Josh McFayden: A new measurement of lepton-flavour universality with the ATLAS experiment

Wednesday 14 Oct 2020, 15:30 → 17:30 Europe/London

A remarkable feature of the Standard Model (SM) is that each lepton flavour (electron, muon, tau) is equally likely to interact with a W boson. This is known as Lepton Flavour Universality.
 

In a recent ATLAS measurement, a novel technique using events with top-quark pairs has been exploited to test the ratio of the probabilities for tau leptons and muons to be produced in W boson decays, R(τ/μ).

 

In the SM, R(τ/μ) is expected to be unity, but a longstanding tension with this prediction has existed since the LEP era, where, from a combination of experiments, R(τ/μ) was measured to be 2.7σ higher than the SM expectation. 

 

If the LEP result were confirmed to O(1%) precision it would correspond to an unambiguous discovery of beyond the SM physics. This latest ATLAS measurement obtains this level a precision - please join the seminar to discover whether or not it agrees with LEP!

 

Connection via Zoom:

Topic: Liverpool HEP Seminar
https://liverpool-ac-uk.zoom.us/j/99542014031?pwd=eXBxUVJkWEZKN0NWcEpJMTRHYmxDZz09

Meeting ID: 995 4201 4031
Password: 6R$m5uB#

2020-10-14_LiverpoolSeminar_ttLFU_mcfayden.pdf