CAS Key Laboratory of Theoretical Physics

Institute of Theoretical Physics

 Chinese Academy of Sciences

Seminar

Title

题目

Speaker

报告人

Affiliation

所在单位

Date

日期

15:00, Dec 25 (Monday), 2017

Venue

地点

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