Low-mass vector-meson production at forward rapidity in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>p</mml:mi> <mml:mo>+</mml:mo> <mml:mi>p</mml:mi> </mml:mrow> </mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>Au</mml:mi> <mml:mo>+</mml:mo> <mml:mi>Au</mml:mi> </mml:mrow> </mml:math> collisions at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msqrt> <mml:msub> <mml:mi>s</mml:mi> <mml:msub> <mml:mrow/> <mml:mrow> <mml:mi>N</mml:mi> <mml:mi>N</mml:mi> </mml:mrow> </mml:msub> </mml:msub> </mml:msqrt> <mml:mo>=</mml:mo> <mml:mn>200</mml:mn> </mml:mrow> </mml:math> GeV

The PHENIX experiment at the Relativistic Heavy Ion Collider has measured low-mass vector-meson ($\ensuremath{\omega}+\ensuremath{\rho}$ and $\ensuremath{\phi}$) production through the dimuon decay channel at forward rapidity $(1.2&lt;|\text{y}|&lt;2.2)$ in $p+p$ and $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{{s}_{{}_{NN}}}=200$ GeV. The low-mass vector-meson yield and nuclear-modification factor were measured as a function of the average number of participating nucleons, $\ensuremath{\langle}{N}_{\mathrm{part}}\ensuremath{\rangle}$, and the transverse momentum ${p}_{T}$. These results were compared with those obtained via the kaon decay channel in a similar ${p}_{T}$ range at midrapidity. The nuclear-modification factors in both rapidity regions are consistent within the uncertainties. A comparison of the $\ensuremath{\omega}+\ensuremath{\rho}$ and $J/\ensuremath{\psi}$ mesons reveals that the light and heavy flavors are consistently suppressed across both ${p}_{T}$ and $\ensuremath{\langle}{N}_{\mathrm{part}}\ensuremath{\rangle}$. In contrast, the $\ensuremath{\phi}$ meson displays a nuclear-modification factor consistent with unity, suggesting strangeness enhancement in the medium formed.