Top-Quark Forward-Backward Asymmetry in Randall-Sundrum Models Beyond the Leading Order
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...
| Main Authors: | , , , , |
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| פורמט: | Journal article |
| יצא לאור: |
2010
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| _version_ | 1826293073812914176 |
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| author | Bauer, M Goertz, F Haisch, U Pfoh, T Westhoff, S |
| author_facet | Bauer, M Goertz, F Haisch, U Pfoh, T Westhoff, S |
| author_sort | Bauer, M |
| collection | OXFORD |
| description | 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. |
| first_indexed | 2024-03-07T03:24:28Z |
| format | Journal article |
| id | oxford-uuid:b88ee5a7-2dbc-4915-828d-8c17cd30533b |
| institution | University of Oxford |
| last_indexed | 2024-03-07T03:24:28Z |
| publishDate | 2010 |
| record_format | dspace |
| spelling | oxford-uuid:b88ee5a7-2dbc-4915-828d-8c17cd30533b2022-03-27T04:56:45ZTop-Quark Forward-Backward Asymmetry in Randall-Sundrum Models Beyond the Leading OrderJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:b88ee5a7-2dbc-4915-828d-8c17cd30533bSymplectic Elements at Oxford2010Bauer, MGoertz, FHaisch, UPfoh, TWesthoff, SWe 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. |
| spellingShingle | Bauer, M Goertz, F Haisch, U Pfoh, T Westhoff, S Top-Quark Forward-Backward Asymmetry in Randall-Sundrum Models Beyond the Leading Order |
| title | Top-Quark Forward-Backward Asymmetry in Randall-Sundrum Models Beyond
the Leading Order |
| title_full | Top-Quark Forward-Backward Asymmetry in Randall-Sundrum Models Beyond
the Leading Order |
| title_fullStr | Top-Quark Forward-Backward Asymmetry in Randall-Sundrum Models Beyond
the Leading Order |
| title_full_unstemmed | Top-Quark Forward-Backward Asymmetry in Randall-Sundrum Models Beyond
the Leading Order |
| title_short | Top-Quark Forward-Backward Asymmetry in Randall-Sundrum Models Beyond
the Leading Order |
| title_sort | top quark forward backward asymmetry in randall sundrum models beyond the leading order |
| work_keys_str_mv | AT bauerm topquarkforwardbackwardasymmetryinrandallsundrummodelsbeyondtheleadingorder AT goertzf topquarkforwardbackwardasymmetryinrandallsundrummodelsbeyondtheleadingorder AT haischu topquarkforwardbackwardasymmetryinrandallsundrummodelsbeyondtheleadingorder AT pfoht topquarkforwardbackwardasymmetryinrandallsundrummodelsbeyondtheleadingorder AT westhoffs topquarkforwardbackwardasymmetryinrandallsundrummodelsbeyondtheleadingorder |