Speaker
Description
The discovery of the Higgs boson at 125 GeV has provided profound insights into the origin of fundamental particle masses in the Standard Model and the mechanism of electroweak symmetry breaking. However, theories beyond the Standard Model suggest the potential existence of additional Higgs bosons in extended parameter spaces. Intriguingly, Run 2 data from both the CMS and ATLAS experiments revealed a non-negligible local excess around 95.4 GeV in the diphoton decay channel. To investigate this anomaly, new searches for low-mass resonances decaying into two photons have been conducted using 13.6 TeV proton-proton collision data collected by the ATLAS detector between 2022 and 2024, corresponding to an integrated luminosity of 168 fb−1.
This analysis focuses on the reconstructed diphoton invariant mass spectrum in the range of 66 GeV to 110 GeV. Two complementary approaches are employed: a model-independent search for a generic spin-0 resonance and a model-dependent search targeting an additional Higgs boson predicted by BSM scenarios. By incorporating advanced multivariate analysis techniques and refined statistical modeling, stringent upper limits at 95% confidence level (CL) are established to both the total production cross-section and the fiducial cross-section times branching ratio.
