Reconstructing a Z' Lagrangian using the LHC and low-energy data

TL;DR

This paper explores how combining LHC data with low-energy experiments can accurately determine the properties of a new Z' boson, highlighting the importance of off-peak data and low-energy measurements.

Contribution

It demonstrates a comprehensive method to reconstruct Z' couplings by integrating collider and low-energy experimental data, reducing degeneracies in parameter determination.

Findings

Off-peak LHC data and Q-weak are crucial for resolving coupling sign degeneracies.

Low-energy Moller scattering can break scaling degeneracies between quark and lepton couplings.

Coupling combinations can be determined with 30-50% uncertainty at 30 fb^-1, and to 10% at 1 ab^-1.

Abstract

We study the potential of the LHC and future low-energy experiments to precisely measure the underlying model parameters of a new Z' boson. We emphasize the complimentary information obtained from both on- and off-peak LHC dilepton data, from the future Q-weak measurement of the weak charge of the proton, and from a proposed measurement of parity violation in low-energy Moller scattering. We demonstrate the importance of off-peak LHC data and Q-weak for removing sign degeneracies between Z' couplings that occur if only on-peak LHC data is studied. A future precision measurement of low-energy Moller scattering can resolve a scaling degeneracy between quark and lepton couplings that remains after analyzing LHC dilepton data, permitting an extraction of the individual Z' couplings rather than combinations of them. We study how precisely Z' properties can be extracted for LHC integrated luminosities ranging from a few inverse femtobarns to super-LHC values of an inverse attobarn. For the several example cases studied with M_Z'=1.5 TeV, we find that coupling combinations can be determined with relative uncertainties reaching 30% with 30 fb^-1 of integrated luminosity, while 50% is possible with 10 fb^-1. With SLHC luminosities of 1 ab^-1, we find that products of quark and lepton couplings can be probed to 10%.