probing the surface $α$ amplitude

The onset of $ΛΛ$ hypernuclear binding

Effect of in-medium $π$ and $η$ propagators to charge symmetry breaking interaction