arXiv subjects

Moran Jia

Publications and source records attributed to Moran Jia.

3 recordsLinked to original sources

arXiv2023

The photon production and collective flows from magnetic induced gluon fusion and splitting in early stage of high energy nuclear collision

We present an event-by-event study of photon production in early stage of high energy nuclear collisions, where the system is dominant by highly occupied of gluons and initialized by McLerran-Venugopalan model. The photons are produced through the gluon fusion and splitting processes when strong magnetic field is included. We study the spectra and collective flows of the photons and show their dependence on transverse momentum $q_{T}$. It is found that in our approach the photons from boost invariant evolving glasma provide visible enhancement on spectrum and obvious contribution on $v_{2}$ of the total direct photons. The results, by weighting on top of parton-hadron-string dynamics (PHSD) model, agree even better with experiment measurements in Au-Au 20\%-40\% centrality collisions at $\sqrt{s_{NN}}=200$GeV.

hep-ph↗

arXiv2021

Fluctuations of topological charge and chiral density in the early stage of high energy nuclear collisions

We study systematically the topological charge density and the chiral density correlations in the early stage of high energy nuclear collisions: the intial condition is given by the McLerran-Venugopalan model and the evolution of the gluon fields is studied via the Classical Yang-Mills equations up to proper time $τ\approx 1$ fm/c for an $SU(2)$ evolving Glasma. Topological charge is related to the gauge invariant $\bm E \cdot \bm B$ where $\bm E$ and $\bm B$ denote the color-electric and color-magnetic fields, while the chiral density is produced via the chiral anomaly of Quantum Chromodynamics. We study how the correlation lengths are related to the collision energy, and how the correlated domains grow up with proper time in the transverse plane for a boost invariant longitudinal expansion. We estimate the correlation lengths of both quantities, that after a short transient results of the order of the typical energy scale of the model, namely the inverse of the saturation scale. We estimate the proper time for the formation of a steady state in which the production of the chiral density in the transverse plane per unit rapidity slows down, as well as the amount of chiral density that would be present at the switch time between the Classical Yang-Mills evolution and the relativistic transport or hydro for the quark-gluon plasma phase.

hep-ph↗

arXiv2016

Photon emission by bremsstrahlung and nonlinear Compton scattering in the interaction of ultraintense laser and plasmas

By implementing the bremsstrahlung with Monte Carlo algorithm into the particle-in-cell code, the bremsstrahlung and nonlinear Compton scattering can be studied simultaneously in comparison way in the laser plasma interactions. The simulations are performed for the laser of different intensities interacting with either low-$Z$ or high-$Z$ target. The relative strength of the two photon emission from bremsstrahlung and nonlinear Compton scattering are compared. The result shows that when an ultrastrong intensity laser interacting with a thin and relative high $Z$ target the nonlinear Compton scattering is dominant, however, when the laser intensity $I < 10^{22} \mathrm{W/cm^2}$, the photon emission contributed by bremsstrahlung is comparable to that from nonlinear Compton scattering. In this case the usual ignorable of bremsstrahlung need to be reconsidered.

physics.plasm-ph↗