Nuclear Theory·nucl-th

Thursday·December 24, 2015

14 papers—6 primary·8 cross-listed

07
Using Wilson flow to study the SU(3) deconfinement transition
Saumen Datta🇮🇳 · Sourendu Gupta🇮🇳 · Andrew Lytle🇮🇳
We explore the use of Wilson flow to study the deconfinement transition in SU(3) gauge theory. We use the flowed Polyakov loop as a renormalized order parameter for the transition, and use it to renormalize the Polyakov loop. We also study the flow properties of the electric and magnetic gluon condensates, and demonstrate that the difference of the flowed operators shows rapid change across the transition point.
↳ hep-lathep-phnucl-thPRD(2016)·25 citations
08
Mesons in strong magnetic fields: (I) General analyses
Koichi Hattori🇯🇵 · Toru Kojo🇨🇳 · Nan Su🇩🇪
We study properties of neutral and charged mesons in strong magnetic fields |eB|>> Lambda_QCD^2 with Lambda_QCD being the QCD renormalization scale. Assuming long-range interactions, we examine magnetic-field dependences of various quantities such as the constituent quark mass, chiral condensate, meson spectra, and meson wavefunctions by analyzing the Schwinger-Dyson and Bethe-Salpeter equations. Based on the density of states obtained from these analyses, we extend the hadron resonance gas (HRG) model to investigate thermodynamics at large B. As B increases the meson energy behaves as a slowly growing function of the meson's transverse momenta, and thus a large number of meson states is accommodated in the low energy domain; the density of states at low temperature is proportional to B^2. This extended transverse phase space in the infrared regime significantly enhances the HRG pressure at finite temperature, so that the system reaches the percolation or chiral restoration regime at lower temperature compared to the case without a magnetic field; this simple picture would offer a gauge invariant and intuitive explanation of the inverse magnetic catalysis.
↳ hep-phhep-lathep-thnucl-thNPA(2016)·75 citations
09
Modification of generalized vector form factors and transverse charge densities of the nucleon in nuclear matter
Ju-Hyun Jung🇦🇹 · Ulugbek Yakhshiev🇰🇷 · Hyun-Chul Kim🇰🇷
We investigate the medium modification of the generalized vector form factors of the nucleon, which include the electromagnetic and energy-momentum tensor form factors, based on an in-medium modified $π$ - $ρ$ - $ω$ soliton model. We find that the vector form factors of the nucleon in nuclear matter fall off faster than those in free space, which implies that the charge radii of the nucleon become larger in nuclear medium than in free space. We also compute the corresponding transverse charge densities of the nucleon in nuclear matter, which clearly reveal the increasing of the nucleon size in nuclear medium.
↳ hep-phhep-latnucl-thPRD(2016)·10 citations
10
The impact of the medium and the jet-medium coupling on jet measurements at RHIC and LHC
Barbara Betz🇩🇪 · Florian Senzel🇩🇪 · Carsten Greiner🇩🇪 · Miklos Gyulassy🇨🇳
We compare a perturbative QCD-based jet-energy loss model to the measured data of the pion nuclear modification factor and the high-pT elliptic flow at RHIC and LHC energies. This jet-energy loss model (BBMG) is currently coupled to state-of-the-art hydrodynamic descriptions. We report on a model extension to medium backgrounds generated by the parton cascade BAMPS. In addition, we study the impact of realistic medium transverse flow fields and a jet-medium coupling which includes the effects of the jet energy, the temperature of the bulk medium, and non-equilibrium effects close to the phase transition. By contrasting the two different background models, we point out that the description of the high-pT elliptic flow for a non-fluctuating medium requires to include such a jet-medium coupling and the transverse flow fields. While the results for both medium backgrounds show a remarkable similarity, there is an impact of the background medium and the background flow on the high-pT elliptic flow.
↳ hep-phhep-exnucl-th3 citations
11
Double vector meson production in $γ γ$ interactions at hadronic colliders
V. P. Goncalves🇸🇪 · B. D. Moreira🇧🇷 · F. S. Navarra🇧🇷
In this paper we revisit the double vector meson production in $γ γ$ interactions at heavy ion collisions and present, by the first time, predictions for the $ρρ$ and $J /Ψ J /Ψ$ production in proton -- nucleus and proton -- proton collisions. In order to obtain realistic predictions for rapidity distributions and total cross sections for the double vector production in ultra peripheral hadronic collisions we take into account of the description of $γ γ \to V V$ cross section at low energies as well as its behaviour at large energies, associated to the gluonic interaction between the color dipoles. Our results demonstrate that the double $ρ$ production is dominated by the low energy behaviour of the $γ γ \to V V$ cross section. In contrast, for the double $J /Ψ$ production, the contribution associated to the description of the QCD dynamics at high energies contributes significantly, mainly in $pp$ collisions. Predictions for the RHIC, LHC, FCC and CEPC - SPPC energies are shown.
↳ hep-phhep-exnucl-exnucl-thEPJC(2016)·24 citations
12
The $η^{'}$ transition form factor from space- and time-like experimental data
Rafel Escribano🇪🇸 · Sergi Gonzalez-Solis🇪🇸 · Pere Masjuan🇩🇪 · Pablo Sanchez-Puertas🇩🇪
The $η^{'}$ transition form factor is reanalyzed in view of the recent BESIII first observation of the Dalitz decay $η^{'} \to γ e^{+} e^{-}$ in both space- and time-like regions at low and intermediate energies using the Padé approximants method. The present analysis provides a suitable parameterization for reproducing the measured form factor in the whole energy region and allows to extract the corresponding low-energy parameters together with a prediction of its values at the origin, related to $Γ_{η^{'} \to γ γ}$ , and the asymptotic limit. The $η$ - $η^{'}$ mixing is reassessed within a mixing scheme compatible with the large- $N_{c}$ chiral perturbation theory at next-to-leading order, with particular attention to the OZI-rule--violating parameters. The $J / ψ$ , $Z \to η^{(')} γ$ decays are also considered and predictions reported.
↳ hep-phhep-exnucl-thPRD(2016)·105 citations
13
Heavy-flavour transport: from large to small systems
A. Beraudo🇮🇹 · A. De Pace🇮🇹 · M. Monteno🇮🇹 · M. Nardi🇮🇹 · F. Prino🇮🇹
Predictions for heavy-flavour production in relativistic heavy-ion experiments provided by the POWLANG transport setup, including now also an in-medium hadronization model, are displayed, After showing some representative findings for the Au-Au and Pb-Pb cases, a special focus will be devoted to the results obtained in the small systems formed in proton(deuteron)-nucleus collisions, where recent experimental data suggest the possible formation of a medium featuring a collective behaviour.
↳ hep-phnucl-exnucl-thNPA(2016)·1 citation
14
Jet formation and interference in a thin QCD medium
Jorge Casalderrey-Solana🇬🇧 · Daniel Pablos🇪🇸 · Konrad Tywoniuk🇪🇸
In heavy-ion collisions, an abundant production of high-energy QCD jets allows to study how these multiparticle sprays are modified as they pass through the quark-gluon plasma. In order to shed new light on this process, we compute the inclusive two-gluon rate off a hard quark propagating through a color deconfined medium at first order in medium opacity. We explicitly impose an energy ordering of the two emitted gluons, such that the "hard" gluon can be thought of as belonging to the jet substructure while the other is a "soft" emission (which can be collinear or medium-induced). Our analysis focusses on two specific limits that clarify the modification of the additional angle- and formation time-ordering of splittings. In one limit, the formation time of the "hard" gluon is short compared to the "soft" gluon formation time, leading to a probabilistic formula for production of and subsequent radiation off a quark-gluon antenna. In the other limit, the ordering of formation is reverted, which automatically leads to the fact that the jet substructure is resolved by the medium. We observe in this case a characteristic delay: the jet radiates as one color current (quark) up to the formation of the "hard" gluon, at which point we observe the onset of radiation of the new color current (gluon). Our computation supports a picture in which the in-medium jet dynamics are described as a collection of subsequent antennas which are resolved by the medium according to their transverse extent.
↳ hep-phhep-thnucl-thJHEP(2016)·32 citations

Affiliations

first authorsco-authorsvia INSPIRE