Z and Z' phenomenology at the LHC

People

Valentin Hirshi, Fabio Maltoni, Francesco Tramontano

Motivations

Many BSM models predict the existence of a parter of the Z with enhanced (suppressed) couplings to heavy (light) fermions.

This might entail a strong suppression of the production rates, as for the Higgs. We explore the idea that, as for the Higgs, the gluon gluon channel might actually provide the leading production channel.

Working plan

Phase I

• Verify (or not) Bij and Glover calculation (paper​). This can be done by explicit

comparison or by checking the decay results.

• Study the heavy top limit of the calculation and build the corresponding EFT.
• Implement the EFT in Feynrules.
• Perform the calculation directly in the EFT and check the results.

Phase II

• Write a code (Mathematica or Fortran or C++) which calculates cross section at hadron colliders.
• Study the NNNLO effects on the Z and Z' inclusive cross section (Fabio has a code for NNLO Z production).
• Implement the effective field theory in MadGraph and the full calculation correction.

Phase III

• Get to know the models which predict a fermiophobic Z' in detail.
• Construct a reasonable parameter space to be studied, including indirect constraints.
• Propose discovery channels at the LHC.

Phase IV

• Write the report and paper

Phase V

• Book the flight to Stocholm

Status and reports

• (Final report​) in attachment.