3 research outputs found
Color coherence in a heavy quark antenna radiating gluons inside a QCD medium
We compute the color coherence effects for soft gluon radiation off antennas
containing heavy quarks in the presence of a QCD medium - in color singlet,
triplet or octet global states. This work completes the studies of antenna
radiation inside a medium which provide a useful picture of the relevance of
interference effects in jet parton showers for the jet quenching phenomenon
observed in high-energy nuclear collisions. The analysis is performed resumming
the multiple scatterings of the partonic system with the medium. The main
conclusion is that decorrelation due to color rotation is more effective in the
case in which at least one of the emitters of the antenna is a heavy quark.
This effect, present both for a heavy-quark-antiquark or a heavy-quark-gluon
antenna is more relevant for the later or for the case in which the energies of
the quark and antiquark are very different. The parameter controlling these
effects involves the dead-cone angle. We find that interferences are cancelled,
spoiling the color correlation of the pair, when where E and {\omega} are the energies of the heavy quark
and the radiated gluon and L is the medium length. In the case of a
heavy-quark-antiquark antenna appears instead of L if the original
splitting is symmetric. The presence or absence of interferences modifies the
energy loss pattern.Comment: 12 page
Unveiling saturation effects from nuclear structure function measurements at the EIC
International audienceWe analyze the possibility of extracting a clear signal of non-linear parton saturation effects from future measurements of nuclear structure functions at the Electron–Ion Collider (EIC), in the small- x region. Our approach consists in generating pseudodata for electron-gold collisions, using the running-coupling Balitsky–Kovchegov evolution equation, and in assessing the compatibility of these saturated pseudodata with existing sets of nuclear parton distribution functions (nPDFs), extrapolated if necessary. The level of disagreement between the two is quantified by applying a Bayesian reweighting technique. This allows to infer the parton distributions needed in order to describe the pseudodata, which we find quite different from the actual distributions, especially for sea quarks and gluons. This tension suggests that, should saturation effects impact the future nuclear structure function data as predicted, a successful refitting of the nPDFs may not be achievable, which would unambiguously signal the presence of non-linear effects