PT Journal
AU Breso-Pla, V
   Falkowski, A
   Gonzalez-Alonso, M
TI A(FB) in the SMEFT: precision Z physics at the LHC
SO Journal of High Energy Physics
JI J. High Energy Phys.
PY 2021
BP 021
EP 27pp
VL 08
IS 8
DI 10.1007/JHEP08(2021)021
LA English
DE Beyond Standard Model; Effective Field Theories
AB We study the forward-backward asymmetry A(FB) in pp -> l(+)l(-) at the Z peak within the Standard Model Effective Field Theory (SMEFT). We find that this observable provides per mille level constraints on the vertex corrections of the Z boson to quarks, which close a flat direction in the electroweak precision SMEFT fit. Moreover, we show that current A(FB) data is precise enough so that its inclusion in the fit improves significantly LEP bounds even in simple New Physics setups. This demonstrates that the LHC can compete with and complement LEP when it comes to precision measurements of the Z boson properties.
ER