Beam thrust cross section for Drell-Yan production at next-to-next-to-leading-logarithmic order.

At the LHC and Tevatron strong initial-state radiation (ISR) plays an important role. It can significantly affect the partonic luminosity available to the hard interaction or contaminate a signal with additional jets and soft radiation. An ideal process to study ISR is isolated Drell-Yan production, pp → Xℓ+ ℓ- without central jets, where the jet veto is provided by the hadronic event shape beam thrust τB. Most hadron collider event shapes are designed to study central jets. In contrast, requiring τ B << 1 provides an inclusive veto of central jets and measures the spectrum of ISR. For τ B << 1 we carry out a resummation of α s(n)ln(m)τ B corrections at next-to-next-to-leading-logarithmic order. This is the first resummation at this order for a hadron-hadron collider event shape. Measurements of τ B at the Tevatron and LHC can provide crucial tests of our understanding of ISR and of τ B's utility as a central jet veto.