Thu·Nov 7, 2024Thursday·November 7, 2024

1. 01*

   Assessing the impact of uniform rotation on the structure of neutron stars

   Marc Salinas🇺🇸 · Jorge Piekarewicz🇺🇸

   Driven by recent laboratory experiments and astronomical observations, significant advances have deepened our understanding of neutron-star physics. NICER's Pulse Profile Modeling has refined our knowledge of neutron star masses and radii, while gravitational-wave detections have revealed key insights into the structure of neutron stars. Particularly relevant is the extraction of the tidal deformability by the LIGO-Virgo collaboration and the most recent determination of stellar radii by NICER, both suggesting a relatively soft equation of state (EOS) at intermediate densities. Additionally, measurements from the PREX collaboration and from pulsar timing suggest instead that the EOS is stiff in the vicinity of saturation density and at the highest densities accessible to date. But how stiff can the EOS be at these very high densities? Recent events featuring compact objects near the "lower mass gap" have raised questions about the existence of very massive neutron stars. Motivated by this finding and in light of new refinements to theoretical models, we explore the possibility that these massive objects may indeed be rapidly rotating neutron stars. We explore how rotation affects both the maximum neutron star mass and their associated radii, and discuss the implications they may have on the equation of state.

   ↳ nucl-thastro-ph.HEastro-ph.SRnucl-exPRC(2025)·3 citations
2. 02*

   A pathway to unveiling neutrinoless $\beta \beta$ decay nuclear matrix elements via $\gamma \gamma$ decay

   Beatriz Romeo🇪🇸 · Damiano Stramaccioni🇮🇹 · Javier Menéndez🇪🇸 · Jose Javier Valiente-Dobón🇮🇹

   We investigate the experimental feasibility of detecting second-order double-magnetic dipole ($\gamma \gamma$-$M1M1$) decays from double isobaric analog states (DIAS), which have recently been found to be strongly correlated with the nuclear matrix elements of neutrinoless $\beta \beta$ decay. Using the nuclear shell model, we compute theoretical branching ratios for $\gamma \gamma$-$M1M1$ decays and compare them with other competing processes, such as single-$\gamma$ decay and proton emission, which represent the dominant decay channels. We also estimate the potential competition from internal conversion and internal pair creation, which can influence the decay dynamics. Additionally, we propose an experimental strategy based on using LaBr${}_3$ scintillators to identify $\gamma \gamma$-$M1M1$ transitions from the DIAS amidst the background of the competing processes. Our approach emphasizes the challenges of isolating the rare $\gamma \gamma$-$M1M1$ decay and suggests ways to enhance the experimental detection sensitivity. Our simulations suggest that it may be possible to access experimentally $\gamma \gamma$-$M1M1$ decays from DIAS, shedding light on the neutrinoless $\beta \beta$ decay nuclear matrix elements.

   ↳ nucl-thhep-exhep-phnucl-exPLB(2025)·4 citations
3. 03*

   Characterization of newly developed large area SiC sensors for the NUMEN experiment

   D. Carbone🇮🇹 · A. Spatafora🇮🇹 · D. Calvo🇮🇹 · F. Guerra🇮🇹 · G.A. Brischetto🇮🇹 · F. Cappuzzello🇮🇹 · M. Cavallaro🇮🇹 · M. Ferrero🇮🇹 · F. La Via🇮🇹 · S. Tudisco (for the NUMEN collaboration)🇮🇹

   First prototypes of large area, p-n junction, silicon carbide (SiC) detectors have been produced as part of an ongoing programme to develop a new particle identification wall for the focal plane detector of the MAGNEX magnetic spectrometer, in preparation for future NUMEN experimental campaigns. First characterizations of sensors from two wafers obtained with epitaxial silicon carbide growth and with different doping concentration are presented. Current (I-V) and capacitance (C-V) characteristics are investigated in order to determine the full depletion voltage and the doping profile. Radioactive {\alpha}-sources are used to measure the energy resolution and estimate the depletion depth.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2024)·5 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.