Center of the quantum affine vertex algebra associated with   trigonometric R-matrix
  We consider the quantum vertex algebra associated with the trigonometric R-matrix in type A as defined by Etingof and Kazhdan. We show that its center is a commutative associative algebra and construct an algebraically independent family of topological generators of the center at the critical level. 
Slaven Ko\v{z}i\'c and Alexander Molev
math.QA math.RT