The line bundles on moduli stacks of principal bundles on a curve
arXiv:0805.2915
Abstract
Let G be an affine reductive algebraic group over an algebraically closed field k. We determine the Picard group of the moduli stacks of principal G-bundles on any smooth projective curve over k.
33 pages, AMSLaTeX. v2: Lemma 4.1.1 corrected