Article

Next-to-Leading Order QCD Corrections to the Production of Two Bottom-Antibottom Pairs at the LHC

Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
Physical Review Letters (Impact Factor: 7.73). 09/2011; 107(10):102002. DOI: 10.1103/PhysRevLett.107.102002
Source: PubMed

ABSTRACT We report the results of a computation of the full next-to-leading order QCD corrections to the production of two bb pairs at the LHC. This calculation at the parton level provides predictions for well separated b jets. The results show that the next-to-leading order corrections lead to an enhancement of the cross section for the central scale choice by roughly 50% with respect to the leading order result. The theoretical uncertainty estimated by variation of the renormalization and factorization scales is strongly reduced by the inclusion of next-to-leading order corrections.

0 Followers
 · 
149 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: We discuss the theoretical bases that underpin the automation of the computations of tree-level and next-to-leading order cross sections, of their matching to parton shower simulations, and of the merging of matched samples that differ by light-parton multiplicities. We present a computer program, MadGraph5_aMC@NLO, capable of handling all these computations -- parton-level fixed order, shower-matched, merged -- in a unified framework whose defining features are flexibility, high level of parallelisation, and human intervention limited to input physics quantities. We demonstrate the potential of the program by presenting selected phenomenological applications relevant to the LHC and to a 1-TeV $e^+e^-$ collider. While next-to-leading order results are restricted to QCD corrections to SM processes in the first public version, we show that from the user viewpoint no changes have to be expected in the case of corrections due to any given renormalisable Lagrangian, and that the implementation of these are well under way.
    Journal of High Energy Physics 04/2014; 2014(7). DOI:10.1007/JHEP07(2014)079 · 6.22 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We investigate the di-Higgs events through $Z_H$-pair production at the CERN Large Hadron Collider including the pure next-to-leading order (NLO) QCD correction and the $gg$-fusion contribution in the framework of the littlest Higgs model with $T$ parity. We employ the diagram subtraction scheme in the QCD NLO calculations to avoid double counting and keep the convergence of the perturbative QCD description for the $Z_H$-pair production. We investigate the dependence of the leading order and QCD corrected integrated cross sections on the renormalization/factorization scale, and find that the total QCD corrections slightly reduce the scale uncertainty in the plotted range. By considering the subsequent decays of the intermediately produced $Z_H$ bosons and adopting the exclusive four-$b$-jet event selection criterion, the QCD correction provides considerable enhancement of the kinematic distributions for final decay products. We find that it is possible to select the signature of the $Z_H$-pair production from possible Standard Model background by taking proper kinematic cut.
    Physical Review D 09/2014; 90(5). DOI:10.1103/PhysRevD.90.054020 · 4.86 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The interpretation of experimental measurements at the LHC requires accurate theoretical predictions for exclusive observables, and in particular the summation of soft and collinear radiation to all orders in perturbation theory. We report on recent progress towards the automated calculation of multi-parton LHC cross sections at next-to-leading order in QCD, including the summation of next-to-leading logarithmic corrections through the combination with parton showers.
    02/2015; 261-262. DOI:10.1016/j.nuclphysbps.2015.03.009

Preview

Download
0 Downloads
Available from