June 9th, 2025
CMS-SUS-23-012
A search for dark matter particles produced in association with a Higgs boson decaying into a pair of τ leptons is performed using data collected in proton-proton collisions at a center-of-mass energy of 13 TeV with the CMS detector. The analysis is based on a data set corresponding to an integrated luminosity of 101 fb-1 collected in 2017-2018. No significant excess over the expected standard model background is observed. This result is interpreted within the frameworks of the 2HDM+a and baryonic Z’ benchmark simplified models. The 2HDM+a model is a type-II two-Higgs-doublet model featuring a heavy pseudoscalar with an additional light pseudoscalar. Upper limits at 95% confidence level are set on the product of the production cross section and the branching fraction for each of these two simplified models. Heavy pseudoscalar boson masses between 400 and 700 GeV are excluded for a light pseudoscalar mass of 100 GeV. For the baryonic Z’ model, a statistical combination is made with an earlier search based on a data set of 36 fb-1 collected in 2016. In this model, Z’ boson masses up to 1050 GeV are excluded for a dark matter particle mass of 1 GeV.
CMS-SUS-23-012
CMS-SUS-23-012
CMS-SUS-23-012
ATLAS Collab.
This paper presents the first observation of top-quark pair production in association with two photons (ttγγ). The measurement is performed in the single-lepton decay channel using proton-proton collision data collected by the ATLAS detector at the Large Hadron Collider. The data correspond to an integrated luminosity of 140 fb-1 recorded during Run 2 at a centre-of-mass energy of 13 TeV. The ttγγ production cross section, measured in a fiducial phase space based on particle-level kinematic criteria for the lepton, photons, and jets, is found to be 2.42+0.58-0.53 fb , corresponding to an observed significance of 5.2 standard deviations. Additionally, the ratio of the production cross section of to top-quark pair production in association with one photon is determined, yielding (3.30+0.70-0.65) x 10-3.
MilliQan Collab.
MilliQan Collab.
