Drell-Yan Constraints on New Electroweak States: LHC as a $p p \to l^+ l^-$ Precision Machine

Understand

The Standard Model extensions with vector-like states which have either zero hypercharge or zero weak isospin are rather poorly constrained by the electroweak precision measurements.

• Such new states would however modify the running of the gauge couplings at high energies.
• As a result, the Drell-Yan process $p p \to l^+ l^-$ at the LHC places useful constraints on these models.
• The relevant observables include both the di-lepton invariant mass distribution $M_{l l}$ and the forward-backward asymmetry $A_{FB}$.