Low-Mass Vector-Meson Production at Forward Rapidity in p+p and Au+Au Collisions at √S_NN=200GeV.

A major objective in high-energy nuclear physics is to understand the properties of the quark-gluon plasma (QGP) formed in relativistic heavy-ion collisions. The φ meson serves as a key probe to study the QGP due to its short lifetime and the weak interaction of its decay muons with the surrounding hadronic matter, making the φ → μ⁺μ⁻ decay channel effective. As a pure ss̄ state, the φ meson provides valuable insight into strangeness enhancement and the mechanisms governing quark and gluon interactions within the QGP, placing strong constraints on theoretical models of parton energy loss and recombination. Previous measurements in small systems at PHENIX have shown cold nuclear matter effects on φ meson production. Extending these measurements to Au+Au collisions may provide insights into hot nuclear matter effects.

In this talk, we present the first measurement of low-mass vector mesons— ω, ρ, and φ —at forward rapidity (1.2 < |y| < 2.2) in p+p and Au+Au collisions at √s_NN = 200 GeV, using the PHENIX detector as a function of transverse momentum (p_T) and the average number of participating nucleons(<N_part>). While the ω + ρ mesons show a significant suppression pattern across the entire p_T and <N_part> range, the φ meson exhibits distinctive patterns: suppression at high pT and in more central collisions, indicating significant nuclear medium effects, and, enhancement in intermediate regions. These results provide valuable information on the effects of the nuclear medium on particle production and the flavor dependence of particle production.