Description
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Talk title: Equilibration and jets in the quark–gluon plasma
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Speaker : Dr. Jasmine Brewer, Massachusetts Institute of Technology (MIT)
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Abstract:
Heavy-ion collision experiments provide a unique window into the structure
of the high-temperature phase of QCD, the quark–gluon plasma. In this talk
we will address aspects of two conceptual approaches to studying the
quark–gluon plasma: the emergence of hydrodynamic behavior and the
modification of jets.
First, we describe a new scenario characterizing the transition of the
quark-gluon plasma from a highly non-equilibrium state at early times
toward a fluid described by hydrodynamics at late times. In this scenario,
the bulk evolution is governed by a set of slow modes that are
"pre-hydrodynamic" in the sense that they are initially distinct from, but
evolve continuously into, hydrodynamic modes in hydrodynamic limit. We
explicitly identify the pre-hydrodynamic modes for a kinetic description of
weakly-coupled Bjorken expanding plasma and demonstrate in the
relaxation-time approximation that the full kinetic theory evolution is
indeed dominated by these modes.
Second, we discuss a data-driven method to estimate the separate energy
loss and modification of quark- and gluon-initiated jets in the quark–gluon
plasma using a statistical technique called topic modeling. Assuming that
jet distributions are a mixture of underlying “quark-like” and “gluon-like”
distributions, we show how to extract quark and gluon jet fractions and
constituent multiplicity distributions as a function of the jet transverse
momentum. These results suggest the potential for an experimental
determination of quark and gluon jet modifications.
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Profile: Jasmine Brewer is currently a Ph.D. candidate in physics at MIT and will be starting in the fall as a fellow at CERN. Her primary research interests are in jet modification in heavy-ion collisions and the far-from-equilibrium evolution of the quark-gluon plasma.
