Search for doubly charged Higgs boson production in multi-lepton final states using 139 fb$$^{-1}$$ of proton–proton collisions at $$\sqrt{s}$$ = 13 TeV with the ATLAS detector


Aad, G ORCID: 0000-0002-6665-4934, Abbott, B ORCID: 0000-0002-5888-2734, Abbott, DC ORCID: 0000-0002-7248-3203, Abeling, K ORCID: 0000-0002-1002-1652, Abidi, SH ORCID: 0000-0002-8496-9294, Aboulhorma, A ORCID: 0000-0002-9987-2292, Abramowicz, H ORCID: 0000-0001-5329-6640, Abreu, H ORCID: 0000-0002-1599-2896, Abulaiti, Y ORCID: 0000-0003-0403-3697, Hoffman, AC Abusleme ORCID: 0000-0003-0762-7204 et al (show 2892 more authors) (2023) Search for doubly charged Higgs boson production in multi-lepton final states using 139 fb$$^{-1}$$ of proton–proton collisions at $$\sqrt{s}$$ = 13 TeV with the ATLAS detector. The European Physical Journal C, 83 (7). 605-.

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Abstract

<jats:title>Abstract</jats:title><jats:p>A search for pair production of doubly charged Higgs bosons (<jats:inline-formula><jats:alternatives><jats:tex-math>$$H^{\pm \pm }$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>H</mml:mi> <mml:mrow> <mml:mo>±</mml:mo> <mml:mo>±</mml:mo> </mml:mrow> </mml:msup> </mml:math></jats:alternatives></jats:inline-formula>), each decaying into a pair of prompt, isolated, and highly energetic leptons with the same electric charge, is presented. The search uses a proton–proton collision data sample at a centre-of-mass energy of 13 TeV corresponding to an integrated luminosity of 139 fb<jats:inline-formula><jats:alternatives><jats:tex-math>$$^{-1}$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mrow /> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:math></jats:alternatives></jats:inline-formula> recorded by the ATLAS detector during Run 2 of the Large Hadron Collider (LHC). This analysis focuses on same-charge leptonic decays, <jats:inline-formula><jats:alternatives><jats:tex-math>$$H^{\pm \pm } \!\rightarrow \ell ^{\pm } \ell ^{\prime \pm }$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mi>H</mml:mi> <mml:mrow> <mml:mo>±</mml:mo> <mml:mo>±</mml:mo> </mml:mrow> </mml:msup> <mml:mspace /> <mml:mo>→</mml:mo> <mml:msup> <mml:mi>ℓ</mml:mi> <mml:mo>±</mml:mo> </mml:msup> <mml:msup> <mml:mi>ℓ</mml:mi> <mml:mrow> <mml:mo>′</mml:mo> <mml:mo>±</mml:mo> </mml:mrow> </mml:msup> </mml:mrow> </mml:math></jats:alternatives></jats:inline-formula> where <jats:inline-formula><jats:alternatives><jats:tex-math>$$\ell , \ell ^\prime \!=\!e, \mu , \tau $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>ℓ</mml:mi> <mml:mo>,</mml:mo> <mml:msup> <mml:mi>ℓ</mml:mi> <mml:mo>′</mml:mo> </mml:msup> <mml:mspace /> <mml:mo>=</mml:mo> <mml:mspace /> <mml:mi>e</mml:mi> <mml:mo>,</mml:mo> <mml:mi>μ</mml:mi> <mml:mo>,</mml:mo> <mml:mi>τ</mml:mi> </mml:mrow> </mml:math></jats:alternatives></jats:inline-formula>, in two-, three-, and four-lepton channels, but only considers final states which include electrons or muons. No evidence of a signal is observed. Corresponding upper limits on the production cross-section of a doubly charged Higgs boson are derived, as a function of its mass <jats:inline-formula><jats:alternatives><jats:tex-math>$$m(H^{\pm \pm })$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>m</mml:mi> <mml:mo>(</mml:mo> <mml:msup> <mml:mi>H</mml:mi> <mml:mrow> <mml:mo>±</mml:mo> <mml:mo>±</mml:mo> </mml:mrow> </mml:msup> <mml:mo>)</mml:mo> </mml:mrow> </mml:math></jats:alternatives></jats:inline-formula>, at 95% confidence level. Assuming that the branching ratios to each of the possible leptonic final states are equal, <jats:inline-formula><jats:alternatives><jats:tex-math>$$\mathcal {B}(H^{\pm \pm } \rightarrow e^\pm e^\pm ) = \mathcal {B}(H^{\pm \pm } \rightarrow e^\pm \mu ^\pm ) = \mathcal {B}(H^{\pm \pm } \rightarrow \mu ^\pm \mu ^\pm ) = \mathcal {B}(H^{\pm \pm } \rightarrow e^\pm \tau ^\pm ) = \mathcal {B}(H^{\pm \pm } \rightarrow \mu ^\pm \tau ^\pm ) = \mathcal {B}(H^{\pm \pm } \rightarrow \tau ^\pm \tau ^\pm ) = 1/6$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>B</mml:mi> <mml:mrow> <mml:mo>(</mml:mo> <mml:msup> <mml:mi>H</mml:mi> <mml:mrow> <mml:mo>±</mml:mo> <mml:mo>±</mml:mo> </mml:mrow> </mml:msup> <mml:mo>→</mml:mo> <mml:msup> <mml:mi>e</mml:mi> <mml:mo>±</mml:mo> </mml:msup> <mml:msup> <mml:mi>e</mml:mi> <mml:mo>±</mml:mo> </mml:msup> <mml:mo>)</mml:mo> </mml:mrow> <mml:mo>=</mml:mo> <mml:mi>B</mml:mi> <mml:mrow> <mml:mo>(</mml:mo> <mml:msup> <mml:mi>H</mml:mi> <mml:mrow> <mml:mo>±</mml:mo> <mml:mo>±</mml:mo> </mml:mrow> </mml:msup> <mml:mo>→</mml:mo> <mml:msup> <mml:mi>e</mml:mi> <mml:mo>±</mml:mo> </mml:msup> <mml:msup> <mml:mi>μ</mml:mi> <mml:mo>±</mml:mo> </mml:msup> <mml:mo>)</mml:mo> </mml:mrow> <mml:mo>=</mml:mo> <mml:mi>B</mml:mi> <mml:mrow> <mml:mo>(</mml:mo> <mml:msup> <mml:mi>H</mml:mi> <mml:mrow> <mml:mo>±</mml:mo> <mml:mo>±</mml:mo> </mml:mrow> </mml:msup> <mml:mo>→</mml:mo> <mml:msup> <mml:mi>μ</mml:mi> <mml:mo>±</mml:mo> </mml:msup> <mml:msup> <mml:mi>μ</mml:mi> <mml:mo>±</mml:mo> </mml:msup> <mml:mo>)</mml:mo> </mml:mrow> <mml:mo>=</mml:mo> <mml:mi>B</mml:mi> <mml:mrow> <mml:mo>(</mml:mo> <mml:msup> <mml:mi>H</mml:mi> <mml:mrow> <mml:mo>±</mml:mo> <mml:mo>±</mml:mo> </mml:mrow> </mml:msup> <mml:mo>→</mml:mo> <mml:msup> <mml:mi>e</mml:mi> <mml:mo>±</mml:mo> </mml:msup> <mml:msup> <mml:mi>τ</mml:mi> <mml:mo>±</mml:mo> </mml:msup> <mml:mo>)</mml:mo> </mml:mrow> <mml:mo>=</mml:mo> <mml:mi>B</mml:mi> <mml:mrow> <mml:mo>(</mml:mo> <mml:msup> <mml:mi>H</mml:mi> <mml:mrow> <mml:mo>±</mml:mo> <mml:mo>±</mml:mo> </mml:mrow> </mml:msup> <mml:mo>→</mml:mo> <mml:msup> <mml:mi>μ</mml:mi> <mml:mo>±</mml:mo> </mml:msup> <mml:msup> <mml:mi>τ</mml:mi> <mml:mo>±</mml:mo> </mml:msup> <mml:mo>)</mml:mo> </mml:mrow> <mml:mo>=</mml:mo> <mml:mi>B</mml:mi> <mml:mrow> <mml:mo>(</mml:mo> <mml:msup> <mml:mi>H</mml:mi> <mml:mrow> <mml:mo>±</mml:mo> <mml:mo>±</mml:mo> </mml:mrow> </mml:msup> <mml:mo>→</mml:mo> <mml:msup> <mml:mi>τ</mml:mi> <mml:mo>±</mml:mo> </mml:msup> <mml:msup> <mml:mi>τ</mml:mi> <mml:mo>±</mml:mo> </mml:msup> <mml:mo>)</mml:mo> </mml:mrow> <mml:mo>=</mml:mo> <mml:mn>1</mml:mn> <mml:mo>/</mml:mo> <mml:mn>6</mml:mn> </mml:mrow> </mml:math></jats:alternatives></jats:inline-formula>, the observed (expected) lower limit on the mass of a doubly charged Higgs boson is 1080 GeV (1065 GeV) within the left-right symmetric type-II seesaw model, which is the strongest limit to date produced by the ATLAS Collaboration. Additionally, this paper provides the first direct test of the Zee–Babu neutrino mass model at the LHC, yielding an observed (expected) lower limit of <jats:inline-formula><jats:alternatives><jats:tex-math>$$m(H^{\pm \pm })$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>m</mml:mi> <mml:mo>(</mml:mo> <mml:msup> <mml:mi>H</mml:mi> <mml:mrow> <mml:mo>±</mml:mo> <mml:mo>±</mml:mo> </mml:mrow> </mml:msup> <mml:mo>)</mml:mo> </mml:mrow> </mml:math></jats:alternatives></jats:inline-formula> = 900 GeV (880 GeV).</jats:p>

Item Type: Article
Divisions: Faculty of Science and Engineering > School of Physical Sciences
Depositing User: Symplectic Admin
Date Deposited: 25 Jul 2023 14:37
Last Modified: 16 Mar 2024 02:47
DOI: 10.1140/epjc/s10052-023-11578-9
Open Access URL: https://link.springer.com/article/10.1140/epjc/s10...
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3171896
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