arXiv subjects

V. Koch

Publications and source records attributed to V. Koch.

39 records · Page 3Linked to original sources

arXiv1997

Properties of Hadrons in the Nuclear Medium

This review is devoted to the discussion of hadron properties in the nuclear medium and its relation to the partial restoration of chiral symmetry. Special attention is given to disentangle in-medium effects due to conventional many-body interactions from those due to the change of the chiral condensate. In particular, we shall discuss medium effects on the Goldstone bosons (pion, kaon and eta), the vector mesons (rho, omega, phi), and the nucleon. Also, for each proposed in-medium effect the experimental consequence and results will be reviewed.

nucl-th↗

arXiv1996

Dilepton Production at SPS-energy Heavy Ion Collisions

The production of dileptons is studied within a hadronic transport model. We investigate the sensitivity of the dilepton spectra to the initial configuration of the hadronic phase in a ultrarelativistic heavy ion collision. Possible in medium correction due to the modifications of pions and the pion form factor in a hadronic gas are discussed.

nucl-th↗

arXiv1992

The Propagation of Quarks in the Spatial Direction in Hot QCD

The dynamics of {\it light} fermions propagating in a spatial direction at high temperatures can be described effectively by a two--dimensional Schrödinger equation with {\it heavy} effective mass $m_{\rm eff} = πT$. Starting from QED, we discuss the transition from three-- to two--dimensional positronium discussing the latter in detail including relativistic effects. In the case of QCD the problem is similar to that of heavy quarkonium. Our effective potential contains the usual Coulomb and confining parts as well as a perturbative spin--spin interaction. The resulting $\bar q q$ ``wave functions" reproduce recent lattice data for the $ρ$ and $π$ channels. The physical meaning of such `confinement' is related to the non--trivial magnetic interaction of color currents in the quark--gluon plasma. Our results do not contradict the idea that the normal electric interaction of color charges is screened and produces no bound states in the usual sense.

hep-ph↗