g7a: Search for medium modification of light vector mesons off nuclei

Spokespersons

D. Weygand, C. Djalali, M. Kossov

Year

2007

Abstract

Data were taken with a beam of tagged photons with energies up to 4 GeV on various nuclear targets. The properties of the ρ vector mesons were investigated via their rare leptonic decay to e⁺e⁻. This decay channel is preferred over hadronic modes in order to eliminate final state interactions in the nuclear matter. The combinatorial background in the mass spectrum was removed by a self-normalizing mixed-event technique. The ρ mass distributions were extracted for each of the targets.

Publication

1. R. Nasseripour, M. Wood, C. Djalali, D. Weygand, C. Tur, U. Mosel, P. Muehlich Search for Medium Modifications of the ρ Meson // Phys. Rev. Lett. 99, 262302 (2007)

Quantities

dY/dM(e⁺, e⁻)   dY/dM_ρ(e⁺, e⁻)

Measurements