Line defects and 5d instanton partition functions

We consider certain line defect operators in five-dimensional susy gauge theories, whose interaction with the self-dual instantons is described by 1d adhm-like gauged quantum mechanics constructed by tong and wong. the partition function in the presence of these operators is known to be a generating function of bps wilson loops in skew symmetric tensor representations of the gauge group. we calculate the partition function and explicitly prove that it is a finite polynomial of the defect mass parameter x, which is an essential property of the defect operator and the wilson loop generating function. the relation between the line defect partition function and the qq-character defined by n . nekrasov is briefly discussed.