A search for exotic decays of the 125 GeV Higgs boson into a pair of new spin-0 particles, H → aa, where one decays into a photon pair and the other into a τ-lepton pair, is presented. Hadronic decays of the τ-leptons are considered and reconstructed using a dedicated tagger for collimated τ-lepton pairs. The search uses 140 fb−1 of proton-proton collision data at a centre-of-mass energy of s = 13 TeV recorded between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider. The search is performed in the mass range of the a boson between 10 GeV and 60 GeV. No significant excess of events is observed above the Standard Model background expectation. Model-independent upper limits at 95% confidence level are set on the branching ratio of the Higgs boson to the γγττ final state, B(H → aa → γγττ), ranging from 0.2% to 2%, depending on the a-boson mass hypothesis.

Aad, G., Aakvaag, E., Abbott, B., Abdelhameed, S., Abeling, K., Abicht, N.J., et al. (2025). Search for Higgs boson decays into a pair of pseudoscalar particles in the γγτhadτhad final state using pp collisions at $$ \sqrt{\textrm{s}} $$ = 13 TeV with the ATLAS detector. JOURNAL OF HIGH ENERGY PHYSICS, 2025(3) [10.1007/jhep03(2025)190].

Search for Higgs boson decays into a pair of pseudoscalar particles in the γγτhadτhad final state using pp collisions at $$ \sqrt{\textrm{s}} $$ = 13 TeV with the ATLAS detector

Di Micco, B.;Di Nardo, R.;Montereali, F.;Orestano, D.;
2025-01-01

Abstract

A search for exotic decays of the 125 GeV Higgs boson into a pair of new spin-0 particles, H → aa, where one decays into a photon pair and the other into a τ-lepton pair, is presented. Hadronic decays of the τ-leptons are considered and reconstructed using a dedicated tagger for collimated τ-lepton pairs. The search uses 140 fb−1 of proton-proton collision data at a centre-of-mass energy of s = 13 TeV recorded between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider. The search is performed in the mass range of the a boson between 10 GeV and 60 GeV. No significant excess of events is observed above the Standard Model background expectation. Model-independent upper limits at 95% confidence level are set on the branching ratio of the Higgs boson to the γγττ final state, B(H → aa → γγττ), ranging from 0.2% to 2%, depending on the a-boson mass hypothesis.
2025
Aad, G., Aakvaag, E., Abbott, B., Abdelhameed, S., Abeling, K., Abicht, N.J., et al. (2025). Search for Higgs boson decays into a pair of pseudoscalar particles in the γγτhadτhad final state using pp collisions at $$ \sqrt{\textrm{s}} $$ = 13 TeV with the ATLAS detector. JOURNAL OF HIGH ENERGY PHYSICS, 2025(3) [10.1007/jhep03(2025)190].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11590/524901
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