Author(s)
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Bern, Z. (UCLA) ; Diana, G. (Saclay, SPhT) ; Dixon, L.J. (CERN ; SLAC) ; Febres Cordero, F. (Simon Bolivar U.) ; Forde, D. (CERN ; NIKHEF, Amsterdam) ; Gleisberg, T. (SLAC) ; Hoeche, S. (SLAC) ; Ita, H. (UCLA) ; Kosower, D.A. (Saclay, SPhT) ; Maitre, D. (CERN ; Durham U.) ; Ozeren, K. (UCLA) |
Note
| Comments: 32 pages, revtex, 17 figures, 3 tables 32 pages, revtex, 17 figures, 3 tables, v2 minor corrections to ME+PS results, no changes to conclusions, added references |
Abstract
| The production of W bosons in association with jets is an important background to new physics at the LHC. Events in which the W carries large transverse momentum and decays leptonically lead to large missing energy and are of particular importance. We show that the left-handed nature of the W coupling, combined with valence quark domination at a pp machine, leads to a large left-handed polarization for both W^+ and W^- bosons at large transverse momenta. The polarization fractions are very stable with respect to QCD corrections. The leptonic decay of the W bosons translates the common left-handed polarization into a strong asymmetry in transverse momentum distributions between positrons and electrons, and between neutrinos and anti-neutrinos (missing transverse energy). Such asymmetries may provide an effective experimental handle on separating W + jets from top quark production, which exhibits very little asymmetry due to C invariance, and from various types of new physics. |