Thu·Jan 23, 2025Thursday·January 23, 2025

1. 01*

   Resonant suppression of the above-barrier fusion cross-section in ${}^{19}$O + ${}^{12}$C

   H. Desilets🇺🇸 · Rohit Kumar🇺🇸 · R. T. deSouza🇺🇸 · S. Hudan🇺🇸 · C. Ciampi🇫🇷 · A. Chbihi🇫🇷 · K. W. Brown🇺🇸 · K. Godbey🇺🇸 · B. Pinheiro🇧🇷 · E. N. Cardozo🇧🇷 · J. Lubian🇧🇷

   Fusion excitation functions for ${}^{19}$O and ${}^{19}$F + ${}^{12}$C were simultaneously measured along with ${}^{20}$O + ${}^{12}$C using the active-target detector MuSIC@Indiana. Examination of the cross-section just above the barrier reveals a significant suppression of fusion for the ${}^{19}$O + ${}^{12}$C system at E${}_{c.m.}$~12 MeV. This suppression may be due to the formation of a transient ${}^{18}$O-n-${}^{12}$C molecule-like complex favored at a particular angular momentum. Mean-field level models are used as a reference to understand the measured fusion excitation functions.

   nucl-exPLB(2025)·5 citations
2. 02*

   Measurement of the multiplicity dependence of $\text{mit}{\rm Y}$ production ratios in $pp$ collisions at $\sqrt{s}=13$ TeV

   LHCb collaboration: R. Aaij · A.S.W. Abdelmotteleb · C. Abellan Beteta · F. Abudinén · T. Ackernley · A. A. Adefisoye · B. Adeva · M. Adinolfi · P. Adlarson · C. Agapopoulou · C.A. Aidala · Z. Ajaltouni and 1139 other authors

   The $\text{mit}{\rm Y}(2S)$ and $\text{mit}{\rm Y}(3S)$ production cross-sections are measured relative to that of the $\text{mit}{\rm Y}(1S)$ meson, as a function of charged-particle multiplicity in proton-proton collisions at a centre-of-mass energy of $13$ TeV. The measurement uses data collected by the LHCb experiment in 2018 corresponding to an integrated luminosity of 2 ${\text{fb}}^{-1}$. Both the $\text{mit}{\rm Y}(2S)$-to-$\text{mit}{\rm Y}(1S)$ and $\text{mit}{\rm Y}(3S)$-to-$\text{mit}{\rm Y}(1S)$ cross-section ratios are found to decrease significantly as a function of event multiplicity, with the $\text{mit}{\rm Y}(3S)$-to-$\text{mit}{\rm Y}(1S)$ ratio showing a steeper decline towards high multiplicity. This hierarchy is qualitatively consistent with the comover model predictions, indicating that final-state interactions play an important role in bottomonia production in high-multiplicity events.

   ↳ hep-exnucl-exJHEP(2025)·13 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.