Chris Young: Lepton Flavour Universality - measuring BR(W->tau+nu)/BR(W->mu+nu) at the LHC

Friday 19 Feb 2021, 12:30 → 14:00 Europe/London

https://zoom.us/j/304578256

In the Standard Model on of the fundamental principles is that the couplings of the W-boson to the different lepton flavours (e, mu, tau) should be identical. Therefore, outside of small phase space effects, the branching ratio of W->l+nu_l should be identical for all flavours of lepton. The most precise previous measurements of the branching ratios of the W boson to the different lepton flavours were from the Large Electron-Positron Collider (LEP) at CERN and showed some tension with the Standard Model. This seminar will describe an ATLAS analysis at the LHC measuring the ratio BR(W->tau+nu)/BR(W->mu+nu) with higher precision than the previous LEP measurements to test this tension with the Standard Model expectation. Top--anti-Top events are used to provide a large sample of W-bosons with which to perform the measurement. One top is then used to trigger and tag the events and the other is used to test the ratio in question.

Connections will begin at 12:30 with the seminar beginning at 13:00. Password for Zoom is NielsBohr

Presentation.pdf