Flavour independent Search for Hadronically decaying Higgs Bosons

The four LEP collaborations ALEPH, DELPHI, L3 and OPAL have collected around 2.5 fb−1 of e +e − data at centre-of-mass energies ranging from 189 to 209 GeV. This note presents the results from a search for neutral Higgs boson production in the processes e +e − →hZ and e +e − → hA where no assumption is made on the flavour of the hadronic decay products of the Higgs boson. No evidence for a signal is observed and the results are presented as model independent limits on the production cross section for neutral Higgs bosons decaying into hadrons as a function of the Higgs boson mass(es). These limits allow to test predictions from a wide range of (future) models. Preliminary combined results from the four collaborations are presented in the hZ channel. In the hA channel results from the OPAL and DELPHI collaboration are presented separately. In the hZ channel, assuming Higgs boson production with a SM cross section decaying exclusively into hadrons, a limit on the mass of the Higgs boson can be set at 112.9 GeV/c2

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements