CERN Accelerating science

ATLAS Slides
Report number	ATL-PHYS-SLIDE-2023-368
Title	Evidence of the rare Higgs boson decay to a Z boson and a photon using ATLAS and CMS Run 2 data
Author(s)	Zhang, Rui (University of Wisconsin Madison (US))
Corporate author(s)	The ATLAS collaboration
Collaboration	ATLAS Collaboration
Submitted by	[email protected] on 30 Aug 2023
Subject category	Particle Physics - Experiment
Accelerator/Facility, Experiment	CERN LHC ; ATLAS
Free keywords	Higgs rare decay ; H to Zy ; Evidence ; HIGGS
Abstract	The first experimental evidence is presented for the rare Higgs boson decay to a Z boson and a photon, with a statistical significance of 3.4 standard deviations. The result is derived from a joint interpretation of the searches performed by the ATLAS and CMS collaborations with their proton-proton collision data sets collected at the CERN LHC during 2015 and 2018. These correspond to integrated luminosities around 140 fb−1 for both experiments, at a centre-of-mass energy of 13 TeV. The observed signal yield is 2.2+-0.7 times the Standard Model prediction, and agrees with the theoretical expectation within 1.9 standard deviations.