Sequential Strangeness Freeze-out

I will describe the latest results from lattice QCD pertaining to a potential flavour hierarchy in the hadronic freeze-out from the QCD crossover region. I will compare these results to a variety of improved hadronic resonance gas calculations and to experimental data of fluctuations of net-charge, net-proton and net-kaon multiplicity distributions, which serve as a proxy for the susceptibilities of conserved quantum numbers on the lattice. I will conclude that there is intriguing evidence for a flavour dependent freeze-out, and I will suggest expansions to the experimental program at RHIC and the LHC that could potentially demonstrate the impact of a flavour separation during hadronization.Comment: 6 pages, 4 figures, SQM 2017 proceeding

Physics with the ALICE Electromagnetic Calorimeter

I will present physics measurements which are achievable in the ALICE experiment at the LHC through the inclusion of a new electromagnetic calorimeter. I will focus on jet measurements in proton proton and heavy ion collisions. Detailed simulations have been performed on jet reconstruction, jet triggering, heavy flavor jet reconstruction through electron identification, gamma-jet reconstruction and the measurements of identified hadrons and resonances in jets. I will show the physics capabilities which are made possible through the combination of calorimeter information with the other detector components in ALICE.Comment: 12 pages, 8 figures, Proceedings for the 25th Winter Workshop on Nuclear Dynamics, Big Sky, Montana (USA), February 1-8, 200

Impact of resonance regeneration and decay on the net-proton fluctuations in a hadron resonance gas

We investigate net-proton fluctuations as important observables measured in heavy-ion collisions within the hadron resonance gas (HRG) model. Special emphasis is given to effects which are a priori not inherent in a thermally and chemically equilibrated HRG approach. In particular, we point out the importance of taking into account the successive regeneration and decay of resonances below the chemical freeze-out, which lead to a randomization of the isospin of nucleons and thus to additional fluctuations in the net-proton number. We find good agreement between our model results and the recent STAR measurements of the higher-order moments of the net-proton distribution

Is there a flavor hierarchy in the deconfinement transition of QCD?

We present possible indications for flavor separation during the QCD crossover transition based on continuum extrapolated lattice QCD calculations of higher order susceptibilities. We base our findings on flavor specific quantities in the light and strange quark sector. We propose a possible experimental verification of our prediction, based on the measurement of higher order moments of identified particle multiplicities. Since all our calculations are performed at zero baryochemical potential, these results are of particular relevance for the heavy ion program at the LHC.Comment: 5 pages, 3 figures, revte

Are there hadronic bound states above the QCD transition temperature?

Recent lattice QCD calculations, at physical pion masses and small lattice spacings that approach the continuum limit, have revealed that non-diagonal quark correlators above the critical temperature are finite up to about 2 $T_c$. Since the transition from hadronic to free partonic degrees of freedom is merely an analytic cross-over, it is likely that, in the temperature regime between 1-2 $T_c$, quark and gluon quasiparticles and pre-hadronic bound states can coexist. The correlator values, in comparison to PNJL model calculations beyond mean-field, indicate that at least part of the mixed phase resides in color-neutral bound states. A similar effect was postulated for the in-medium fragmentation process, i.e. for partons which do not thermalize with the system and thus constitute the non-equilibrium component of the particle emission spectrum from a deconfined plasma phase. Here, for the first time we investigate the likelihood of forming bound states also in the equilibrated, parton dominated phase above $T_c$ which is described by lattice QCD.Comment: 15 pages, 4 Figure