Eur. Phys. J. C (2011) 71: 1628
https://doi.org/10.1140/epjc/s10052-011-1628-z

Regular Article - Theoretical Physics

Forward–backward correlations and event shapes as probes of minimum-bias event properties

¹ Department of Physics and Astronomy, Kelvin Building, University of Glasgow, Glasgow, G12 8QQ, Scotland, UK
² European Organization for Nuclear Research, CERN, 1211, Genève 23, Switzerland

^* e-mail: skands@fnal.gov

Received: 31 January 2011
Published online: 6 May 2011

Abstract

Measurements of inclusive observables, such as particle multiplicities and momentum spectra, have already delivered important information on soft-inclusive (“minimum-bias”) physics at the Large Hadron Collider. In order to gain a more complete understanding, however, it is necessary to include also observables that probe the structure of the studied events. We argue that forward–backward (FB) correlations and event-shape observables may be particularly useful first steps in this respect. We study the sensitivity of several different types of FB correlations and two event-shape variables—transverse thrust and transverse thrust minor—to various sources of theoretical uncertainty: multiple parton interactions, parton showers, color (re)connections, and hadronization. The power of each observable to furnish constraints on Monte Carlo models is illustrated by including comparisons between several recent, and qualitatively different, Pythia 6 tunes, for pp collisions at .