Nuclear Theory·nucl-th

Thursday·March 12, 2020

8 papers—3 primary·5 cross-listed

01
Role of individual components of two-nucleon interaction in nuclear matrix elements of $2 ν β β$ and $0 ν β β$ of $^{48}$ Ca: Beyond the closure approximation
Shahariar Sarkar🇮🇳 · Pawan Kumar🇮🇳 · Kanhaiya Jha🇮🇳 · P.K. Raina🇮🇳
In the present work, we examine the role of central (C), spin-orbit (SO) and tensor (T) components of two-nucleon interaction in the nuclear matrix elements (NMEs) of the two-neutrino double beta decay ( $2 ν β β$ ) and the light neutrino-exchange mechanism of neutrinoless double beta decay ( $0 ν β β$ ) of $^{48}$ Ca in closure approximation and nonclosure approach. The NMEs are calculated in the nuclear shell-model framework using two-nucleon effective interaction GXPF1A used for $p f$ shell. The decomposition of the shell model two-nucleon interaction into its individual components is performed using the spin-tensor decomposition (STD). The NMEs for $2 ν β β$ are calculated in running nonclosure method. The NMEs for $0 ν β β$ are calculated with four different methods, namely, closure, running closure, running nonclosure, and mixed method. Results show that the magnitude of NMEs for $2 ν β β$ decreases about 7\% with the C+SO component of the interaction as compared to the C component. The magnitude of NMEs is further decreased about 9\% by adding T component to the C+SO component. The NMEs of $0 ν β β$ calculated in running nonclosure method are enhanced by about 8-10\%, 8-10\%, and 9-12\%, respectively, as compared to corresponding NMEs calculated in running closure method with C, C+SO components and total (C+SO+T) GXPF1A interaction for different SRC parametrization. For both $2 ν β β$ and $0 ν β β$ , the NMEs calculated with C+SO component is in opposite phase with the NMEs calculated with C component and the total GXPF1A interaction.
nucl-th0 citations
02
Investigation of contributions of the $2_{2}^{+}$ resonance in $^{6}$ He via analysis of $^{6}$ He( $p$ , $p^{'}$ )
Shoya Ogawa · Takuma Matsumoto
We investigate the contribution of the $2_{2}^{+}$ resonance in $^{6}$ He to observables via analysis of the $^{6}$ He( $p, p^{'}$ ) reaction by using the continuum-discretized coupled channels method combined with the complex-scaling method. In this study, we obtain the $2_{2}^{+}$ state with the resonant energy 2.25 MeV and the decay width 3.75 MeV and analyse contributions of resonances and nonresonant continuum states to the cross section separately. It is found that the $2_{2}^{+}$ state plays an important role in the energy spectrum. Furthermore, contributions of nonresonant continuum states are also important to clarify the properties of the $2_{2}^{+}$ state.
nucl-thPRC(2020)·8 citations
03
Optical potentials, retarded Green's functions and nonorthogonality
Michael C. Birse (University of Manchester)
An approach is outline to constructing an optical potential that includes the effects of antisymmetry and target recoil. it is based on the retarded Green's function, which could make it a better starting point for applications to direct nuclear reactions, particularly when extended to coupled channels. Its form retains a simple connection to folding potentials, even in the presence of three-body forces.
nucl-thPRC(2020)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE

Role of individual components of two-nucleon interaction in nuclear matrix elements of 2νββ and 0νββ of 48Ca: Beyond the closure approximation

Investigation of contributions of the 22+​ resonance in 6He via analysis of 6He(p, p′)

Optical potentials, retarded Green's functions and nonorthogonality

Affiliations

Role of individual components of two-nucleon interaction in nuclear matrix elements of $2 ν β β$ and $0 ν β β$ of $^{48}$ Ca: Beyond the closure approximation

Investigation of contributions of the $2_{2}^{+}$ resonance in $^{6}$ He via analysis of $^{6}$ He( $p$ , $p^{'}$ )