B-TAGGING AND SEARCHES FOR NEW PHYSICS BEYOND THE STANDARD MODEL

The article is devoted to the searches for new particles predicted by physics beyond the Standard Model through the b-tagging algorithm. The dependence of b-tagging efficiency on the jet identification, impact parameter identification, secondary vertex identification, kinematic cuts is studied with the help of computer programs Pythia 8.2 and Fastjet 3.3.0. The selection criteria for kinematic parameters, their ratios for an optimal result on the reconstruction of the vertices of heavy particles are found.

The ATLAS trigger menu design for higher luminosities in Run 2

ATLAS utilizes a two-level trigger system in Run-2 to reduce the bunch-crossing rate of 40 MHz to an average recording rate of about 1 kHz. Events are selected based on physics signatures such as presence of energetic leptons, photons, jets or large missing energy. Despite the limited time available for processing collision events, the trigger system is able to exploit topological information as well as multi-variate methods, for example for b-tagging or tau identification. The ATLAS trigger menu specifies which triggers are used during data taking and how much rate a given trigger is allocated. For 2018 data taking, the trigger selections and menus have been improved to handle expected luminosities above 2 × 1034 cm−2 s−1 and to ensure robustness in the presence of multiple interactions per bunch crossing (pile-up).