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M. Bluhm

Publications and source records attributed to M. Bluhm.

29 records · Page 2Linked to original sources
arXiv2007

Do we know eventually p(e)?

A quasi-particle model is employed to derive from available lattice QCD calculations an equation of state useable in hydrodynamical simulations of the expansion stage of strongly interacting matter created in ultra-relativistic heavy-ion collisions. Various lattice results give an astonishing agreement of the pressure as a function of energy density at large energy densities supposed the pseudo-critical temperature is in the range $170 \pm 15$ MeV, while in the transition region the equation of state is not yet well constrained. Therefore, one can construct a family of equations of state by bridging the uncertain region from the uniquely given high-energy density region part to a hadronic equation of state by suitable interpolation together with the extrapolation to non-zero baryon density by means of the quasi-particle model. We present a series of tests of the model, discuss the chiral extrapolation and the role of Landau damping. We also briefly sketch the path of cosmic matter in the early universe in the phase diagram.

hep-ph↗
arXiv2007

Thermal Dileptons at LHC

We predict dilepton invariant-mass spectra for central 5.5 ATeV Pb-Pb collisions at LHC. Hadronic emission in the low-mass region is calculated using in-medium spectral functions of light vector mesons within hadronic many-body theory. In the intermediate-mass region thermal radiation from the Quark-Gluon Plasma, evaluated perturbatively with hard-thermal loop corrections, takes over. An important source over the entire mass range are decays of correlated open-charm hadrons, rendering the nuclear modification of charm and bottom spectra a critical ingredient.

hep-ph↗
arXiv2007

A Family of Equations of State Based on Lattice QCD: Impact on Flow in Ultrarelativistic Heavy-Ion Collisions

We construct a family of equations of state within a quasiparticle model by relating pressure, energy density, baryon density and susceptibilities adjusted to first-principles lattice QCD calculations. The relation between pressure and energy density from lattice QCD is surprisingly insensitive to details of the simulations. Effects from different lattice actions, quark masses and lattice spacings used in the simulations show up mostly in the quark-hadron phase transition region which we bridge over by a set of interpolations to a hadron resonance gas equation of state. Within our optimized quasiparticle model we then examine the equation of state along isentropic expansion trajectories at small net baryon densities, as relevant for experiments and hydrodynamic simulations at RHIC and LHC energies. We illustrate its impact on azimuthal flow anisotropies and transverse momentum spectra of various hadron species.

hep-ph↗
arXiv2006

Quasi-particle perspective on critical end-point

Within a quasi-particle model for the equation of state of strongly interacting matter for two quark flavors we include phenomenologically features of the QCD critical point and discuss its impact on the equation of state. In particular, we investigate the influence on the quark number susceptibility and the pattern of isentropic trajectories which describe the evolutionary paths of matter during the hydrodynamical expansion of a heavy-ion collision.

hep-ph↗
arXiv2006

Quasi-particle perspective on QCD matter and critical end point effects

Our quasi-particle model is compared with recent lattice QCD data at finite temperature and baryon number density with emphasis on the coefficients in the Taylor series expansion of thermodynamic observables. The inclusion of static critical end point effects into the equation of state is discussed.

hep-ph↗
arXiv2005

QCD matter within a quasi-particle model and the critical end point

We compare our quasi-particle model with recent lattice QCD results for the equation of state at finite temperature and baryo-chemical potential. The inclusion of the QCD critical end point into models is discussed. We propose a family of equations of state to be employed in hydrodynamical calculations of particle spectra at RHIC energies and compare with the differential azimuthal anisotropy of strange and charm hadrons.

hep-ph↗
arXiv2005

Quasi-particle model of strongly interacting matter

The successful quasi-particle model is compared with recent lattice data of the coefficients in the Taylor series expansion of the excess pressure at finite temperature and baryon density. A chain of approximations, starting from QCD to arrive at the model expressions for the entropy density, is presented.

hep-ph↗
arXiv2004

The QCD equation of state near T_0 within a quasi-particle model

We present a description of the equation of state of strongly interacting matter within a quasi-particle model. The model is adjusted to lattice QCD data near the deconfinement temperature $T_c$. We compare in detail the excess pressure at non-vanishing chemical potential and its expansion coefficients with two-flavor lattice QCD calculations and outline prospects of the extrapolation to large baryon density.

hep-ph↗
arXiv2004

Strangeness and charm in QCD matter

Strangeness and charm degrees of freedom in strongly interacting matter are discussed within a quasi-particle model adjusted to lattice QCD data. The model allows to extrapolate lattice QCD data to large baryo-chemical potential. We outline the thermal evolution of matter in the early universe at and slightly after confinement and comment briefly on charm dynamics in relativistic heavy-ion collisions.

hep-ph↗
arXiv2004

A unique parameterization of the QCD equation of state below and above T_c

We present a unique parameterization of the equation of state of strongly interacting matter in the temperature interval 0.6 T_c ... 3 T_c at μ= 0 within a quasi-particle model based on quark and gluon degrees of freedom. The extension to non-vanishing baryon-chemical potential is discussed.

hep-ph↗