Diffraction 2016 abstract (version 2)

Resent results from the STAR experiment on Vector Meson (VM) production 
in ultra peripheral AuAu collisions at RHIC.

Leszek Adamczyk, AGH UST Cracow, for the STAR Collaboration

In this talk we shall present the measurements involving photonuclear production
of vector meson (rho, omega, J/psi) and non-resonant pion pair in AuAu ultra peripheral
collisions (UPC) at RHIC.  Measurements of the relative amplitudes of the light vector
mesons and direct pion pair components will be presented, along with the phase angle
between the rho and omega components. The  negative of the four momentum transfer
squered (t) spectrum shows coherent and incoherent components. The coherent component
exhibits visible diffraction minima. Preliminary results for the cross section as a function
J/psi rapidity and transverse momentum will be presented and compared to models.
Plans for the future will also be discussed.