arXiv subjects

Hao Ma

Publications and source records attributed to Hao Ma.

150 records · Page 9Linked to original sources

arXiv2012

In-medium antenna radiation in t-channel

The color coherence effects in the medium modification to the initial state radiation are studied via a simple setup which allows these effects to be pronounced. The medium-induced gluon radiation spectrum off a hard quark which suffers a highly virtual photon scattering and subsequently crosses a dilute QCD medium of finite size is obtained. The angular distribution of the medium-induced gluon radiation spectrum is modified when the interference contributions between the incoming and outgoing quarks at a finite scattering angle are included.

hep-ph↗

arXiv2012

Medium-induced soft gluon radiation in DIS

We study color coherence effects on the medium-induced soft gluon radiation off an asymptotic quark hit by a virtual photon traversing a hot and dense QCD medium. The transverse momentum spectrum of the emitted gluon is computed at 1st order in the opacity expansion. The interference effects between the initial and final state radiation modify the soft gluon spectrum when a finite angle between the incoming and outgoing quarks is considered, presenting a soft divergence. We comment on possible implications on observables in eA collisions.

hep-ph↗

arXiv2011

Coherence effects and broadening in medium-induced QCD radiation off a massive $q {\bar q}$ antenna

Studies of medium-induced QCD radiation usually rely on the calculation of single-gluon radiation spectrum off an energetic parton traversing an extended colored medium. Recently, the importance of interference effects between emitters in the medium has been explored. In this work we extend previous studies by calculating the single-gluon coherent spectrum off an antenna consisting of a massive quark-antiquark pair. Interferences dominate the spectrum of soft gluons, which are mainly emitted outside of the cone made by the antenna opening angle, while the antenna results in a superposition of independent emitters above a critical gluon energy scale. We study the interplay between the dead-cone effect and medium-induced jet broadening in both cases of soft and hard gluons and present results on energy loss distributions.

hep-ph↗

arXiv2011

Broadening in Medium-induced QCD Radiation off a $q {\bar q}$ Antenna

In this contribution, the one-gluon radiation spectrum off a massive quark-antiquark ($q {\bar q}$) antenna traversing a QCD medium is calculated in the eikonal approximation. The interference between emissions from the quark and the antiquark is considered. The gluon spectrum computed at first order in the opacity expansion is collinear finite but infrared divergent, which is in contrast with the result obtained from an independent emitter which is both infrared and collinear finite. Phenomenological consequences on the broadening of the emitted gluon are investigated. In the soft gluon emission limit, the interference between emitters causes a different broadening style from the typical {\bf k}-broadening in the case of an independent emitter.

hep-ph↗

arXiv2011

Mass effect and coherence in medium-induced QCD radiation off a $q {\bar q}$ antenna

The medium-induced one-gluon radiation spectrum off a massive quark-antiquark ($q {\bar q}$) antenna traversing a colored QCD medium is calculated in this contribution. The gluon spectrum off the antenna computed at first order in the opacity expansion is collinear finite but infrared divergent, which is different from the result obtained from an independent emitter which is both infrared and collinear finite. The interference between emitters dominates the soft gluon radiation when the antenna opening angle is small and the emitted gluon is soft, whereas the antenna behaves like a superposition of independent emitters when the opening angle is large and the radiated gluon is hard. As a phenomenological consequence, we investigate the energy lost by the projectiles due to the radiation. In general, the size of the mass effects is similar in both cases.

hep-ph↗

arXiv2011

Medium-induced multi-photon radiation

We study the spectrum of multi-photon radiation off a fast quark in medium in the BDMPS/ASW approach. We reproduce the medium-induced one-photon radiation spectrum in dipole approximation, and go on to calculate the two-photon radiation in the Molière limit. We find that in this limit the LPM effect holds for medium-induced two-photon ladder emission.

hep-ph↗