A new LHC search for dark matter produced via heavy Higgs bosons using simplified models

Searches for dark matter produced via scalar resonances in final states consisting of Standard Model (SM) particles and missing transverse momentum are of high relevance at the LHC. Motivated by dark-matter portal models, most existing searches are optimized for unbalanced decay topologies for which the missing momentum recoils against the visible SM particles. In this work, we show that existing searches are also sensitive to a wider class of models, which we characterize by a recently presented simplified model framework. We point out that searches for models with a balanced decay topology can be further improved with more dedicated analysis strategies. For this study, we investigate the feasibility of a new search for bottom-quark associated neutral Higgs production with a $b \bar b Z + p_\text{T}^\text{miss}$ final state and perform a detailed collider analysis. Our projected results in the different simplified model topologies investigated here can be easily reinterpreted in a wide range of models of physics beyond the SM, which we explicitly demonstrate for the example of the Two-Higgs-Doublet model with an additional pseudoscalar Higgs boson.Comment: 27 pages, 8 figures, 4 table

Comparison of CMS measurements with predictions at NLO applying the Parton Branching Method and PYTHIA

In August 2023, more than 30 students joined the Special Remote DESY summer-school to work on projects of importance for LHC experiments. In a dedicated initiative, analyses that had not been incorporated into the RIVET package were implemented and verified. Here, a brief description of the accomplished work is given, and a comparison of the measurements with predictions obtained from matched standard parton shower Monte Carlo event generators as well as with those obtained from Parton-Branching TMDs with corresponding parton showers are presented

Making the most of Yukawa couplings: searching for Dark Matter accompanied by heavy quarks

Among the foremost alternatives to unravel the mysteries of Dark Matter (DM) is the search for invisible particles at colliders. The main experiments at the Large Hadron Collider (LHC) are engaged in an intense search program to identify any evidence of non-standard unbalanced transverse momentum. Should this DM hunt be successful and the manifestation consistent with any of the various theoretical scenarios, it could be a first indication of the particle-like nature of this unknown matter. A large number of these models propose that the coupling between the DM mediators and the Standard Model (SM) fermions is of Yukawa type, thus favoring at the LHC the associated production of DM with top-quarks or b-quarks. Such consideration turns out to be one of the leading motivations for many of the analyses that have a particular focus on heavy flavour fermions accompanying the DM particles in the final state. The most recent experimental efforts and some of the prospects in this direction will be the primary topic of this talk

Additional neutral light Higgs bosons at ATLAS and CMS

The latest results about searches for light neutral Higgs bosons performed by ATLAS and CMS will be presented. This covers exotic decays like h->aa or h->Za, and the prompt productions of a light pseudoscalar (bba a->tautau, light a->gamma+gamma, ...)

Dark matter searches at CMS and ATLAS

A glimpse into the most recent searches for Dark Matter at the LHC performed by the ATLAS and CMS collaborations is presented. The results covered in this document are all based on Run-2 proton-proton collision data recorded at $\sqrt{s}=13\text{ TeV}$ and corresponding to an integrated luminosity of just under 140 fb\textsuperscript{-1}.A glimpse into the most recent searches for Dark Matter at the LHC performed by the ATLAS and CMS collaborations is presented. The results covered in this document are all based on Run-2 proton-proton collision data recorded at $\sqrt{s}=13\text{ TeV}$ and corresponding to an integrated luminosity of just under 140 $\text{fb}^{-1}

Search for Light Bosons in Exotic Decays of the 125 GeV Higgs Boson

A search for pairs of light bosons produced from decays of the 125 GeV Higgs boson is presented. The search covers the light boson mass region where the particle could have an enhanced decay rate to a pair of τ leptons, according to different models and scenarios.The leptonic decay channels corresponding to the 4τ and 2μ2τ final states are used. The search is based on proton-proton collisions collected by the CMS experiment in 2016 at a center-of-mass energy of 13 TeV. This dataset corresponds to an integrated luminosity of 35.9 fb^{-1} .The analysis is motivated by many theories beyond the Standard Model that suggest modifications in the Higgs sector. The prevailing tendency among these new models is to extend the group structure of the scalar sector, thus resulting in an increased number of physical states in their spectrum. The additional bosons could couple to both the 125 GeV Higgs boson and the rest of the particles in the theory, which allows their detection through different production and decay mechanisms.Two different approaches used for the analysis of the data are presented. The first strategy targets boosted event topologies, occurring for light bosons with masses between 4 and 15 GeV. The second method employs a modified event selection technique combined with a more powerful final discriminant to be able to extend the mass range up to 21 GeV. In both approaches, no significant deviation beyond the expectation from the Standard Model is observed. Observed and expected upper limits at 95% confidence level on the product of the Higgs boson production cross-section relative to that in the Standard Model and the branching fraction into the 4τ final state are set. Interpretations of the experimental results in the context of a specific theoretical model are also provided

Recent results of SUSY searches at CMS

A compendium of the most recent results obtained by the CMS collaboration on searches for supersymmetry is presented. The list comprises a combination of several searches for the electroweak production of winos, binos, higgsinos, and sleptons, the latest efforts devoted to analyses exploiting final states with multiple photons and jets, and a dedicated search for long-lived supersymmetric particles. All results covered here are based on proton-proton collision data at √s = 13 TeV, collected between 2016 and 2018 by the CMS detector at the LHC, and corresponding to an integrated luminosity of around 137 fb^-1

Searches for an exotic decay of the Higgs boson to a pair of pseudoscalars in CMS

Several theories extending the Standard Model (SM) have predicted the existence of addi- tional Higgs bosons. Searches for these extra Higgs bosons have focused primarily on general two Higgs doublet models (2HDM), however models where the two Higgs doublets are extended by one additional Higgs singlet complex field (2HD+1S) are consistent with SM measurements and constraints from searches for additional Higgs bosons. Moreover, 2HD+1S models such as the next-to-minimal supersymmetric (NMSSM) models can solve the so-called μ-problem of the MSSM and comfortably accommodate the 125 GeV Higgs boson in the mass spectrum. Here a series of searches performed in CMS on possible exotic decays of the Higgs boson to a pair of pseudoscalars considering different decay channels are presented. The searches cover a wide range of masses for the pseudoscalar boson, which span from very boosted to non-boosted topologies

Recent results of SUSY searches at CMS

A compendium of the most recent results obtained by the CMS collaboration on searches for supersymmetry is presented. The list comprises a combination of several searches for the electroweak production of winos, binos, higgsinos, and sleptons, the latest efforts devoted to analyses exploiting final states with multiple photons and jets, and a dedicated search for long-lived supersymmetric particles. All results covered here are based on proton-proton collision data at , collected between 2016 and 2018 by the CMS detector at the LHC, and corresponding to an integrated luminosity of around