Wed·Sep 21, 2022Wednesday·September 21, 2022

1. 01*

   Collective-model description of shape coexistence and intruder states in cadmium isotopes based on a relativistic energy density functional

   K. Nomura🇭🇷 · K.E. Karakatsanis🇬🇷

   Low-energy structure of even-even ${}^{108-116}$Cd isotopes is analyzed using a collective model that is based on the nuclear density functional theory. Spectroscopic properties are computed by solving the triaxial quadrupole collective Hamiltonian, with parameters determined by the constrained self-consistent mean-field calculations within the relativistic Hartree-Bogoliubov method employing a universal energy density functional and a pairing force. The collective Hamiltonian reproduces the observed quadrupole phonon states of vibrational character, which are based on the moderately deformed equilibrium minimum in the mean-field potential energy surface. In addition, the calculation yields a low-lying excited $0^{+}$ band and a $\gamma$-vibrational band that are associated with a deformed local minimum close in energy to the ground state, consistently with the empirical interpretation of these bands as intruder bands. Observed energy spectra, $B(E2)$, and ${\rho }^2(E0)$ values are, in general, reproduced reasonably well.

   ↳ nucl-thnucl-exPRC(2022)·9 citations
2. 02*

   Search for Majoron-like particles with CUPID-0

   CUPID-0 Collaboration: O. Azzolini🇮🇹 · J.W. Beeman🇺🇸 · F. Bellini🇮🇹 · M. Beretta🇮🇹 · M. Biassoni🇮🇹 · C. Brofferio🇮🇹 · C. Bucci🇮🇹 · S. Capelli🇮🇹 · V. Caracciolo🇮🇹 · L. Cardani🇮🇹 · P. Carniti🇮🇹 · N. Casali🇮🇹 and 40 other authors

   We present the first search for the Majoron-emitting modes of the neutrinoless double $\beta$ decay ($0\nu \beta \beta {\chi }_0$) using scintillating cryogenic calorimeters. We analysed the CUPID-0 Phase I data using a Bayesian approach to reconstruct the background sources activities, and evaluate the potential contribution of the ${}^{82}$Se $0\nu \beta \beta {\chi }_0$. We considered several possible theoretical models which predict the existence of a Majoron-like boson coupling to the neutrino. The energy spectra arising from the emission of such bosons in the neutrinoless double $\beta$ decay have spectral indices $n=$ 1, 2, 3 or 7. We found no evidence of any of these decay modes, setting a lower limit (90% of credibility interval) on the half-life of 1.2 $\times$ 10${}^{23}$ yr in the case of $n=$ 1, 3.8 $\times$ 10${}^{22}$ yr for $n=$ 2, 1.4 $\times$ 10${}^{22}$ yr for $n=$ 3 and 2.2 $\times$ 10${}^{21}$ yr for $n=$ 7. These are the best limits on the $0\nu \beta \beta {\chi }_0$ half-life of the ${}^{82}$Se, and demonstrate the potentiality of the CUPID-0 technology in this field.

   ↳ hep-exnucl-exphysics.ins-detPRD(2023)·19 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.