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| (Seminar)Bottom-quark Forward-Backward Asymmetry, Dark Matter and the LHC |
| 2017-12-25
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| CAS Key Laboratory of Theoretical Physics | | Institute of Theoretical Physics | | Chinese Academy of Sciences | | Seminar | | Title 题目 | Bottom-quark Forward-Backward Asymmetry, Dark Matter and the LHC | | Speaker 报告人 | Xiaoping Wang | | Affiliation 所在单位 | Argonne National Lab | | Date 日期 | 15:00, Dec 25 (Monday), 2017 | | Venue 地点 | 新楼6420 | | Abstract 摘要 | The LEP experiment at CERN provided accurate measurements of the $Z$ neutral gauge boson properties. Although all measurements agree well with the SM predictions, the forward backward asymmetry of the bottom-quark remains almost 3$\sigma$ away from the SM value. We proposed that this anomaly may be explained by the existence of a new $U(1)_D$ gauge boson, which couples with opposite charges to the right-handed components of the bottom and charm quarks. Cancellation of gauge anomalies demands the presence of a vector-like singlet charged lepton as well as a neutral Dirac (or Majorana) particle that provides a Dark Matter candidate. Constraints from precision measurements imply that the mass of the new gauge boson should be around $115$~GeV. We discuss the experimental constraints on this scenario, including the existence of a di-jet resonance excess at an invariant mass similar to the mass of this new gauge boson, observed in boosted topologies at the CMS experiment. | | Contact person 所内联系人 | Jing Shu(舒菁) |
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