24–26 May 2021
University of Pittsburgh
US/Eastern timezone

The anomalous $Zb\bar{b}$ couplings: From LEP to LHC

25 May 2021, 14:30
15m
BSM BSM III

Speaker

Dr Bin Yan (Los Alamos National Laboratory)

Description

The bottom quark forward-backward asymmetry ($A_{FB}^b$) data at LEP exhibits a long-standing discrepancy with the standard model prediction.
We propose a novel method to probe the $Zb\bar{b}$ interactions through $gg\to Zh$ production at the LHC, which is sensitive to the axial-vector component of the $Zb\bar{b}$ couplings. We demonstrate that the $Zh$ data collected at the 13 TeV LHC can already resolve the apparent degeneracy of the anomalous $Zb\bar{b}$ couplings implied by the LEP precision electroweak measurements, with a strong dependence on the observed distribution of the $Z$ boson transverse momentum.
We also show the potential of the HL-LHC to either verify or exclude
the anomalous $Zb\bar{b}$ couplings observed at LEP through measuring the $Zh$ production rate
at the HL-LHC, and this conclusion is not sensitive to possible new physics contribution induced by top quark or Higgs boson anomalous couplings in the loop.

Primary author

Dr Bin Yan (Los Alamos National Laboratory)

Co-author

Prof. C.-P. Yuan (MSU)

Presentation materials