Search for the SM Higgs boson in VH(bb) channel using the ATLAS detector

ATLAS results in the search for the Higgs boson in the VH production mode with the Higgs decaying to a b-quark pair will be given, using approximately 10 fb-1 of pp collision data collected at 13 TeV

Multi­-Threaded Algorithms for General purpose Graphics Processor Units in the ATLAS High Level Trigger

General purpose Graphics Processor Units (GPGPU) are being evaluated for possible future inclusion in an upgraded ATLAS High Level Trigger farm. We have developed a demonstrator including GPGPU implementations of Inner Detector and Muon tracking and Calorimeter clustering within the ATLAS software framework. ATLAS is a general purpose particle physics experiment located on the LHC collider at CERN. The ATLAS Trigger system consists of two levels, with level 1 implemented in hardware and the High Level Trigger implemented in software running on a farm of commodity CPU. The High Level Trigger reduces the trigger rate from the 100 kHz level 1 acceptance rate to 1 kHz for recording, requiring an average per­-event processing time of ~250 ms for this task. The selection in the high level trigger is based on reconstructing tracks in the Inner Detector and Muon Spectrometer and clusters of energy deposited in the Calorimeter. Performing this reconstruction within the available farm resources presents a significant challenge that will increase significantly with future LHC upgrades. During the LHC data­taking period starting in 2021, luminosity will reach up to three times the original design value. Luminosity will increase further to 7.5 times the design value in 2026 following LHC and ATLAS upgrades. Corresponding improvements in the speed of the reconstruction code will be needed to provide the required trigger selection power within affordable computing resources. Key factors determining the potential benefit of including GPGPU as part of the HLT processor farm are the relative speed of the CPU and GPU algorithm implementations, the relative execution times of the GPU algorithms and serial code remaining on the CPU, the number of GPU required and the relative financial cost of the selected GPU. We give a brief overview of the algorithms implemented and present new measurements that compare the performance of various configurations exploiting different GPU cards

Search for High-Mass Resonances Decaying to τν\tau\nu in pp Collisions at s\sqrt{s}=13 TeV with the ATLAS Detector

A search for high-mass resonances decaying to τν using proton-proton collisions at s=13  TeV produced by the Large Hadron Collider is presented. Only τ-lepton decays with hadrons in the final state are considered. The data were recorded with the ATLAS detector and correspond to an integrated luminosity of 36.1  fb-1. No statistically significant excess above the standard model expectation is observed; model-independent upper limits are set on the visible τν production cross section. Heavy W′ bosons with masses less than 3.7 TeV in the sequential standard model and masses less than 2.2–3.8 TeV depending on the coupling in the nonuniversal G(221) model are excluded at the 95% credibility level.Peer Reviewe