Apparent and Actual Shifts in Mass and Width of Phi Mesons Produced in Heavy-Ion Collisions
Abstract
We present a method of analyzing invariant-mass spectra of kaon pairs resulting from decay of
ϕ
mesons produced in high-energy heavy-ion collisions. It can be used to extract the shifts in the mass and the width (
ΔM
and
ΔΓ
) of the
ϕ
mesons when they are inside the dense matter formed in these collisions. We illustrate our method with the help of available preliminary data. Extracted values of
ΔM
and
ΔΓ
are significantly larger than those obtained with an earlier method. Our results are consistent with the experimentally observed
p
T
dependence of the mass shift. Finally, we present a phenomenological relation between
ΔM
and
ΔΓ
. It provides a useful constraint on theories which predict the values of these two quantities.