Dileptons from vector mesons with dropping masses in a nonequilibrium quantum field theoretical framework
نویسندگان
چکیده
The influence of time dependent medium modifications of low mass vector mesons on dilepton production is investigated using nonequilibrium quantum field theory. By working in the two-time representation memory effects are fully taken into account. For different scenarios the resulting dilepton yields are compared to quasi-equilibrium calculations and remarkable differences are found leading to the conclusion that memory effects can not be neglected when calculating dilepton yields from heavy ion collisions. Emphasis is put on a dropping mass scenario since it was recently claimed to be ruled out by the NA60 data. Here the memory effects turn out to be particularly important.
منابع مشابه
Dilepton yields from brown-rho scaled vector mesons including memory effects.
Scenarios with dropping vector meson masses, motivated by the work of Brown and Rho, have been strongly discussed after recent NA60 Collaboration data were presented. In this Letter they are investigated within a nonequilibrium field theoretical description that includes quantum mechanical memory. Dimuon yields are calculated by application of a model for the fireball, and strong modifications ...
متن کاملA Hidden Local Field Theory Description of Dileptons in Relativistic Heavy Ion Collisions
Using the notion of “hadronic freedom” inferred from the vector manifestation of hidden local symmetry we argue that, contrary to the commonly held belief, the dileptons measured in relativistic heavy-ion collisions do not carry useful information directly relevant to the spontaneous breaking of chiral symmetry and hence to the mechanism for mass generation of light-quark hadrons. The dileptons...
متن کامل- th / 0 10 80 55 v 1 2 4 A ug 2 00 1 ρ / ω properties from dilepton spectra in pA reactions at 12 GeV ∗
The dilepton production from pC and pCu collisions at Tlab = 12 GeV is calculated using the semi-classical BUU transport model, that includes the off-shell propagation of vector mesons nonperturbatively and calculates the width of the vector mesons dynamically. It is found that the collisional broadening of the vector meson width and dropping vector meson masses lead to a small enhancement of t...
متن کاملΡ/ω Properties from Dilepton Spectra in Pa Reactions at 12 Gev *
The dilepton production from pC and pCu collisions at Tlab = 12 GeV is calculated using the semi-classical BUU transport model, that includes the off-shell propagation of vector mesons nonperturbatively and calculates the width of the vector mesons dynamically. It is found that the collisional broadening of the vector meson width and dropping vector meson masses lead to a small enhancement of t...
متن کامل- th / 9 80 90 56 v 2 2 D ec 1 99 8 Low - mass dileptons and dropping rho meson mass
Using the transport model, we have studied dilepton production from heavy-ion collisions at Bevalac energies. It is found that the enhanced production of low-mass dileptons observed in the experiment by the DLS collaboration cannot be explained by the dropping of hadron masses, in particular the ρ-meson mass, in dense matter. One of the most exciting physics one expects to learn from relativist...
متن کامل