Search for the γZ decay mode of heavy photophobic axion-like particles at the LHC

A bstract We assume the coupling of Axion-like particle (ALP) to diphoton g aγγ ~ 0 and accomplish detailed analyses for the γZ decay mode of such heavy photophobic ALPs at the high luminosity-Large Hadron Collider (HL-LHC). ALPs are produced with two jets via both the s -channel vector boson exchange and vector boson fusion processes, with the signal process pp → jja (→ γZ (→ ℓ + ℓ − )) for ℓ = e , μ . Signal and background events are simulated at the detector-level. Preselection criteria target events with one photon, two oppositely charged electrons or muons, and two non- b -tagged jets. The ALP mass is reconstructed, and kinematic observables are input into a machine learning-based multivariate analysis for optimal background rejection. Discover sensitivities on the ALP’s coupling to di- W boson, g aWW , are presented in the mass range from 100 to 4000 GeV at center-of-mass energy $$ \sqrt{s} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> </mml:math> = 14 TeV and integrated luminosity $$ \mathcal{L} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>L</mml:mi> </mml:math> = 3 ab − 1 and 140 fb − 1 . Sensitivities on the production cross section σ ( pp → jja ) times the branching ratio Br( a → γZ ) are also presented.