Particle Seminar

Monday, August 17, 2020

Speaker: Bruna Pascual Dias

Affiliation: U de Montreal

Time: 2:30PM -- 3:30PM

Location: Virtual seminar on zoom

Title: LHC Constraints on Scalar Diquarks

The Standard Model of particle physics explains with great success how fundamental particles interact. However, to explain some contemporary challenges of the domain, we need to search for physics beyond the Standard Model. In this seminar, I will describe a model of new physics that considers the addition of a single new scalar particle that couples to two quarks, a scalar diquark. These particles are present, for instance, in models with E6 symmetry or in supersymmetry with R-parity violation. Previous works on low-energy constraints show that the most promising states are the scalar diquarks which have an antisymmetric coupling to pairs of right-handed up-type or down-type quarks. Although these particles have not yet been observed at the Large Hadron Collider (LHC), its contribution to hadronic processes offers an opportunity to set limits on its parameters. Recent high-energy data from the LHC can be used to compare the theoretical predictions of these models and quantify their viability by providing new constraints. First, I will show the results from direct searches in the production of dijet, the experimental signature of the decay of these particles, which improve the constraints found in the literature. I will also discuss the contributions of the diquark that couples to up-type quarks to the experimental measurements of the single-top-production cross section.