{Search for direct production of GeV-scale resonances decaying to a pair of muons in proton-proton collisions at s \sqrt{s} = 13 TeV}

A search for direct production of low-mass dimuon resonances is performed using = 13 TeV proton-proton collision data collected by the CMS experiment during the 2017–2018 operation of the CERN LHC with an integrated luminosity of 96.6 fb−1. The search exploits a dedicated high-rate trigger stream that records events with two muons with transverse momenta as low as 3 GeV but does not include the full event information. The search is performed by looking for narrow peaks in the dimuon mass spectrum in the ranges of 1.1–2.6 GeV and 4.2–7.9 GeV. No significant excess of events above the expectation from the standard model background is observed. Model-independent limits on production rates of dimuon resonances within the experimental fiducial acceptance are set. Competitive or world’s best limits are set at 90% confidence level for a minimal dark photon model and for a scenario with two Higgs doublets and an extra complex scalar singlet (2HDM+S). Values of the squared kinetic mixing coefficient ε2 in the dark photon model above 10−6 are excluded over most of the mass range of the search. In the 2HDM+S, values of the mixing angle sin(θH) above 0.08 are excluded over most of the mass range of the search with a fixed ratio of the Higgs doublets vacuum expectation tan β = 0.5

Predicting outcome in hyper-acute stroke: validation of a prognostic model in the Third International Stroke Trial (IST3)

Background and purpose: Models are used to adjust for case mix and to stratify treatment allocation in clinical trials and can, if accurate enough, be used to aid decision-making in individual patients. We aimed to validate, in patients assessed within 6 hours of onset, a previously described six simple variable (SSV) model that was developed in stroke patients who were assessed sub-acutely. The explanatory variables in the model are age, living alone, independent pre-stroke, Glasgow Coma Scale verbal score, ability to lift arms and ability to walk. Methods: The six variables were collected at randomisation in the Third International Stroke Trial (IST3) trial of recombinant tissue plasminogen activator in ischaemic stroke. We assessed survival to 30 days and functional status at 6 months using the Oxford Handicap Scale. We constructed receiver operator characteristic (ROC) curves to establish the model's discriminatory performance and tested its calibration by charting predicted versus actual outcomes. Results: 537 patients (mean age, 74 years) were included, of whom 422 (79%) survived 30 days and 179 (33%) were alive and independent at 6 months. The SSV model had an area under the ROC curve of 0.73 for 30-day survival and 0.82 for independent survival at 6 months. Calibration was satisfactory. Conclusions: This study confirms the external validity of the SSV model in an ischaemic stroke population assessed within 6 hours of symptom onset. The SSV model comprising easily collected variables can therefore be used to stratify patients in hyper-acute stroke trials, but probably is not accurate enough for decision-making in individual patients

Detection methods for the Cherenkov Telescope Array at very-short exposure times

The Cherenkov Telescope Array (CTA) will be the next generation ground-based observatory for very-high-energy (VHE) gamma-ray astronomy, with the deployment of tens of highly sensitive and fast-reacting Cherenkov telescopes. It will cover a wide energy range (20 GeV - 300 TeV) with unprecedented sensitivity. To maximize the scientific return, the observatory will be provided with an online software system that will perform the first analysis of scientific data in real-time. This study investigates the precision and accuracy of available science tools and analysis techniques for the short-term detection of gamma-ray sources, in terms of sky localization, detection significance and, if significant detection is achieved, a first estimation of the integral photon flux. The scope is to evaluate the feasibility of the algorithms' implementation in the real-time analysis of CTA. In this contribution we present a general overview of the methods and some of the results for the test case of the short-term detection of a gamma-ray burst afterglow, as the VHE counterpart of a gravitational wave event