Thu·Sep 9, 2021Thursday·September 9, 2021

1. 01*

   Asymmetric longitudinal flow decorrelations in proton-nucleus collisions

   Xiang-Yu Wu🇨🇳 · Guang-You Qin🇨🇳

   We perform the first study on asymmetric longitudinal decorrelations of elliptic, triangular and quadrangular flows in proton-nucleus collisions at the LHC and RHIC energies. To measure the longitudinal flow decorrelations for asymmetric collision systems, we propose a new set of rapidity-asymmetric flow decorrelation functions. Our event-by-event hydrodynamic calculations show that the flow decorrelations in proton-going direction are larger than those in nucleus-going direction. We also find that proton-nucleus collisions at RHIC have larger longitudinal flow decorrelation effects than those at the LHC. Our study opens a new window to probe the longitudinal properties and the origin of flows in relativistic nuclear collisions.

   ↳ hep-phnucl-exnucl-th13 citations
2. 02*

   Effects of chiral symmetry restoration on meson and dilepton production in relativistic heavy-ion collisions

   A.B. Larionov🇷🇺 · L. von Smekal🇩🇪

   We include effects of chiral symmetry and its restoration in the kinetic equations for baryon propagation and explore the consequences for $\eta$, ${\pi }^0$, $\rho$ and dilepton production in heavy-ion collisions at 1-2A GeV. Numerical calculations are performed using the GiBUU microscopic transport model supplemented by the parity-doublet model for the mean fields of the nucleon and the $N^{\ast }(1535)$ resonance. In this chiral model, a strong dropping of the Dirac mass of the $N^{\ast }(1535)$ in the high-density stage of a collision leads to a considerable enhancement in the production of this resonance as compared to the standard (non-linear) Walecka model. As the system expands, the Dirac masses of these abundant soft $N^{\ast }(1535)$ resonances gradually increase and ultimately cross the $N\eta$ decay threshold. As a result, an enhanced low-energy $\eta$ production is observed in the calculations with chiral mean fields. Comparing with TAPS data on $\eta$ and ${\pi }^0$ production we find that the chiral model improves the agreement for the $m_t$-spectra of $\eta$'s at small $m_t$ in heavy colliding systems. A similar enhancement is also observed in the soft $\rho$ production due to chiral symmetry and its partial restoration. The resulting dilepton yields at low and intermediate invariant masses are slightly enhanced due to these chiral effects which further improve the agreement between GiBUU transport simulations and HADES data for C+C at 1A GeV.

   ↳ nucl-thhep-exhep-phnucl-exPRC(2022)·12 citations
3. 03*

   The Dynamics of Ions on Phased Radio-frequency Carpets in High Pressure Gases and Application for Barium Tagging in Xenon Gas Time Projection Chambers

   NEXT Collaboration: B.J.P. Jones🇺🇸 · A. Raymond🇺🇸 · K. Woodruff🇺🇸 · N. Byrnes🇺🇸 · A.A. Denisenko🇺🇸 · F.W. Foss🇺🇸 · K. Navarro🇺🇸 · D.R. Nygren🇺🇸 · T.T. Vuong🇺🇸 · C. Adams🇺🇸 · H. Almazán🇩🇪 · V. Álvarez🇪🇸 and 97 other authors

   Radio-frequency (RF) carpets with ultra-fine pitches are examined for ion transport in gases at atmospheric pressures and above. We develop new analytic and computational methods for modeling RF ion transport at densities where dynamics are strongly influenced by buffer gas collisions. An analytic description of levitating and sweeping forces from phased arrays is obtained, then thermodynamic and kinetic principles are used to calculate ion loss rates in the presence of collisions. This methodology is validated against detailed microscopic SIMION simulations. We then explore a parameter space of special interest for neutrinoless double beta decay experiments: transport of barium ions in xenon at pressures from 1 to 10 bar. Our computations account for molecular ion formation and pressure dependent mobility as well as finite temperature effects. We discuss the challenges associated with achieving suitable operating conditions, which lie beyond the capabilities of existing devices, using presently available or near-future manufacturing techniques.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(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.