φ-meson mass modification in heavy-ion collisions

We recently presented 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 (ΔΜ and ΔΓ) of the φ mesons when they are inside the dense matter formed in these collisions. We have now performed a Monte-Carlo simulation of this process. We illustrate our method with the help of available preliminary data. Extracted value of ΔΜ is significantly larger than that obtained with an earlier method. Our results are consistent with the experimentally observed pT dependence of the mass shift. (author)