Interference effects in dilepton resonance searches for Z' bosons and dark matter mediators

Abstract

New Z' gauge bosons arise in many extensions of the Standard Model and predict resonances in the dilepton invariant mass spectrum. Searches for such resonances therefore provide important constraints on many models of new physics, but the resulting bounds are often calculated without interference effects. In this work we show that the effect of interference is significant and cannot be neglected whenever the Z' width is large (for example because of an invisible contribution). To illustrate this point, we implement and validate the most recent 139 fb${}^{-1}$ dilepton search from ATLAS and obtain exclusion limits on general Z' models as well as on simplified dark matter models with spin-1 mediators. We find that interference can substantially strengthen the bound on the Z' couplings and push exclusion limits for dark matter simplified models to higher values of the Z' mass. Together with this study we release the open-source code ZPEED, which provides fast likelihoods and exclusion bounds for general Z' models.

arXiv commentv2 matches version accepted by JHEP. 14 pages + appendices, 9 figures + 1 table, ZPEED code to calculate dilepton likelihoods available at http://github.com/kahlhoefer/ZPEED

References in corpus (42)

• Parton distributions for the LHC
• Asymptotic formulae for likelihood-based tests of new physics
• DELPHES 3, A modular framework for fast simulation of a generic collider experiment
• The Physics of Heavy Z' Gauge Bosons
• Simplified Models for Dark Matter Searches at the LHC
• TikZ-Feynman: Feynman diagrams with TikZ
• Implications of unitarity and gauge invariance for simplified dark matter models
• Characterising dark matter searches at colliders and direct detection experiments: Vector mediators
• The Dark Z' Portal: Direct, Indirect and Collider Searches
• Constraining Dark Sectors at Colliders: Beyond the Effective Theory Approach
• Light dark matter and $Z^{\prime }$ dark force at colliders
• Z' physics with early LHC data
• Z'_{B-L} discovery potential at the LHC for \sqrt{s}=7 TeV
• LHC and Tevatron bounds on the dark matter direct detection cross-section for vector mediators
• Dark Matter Complementarity and the Z${}^{\prime }$ Portal
• Invisible Z' and dark matter: LHC vs LUX constraints
• Simplified Models vs. Effective Field Theory Approaches in Dark Matter Searches
• Constraining Dark Sectors with Monojets and Dijets
• Axial Dark Matter: the case for an invisible Z'
• How to save the WIMP: global analysis of a dark matter model with two s-channel mediators
• Anomaly-Free Dark Matter Models are not so Simple
• Next-to-Leading Order Predictions for Dark Matter Production at Hadron Colliders
• Interplay and Characterization of Dark Matter Searches at Colliders and in Direct Detection Experiments
• Searching for Low Mass Dark Portal at the LHC
• $Z^{\prime }$ discovery potential at the LHC in the minimal $B-L$ extension of the Standard Model
• Anticipating Non-Resonant New Physics in Dilepton Angular Spectra at the LHC
• Z' at the LHC: Interference and Finite Width Effects in Drell-Yan
• Mapping monojet constraints onto Simplified Dark Matter Models
• Hunting the dark Higgs
• $Z^{\prime }$ Mediated WIMPs: Dead, Dying, or Soon to be Detected?
• Augury of Darkness: The Low-Mass Dark Z' Portal
• Collide and Conquer: Constraints on Simplified Dark Matter Models using Mono-X Collider Searches
• Complementarity of DM Searches in a Consistent Simplified Model: the Case of Z'
• Production of Z'-Boson Resonances with Large Width at the LHC
• Making the Most of the Relic Density for Dark Matter Searches at the LHC 14 TeV Run
• Anomaly-free Dark Matter with Harmless Direct Detection Constraints
• Drell-Yan production of multi Z'-bosons at the LHC within Non-Universal ED and 4D Composite Higgs Models
• Characterizing dark matter at the LHC in Drell-Yan events
• Little Z' Models
• Non-exotic $Z^{\prime }$ signals in ${\ell }^{+}{\ell }^{-}$, $b\bar{b}$ and $t\bar{t}$ final states at the LHC
• Whac-a-constraint with anomaly-free dark matter models
• Constraining $Z^{\prime }$ widths from $p_T$ measurements in Drell-Yan processes

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