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.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
ATLAS collaboration, Search for new resonances in mass distributions of jet pairs using 139 fb−1 of pp collisions at \( \sqrt{s} \) = 13 TeV with the ATLAS detector, arXiv:1910.08447 [INSPIRE].
CMS collaboration, Search for high mass dijet resonances with a new background prediction method in proton-proton collisions at \( \sqrt{s} \) = 13 TeV, arXiv:1911.03947 [INSPIRE].
ATLAS collaboration, Search for new high-mass phenomena in the dilepton final state using 36 fb−1 of proton-proton collision data at \( \sqrt{s} \) = 13 TeV with the ATLAS detector, JHEP 10 (2017) 182 [arXiv:1707.02424] [INSPIRE].
CMS collaboration, Search for high-mass resonances in dilepton final states in proton-proton collisions at \( \sqrt{s} \) = 13 TeV, JHEP 06 (2018) 120 [arXiv:1803.06292] [INSPIRE].
ATLAS collaboration, Search for high-mass dilepton resonances using 139 fb−1 of pp collision data collected at \( \sqrt{s} \) = 13 TeV with the ATLAS detector, Phys. Lett. B 796 (2019) 68 [arXiv:1903.06248] [INSPIRE].
CMS collaboration, Search for a narrow resonance in high-mass dilepton final states in proton-proton collisions using 140 fb−1 of data at \( \sqrt{s} \) = 13 TeV, CMS-PAS-EXO-19-019 (2019).
H. An, X. Ji and L.-T. Wang, Light dark matter and Z′ dark force at colliders, JHEP 07 (2012) 182 [arXiv:1202.2894] [INSPIRE].
H. An, R. Huo and L.-T. Wang, Searching for low mass dark portal at the LHC, Phys. Dark Univ. 2 (2013) 50 [arXiv:1212.2221] [INSPIRE].
E. Accomando et al., Z′ at the LHC: interference and finite width effects in Drell-Yan, JHEP 10 (2013) 153 [arXiv:1304.6700] [INSPIRE].
A. Belyaev, S.F. King and P. Svantesson, Little Z′ models, Phys. Rev. D 88 (2013) 035015 [arXiv:1303.0770] [INSPIRE].
E. Accomando et al., Z′ physics with early LHC data, Phys. Rev. D 83 (2011) 075012 [arXiv:1010.6058] [INSPIRE].
L. Basso et al., Z′ discovery potential at the LHC in the minimal B − L extension of the Standard Model, Eur. Phys. J. C 71 (2011) 1613 [arXiv:1002.3586] [INSPIRE].
E. Accomando et al., Production of Z′-boson resonances with large width at the LHC, Phys. Lett. B 803 (2020) 135293 [arXiv:1910.13759] [INSPIRE].
G. Altarelli, B. Mele and M. Ruiz-Altaba, Searching for new heavy vector bosons in \( p\overline{p} \) colliders, Z. Phys. C 45 (1989) 109 [Erratum ibid. C 47 (1990) 676] [INSPIRE].
P. Langacker, The physics of heavy Z′ gauge bosons, Rev. Mod. Phys. 81 (2009) 1199 [arXiv:0801.1345] [INSPIRE].
Y.G. Kim and K.Y. Lee, Direct search for heavy gauge bosons at the LHC in the nonuniversal SU(2) model, Phys. Rev. D 90 (2014) 117702 [arXiv:1405.7762] [INSPIRE].
L. Basso, K. Mimasu and S. Moretti, Non-exotic Z′ signals in ℓ+ℓ−, \( b\overline{b}\ and\ t\overline{t} \) final states at the LHC, JHEP 11 (2012) 060 [arXiv:1208.0019] [INSPIRE].
E. Accomando et al., Drell-Yan production of multi Z′-bosons at the LHC within non-universal ED and 4D composite Higgs models, JHEP 07 (2016) 068 [arXiv:1602.05438] [INSPIRE].
E. Accomando, J. Fiaschi, S. Moretti and C.H. Shepherd-Themistocleous, Constraining Z′ widths from pT measurements in Drell-Yan processes, Phys. Rev. D 96 (2017) 075019 [arXiv:1703.04360] [INSPIRE].
A. Alves et al., Augury of darkness: the low-mass dark Z′ portal, JHEP 04 (2017) 164 [arXiv:1612.07282] [INSPIRE].
A.V. Gulov, A.A. Pankov, A.O. Pevzner and V.V. Skalozub, Model-independent constraints on the Abelian Z′ couplings within the ATLAS data on the dilepton production processes at \( \sqrt{s} \) = 13 TeV, Nonlin. Phenom. Complex Syst. 21 (2018) 21 [arXiv:1803.07532] [INSPIRE].
P. Langacker, Grand unified theories and proton decay, Phys. Rept. 72 (1981) 185 [INSPIRE].
J.L. Hewett and T.G. Rizzo, Low-energy phenomenology of superstring inspired E6 models, Phys. Rept. 183 (1989) 193 [INSPIRE].
S.A. Malik et al., Interplay and characterization of dark matter searches at colliders and in direct detection experiments, Phys. Dark Univ. 9-10 (2015) 51 [arXiv:1409.4075] [INSPIRE].
J. Abdallah et al., Simplified models for dark matter searches at the LHC, Phys. Dark Univ. 9-10 (2015) 8 [arXiv:1506.03116] [INSPIRE].
A. Albert et al., Towards the next generation of simplified dark matter models, Phys. Dark Univ. 16 (2017) 49 [arXiv:1607.06680] [INSPIRE].
M.T. Frandsen et al., LHC and Tevatron bounds on the dark matter direct detection cross-section for vector mediators, JHEP 07 (2012) 123 [arXiv:1204.3839] [INSPIRE].
P.J. Fox and C. Williams, Next-to-leading order predictions for dark matter production at hadron colliders, Phys. Rev. D 87 (2013) 054030 [arXiv:1211.6390] [INSPIRE].
A. Alves, S. Profumo and F.S. Queiroz, The dark Z′ portal: direct, indirect and collider searches, JHEP 04 (2014) 063 [arXiv:1312.5281] [INSPIRE].
G. Arcadi, Y. Mambrini, M.H.G. Tytgat and B. Zaldivar, Invisible Z′ and dark matter: LHC vs LUX constraints, JHEP 03 (2014) 134 [arXiv:1401.0221] [INSPIRE].
O. Buchmueller, M.J. Dolan, S.A. Malik and C. McCabe, Characterising dark matter searches at colliders and direct detection experiments: vector mediators, JHEP 01 (2015) 037 [arXiv:1407.8257] [INSPIRE].
O. Lebedev and Y. Mambrini, Axial dark matter: the case for an invisible Z′ , Phys. Lett. B 734 (2014) 350 [arXiv:1403.4837] [INSPIRE].
P. Harris, V.V. Khoze, M. Spannowsky and C. Williams, Constraining dark sectors at colliders: beyond the effective theory approach, Phys. Rev. D 91 (2015) 055009 [arXiv:1411.0535] [INSPIRE].
G. Busoni et al., Making the most of the relic density for dark matter searches at the LHC 14 TeV run, JCAP 03 (2015) 022 [arXiv:1410.7409] [INSPIRE].
M. Fairbairn and J. Heal, Complementarity of dark matter searches at resonance, Phys. Rev. D 90 (2014) 115019 [arXiv:1406.3288] [INSPIRE].
W. Altmannshofer et al., Dark matter signals in dilepton production at hadron colliders, Phys. Rev. D 91 (2015) 115006 [arXiv:1411.6743] [INSPIRE].
T. Jacques and K. Nordström, Mapping monojet constraints onto simplified dark matter models, JHEP 06 (2015) 142 [arXiv:1502.05721] [INSPIRE].
A. Alves, A. Berlin, S. Profumo and F.S. Queiroz, Dark matter complementarity and the Z′ portal, Phys. Rev. D 92 (2015) 083004 [arXiv:1501.03490] [INSPIRE].
M. Chala et al., Constraining dark sectors with monojets and dijets, JHEP 07 (2015) 089 [arXiv:1503.05916] [INSPIRE].
A. De Simone and T. Jacques, Simplified models vs. effective field theory approaches in dark matter searches, Eur. Phys. J. C 76 (2016) 367 [arXiv:1603.08002] [INSPIRE].
A.J. Brennan, M.F. McDonald, J. Gramling and T.D. Jacques, Collide and conquer: constraints on simplified dark matter models using Mono-X collider searches, JHEP 05 (2016) 112 [arXiv:1603.01366] [INSPIRE].
T. Jacques et al., Complementarity of DM searches in a consistent simplified model: the case of Z′, JHEP 10 (2016) 071 [Erratum ibid. 01 (2019) 127] [arXiv:1605.06513] [INSPIRE].
R.M. Capdevilla, A. Delgado, A. Martin and N. Raj, Characterizing dark matter at the LHC in Drell-Yan events, Phys. Rev. D 97 (2018) 035016 [arXiv:1709.00439] [INSPIRE].
C. Blanco, M. Escudero, D. Hooper and S.J. Witte, Z′ mediated WIMPs: dead, dying, or soon to be detected?, JCAP 11 (2019) 024 [arXiv:1907.05893] [INSPIRE].
G. Busoni et al., Recommendations on presenting LHC searches for missing transverse energy signals using simplified s-channel models of dark matter, Phys. Dark Univ. 27 (2020) 100365 [arXiv:1603.04156] [INSPIRE].
A. Albert et al., Recommendations of the LHC dark matter working group: comparing LHC searches for dark matter mediators in visible and invisible decay channels and calculations of the thermal relic density, Phys. Dark Univ. 26 (2019) 100377 [arXiv:1703.05703] [INSPIRE].
F. Kahlhoefer, K. Schmidt-Hoberg, T. Schwetz and S. Vogl, Implications of unitarity and gauge invariance for simplified dark matter models, JHEP 02 (2016) 016 [arXiv:1510.02110] [INSPIRE].
M. Duerr et al., How to save the WIMP: global analysis of a dark matter model with two s-channel mediators, JHEP 09 (2016) 042 [arXiv:1606.07609] [INSPIRE].
M. Duerr et al., Hunting the dark Higgs, JHEP 04 (2017) 143 [arXiv:1701.08780] [INSPIRE].
J. Ellis, M. Fairbairn and P. Tunney, Anomaly-free dark matter models are not so simple, JHEP 08 (2017) 053 [arXiv:1704.03850] [INSPIRE].
J. Ellis, M. Fairbairn and P. Tunney, Phenomenological constraints on anomaly-free dark matter models, arXiv:1807.02503 [INSPIRE].
S. Caron, J.A. Casas, J. Quilis and R. Ruiz de Austri, Anomaly-free dark matter with harmless direct detection constraints, JHEP 12 (2018) 126 [arXiv:1807.07921] [INSPIRE].
S. El Hedri and K. Nordström, Whac-a-constraint with anomaly-free dark matter models, SciPost Phys. 6 (2019) 020 [arXiv:1809.02453] [INSPIRE].
N. Raj, Anticipating nonresonant new physics in dilepton angular spectra at the LHC, Phys. Rev. D 95 (2017) 015011 [arXiv:1610.03795] [INSPIRE].
J. Ellis, TikZ-Feynman: Feynman diagrams with TikZ, Comput. Phys. Commun. 210 (2017) 103 [arXiv:1601.05437] [INSPIRE].
A.D. Martin, W.J. Stirling, R.S. Thorne and G. Watt, Parton distributions for the LHC, Eur. Phys. J. C 63 (2009) 189 [arXiv:0901.0002] [INSPIRE].
DELPHES 3 collaboration, DELPHES 3, a modular framework for fast simulation of a generic collider experiment, JHEP 02 (2014) 057 [arXiv:1307.6346] [INSPIRE].
ATLAS and CMS collaborations and the LHC Higgs Combination Group, Procedure for the LHC Higgs boson search combination in Summer 2011, ATL-PHYS-PUB-2011-011 (2011).
G. Cowan, K. Cranmer, E. Gross and O. Vitells, Asymptotic formulae for likelihood-based tests of new physics, Eur. Phys. J. C 71 (2011) 1554 [Erratum ibid. C 73 (2013) 2501] [arXiv:1007.1727] [INSPIRE].
Open Access
This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited
Author information
Authors and Affiliations
Corresponding author
Additional information
ArXiv ePrint: 1912.06374
Rights and permissions
Open Access . This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited.
About this article
Cite this article
Kahlhoefer, F., Mück, A., Schulte, S. et al. Interference effects in dilepton resonance searches for Z′ bosons and dark matter mediators. J. High Energ. Phys. 2020, 104 (2020). https://doi.org/10.1007/JHEP03(2020)104
Received:
Accepted:
Published:
DOI: https://doi.org/10.1007/JHEP03(2020)104