Fri·Dec 14, 2018Friday·December 14, 2018

1. 01*

   Suppression of light nuclei production in collisions of small systems at the Large Hadron Collider

   Kai-Jia Sun🇺🇸 · Che Ming Ko🇺🇸 · Benjamin Dönigus🇩🇪

   We show that the recently observed suppression of the yield ratio of deuteron to proton and of helium-3 to proton in p+p collisions compared to those in p+Pb or Pb+Pb collisions by the ALICE Collaboration at the Large Hadron Collider (LHC) can be explained if light nuclei are produced from the coalescence of nucleons at the kinetic freeze-out of these collisions. This suppression is attributed to the non-negligible sizes of deuteron and helium-3 compared to the size of the nucleon emission source in collisions of small systems, which reduces the overlap of their internal wave functions with those of nucleons. The same model is also used to study the production of triton and hypertriton in heavy-ion collisions at the LHC. Compared to helium-3 in events of low charged particle multiplicity, the triton is less suppressed due to its smaller size and the hypertriton is even more suppressed as a result of its much larger size.

   ↳ nucl-thhep-phnucl-exPLB(2019)·129 citations
2. 02*

   Two-neutron transfer reactions and shape phase transitions in the microscopically-formulated interacting boson model

   K. Nomura🇭🇷 · Y. Zhang🇨🇳

   Two-neutron transfer reactions are studied within the interacting boson model based on the nuclear energy density functional theory. Constrained self-consistent mean-field calculations with the Skyrme energy density functional are performed to provide microscopic input to completely determine the Hamiltonian of the IBM. Spectroscopic properties are calculated only from the nucleonic degrees of freedom. This method is applied to study the $(t,p)$ and $(p,t)$ transfer reactions in the assorted set of rare-earth nuclei ${}^{146-158}$Sm, ${}^{148-160}$Gd, and ${}^{150-162}$Dy, where spherical-to-axially-deformed shape phase transition is suggested to occur at the neutron number $N\approx 90$. The results are compared with those from the purely phenomenological IBM calculations, as well as with the available experimental data. The calculated $(t,p)$ and $(p,t)$ transfer reaction intensities, from both the microscopic and phenomenological IBM frameworks, signal the rapid nuclear structural change at particular nucleon numbers.

   ↳ nucl-thnucl-exPRC(2019)·16 citations
3. 03*

   Photon-photon scattering in the resonance region at midrapidity at the LHC

   R.Schicker🇩🇪 · Mariola Klusek-Gawenda🇵🇱 · A. Szczurek🇵🇱

   A study is presented to extend the measurements of photon-photon scattering in ultra-peripheral Pb-Pb collisions at the LHC into the mass region of the pseudoscalar resonances $\eta$ and ${\eta }^{\prime }$. The elementary photon-photon scattering cross section is presented. The cross section for photon-photon scattering in Pb-Pb is derived by convoluting the elementary photon-photon cross section with the Pb-Pb photon luminosity. The main background to two-photon final states, arising from double ${\pi }^0$ production with two of the four decay photons escaping detection, is examined, and possible kinematical conditions are discussed to optimize the signal-to-background ratio for such measurements at mid-rapidity.

   ↳ hep-phnucl-exActa Phys.Polon.Supp.(2019)·0 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.