Fri·Mar 1, 2024Friday·March 1, 2024

1. 01*

   Transverse asymmetry of individual $\gamma$-rays in the ${}^{139}$La($\vec{n}$, $\gamma$)${}^{140}$La reaction

   M.Okuizumi🇯🇵 · C.J.Auton🇯🇵 · S.Endo🇯🇵 · H.Fujioka🇯🇵 · K.Hirota🇯🇵 · T.Ino🇯🇵 · K.Ishizaki🇯🇵 · A.Kimura🇯🇵 · M.Kitaguchi🇯🇵 · J.Koga · S.Makise🇯🇵 · Y.Niinomi and 12 other authors

   The enhancement of the parity-violating asymmetry in the vicinity of $p$-wave compound nuclear resonances was observed for a variety of medium-heavy nuclei. The enhanced parity-violating asymmetry can be understood using the $s$-$p$ mixing model. The $s$-$p$ mixing model predicts several neutron energy-dependent angular correlations between the neutron momentum ${\vec{k}}_n$, neutron spin ${\vec{\sigma }}_n$, $\gamma$-ray momentum ${\vec{k}}_{\gamma }$, and $\gamma$-ray polarization ${\vec{\sigma }}_{\gamma }$ in the $(n,\gamma )$ reaction. In this paper, the improved value of the transverse asymmetry of $\gamma$-ray emissions, corresponding to a correlation term ${\vec{\sigma }}_n\cdot ({\vec{k}}_n\times {\vec{k}}_{\gamma })$ in the ${}^{139}\mathrm{La}(\vec{n},\gamma {)}^{140}\mathrm{La}$ reaction, and the transverse asymmetries in the transitions to several low excited states of ${}^{140}\mathrm{La}$ are reported.

   nucl-exPRC(2025)·1 citation
2. 02*

   A direct probe of $\Lambda$ potential in nuclear medium

   Gao-Chan Yong🇨🇳

   Using the Liège intranuclear-cascade model together with the ablation model ABLA, an investigation is conducted into the effects of $\Lambda$ potential in $\Lambda$-nucleus and $\Lambda$-hypernucleus-nucleus collisions across various beam energies. The findings show that the angle and transverse-momentum distributions of scattered $\Lambda$ hyperon, the scattering cross section of the $\Lambda$ hyperon in $\Lambda$-nucleus collisions as well as the rapidity distribution of $\Lambda$ hyperon in $\Lambda$-hypernucleus-nucleus collisions are significantly influenced by the strength of the $\Lambda$ potential in these scattering reactions across various beam energies. These demonstrations, unhindered by the uncertainties of $\Lambda$ and hypernuclei productions in nuclear medium, allow for a direct investigation of the $\Lambda$ potential, especially its momentum dependence. The criticality of probing the $\Lambda$ potential is closely associated with the resolution of the "hyperon puzzle" in neutron stars.

   ↳ nucl-thhep-exhep-phnucl-exPLB(2024)·4 citations
3. 03*

   Slicing Pomerons in ultraperipheral collisions using forward neutrons from nuclear breakup

   M. Alvioli (CNR IRPI, Perugia and INFN, Perugia)🇮🇹 · V. Guzey (Jyvaskyla U. and Helsinki Inst. of Phys.)🇫🇮 · M. Strikman (Penn State U.)🇺🇸

   We argue that measurements of forward neutrons from nuclear breakup in inclusive high energy photon-nucleus ($\gamma A$) scattering provide a novel way to study small-$x$ dynamics of QCD in heavy-ion ultraperipheral collisions (UPCs). Using models for hadronic fluctuations of the real photon and neutron emission in nuclear fragmentation, we calculate the distribution over the number of evaporation neutrons produced in $\gamma Pb$ collisions at the LHC. We show that it is correlated with the number of wounded nucleons (inelastic collisions) and, hence, can constrain the mechanism of nuclear shadowing and its $x$ dependence.

   ↳ hep-phhep-exnucl-exPRC(2024)·9 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.