An asymptotic formula for the pion decay constant in a large volume

We derive an asymptotic formula a la Luscher for the finite-volume correction to the pion decay constant: this is expressed as an integral over the <3pi\A(mu)\0> amplitude after proper subtraction of the pion pole contribution. We analyze the formula numerically at leading and next-to-leading order in the chiral expansion. (C) 2004 Elsevier B.V. All rights reserved.