Fri·Sep 19, 2025Friday·September 19, 2025

1. 01*

   Aspects of Single Particle Excitations and Collectivity in ${}^{69}$Ga

   Anil Sharma · S. Nandi🇫🇷 · S. Samanta🇮🇳 · S. Kundu · A. Das · S. S. Ghugre🇮🇳 · S. S. Tiwary · I. Bala · R. P. Singh · S. Muralithar · R. Raut🇮🇳

   The excitation scheme of the ${}^{69}$Ga ($Z=31,N=38$) nucleus has been studied following its population in ${}^{59}$Co(${}^{13}$C,2pn) reaction at $E_{lab}=45,50$ MeV, and using an array of Compton suppressed HPGe clover detectors as the detection system. The existing level scheme has been considerably extended with identification of new $\gamma$-ray transitions and their multipolarity assignments. The level energies have been calculated in the framework of the large basis shell model and their overlap with the experimental values has been satisfactory, subject to the choice of the interaction. The band structures identified in the nucleus have been characterized with the Moment of Inertia (MOI) and aligned angular momentum, and compared to those of the similar structures in the neighboring isotopes. The shapes corresponding to these bands have been probed in the light of their Total Routhian Surface (TRS) that exhibited varied deformation characteristics, such as prolate and $\gamma$-softness, associated with the individual sequences. Further, evidence of strong octupole correlation has been identified from an E3 transition between bands of opposite parities. The study comprehensively brings forth multiple aspects of single particle and collective characteristics in the level structure of ${}^{69}$Ga.

   nucl-exPRC(2026)·2 citations
2. 02*

   Refining the deep sub-barrier 12C+12C excitation function with STELLA

   J. Nippert🇫🇷 · S. Courtin🇫🇷 · M. Heine🇫🇷 · D.G. Jenkins🇬🇧 · P. Adsley🇫🇷 · A. Bonhomme🇫🇷 · R. Canavan🇬🇧 · D. Curien🇫🇷 · T. Dumont🇫🇷 · E. Gregor🇫🇷 · G. Harmant🇫🇷 · E. Monpribat🇫🇷 and 18 other authors

   Purpose: We have investigated the cross section around the lowest direct coincident gamma-particle measurements, where previously only limits could be established with the aim of obtaining a detailed description of the excitation function. We have furthermore analysed the ratio of extreme decay branching into the first excited state of daughter nuclei with alpha or proton emission at relative kinetic energies where previous measurements are in disagreement with each other. Conclusions: Our findings in the astrophysics RoI support reaction-rate models with a lower average S-factor trend, that deviates significantly from standard extrapolations between 2.2 MeV and 2.6 MeV, for stellar carbon burning simulations of up to 25 Msol stars. Based on our data, an overall increase of the S-factor at deep subbarrier energy cannot be confirmed. The extremely low ratio of the branching into the first excited state with proton over alpha emission of ~ 2% at 3.23 MeV might indicate the presence of alpha cluster compound states in 24Mg. This highly favours {\alpha} emission with fundamental consequences in possible stellar carbon burning sites.

   nucl-exastro-ph.HEastro-ph.SRnucl-thPRC(2025)·5 citations
3. 03*

   Secondary bow with ripples in ${}^{12}$C+${}^{12}$C rainbow scattering

   S. Ohkubo · Y. Hirabayashi🇯🇵

   We report, {for the first time, the emergence of} a secondary bow with ripples in ${}^{12}$C+${}^{12}$C nuclear rainbow scattering. This finding was achieved by studying the experimental angular distributions in ${}^{12}$C+${}^{12}$C scattering at incident energies $E_L$= 240 and 300 MeV, utilizing an extended double-folding model. This model accurately describes all diagonal and off-diagonal coupling potentials derived from the microscopic wave functions for ${}^{12}$C. Although the observed angular distributions of rainbow scattering at large angles (approaching $90^{\circ }$) are complicated by the symmetrization of two identical bosonic nuclei, the Airy minimum, associated with a dynamically generated secondary bow with ripples, is clearly identified at approximately 77${}^{\circ }$ for 240 MeV in the fall-off region of the primary nuclear rainbow. This {finding}, along with previous findings in the ${}^{16}$O+${}^{12}$C and ${}^{13}$C+${}^{12}$C systems, {reinforces} the concept of a secondary bow in nuclear rainbow scattering.

   ↳ nucl-thnucl-exEPJA(2025)·2 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.