A Note on the Connection between Non-Additive Entropy and h-Derivative.

In order to study as a whole a wide part of entropy measures, we introduce a two-parameter non-extensive entropic form with respect to the h-derivative, which generalizes the conventional Newton-Leibniz calculus. This new entropy, Sh,h', is proved to describe the non-extensive systems and recover several types of well-known non-extensive entropic expressions, such as the Tsallis entropy, the Abe entropy, the Shafee entropy, the Kaniadakis entropy and even the classical Boltzmann-Gibbs one. As a generalized entropy, its corresponding properties are also analyzed.

Momentum imbalance of isolated photon-tagged jet production at RHIC and LHC.

In collisions of ultrarelativistic nuclei, photon-tagged jets provide a unique opportunity to compare jet production and modification due to parton shower formation and propagation in strongly interacting matter at vastly different center-of-mass energies. We present first results for the cross sections of jets tagged by an isolated photon to O(α(em)α(s)(2)) in central Au+Au reactions with sqrt[s(NN)] = 200 GeV at RHIC and central Pb + Pb reactions with sqrt[s(NN)] = 2.76 TeV at LHC. We evaluate the increase in the transverse momentum imbalance of the observed γ + jet state, induced by the dissipation of the parton shower energy due to strong final-state interactions. Theoretical predictions to help interpret recent and upcoming experimental data are presented.

Jet tomography of high-energy nucleus-nucleus collisions at next-to-leading order.

We demonstrate that jet observables are highly sensitive to the characteristics of the vacuum and the in-medium QCD parton showers and propose techniques that exploit this sensitivity to constrain the mechanism of quark and gluon energy loss in strongly interacting plasmas. As a first example, we calculate the inclusive jet cross section in high-energy nucleus-nucleus collisions to O(alpha(s)(3)). Theoretical predictions for the medium-induced jet broadening and the suppression of the jet production rate due to cold and hot nuclear matter effects in Au+Au and Cu+Cu reactions at RHIC are presented.

Heavy quark energy loss in a nuclear medium.

Multiple scattering, modified fragmentation functions, and radiative energy loss of a heavy-quark propagating in a nuclear medium are investigated in perturbative QCD. Because of the quark mass dependence of the gluon formation time, the medium size dependence of heavy-quark energy loss is found to change from a linear to a quadratic form when the initial energy and momentum scale are increased relative to the quark mass. The radiative energy loss is also significantly suppressed relative to a light quark due to the suppression of collinear gluon emission by a heavy quark.