Top-philic Z forces at the LHC

  • Patrick J. Fox
  • Ian Low
  • Yue Zhang
Open Access
Regular Article - Theoretical Physics


Despite extensive searches for an additional neutral massive gauge boson at the LHC, a Z at the weak scale could still be present if its couplings to the first two generations of quarks are suppressed, in which case the production in hadron colliders relies on tree-level processes in association with heavy flavors or one-loop processes in association with a jet. We consider the low-energy effective theory of a top-philic Z and present possible UV completions. We clarify theoretical subtleties in evaluating the production of a top-philic Z at the LHC and examine carefully the treatment of ananomalous Z current in the low-energy effective theory. Recipes for properly computing the production rate in the Z + j channel are given. We discuss constraints from colliders and low-energy probes of new physics. As an application, we apply these considerations to models that use a weak-scale Z to explain possible violations of lepton universality in B meson decays, and show that the future running of a high luminosity LHC can potentially cover much of the remaining parameter space favored by this particular interpretation of the B physics anomaly.


Anomalies in Field and String Theories Beyond Standard Model 


Open Access

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Copyright information

© The Author(s) 2018

Authors and Affiliations

  1. 1.Theoretical Physics Department, FermilabBataviaU.S.A.
  2. 2.High Energy Physics Division, Argonne National LaboratoryArgonneU.S.A.
  3. 3.Department of Physics and AstronomyNorthwestern UniversityEvanstonU.S.A.
  4. 4.Theoretical Physics Department, CERNGeneva 23Switzerland

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