Effective K-factors for $gg \to H \to WW\to l\nu l\nu$ at the LHC

Davatz, G.; Dittmar, M.; Grazzini, M.; Pauss, F.; Dissertori, G.

doi:10.1088/1126-6708/2004/05/009

Article
Report number	hep-ph/0402218 ; CERN-PH-TH-2004-035 ; CERN-PH-TH-2004-035
Title	Effective K-factors for $gg \to H \to WW\to l\nu l\nu$ at the LHC
Related title	Large Hadron Collider
Author(s)	Davatz, G. (Zurich, ETH) ; Dissertori, G. (Zurich, ETH) ; Dittmar, M. (Zurich, ETH) ; Grazzini, M. (CERN) ; Pauss, F. (Zurich, ETH)
Affiliation	(CERN)
Publication	2004
Imprint	20 Feb 2004
Number of pages	16
Note	16 pages, 8 eps figures, comparison of jet veto efficiencies between PYTHIA and HERWIG added, to appear on JHEP Report-no: CERN-PH-TH/2004-035
In:	JHEP 05 (2004) 009
DOI	10.1088/1126-6708/2004/05/009
Subject category	Particle Physics - Phenomenology
Abstract	A simulation of the search for the Standard Model Higgs boson at the LHC, in the channel gg -> H -> WW -> lnu lnu, is described. Higher-order QCD corrections are taken into account by using a reweighting procedure, which allows us to combine event rates obtained with the PYTHIA Monte Carlo program with the most up-to-date theoretical predictions for the transverse-momentum spectra of the Higgs signal and its corresponding WW background. With this method the discovery potential for Higgs masses between 140 and 180 GeV is recalculated and the potential statistical significance of this channel is found to increase considerably. For a Higgs mass of 165 GeV a signal-to-background ratio of almost 2:1 can be obtained. A statistical significance of five standard deviations might already be achieved with an integrated luminosity close to 0.4 fb^{-1}. Using this approach, an experimental effective K-factor of about 2.04 is obtained for the considered Higgs signature, which is only about 15 % smaller than the theoretical inclusive K-factor.