Energy loss of quarks in deconfined matter at RHIC: photon-tagged jets, single electron and dilepton spectra from open charm

We report a first attempt (i) to derive constraints on the energy loss of charm quarks in a deconfined medium from the recent PHENIX data of single-electron transverse momentum spectra and (ii) to estimate the resulting suppression of dileptons from correlated semi-leptonic decays of open charmed mesons. The momentum imbalance of photon-tagged light-quark jets is also considered.Comment: contribution to Quark Matter 2002, Nantes, France, July 18 - 24, 200

Physical Information in the Thermal Continuum Dilepton Spectra

We consider the intermediate mass continuum of dileptons (between $\phi$ and $J/\psi$) in ultrarelativistic heavy--ion collisions. The thermal signal depends essentially on thermodynamic state parameters of the hottest parton stage as $(\tau_i\lambda^q_iT_i^3)^2$ convoluted with an involved detector acceptance function. A refined analysis of the transverse pair momentum spectrum at fixed dilepton transverse mass can reveal the maximum temperature of parton matter.Comment: 3 LaTeX pages including eps figures, contribution to the Erice School on Nuclear Physics 1998 (to be published in "Progress in Particle and Nuclear Physics"

Thermalization of Hadrons via Hagedorn States

Hagedorn states are characterized by being very massive hadron-like resonances and by not being limited to quantum numbers of known hadrons. To generate such a zoo of different Hagedorn states, a covariantly formulated bootstrap equation is solved by ensuring energy conservation and conservation of baryon number $B$, strangeness $S$ and electric charge $Q$. The numerical solution of this equation provides Hagedorn spectra, which enable to obtain the decay width for Hagedorn states needed in cascading decay simulations. A single (heavy) Hagedorn state cascades by various two-body decay channels subsequently into final stable hadrons. All final hadronic observables like masses, spectral functions and decay branching ratios for hadronic feed down are taken from the hadronic transport model UrQMD. Strikingly, the final energy spectra of resulting hadrons are exponential showing a thermal-like distribution with the characteristic Hagedorn temperature

Hadron attenuation by (pre)hadronic FSI at HERMES

We investigate hadron production in deep inelastic lepton-nucleus scattering in the kinematic regime of the HERMES experiment. Our calculations are carried out in the framework of a BUU transport model which contains the Lund event generators PYTHIA and FRITIOF for the simulation of high-energy elementary interactions. For the first time we consistently use the complete four-dimensional information of the Lund string break up vertices as input for our transport theoretical studies of (pre)hadronic final state interactions. We compare our results with experimental HERMES data on charged hadron attenuation.Comment: 6 pages, 2 figures, Presented at First Workshop on Quark-Hadron Duality and the Transition to pQCD, Frascati, Italy, 6-8 June 200