Experimental Studies of the Higgs Mechanism in the Standard Model and Beyond

Suny At Stony Brook, Stony Brook NY

Investigators

Abstract

The start-up of the Large Hadron Collider (LHC) a decade ago ushered in a new era of research in hitherto inaccessible energy regimes. The discovery of the Higgs boson is the first major highlight of the LHC program, which established that the predicted particle content and interactions of the Standard Model (SM) are complete. Despite this success, the SM is widely believed to be an incomplete theory. Ongoing studies must determine whether or not this new Higgs boson is that of the SM, and new experimental data are essential to discover if and how Nature has chosen to extend the SM. These studies include new measurements and searches for new physics, primarily using data recorded at a center-of-mass energy of 13 TeV. The physics analysis activities form a comprehensive program to extend characterization of Higgs boson properties. This project will analyze data collected with the ATLAS experiment at CERN’s Large Hadron Collider. The research includes standard model di-boson measurements, Higgs boson decay properties, and speculative Beyond–the–Standard–Model searches involving Higgs boson production and decay. In addition, the Stony Brook group will lead activities in ATLAS maintenance and operations, algorithm development, and detector upgrades. With the Higgs’ key role in standard model electroweak symmetry breaking, as well as being the only known elementary scalar particle, exploration of its properties is central to particle physics. To that end, this project includes studies of WW production to understand the role of the Higgs boson in vector boson scattering and searches for new physics through modified quartic couplings in boson scattering, studies of the properties of the Higgs boson in associated production focusing on the newly established bottom-antibottom decay mode, extending the sensitivity to higher transverse momenta based on jet substructure techniques and improved b-tagging, and searches for the rare and BSM modes. The Stony Brook group has responsibilities for liquid argon calorimeter operations including the installation and commissioning of the Phase I upgrade liquid argon Back End upgrade electronics, and responsibilities for silicon detector operations. They are involved in the ATLAS tracker upgrade R&D and have design, testing and production responsibilities for the HL-LHC liquid argon calorimeter read-out digital processor system. This work provides undergraduate and graduate students with the opportunity to participate in leading edge scientific research and instrumentation development. Undergraduate students have the opportunity to participate both through academic year research activities and through the group’s participation in the Stony Brook REU program. This project includes a program of student and community education to be initially hosted at Stony Brook and then more broadly. The group also participates in the local QuarkNet efforts and will host the Higgs Couplings 2020 conference, which will include a public day with lectures and a panel discussion. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.