Nuclear Theory·nucl-th

Thursday·December 14, 2017

9 papers—6 primary·3 cross-listed

07
[Submitted on 12 Dec 2017] (cross-list from hep-ph)
Incoherent diffractive photoproduction of $J / ψ$ and $Υ$ on heavy nuclei in the color dipole approach
Agnieszka Łuszczak🇩🇪 · Wolfgang Schäfer🇵🇱
We calculate cross sections and transverse momentum distributions for the incoherent diffractive production of vector mesons $J / ψ$ and $Υ$ on heavy nuclei. In distinction to coherent diffraction, the nucleus is allowed to break up, but except for the vector meson no new particles are produced in the reaction. Within the color dipole approach, we derive the multiple scattering expansion of the incoherent diffractive cross section as an expansion over quasielastic scatterings of the color dipole. We also compare our results to the measurement of the ALICE collaboration for incoherent $J / ψ$ production at $s_{NN} = 2.76 TeV$ and show predictions at $s_{NN} = 5.02 TeV$ . We also briefly discuss a possible contribution to $J / ψ$ production in peripheral collisions in the $70 \div 90%$ centrality class.
Comments:
18 pages, 8 figs
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1712.04502 [pdf]
PRC(2018)·21 citations
08
[Submitted on 13 Dec 2017] (cross-list from hep-ph)
Revisiting the axial anomaly for light mesons and baryons
Francesco Giacosa🇩🇪
The axial anomaly is responsible for the masses and mixing of the mesons $η$ and $η^{'}$ . An open question is if (and to what extent) it affects also other hadrons. We show that anomalous terms can be important to understand the spectroscopy of the pseudotensor mesons $η_{2} (1645)$ and $η_{2} (1870)$ . In fact, pseudotensor mesons belong to a so-called heterochiral multiplet, for which a quadratic mixing term between nonstrange and strange isoscalar members arises. On the contrary, for so-called homochiral multiplets, such as the ground-state (axial-)vector and tensor mesons, this mixing is not possible, hence one can easily understand why the isoscalar members of these multiplets are almost purely nonstrange and strange, respectively. Moreover, the axial anomaly can be also coupled to baryons (within the mirror assignment), and thus it helps to explain the large decay width $N^{*} (1535) \to N η$ and to clarify which baryons are chiral partners.
Comments:
6 pages. Prepared for the proceedings of the XVII International Conference on Hadron Spectroscopy and Structure - Hadron2017, 25-29 September, 2017, University of Salamanca, Salamanca, Spain
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1712.04664 [pdf]
PoS(2018)·3 citations
09
[Submitted on 13 Dec 2017] (cross-list from hep-ph)
Lepton-rich cold QCD matter in protoneutron stars
J. C. Jiménez🇧🇷 · E. S. Fraga🇧🇷
We investigate protoneutron star matter using the state-of-the-art perturbative equation of state for cold and dense QCD in the presence of a fixed lepton fraction in which both electrons and neutrinos are included. Besides computing the modifications in the equation of state due to the presence of trapped neutrinos, we show that stable strange quark matter has a more restricted parameter space. We also study the possibility of nucleation of unpaired quark matter in the core of protoneutron stars by matching the lepton-rich QCD pressure onto a hadronic equation of state, namely TM1 with trapped neutrinos. Using the inherent dependence of perturbative QCD on the renormalization scale parameter, we provide a measure of the uncertainty in the observables we compute.
Comments:
9 pages, 9 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
1712.04773 [pdf]
PRD(2018)·7 citations

Affiliations

first authorsco-authorsvia INSPIRE

Incoherent diffractive photoproduction of J/ψ and Υ on heavy nuclei in the color dipole approach

Revisiting the axial anomaly for light mesons and baryons

Lepton-rich cold QCD matter in protoneutron stars

Affiliations

Incoherent diffractive photoproduction of $J / ψ$ and $Υ$ on heavy nuclei in the color dipole approach