Speaker: Dr. Junmou Chen, University of Pittsburgh
Time & Date: 16:00 26th Dec. 2017
Address: Room 208 in the School of Physics
Titel: EW Splitting Functions and High EnergyShowering
Abstract: We derive the electroweak (EW) collinearsplitting functions up to single logs. We first derive the splitting functionsin the unbroken limit, and then we systematically incorporate effects ofEW symmetry breaking (EWSB), by imposing a particularly convenient gauge choice(dubbed “Goldstone Equivalence Gauge”) that disentangles the effects ofGoldstone bosons and gauge fields in the presence of EWSB. As a result, we areable to derive splitting functions up to leading power corrections in v/E. Wealso implement a comprehensive, practical EW showering scheme based on thesesplitting functions using a Sudakov evolution formalism. The implementation ofEW showering includes novel features such as “ultra-collinear” splittings,matching between shower and decay, and mixed-state evolution of neutral bosons(γ/Z/h) using density-matrices, kinematic back-reaction corrections inmulti-stage showers. We demonstrate those new phenomena and features at O(1–10TeV) energies with some examples.
