2020/03/09 by Shahariar Sarkar, Y. Iwata, Yoritaka Iwata +1
Physics and Astronomy · #Double beta decay #Isoscalar #Neutrino #Neutrino Physics Research #Nuclear physics #Nuclear physics research studies #Nucleon #Particle physics #Particle physics theoretical and experimental studies #Physics #nucl-th
paper · pdf · doi:10.1103/physrevc.102.034317
published as Phys. Rev. C 102, 034317 (2020) · 13 pages, 6 figures, to be submitted in PHYSICAL REV. C
arxiv created 2020/03/09 · openalex created_date 2020/03/13 · openalex publication_date 2020/09/14 · arxiv updated 2020/09/23 · openalex updated_date 2026/08/05
The \ensuremathλ and m_\ensuremathβ\ensuremathβ mechanisms of neutrinoless double beta decay (0\ensuremathν\ensuremathβ\ensuremathβ) occur with light neutrino exchange via WL\ensuremath-WR and WL\ensuremath-WL mediation, respectively. In the present study, we calculate the nuclear matrix elements (NMEs) for the m_\ensuremathβ\ensuremathβ and \ensuremathλ mechanisms of 0\ensuremathν\ensuremathβ\ensuremathβ, which has origin in the left-right symmetric model with right-handed gauge boson at TeV scale. The NMEs are calculated for one of the 0\ensuremathν\ensuremathβ\ensuremathβ decaying isotope 48Ca in the interacting nuclear shell-model using the GXPF1A effective interaction of pf shell. The NMEs are calculated in both closure and nonclosure approaches using four different methods: closure, running closure, running nonclosure, and mixed methods. All the NMEs are calculated incorporating the effects of the finite size of nucleons and the revisited higher-order terms such as pseudoscalar and weak magnetism terms of the nucleon currents. Inclusion of the short-range nature of nucleon-nucleon interaction in Miller-Spencer, CD-Bonn, and AV18 parametrizations is also taken care of. We have used closure energy \ensuremath⟨E\ensuremath⟩=0.5 MeV, which is near to the optimal value of closure energy that is extracted by examining the dependence of NMEs with closure energy in closure and mixed methods. The comparative dependence of the running closure and running nonclosure NMEs with the spin-parity of the allowed states of intermediate nucleus 48Sc, the coupled spin-parity of the two initial decaying neutrons and the final two protons, the cutoff excitation energy of 48Sc, and the cutoff number of states of 48Sc are examined. The neutrino momentum and radial distribution of different types of NMEs are explored. It is found that there is a significant enhancement in MqGT-type NMEs, which originates from the large momentum distribution for the inclusion of the higher-order pseudoscalar term of the nucleon currents.