Speaker
Description
Two-particle azimuthal correlation has been proposed to be one of the most direct and sensitive channels to access the nonlinear gluon dynamics in nuclei. Color Glass Condensate (CGC) predicts a suppression of back-to-back correlation in $p(d)+$A collisions compared to $p$$+$$p$ collisions. In $d+$A collisions, the double-parton scattering (DPS) can be an alternative explanation of the suppression \cite{Strikman:2010bg}. A comparison of suppression in $d+$A and $p+$A with the same kinematics provides an opportunity to study the impact of DPS. During the 2015 and 2016 RHIC runs, STAR collected data with the Forward Meson Spectrometer (FMS, 2.6 $\leq$ $\eta$ $\leq$ 4.0) in $p$$+$$p$, $p+$Al, $p$+Au and $d$+Au collisions at $\sqrt{s_{\rm {NN}}}=200$ GeV, which enables the measurements of azimuthal correlations of neutral pions in the forward region. In this talk, we will present the preliminary results on forward di-$\pi^{0}$ correlations as a function of event activity and $\pi^{0}$'s transverse momenta in $p$$+$$p$, $p+$Al and $p+$Au collisions, together with an analysis update of the same measurements in $d+$Au collisions.
\bibitem{Strikman:2010bg}
M. Strikman and W. Vogelsang, Phys. Rev. D \textbf{83}, 034029 (2011), 1009.6123.
