Search for the Decay of the Higgs Boson to Charm Quarks with the ATLAS Experiment

Abstract

A direct search for the standard model Higgs boson decaying to a pair of charm quarks is presented. Associated production of the Higgs and Z bosons, in the decay mode ZH→ℓ^{+}ℓ^{-}cc[over ¯] is studied. A data set with an integrated luminosity of 36.1 fb^{-1} of pp collisions at sqrt[s]=13TeV recorded by the ATLAS experiment at the LHC is used. The H→cc[over ¯] signature is identified using charm-tagging algorithms. The observed (expected) upper limit on σ(pp→ZH)×B(H→cc[over ¯]) is 2.7 (3.9_{-1.1}^{+2.1}) pb at the 95% confidence level for a Higgs boson mass of 125 GeV, while the standard model value is 26 fb.

Threshold cusps and triangle singularities in hadronic reactions

“…TS contributions [442,448]. More importantly, the existence of the X(5568) was not confirmed in several subsequent experiments [449][450][451][452]. In contrast, the DK and BK S-wave interactions in the isospin-0 channel are generally supposed to be strong and attractive enough to generate a bound state corresponding to the D * s0 (2317) and its bottom partner, see, e.g., Ref.…”

Flavourful SMEFT likelihood for Higgs and electroweak data

“…Namely, it is possible to leave also the Wilson coefficient [C uϕ ] 22 as a free parameter in the fit. This is thanks to the direct measurement of the h → cc signal strength at the LHC, which constrains the possible magnitude of charm Yukawa coupling modifications due to [C uϕ ] 22 . In the relaxed 32-parameter fit the results are mostly unchanged with respect to those displayed in Table II, except for a threefold increase of the error on the parameter δc z .…”

“…3. We include the most recent Higgs signal strength combinations from ATLAS and CMS based on up to 80 fb −1 of the Run-2 data [21,22].…”

“…We follow the standard Wilson coefficient exchange format (WCxf) [20], such that our results can be easily imported by other analysis codes.3. We include the most recent Higgs signal strength combinations from ATLAS and CMS based on up to 80 fb −1 of the Run-2 data [21,22].Simultaneously to interpretations of high-energy collider data, much progress has been made on the front of lowenergy observables measured at energies well below the weak scale. In Refs.…”

Collider constraints on lepton flavor violation in the 2HDM

“…We note here that in the absence of the Φ 2 Yukawa couplings (the Y 's), the H would 2 The presence of any of the Y U 's or Y D 's would enhance the H production. However, the light quark Yukawas are strongly constrained by dijet searches [18] and the 125 GeV Higgs data [19]. Moreover, light quark Yukawas would dilute the H LFV branching ratios.…”