Interpretation of LHC excesses in ditop and ditau channels as a 400-GeV pseudoscalar resonance

Abstract Since the discovery in 2012 of the Higgs boson at the LHC, as the last missing piece of the Standard Model of particle physics, any hint of new physics has been intensively searched for, with no confirmation to date. There are however slight deviations from the SM that are worth investigati...

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Autores principales:	Ernesto Arganda, Leandro Da Rold, Daniel A. Díaz, Anibal D. Medina
Formato:	article
Lenguaje:	EN
Publicado:	SpringerOpen 2021
Materias:	Beyond Standard Model Technicolor and Composite Models Higgs Physics Nuclear and particle physics. Atomic energy. Radioactivity QC770-798
Acceso en línea:	https://doaj.org/article/e0ebcb79f78341229ebbddc36c2be153
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spelling	oai:doaj.org-article:e0ebcb79f78341229ebbddc36c2be1532021-11-21T12:41:30ZInterpretation of LHC excesses in ditop and ditau channels as a 400-GeV pseudoscalar resonance10.1007/JHEP11(2021)1191029-8479https://doaj.org/article/e0ebcb79f78341229ebbddc36c2be1532021-11-01T00:00:00Zhttps://doi.org/10.1007/JHEP11(2021)119https://doaj.org/toc/1029-8479Abstract Since the discovery in 2012 of the Higgs boson at the LHC, as the last missing piece of the Standard Model of particle physics, any hint of new physics has been intensively searched for, with no confirmation to date. There are however slight deviations from the SM that are worth investigating. The CMS collaboration has reported, in a search for heavy resonances decaying in t t ¯ $$ \overline{t} $$ with a 13-TeV center-of-mass energy and a luminosity of 35.9 fb −1, deviations from the SM predictions at the 3.5σ level locally (1.9σ after the look-elsewhere effect). In addition, in the ditau final state search performed by the ATLAS collaboration at s $$ \sqrt{s} $$ = 13 TeV and L $$ \mathcal{L} $$ = 139 fb −1, deviations from the SM at the 2σ level have been also observed. Interestingly, both slight excesses are compatible with a new pseudoscalar boson with a mass around 400 GeV that couples at least to fermions of the third generation and gluons. Starting from a purely phenomenological perspective, we inspect the possibility that a 400-GeV pseudoscalar can account for these deviations and at the same time satisfy the constraints on the rest of the channels that it gives contributions to and that are analyzed by the ATLAS and CMS experiments. After obtaining the range of effective couplings compatible with all experimental measurements, we study the gauge invariant UV completions that can give rise to this type of pseudoscalar resonance, which can be accommodated in an SO(6)/SO(5) model with consistency at the 1σ level and in a SO(5) × U(1) P × U(1) X /SO(4) × U(1) X at the 2σ level, while exceedingly large quartic couplings would be necessary to account for it in a general two Higgs doublet model.Ernesto ArgandaLeandro Da RoldDaniel A. DíazAnibal D. MedinaSpringerOpenarticleBeyond Standard ModelTechnicolor and Composite ModelsHiggs PhysicsNuclear and particle physics. Atomic energy. RadioactivityQC770-798ENJournal of High Energy Physics, Vol 2021, Iss 11, Pp 1-28 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Beyond Standard Model Technicolor and Composite Models Higgs Physics Nuclear and particle physics. Atomic energy. Radioactivity QC770-798
spellingShingle	Beyond Standard Model Technicolor and Composite Models Higgs Physics Nuclear and particle physics. Atomic energy. Radioactivity QC770-798 Ernesto Arganda Leandro Da Rold Daniel A. Díaz Anibal D. Medina Interpretation of LHC excesses in ditop and ditau channels as a 400-GeV pseudoscalar resonance
description	Abstract Since the discovery in 2012 of the Higgs boson at the LHC, as the last missing piece of the Standard Model of particle physics, any hint of new physics has been intensively searched for, with no confirmation to date. There are however slight deviations from the SM that are worth investigating. The CMS collaboration has reported, in a search for heavy resonances decaying in t t ¯ $$ \overline{t} $$ with a 13-TeV center-of-mass energy and a luminosity of 35.9 fb −1, deviations from the SM predictions at the 3.5σ level locally (1.9σ after the look-elsewhere effect). In addition, in the ditau final state search performed by the ATLAS collaboration at s $$ \sqrt{s} $$ = 13 TeV and L $$ \mathcal{L} $$ = 139 fb −1, deviations from the SM at the 2σ level have been also observed. Interestingly, both slight excesses are compatible with a new pseudoscalar boson with a mass around 400 GeV that couples at least to fermions of the third generation and gluons. Starting from a purely phenomenological perspective, we inspect the possibility that a 400-GeV pseudoscalar can account for these deviations and at the same time satisfy the constraints on the rest of the channels that it gives contributions to and that are analyzed by the ATLAS and CMS experiments. After obtaining the range of effective couplings compatible with all experimental measurements, we study the gauge invariant UV completions that can give rise to this type of pseudoscalar resonance, which can be accommodated in an SO(6)/SO(5) model with consistency at the 1σ level and in a SO(5) × U(1) P × U(1) X /SO(4) × U(1) X at the 2σ level, while exceedingly large quartic couplings would be necessary to account for it in a general two Higgs doublet model.
format	article
author	Ernesto Arganda Leandro Da Rold Daniel A. Díaz Anibal D. Medina
author_facet	Ernesto Arganda Leandro Da Rold Daniel A. Díaz Anibal D. Medina
author_sort	Ernesto Arganda
title	Interpretation of LHC excesses in ditop and ditau channels as a 400-GeV pseudoscalar resonance
title_short	Interpretation of LHC excesses in ditop and ditau channels as a 400-GeV pseudoscalar resonance
title_full	Interpretation of LHC excesses in ditop and ditau channels as a 400-GeV pseudoscalar resonance
title_fullStr	Interpretation of LHC excesses in ditop and ditau channels as a 400-GeV pseudoscalar resonance
title_full_unstemmed	Interpretation of LHC excesses in ditop and ditau channels as a 400-GeV pseudoscalar resonance
title_sort	interpretation of lhc excesses in ditop and ditau channels as a 400-gev pseudoscalar resonance
publisher	SpringerOpen
publishDate	2021
url	https://doaj.org/article/e0ebcb79f78341229ebbddc36c2be153
work_keys_str_mv	AT ernestoarganda interpretationoflhcexcessesinditopandditauchannelsasa400gevpseudoscalarresonance AT leandrodarold interpretationoflhcexcessesinditopandditauchannelsasa400gevpseudoscalarresonance AT danieladiaz interpretationoflhcexcessesinditopandditauchannelsasa400gevpseudoscalarresonance AT anibaldmedina interpretationoflhcexcessesinditopandditauchannelsasa400gevpseudoscalarresonance
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Interpretation of LHC excesses in ditop and ditau channels as a 400-GeV pseudoscalar resonance

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