Search for ZZ resonances in the 2ℓ2ν final state in proton-proton collisions at 13 TeV

Abstract

A search for heavy resonances decaying to a pair of Z bosons is performed using data collected with the CMS detector at the LHC. Events are selected by requiring two oppositely charged leptons (electrons or muons), consistent with the decay of a Z boson, and large missing transverse momentum, which is interpreted as arising from the decay of a second Z boson to two neutrinos. The analysis uses data from protonproton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb −1 . The hypothesis of a spin-2 bulk graviton (X) decaying to a pair of Z bosons is examined for 600 ≤ m X ≤ 2500 GeV and upper limits at 95% confidence level are set on the product of the production cross section and branching fraction of X → ZZ ranging from 100 to 4 fb. For bulk graviton models characterized by a curvature scale parameterk = 0.5 in the extra dimension, the region m X < 800 GeV is excluded, providing the most stringent limit reported to date. Variations of the model considering the possibility of a wide resonance produced exclusively via gluon-gluon fusion or qq annihilation are also examined.

Common exotic decays of top partners

“…The pseudo-scalar a can be directly produced at the LHC in gluon fusion. 4 As the BRs of a are determined as given in figure 2, bounds from ATLAS and CMS resonance searches in the channels jj [80][81][82][83][84][85], Zγ [86][87][88] and γγ [89][90][91][92] can be translated into bounds on the decay constant f a , which controls the direct production cross section [30,58] by the couplings given in eq. (2.6).…”

Search for heavy particles decaying into top-quark pairs using lepton-plus-jets events in proton–proton collisions at $$\sqrt{s} = 13$$ s = 13 $$\text {TeV}$$ TeV with the ATLAS detector

“…The ATLAS Collaboration's search for such gravitons in √ s = 8 TeV data in the t t decay channel set cross-section limits but did not exclude any graviton masses [1], while the search for the same model in the G KK → Z Z channel [13] excluded a Bulk RS G KK with mass less than 740 GeV. The CMS Collaboration performed searches in the G KK → Z Z and G KK → WW decay channels [14,15] excluding such RS gravitons with masses less than 1.3 TeV.…”

Light Scalars in Composite Higgs Models

“…Many different final states are searched for at the LHC. We include the following Run-II searches by CMS [71][72][73][74][75][76][77][78] and ATLAS [79][80][81][82].…”