Top-Quark Forward-Backward Asymmetry in Randall-Sundrum Models Beyond the Leading Order
arXiv:1008.0742 · doi:10.1007/JHEP11(2010)039
Abstract
We calculate the ttbar forward-backward asymmetry, A_FB^t, in Randall-Sundrum (RS) models taking into account the dominant next-to-leading order (NLO) corrections in QCD. At Born level we include the exchange of Kaluza-Klein (KK) gluons and photons, the Z boson and its KK excitations, as well as the Higgs boson, whereas beyond the leading order (LO) we consider the interference of tree-level KK-gluon exchange with one-loop QCD box diagrams and the corresponding bremsstrahlungs corrections. We find that the strong suppression of LO effects, that arises due to the elementary nature and the mostly vector-like couplings of light quarks, is lifted at NLO after paying the price of an additional factor of alpha_s/(4 pi). In spite of this enhancement, the resulting RS corrections in A_FB^t remain marginal, leaving the predicted asymmetry SM-like. As our arguments are solely based on the smallness of the axial-vector couplings of light quarks to the strong sector, our findings are model-independent and apply to many scenarios of new physics that address the flavor problem via geometrical sequestering.
29 pages, 1 table, 5 figures; v2: matches version published in JHEP
References in corpus (7)
- Parton distributions for the LHC
- Flavor Physics in the Randall-Sundrum Model: I. Theoretical Setup and Electroweak Precision Tests
- Updated predictions for the total production cross sections of top and of heavier quark pairs at the Tevatron and at the LHC
- First measurement of the forward-backward charge asymmetry in top quark pair production
- Delta F=2 Observables and Fine-Tuning in a Warped Extra Dimension with Custodial Protection
- The Custodial Randall-Sundrum Model: From Precision Tests to Higgs Physics
- Search for ttbar resonances in the lepton plus jets final state in ppbar collisions at sqrt{s}=1.96TeV
Cited by in corpus (7)
- Top Quark Forward-Backward Asymmetry and Same-Sign Top Quark Pairs
- Forward-backward asymmetry in top quark production from light colored scalars in SO(10) model
- Tevatron Asymmetry of Tops in a W',Z' Model
- Top quark forward-backward asymmetry at Tevatron and its implications at the LHC
- Gluon excitations in t tbar production at hadron colliders
- One-side forward-backward asymmetry at the LHC
- Evidence for a Mass Dependent Forward-Backward Asymmetry in Top Quark Pair Production