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: 7.94). 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 0
 · 
0 Bookmarks
 · 
79 Views
  • Source
    [show abstract] [hide abstract]
    ABSTRACT: We study the 8 TeV LHC reach on pair produced heavy flavored di-jet resonances. Motivated by theories of R-parity violation in supersymmetry we concentrate on a final state with two b-jets and two light jets. We exploit b-tagging to reject the background and discuss its importance at the trigger level to probe light stops. We present kinematical selections that can be used to isolate the signal as a bump in the mass distribution of the candidate resonances. We find that stops with R-parity violating couplings giving rise to fully hadronic final states can be observed in the current run of the LHC. Remarkably, the LHC can probe stop masses well within the range predicted by naturalness.
    European Physical Journal C 12/2012; 73(5). · 5.25 Impact Factor
  • Source
    [show abstract] [hide abstract]
    ABSTRACT: Both the ATLAS and CMS collaborations have reported a Standard Model Higgs-like excess at around $m_h = 125$ GeV. If an SM-like Higgs particle is discovered in this particular mass range, an important additional test of the SM electroweak symmetry breaking sector is the measurement of the Higgs self-interactions. We investigate the prospects of measuring the Higgs self-coupling for $m_h=125 \gev$ in the dominant SM decay channels in boosted and unboosted kinematical regimes. We further enhance sensitivity by considering dihiggs systems recoiling against a hard jet. This configuration exhibits a large sensitivity to the Higgs self-coupling which can be accessed in subjet-based analyses. Combining our analyses allows constraints to be set on the Higgs self-coupling at the LHC.
    Journal of High Energy Physics 06/2012; 2012(10). · 5.62 Impact Factor
  • Source
    [show abstract] [hide abstract]
    ABSTRACT: We present details of a calculation of the cross section for hadronic top-antitop production in next-to-leading order (NLO) QCD, including the decays of the top and antitop into bottom quarks and leptons. This calculation is based on matrix elements for \nu e e+ \mu- \bar{\nu}_{\mu}b\bar{b} production and includes all non-resonant diagrams, interferences, and off-shell effects of the top quarks. Such contributions are formally suppressed by the top-quark width and turn out to be small in the inclusive cross section. However, they can be strongly enhanced in exclusive observables that play an important role in Higgs and new-physics searches. Also non-resonant and off-shell effects due to the finite W-boson width are investigated in detail, but their impact is much smaller than naively expected. We also introduce a matching approach to improve NLO calculations involving intermediate unstable particles. Using a fixed QCD scale leads to perturbative instabilities in the high-energy tails of distributions, but an appropriate dynamical scale stabilises NLO predictions. Numerical results for the total cross section, several distributions, and asymmetries are presented for Tevatron and the LHC at 7 TeV, 8 TeV, and 14 TeV.
    Journal of High Energy Physics 07/2012; 2012(10). · 5.62 Impact Factor

Full-text

View
0 Downloads
Available from