Mon·Nov 29, 2021Monday·November 29, 2021

1. 01*

   Charge-changing cross sections for ${}^{42\text{–}51}$Ca and effect of charged-particle evaporation induced by neutron removal reaction

   M. Tanaka🇯🇵 · M. Takechi🇩🇪 · A. Homma · A. Prochazka · M. Fukuda · D. Nishimura🇯🇵 · T. Suzuki🇯🇵 · T. Moriguchi · D.S. Ahn🇯🇵 · A. Aimaganbetov · M. Amano · H. Arakawa and 56 other authors

   Charge-changing cross sections ${\sigma }_{\mathrm{CC}}$ for ${}^{42\text{–}51}$Ca on a carbon target at around 280~MeV/nucleon have been measured. The measured ${\sigma }_{\mathrm{CC}}$ values differ significantly from the previously developed calculations based on the Glauber model. However, through introduction of the charged-particle evaporation effect induced by the neutron-removal reaction in addition to the Glauber-model calculation, experimental ${\sigma }_{\mathrm{CC}}$ values on ${}^{12}$C at around 300~MeV/nucleon for nuclides from C to Fe isotopes are all reproduced with approximately 1\% accuracy. This proposed model systematically reproduces ${\sigma }_{\mathrm{CC}}$ data without phenomenological corrections, and can also explain experimental ${\sigma }_{\mathrm{CC}}$ values obtained in other energy regions.

   nucl-exnucl-thPRC(2022)·21 citations
2. 02*

   Multi-Source Thermal Model Describing Transverse Momentum Spectra of Final-State Particles in High Energy Collisions

   Fu-Hu Liu🇨🇳 · Jia-Yu Chen🇨🇳 · Qiang Zhang🇨🇳

   In this mini review article, the transverse momentum spectra of final-state particles produced in high energy hadron-hadron, hadron-nucleus, and nucleus-nucleus collisions described by the multi-source thermal model at the quark or parton level is summarized. In the model, the participant or contributor quarks or partons are considered to contribute together to the transverse momentum distribution of final-state particles with different modes of contributions. The concrete mode of contribution is generally determined by the difference of azimuthal angles of contributor partons in their emissions.

   ↳ hep-phhep-exnucl-exnucl-thAdv.High Energy Phys.(2022)·4 citations
3. 03*

   $D^{+}{D}^{-}$ hadronic atom and its production in $pp$ and $p\bar{p}$ collisions

   Pan-Pan Shi🇨🇳 · Zhen-Hua Zhang🇨🇳 · Feng-Kun Guo🇨🇳 · Zhi Yang🇨🇳

   There must be Coulomb bound states of a pair of hadrons, which are stable against the strong interaction, with opposite electric charges. Such bound states are hadronic atoms. We study the properties and the production of the ground-state $D^{+}{D}^{-}$ hadronic atom $A_{D^{+}{D}^{-}}$, called dionium, with quantum numbers $J^{PC}=0^{++}$. Using a nonrelativistic effective field theory for the $D^0{\bar{D}}^0$-$D^{+}{D}^{-}$ coupled-channel system, the mass of the ground-state dionium is predicted to be $(3739.3\pm 0.1)\text{MeV}$, with the binding energy reduced by about 10% compared to the Coulomb binding energy due to the strong interaction. Its width for the decay into the neutral $D^0{\bar{D}}^0$ channel is predicted to be $1.8_{-0.6}^{+1.4}$ keV using lattice inputs for the $D\bar{D}$ strong interaction. The cross section for the inclusive prompt production of the dionium at CMS and LHCb and that for the direct production $p\bar{p}\to A_{D^{+}{D}^{-}}$ at PANDA are estimated at an order-of-magnitude level. In particular, we expect that $\mathcal{O}(10^3\sim 10^5)$ events of the reaction chain $p\bar{p}\to A_{D^{+}{D}^{-}}\to D^0{\bar{D}}^0\to K^{-}{\pi }^{+}{K}^{+}{\pi }^{-}$ can be collected at PANDA, and valuable information on the charmed meson interaction and on understanding charmoniumlike states will be obtained.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2022)·13 citations
4. 04*

   Bottomonium observables in an open quantum system using the quantum trajectories method

   Peter Vander Griend🇩🇪

   We solve the Lindblad equation describing the Brownian motion of a Coulombic heavy quark-antiquark pair in a strongly coupled quark gluon plasma using the Monte Carlo wave function method. The Lindblad equation has been derived in the framework of pNRQCD and fully accounts for the quantum and non-Abelian nature of the system. The hydrodynamics of the plasma is realistically implemented through a 3+1D dissipative hydrodynamics code. We compute the bottomonium nuclear modification factor and elliptic flow and compare with the most recent LHC data. The computation does not rely on any free parameter, as it depends on two transport coefficients that have been evaluated independently in lattice QCD. Our final results, which include late-time feed down of excited states, agree well with the available data from LHC 5.02 TeV PbPb collisions.

   ↳ hep-phnucl-exnucl-thphysics.comp-phEPJ Web Conf.(2022)·4 citations
5. 05*

   Collectivity of $J/\psi$ Mesons in Heavy-Ion Collisions

   Min He🇨🇳 · Biaogang Wu🇺🇸 · Ralf Rapp🇺🇸

   The production of $J/\psi$ mesons in heavy-ion collisions at the Large Hadron Collider is believed to be dominated by the recombination of charm and anti-charm quarks in a hot QCD medium. However, measurements of the elliptic flow ($v_2$) of $J/\psi$ mesons in these reactions are not well described by existing calculations of $J/\psi$ recombination for transverse momenta $p_T\ge$4 GeV. Here, we revisit these calculations in two main aspects. By employing the resonance recombination model, we implement distribution functions of charm quarks transported through the quark-gluon plasma using state-of-the-art Langevin simulations, and we account for the space-momentum correlations of the diffusing charm and anti-charm quarks in the hydrodynamically expanding fireball. These improvements extend the relevance of the recombination processes to substantially larger momenta than before. In addition, we revisit the suppression of the primordially produced $J/\psi$ mesons by propagating them through the same hydrodynamic medium, leading to a marked increase of the $v_2$ of this component over previous estimates. Combining these developments into a calculation of the $p_T$-dependent nuclear modification factor and $v_2$ of inclusive $J/\psi$ production in semi-central Pb-Pb collisions at the LHC, we find a good description of the experimental results by the ALICE collaboration. Our results thus resolve the above-mentioned $v_2$ puzzle and imply the relevance of recombination processes for $p_T$'s of up to $\sim$8 GeV.

   ↳ nucl-thhep-phnucl-exPRL(2022)·53 citations
6. 06*

   How many particles do make a fluid? Qualifying collective behavior in expanding ultracold gases

   Stefan Floerchinger🇩🇪 · Giuliano Giacalone🇩🇪 · Lars H. Heyen🇩🇪 · Leena Tharwat🇩🇪

   Collective phenomena in quantum many-body systems are often described in terms of hydrodynamics, an appropriate framework when the involved particle numbers are effectively macroscopic. We propose to use experiments on expanding clouds of few and many interacting cold atoms to investigate the emergence of hydrodynamics as a function of particle number. We consider gases confined in two-dimensional elliptically-deformed traps, and we employ the manifestation of elliptic flow as an indicator of collective behavior. We quantify the response of the gas to the deformation of the trapping potential, and show how such information can be used to establish how many atoms are needed for the system to develop a degree of collectivity comparable to that expected in the hydrodynamic limit. This method permits one, in particular, to exploit observations made in expanding atomic gases to shed light on the apparent hydrodynamic behaviour of mesoscopic systems of quarks and gluons formed in the scattering of light ions in high-energy collider experiments.

   ↳ cond-mat.quant-gasnucl-exnucl-thPRC(2022)·16 citations
7. 07*

   Heavy-Light Susceptibilities in a Strongly Coupled Quark-Gluon Plasma

   Shuai Y. F. Liu🇨🇳 · Ralf Rapp🇺🇸

   Quark number susceptibilities as computed in lattice QCD are commonly believed to provide insights into the microscopic structure of QCD matter, in particular its degrees of freedom. We generalize a previously constructed partonic $T$-matrix approach to finite chemical potential to calculate various susceptibilities, in particular for configurations containing a heavy charm quark. At vanishing chemical potential and moderate temperatures, this approach predicts large collisional widths of partons generated by dynamically formed hadronic resonance states which lead to transport parameters characteristic for a strongly coupled system. The quark chemical potential dependence is implemented into the propagators and the in-medium color potential, where two newly introduced parameters for the thermal and screening masses are fixed through a fit to the baryon number susceptibility, ${\chi }_2^B$. With this setup, we calculate heavy-light susceptibilities without further tuning; the results qualitatively agree with the lattice-QCD (lQCD) data for both ${\chi }_{11}^{uc}$ and ${\chi }_{22}^{uc}$. This implies that the lQCD results are compatible with a significant content of broad $D$-meson and charm-light diquark bound states in a moderately hot QGP.

   ↳ hep-phhep-latnucl-exnucl-thPRC(2022)·10 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.