arXiv subjects

Deepak Patel

Publications and source records attributed to Deepak Patel.

8 recordsLinked to original sources

arXiv2025

Large-scale shell-model investigation of $2\nu$ECEC in $^{132}$Ba and $^{78}$Kr

We present a theoretical investigation of two-neutrino double electron capture ($2\nu$ECEC) in $^{132}$Ba and $^{78}$Kr based on large-scale shell-model calculations. The nuclear matrix elements (NMEs) for the $2\nu$ECEC process in $^{132}$Ba and $^{78}$Kr are calculated using the SN100PN and GWBXG effective interactions, respectively. The reliability of the employed interactions is first examined through a comparison of the calculated and experimental spectroscopic properties of the parent, intermediate, and granddaughter nuclei involved in the decay. We also examine the cumulative contribution of the $2\nu$ECEC NME with respect to the $1^+$ state energies in the intermediate nuclei. The present results provide an updated and improved shell-model estimate of the $2\nu$ECEC NME and half-life for $^{78}$Kr relative to earlier studies, and a baseline theoretical prediction for $^{132}$Ba that may assist future experimental efforts in constraining this rare decay mode.

nucl-th↗

arXiv2025

Modification of single-hole-like states by configuration mixing in the $^{99-131}$In

Large-scale shell-model calculations are performed for the $9/2^+_{\rm g.s.}$, $1/2^-_1$, $3/2^-_1$, and $5/2^-_1$ states in the odd-$A$ indium isotopes with $N=50-82$. The calculated energy levels, electromagnetic moments, and spectroscopic factors exhibit remarkable agreement with the experimental data due to significant configuration mixing for the neutron numbers away from the closed shells. The $1/2^-_1$ energy levels closely follow the trend of effective single-particle energies, which are determined using the fractional occupancies of neutron orbitals. However, configuration mixing with the proton $p_{3/2}$ and $f_{5/2}$ orbitals in the actual shell-model calculations plays a crucial role in accurately reproducing the positions of the $1/2^-_1$ levels, ensuring better agreement with the experimental data across the entire isotopic chain.

nucl-th↗

arXiv2024

Large-scale shell-model study of 2$\nu$ECEC process in $^{78}$Kr

In this work, we present the systematic study of $2\nu$ECEC process in the $^{78}$Kr using large-scale shell-model calculations with the GWBXG effective interaction. We first validate the efficiency of the utilized interaction by comparing the theoretical low-lying energy spectra, the kinematic moment of inertia, and reduced transition probabilities with the experimental data for both the parent and grand-daughter nuclei $^{78}$Kr and $^{78}$Se, respectively. Additionally, we examine the shell-model level densities of the $1^+$ states in the intermediate nucleus $^{78}$Br, comparing them with the predictions from the Back-shifted Fermi gas model. We analyze the variation of cumulative nuclear matrix elements (NMEs) for the $2\nu$ECEC process in $^{78}$Kr as a function of $1^+$ state energies in the intermediate nucleus $^{78}$Br up to the saturation level. Our estimated half-life for $^{78}$Kr, extracted from the shell-model predicted NMEs, shows good agreement with the experimental value. The Gamow-Teller transitions from the lowest $1^+$ state of $^{78}$Br via both the EC$+\beta^+$ and $\beta^-$-channels are also discussed.

nucl-th↗

arXiv2024

Systematic shell-model analysis of $2\nu\beta\beta$ decay of $^{76}$Ge and $^{96}$Zr to the ground and excited states of $^{76}$Se and $^{96}$Mo

In this work, we have studied the $2\nu\beta\beta$ decay of $^{76}$Ge and $^{96}$Zr isotopes utilizing large-scale shell-model calculations. The GWBXG effective interaction has been employed in the calculation of $2\nu\beta\beta$-decay nuclear matrix elements (NMEs). We have tested the effective interaction by comparing the predicted spectroscopic properties, such as energy spectra and transition probabilities, with the available experimental data. The variation of cumulative NMEs with respect to the $1^+$ state energies of the intermediate nucleus is also studied, corresponding to $0^+_{\rm g.s.}\rightarrow0^+_{\rm g.s.}$, $0^+_{\rm g.s.}\rightarrow0^+_{2}$, and $0^+_{\rm g.s.}\rightarrow2^+_{1}$ transitions between the parent and grand-daughter nuclei. The effective values of axial-vector coupling strength ($g_A^{\rm eff}$) are calculated using the predicted NMEs and experimental half-lives for $0^+_{\rm g.s.}\rightarrow0^+_{\rm g.s.}$ transitions. The extracted half-lives for $0^+_{\rm g.s.}\rightarrow0^+_{2}$, and $0^+_{\rm g.s.}\rightarrow2^+_{1}$ transitions using the shell-model predicted NMEs are consistent with the recent experimental data. The comparison of the shell-model predicted NMEs with previous NMEs available in the literature is discussed. Also, the computed branching ratios for the $2\nu\beta\beta$ decay of $^{76}$Ge and both the $2\nu\beta\beta$ and single-$\beta$ decay of $^{96}$Zr are reported corresponding to the calculated $g_A^{\rm eff}$ values.

nucl-th↗

arXiv2024

Systematic shell-model study of structure and isomeric states in $^{204-213}$Bi isotopes

In this work, we have performed systematic shell-model calculations for Bi isotopes with $A=$ 204-213 using KHH7B and KHM3Y effective interactions. We have reported yrast and non-yrast shell-model states corresponding to the available experimental data. From the comparison with the experimental data, we could assign spin and parity of several unconfirmed states. We have also calculated electromagnetic properties and compared them with the available experimental data and predicted where experimental data are not available. This study also includes a detailed discussion of multiple isomeric states based on computed shell-model configurations and their respective half-lives.

nucl-th↗

arXiv2024

Systematic shell-model study of $^{99-129}$Cd isotopes and isomers in neutron-rich $^{127-131}$In isotopes

Systematic shell-model calculations are presented for odd-mass Cd isotopes with $N=51-81$ utilizing a combination of a $G$-matrix interaction and a semiempirical one. The excited energy spectra and electromagnetic transition probabilities are compared with the recently available experimental data. We have found that the observed quadrupole moments in the $11/2^-_1$ states that linearly change with the neutron number are well accounted for by the dominance of prolate shapes throughout the Cd isotope chain. We have also described the properties of several isomeric states in neutron-rich $^{127-131}$In isotopes that were recently observed in Jyv\"askyl\"a.

nucl-th↗

arXiv2023

Large-scale shell-model study of two-neutrino double-beta decay of $^{82}$Se, $^{94}$Zr, $^{108}$Cd, $^{124}$Sn, $^{128}$Te, $^{130}$Te, $^{136}$Xe, and $^{150}$Nd

Large-scale shell-model calculations have been performed for the study of two neutrino double-beta ($2\nu\beta\beta$) decay in $^{82}$Se, $^{94}$Zr, $^{108}$Cd, $^{124}$Sn, $^{128}$Te, $^{130}$Te, $^{136}$Xe, and $^{150}$Nd. We have employed JUN45 interaction to calculate the nuclear matrix element (NME) for $2\nu\beta\beta$ decay in $^{82}$Se. In the case of $^{94}$Zr, the glekpn effective interaction is used. For $^{108}$Cd, we have used a realistic effective interaction derived through the G-matrix approach. In the case of $^{124}$Sn, $^{128,130}$Te and $^{136}$Xe, the sn100pn effective interaction is employed. For $^{150}$Nd, we have used KHHE effective interaction based on holes in a $^{208}$Pb core. We have extracted the half-lives of these nuclei for the $2\nu\beta\beta$ decay with the help of calculated NME. Our results are consistent with the available experimental half-lives. The variation of cumulative $2\nu\beta\beta$ NME with respect to the excitation energy of the intermediate $1^+$ states is also shown, and in all cases, it is ensured that their values are almost saturated. In the present work we have calculated more intermediate $1^+$ states as much as possible in comparison to results available in the literature.

nucl-th↗

arXiv2023

Systematic shell-model study of $^{98-130}$Cd isotopes and $8^+$ isomeric states

We present systematic shell-model studies of even-even $^{98-130}$Cd isotopes using a realistic effective shell-model interaction derived from the G-matrix approach with an inert core $^{88}$Sr. Our calculated low-lying excited energy spectra and electromagnetic properties are compared with the experimental data. On the basis of recently available experimental data, we predict spins and parities corresponding to unconfirmed states. We also discuss the properties of $8^+$ isomeric states in $^{98-104,130}$Cd isotopes.

nucl-th↗