Search for heavy resonances decaying into a W or Z boson and a Higgs boson in final states with leptons and b-jets in 36 fb−1 of $$ \sqrt{s}=13 $$ TeV pp collisions with the ATLAS detector

Abstract

Search for heavy resonances decaying into a W or Z boson and a Higgs boson in final states with leptons and b-jets in 36 fb −1 of √ s = 13 TeV pp collisions with the ATLAS detectorThe ATLAS Collaboration A search is conducted for new resonances decaying into a W or Z boson and a 125 GeV Higgs boson in the ννbb, ± νbb, and + − bb final states, where ± = e ± or µ ± , in pp collisions at √ s = 13 TeV. The data used correspond to a total integrated luminosity of 36.1 fb −1 collected with the ATLAS detector at the Large Hadron Collider during the 2015 and 2016 data-taking periods. The search is conducted by examining the reconstructed invariant or transverse mass distributions of Wh and Zh candidates for evidence of a localised excess in the mass range of 220 GeV up to 5 TeV. No significant excess is observed and the results are interpreted in terms of constraints on the production cross-section times branching fraction of heavy W and Z resonances in heavy-vector-triplet models and the CP-odd scalar boson A in two-Higgs-doublet models. Upper limits are placed at the 95% confidence level and range between 9.0 × 10 −4 pb and 8.1 × 10 −1 pb depending on the model and mass of the resonance.

Loop effects on the Higgs decay widths in extended Higgs models

“…One is the existence of additional scalar states, and the other is deviations of the interactions for the SMlike Higgs boson from the SM prediction due to the mixing with other neutral scalars as well as loop effects of additional scalars. The current LHC Higgs program clearly targets them [21], and has been seeking for extra scalars in the direct searches [22][23][24][25] and looking for deviations in the Higgs coupling measurements [1,22,26], which already put constraints on the parameter space of extended Higgs models. In this work, we focus on the latter aspect; i.e., deviations from the SM via precise measurements at the LHC as well as in the future experiments, where more accurate theoretical predictions are required not only in the SM but also in NP models.…”

Reducing the quadratic divergence in the Higgs boson mass squared without top partners

“…These points will be represented in blue in the figures shown in this section. For each of these points and for the different BSM Higgs bosons, we compute the cross-section times branching ratio for each of the production and decay channels listed in section IV and compare it to the results from the ATLAS searches [59][60][61][64][65][66]. We consider that a parameter point is not excluded at the LHC if h , A 0 , and H ± are all heavier than 250 GeV and, for each detection channel, the ratio of the σ×Br over the 95% confidence limit found by ATLAS is less than 1.…”

Searches for high-mass resonances decaying to pairs of bosons using the ATLAS detector

“…Figure 1 presents a sketch, combining a variety of upper limits set on the collection of diboson channels, covering various spin hypotheses and a broad mass range from 200 GeV up to 6.8 TeV. Figure 1: Combining upper limits set on various diboson channels, covering a broad mass range and spin hypotheses -graphical representation of results published in [3,4,5,7,8,9,10,11]…”