Search for additional heavy neutral Higgs and gauge bosons in the ditau final state produced in 36 fb$^{-1}$ of $pp$ collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector (1709.07242v2)

Abstract: A search for heavy neutral Higgs bosons and $Z^{\prime}$ bosons is performed using a data sample corresponding to an integrated luminosity of 36.1 fb$^{-1}$ from proton-proton collisions at $\sqrt{s}$ = 13 TeV recorded by the ATLAS detector at the LHC during 2015 and 2016. The heavy resonance is assumed to decay to $\tau^+\tau^-$ with at least one tau lepton decaying to final states with hadrons and a neutrino. The search is performed in the mass range of 0.2-2.25 TeV for Higgs bosons and 0.2-4.0 TeV for $Z^{\prime}$ bosons. The data are in good agreement with the background predicted by the Standard Model. The results are interpreted in benchmark scenarios. In the context of the hMSSM scenario, the data exclude $\tan\beta > 1.0$ for $m_A$ = 0.25 TeV and $\tan\beta > 42$ for $m_A$ = 1.5 TeV at the 95% confidence level. For the Sequential Standard Model, $Z^{\prime}_\mathrm{SSM}$ with $m_{Z^{\prime}} < 2.42$ TeV is excluded at 95% confidence level, while $Z^{\prime}_\mathrm{NU}$ with $m_{Z^{\prime}} < 2.25$ TeV is excluded for the non-universal $G(221)$ model that exhibits enhanced couplings to third-generation fermions.

• The paper establishes exclusion limits for heavy neutral Higgs and Z′ bosons with confidence intervals varying by mass, aligning with Standard Model predictions.
• It analyzes 36.1 fb⁻¹ of pp collision data using gluon-gluon fusion and b-associated production, yielding cross-section bounds as low as 0.0037 pb.
• The methodology optimizes event categorization and leverages tau-lepton tagging to refine searches for non-Standard Model boson phenomena.

Analysis of Heavy Neutral Higgs and Gauge Bosons in Ditau Final State via ATLAS Detector

This collection of research, conducted by the ATLAS Collaboration, aims to investigate the presence of additional heavy neutral Higgs bosons, as well as gauge bosons, which decay into ditau final states. The data stems from proton-proton collision samples during 2015 and 2016 at a center-of-mass energy of 13 TeV, with an integrated luminosity of 36.1 fb^-1 collected using the ATLAS detector at the Large Hadron Collider (LHC). Key interests lie in Higgs bosons within a mass range of 0.2 to 2.25 TeV and Z bosons extending from 0.2 to 4 TeV, assessed against Standard Model background projections.

The results indicate that the data aligns closely with the Standard Model predictions. In the hMSSM scenario examinations, exclusions were set with confidence limits: a tanβ > 1.0 exclusion for m_A = 0.25 TeV improving up to tanβ > 42 for m_A = 1.5 TeV at 95% CL. Additionally, the Sequential Standard Model constrains Z′ masses below 2.42 TeV. Analyses were extensively partitioned into event categories and channels aimed at optimizing detection sensitivity across gluon-gluon fusion and b-production modalities.

Numerical Outcomes

The cross-section limits determined are between 0.78–0.0058 pb for gluon-gluon fusion and 0.70–0.0037 pb for b-associated production of scalar bosons within tested mass bounds. While for the Z bosons via Drell–Yan mechanisms, limits stretch from 1.56–0.0072 pb. These measures were established under the hypothesis of negligible natural boson width relative to experimental resolution.

Implications and Future Directions

This research supports an informed understanding of the constraints on additional scalar and vector boson models, notably in supersymmetric and alternative gauge scenarios. Further investigations with enhanced luminosity and refined precision in tau-lepton coupling and tagging could enhance the depth and breadth of such searches, potentially confirming extensions outside the Standard Model which incorporate new symmetries or hidden sector interactions.

This paper sheds light on potential avenues concerning the scalar sector's extensions and further positions the ATLAS experiment's strategic role in future particle physics explorations. As the luminosity and energy capabilities of the LHC continue to augment, they will likely enable even more comprehensive searches and perhaps enable the identification of non-SM Higgs phenomena or additional gauge bosons providing insight into the outer boundaries of current theoretical frameworks.