Left-Handed W Bosons at the LHC

Bern, Z.; Febres Cordero, F.; Diana, G.; Ita, H.; Ozeren, K.; Forde, D.; Maitre, D.; Gleisberg, T.; Hoeche, S.; Dixon, L.J.; Kosower, D.A.

doi:10.1103/PhysRevD.84.034008

Article
Report number	SLAC-PUB-14409 ; CERN-PH-TH-2011-062 ; UCLA-11-TEP-10 ; SB-F-386-11 ; SACLAY-IPHT-T11-040 ; IPPP-11-15 ; NIKHEF-2011-006 ; arXiv:1103.5445 ; SLAC-PUB-14409 ; CERN-PH-TH-2011-062 ; UCLA-11-TEP-10 ; SB-F-386-11 ; NIKHEF-2011-006 ; SACLAY-IPHT-T11-040 ; IPPP-11-15
Title	Left-Handed W Bosons at the LHC
Author(s)	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)
Publication	2011
Imprint	29 Mar 2011
Number of pages	32
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
In:	Phys. Rev. D 84 (2011) 034008
DOI	10.1103/PhysRevD.84.034008
Subject category	Particle Physics - Phenomenology
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.
Copyright/License	Preprint: © 2011-2024 CERN (License: CC-BY-3.0)

$The ratio of the charged-lepton $E_T$ distributions at the LHC for $W^+$ and $W^-$ production in association with three jets, evaluated at NLO~\cite{W3jDistributions}.$ $When a $W^+$ is produced at lowest order by $u(x_1)\bar{d}(x_2) \to W^+$ with $x_1 > x_2$, it is 100\% left-handed polarized along its direction of motion, which is along the beam axis in the quark direction. Thick (black) arrows represent spin vectors; the other arrows represent momentum vectors in the $pp$ center-of-mass frame.$ $The two Feynman graphs for the subprocess $ug\to W^+d$.$ Show more plots

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Notice créée le 2011-03-29, modifiée le 2018-08-11

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