Thu·Feb 18, 2021Thursday·February 18, 2021

1. 01*

   Some Aspects on Identification, Decay Properties and Nuclear Structure of the Heaviest Nuclei

   Fritz Peter Hessberger

   Synthesis of new elements at the upper border of the charts of nuclei and investigation of their decay properties and nuclear structure has been one of the main research topics in low energy nuclear physics since more than five decades. Main items are the quest for the heaviest nuclei that can exist and the verification of the theoretical predicted spherical proton and neutron shells at Z = 114, 120 or 126 and N = 172 or 184. The scope of the present paper is to illustrate some technical and physical aspects in investigation of the heaviest nuclei ('superheavy nuclei') and to critical discuss some selected results, which from a strict scientific point of view are not completely clear so far, making partly also suggestions for alternatively interpretations. A complete review of the whole field of superheavy element research, however, is out of the scope of this paper.

   nucl-ex1 citation
2. 02*

   Astrophysics with heavy-ion beams

   P. Senger🇩🇪

   The Facility for Antiproton and Ion Research (FAIR), an international accelerator centre, is under construction in Darmstadt, Germany. FAIR will provide high-intensity primary beams of protons and heavy-ions, and intense secondary beams of antiprotons and of rare short-lived isotopes. These beams, together with a variety of modern experimental setups, will allow to perform a unique research program on nuclear astrophysics, including the exploration of the nucleosynthesis in the universe, and the exploration of QCD matter at high baryon densities, in order to shed light on the properties of neutron stars, and the dynamics of neutron star mergers. The Compressed Baryonic Matter (CBM) experiment at FAIR will investigate collisions between heavy nuclei, and measure various diagnostic probes, which are sensitive to the high-density equation-of-state (EOS), and to the microscopic degrees-of-freedom of high-density matter. The CBM physics program will be discussed.

   nucl-exPhys.Scripta(2021)·18 citations
3. 03*

   $D{\bar{D}}^{\ast }$ scattering and ${\chi }_{c1}(3872)$ in nuclear matter

   M. Albaladejo🇺🇸 · J. M. Nieves🇪🇸 · L. Tolos🇪🇸

   We study the behaviour of the ${\chi }_{c1}(3872)$, also known as $X(3872)$, in dense nuclear matter. We begin from a picture in vacuum of the $X(3872)$ as a purely molecular $(D{\bar{D}}^{\ast }-c.c.)$ state, generated as a bound state from a heavy-quark symmetry leading-order interaction between the charmed mesons, and analyze the $D{\bar{D}}^{\ast }$ scattering $T-$matrix ($T_{D{\bar{D}}^{\ast }}$) inside of the medium. Next, we consider also mixed-molecular scenarios and, in all cases, we determine the corresponding $X(3872)$ spectral function and the $D{\bar{D}}^{\ast }$ amplitude, with the mesons embedded in the dense environment. We find important nuclear corrections for $T_{D{\bar{D}}^{\ast }}$ and the pole position of the resonance, and discuss the dependence of these results on the $D{\bar{D}}^{\ast }$ molecular component in the $X(3872)$ wave-function. These predictions could be tested in the finite-density regime that can be accessed in the future CBM and PANDA experiments at FAIR.

   ↳ hep-phhep-exhep-thnucl-ex+1PRC(2021)·23 citations
4. 04*

   Collider constraints on axion-like particles

   David d'Enterria🇨🇭

   The current status and future prospects of searches for axion-like particles (ALPs) at colliders, mostly focused on the CERN LHC, are summarized. Constraints on ALPs with masses above a few GeV that couple to photons, as well as to Z or Higgs bosons, have been set at the LHC through searches for new $a\to \gamma \gamma$ resonances in di-, tri-, and four-photon final states. Inclusive and exclusive diphotons in proton-proton and lead-lead collisions, pp, PbPb $\to a\to \gamma \gamma (+X)$, as well as exotic Z and Higgs boson decays, pp $\to \mathrm{Z},\mathrm{H}\to a\gamma \to 3\gamma$ and pp $\to \mathrm{H}\to aa\to 4\gamma$, have been analyzed. Exclusive searches in PbPb collisions provide the best exclusion limits for ALP masses $m_a\approx 5-$100 GeV, whereas the other channels are the most competitive ones over $m_a\approx 100$ GeV$-$2.6 TeV. Integrated ALP production cross sections up to $\sim$100 nb are excluded at 95% confidence level, corresponding to constraints on axion-photon couplings down to $g_{a\gamma }\approx$ 0.05 TeV${}^{-1}$, over broad mass ranges. Factors of 10$-$100 improvements in these limits are expected at the LHC approaching $g_{a\gamma }\approx 10^{-3}$ TeV${}^{-1}$ over $m_a\approx 1$ GeV$-$5 TeV in the next decade.

   ↳ hep-exhep-phnucl-exnucl-th87 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.