Abstract: 

B-hadrons are characterized by their relatively long lifetime and heavy mass. Tagging jets containing b-hadrons (b-tagging) plays a critical role in many physics programs at the LHC such as Standard Model (SM) measurements and searches for exotic heavy particles. Many Beyond Standard Model (BSM) scenarios predict new particles with even longer lifetimes compared with that of b-hadrons. Such long-lived particles have similar decay topologies as b-hadrons but they are more extreme. Studying both the long-lived particles in SM and beyond is a very intriguing topic. On one hand, b-tagging performance in data needs to be measured via various methods to achieve higher precision, on the other hand, reconstructing decay products from exotic long-lived particles is very challenging but awarding. In this talk, I will discuss the application of b-tagging followed by specific b-tagging efficiency measurements and dedicated long-lived particle searches followed by the optimization of long-lived particle reconstruction.

Biography:

Bingxuan Liu is a senior postdoctoral researcher, working with the ATLAS group at Simon Fraser University (Canada). His current research projects include dedicated long-lived particle searches and updating the ATLAS large radius tracking for Run 3. He was a postdoctoral researcher at Argonne National Laboratory (US)  from Autumn 2016 to Spring 2020, during which he was leading the ATLAS Flavor Tagging Calibration Sub-group to provide high quality recommendations on flavor tagging for the entire ATLAS collaboration and several exotic heavy particle searches. He has been based at CERN since 2016 and has made significant contributions to ATLAS operation tasks including Tile Calorimeter maintenance and Trigger and Data Acquisition (TDAQ) commissioning. In 2016, he obtained his Ph.D at The Ohio State University (Advisor: Stan Durkin) in the CMS collaboration. His graduate research projects involved long-lived particle searches, muon reconstruction and high-level trigger integration. He obtained his bachelor degree at the University of Electronic Science and Technology of China (UESTC), majoring in applied physics.