Thu·Mar 9, 2017Thursday·March 9, 2017

1. 01*

   Improved Quark Coalescence for a Multi-Phase Transport Model

   Yuncun He🇨🇳 · Zi-Wei Lin🇺🇸

   The string melting version of a multi-phase transport model is often applied to high-energy heavy-ion collisions since the dense matter thus formed is expected to be in parton degrees of freedom. In this work we improve its quark coalescence component, which describes the hadronization of the partonic matter to a hadronic matter. We removed the previous constraint that forced the numbers of mesons, baryons, and antibaryons in an event to be separately conserved through the quark coalescence process. A quark now could form either a meson or a baryon depending on the distance to its coalescence partner(s). We then compare results from the improved model with the experimental data on hadron $dN/dy$, $p_{{}_{\mathrm{T}}}$ spectra, and $v_2$ in heavy-ion collisions from $\sqrt{s_{{}_{\mathrm{NN}}}}=62.4$ GeV to $5.02$ TeV. We show that, besides being able to describe these observables for low-$p_{{}_{\mathrm{T}}}$ pions and kaons, the improved model also better describes the low-$p_{{}_{\mathrm{T}}}$ baryon observables in general, especially the baryon $p_{{}_{\mathrm{T}}}$ spectra and antibaryon-to-baryon ratios for multistrange baryons.

   ↳ nucl-thnucl-exPRC(2017)·103 citations
2. 02*

   Quantum tunneling with friction

   M. Tokieda · K. Hagino

   Using the phenomenological quantum friction models introduced by Caldirola-Kanai, Kostin, and Albrecht, we study quantum tunneling of a one-dimensional potential in the presence of energy dissipation. To this end, we calculate the tunneling probability using a time-dependent wave packet method. The friction reduces the tunneling probability. We show that the three models provide similar penetrabilities to each other, among which the Caldirola-Kanai model requires the least numerical effort. We also discuss the effect of energy dissipation on quantum tunneling in terms of barrier distributions.

   ↳ nucl-thnucl-exquant-phPRC(2017)·18 citations
3. 03*

   Onset of $\eta$-nuclear binding in a pionless EFT approach

   N. Barnea🇮🇱 · B. Bazak🇫🇷 · E. Friedman🇮🇱 · A. Gal🇮🇱

   $\eta NNN$ and $\eta NNNN$ bound states are explored in stochastic variational method (SVM) calculations within a pionless effective field theory (EFT) approach at leading order. The theoretical input consists of regulated $NN$ and $NNN$ contact terms, and a regulated energy dependent $\eta N$ contact term derived from coupled-channel models of the $N^{\ast }(1535)$ nucleon resonance plus a regulated $\eta NN$ contact term. A self consistency procedure is applied to deal with the energy dependence of the $\eta N$ subthreshold input, resulting in a weak dependence of the calculated $\eta$-nuclear binding energies on the EFT regulator. It is found, in terms of the $\eta N$ scattering length $a_{\eta N}$, that the onset of binding $\eta {}^3$He requires a minimal value of Re$a_{\eta N}$ close to 1 fm, yielding then a few MeV $\eta$ binding in $\eta {}^4$He. The onset of binding $\eta {}^4$He requires a lower value of Re$a_{\eta N}$, but exceeding 0.7 fm.

   ↳ nucl-thhep-phnucl-exPLB(2017)·37 citations
4. 04*

   Nuclear parton density functions from jet production in DIS at the EIC

   M. Klasen🇩🇪 · K. Kovarik🇩🇪 · J. Potthoff🇩🇪

   We investigate the potential of inclusive-jet production in deep-inelastic scattering (DIS) at a future Electron-Ion Collider (EIC) to improve our current knowledge of nuclear parton density functions (PDFs). We demonstrate that the kinematic reach is extended similarly to inclusive DIS, but that the uncertainty of the nuclear PDFs, in particular of the gluon density at low Bjorken-x, is considerably reduced, by up to an order of magnitude compared to the present situation. Using an approximate next-to-next-to-leading order (aNNLO) calculation implemented in the program JetViP, we also make predictions for three different EIC designs and for four different light and heavy nuclei.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2017)·36 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.