Comparisons between p+p and p+A at forward rapidity at STAR

The Solenoid Tracker at RHIC (STAR) experiment has already released preliminary results for transverse single spin asymmetries ( A_N) for π⁰ production, comparing proton-proton (p+p) and proton-gold (p+Au) collisions at forward rapidity (η∼3.0) at √s =200 GeV. This presentation will include an update on related studies of the ratio of the p+p and p+Au cross sections in the same kinematic region as the previous A_N measurements, using data from the STAR Forward Meson Spectrometer (FMS). The data were from the 2015 RHIC run to study  p+p, p+Au, and p+Al collisions. The presentation will discuss progress toward a measurement of cross section ratios between p+p and p+A. The asymmetry measurements and associated cross section ratios may provide insight into nuclear modification in the kinematic region where gluon saturation effects might be present.