Wednesday 4 Nov 2020, 15:00 → 17:00
https://indico.cern.ch/event/965598/

20-25 participants

# NLO QCD and EW corrections to vector-boson scattering into ZZ at the LHC
Timo Schmidt 

Q: why ml'+l- > 4GeV?
A: it should be some experimental cuts to get rid of some background.

# Elastic positivity vs extremal positivity bounds in SMEFT: a case study in transversal electroweak gauge-boson scatterings
Cen Zhang

Q: Why the integral on slide 7 is not diverging?
A: Apparently it is due to the behaviour of the function M which should not be more divergent than s * log s.

Q: Do bounds depend on the truncation of the EFT? Do they change if dim 10 operators etc are added?
A: Yes, the positivity bounds are a property of the scattering amplitude, that is then matched to the SMEFT. So if the set of operators is changed, the constraints act on a different combination of parameters.

# Systematizing and addressing theory uncertainties of unitarization with the Inverse Amplitude
Felipe J. Llanes-Estrada

Q: Can you generalise to SMEFT?
A: In principle yes. The IAM uses an expansion in momenta, that can be also matched to SMEFT operators. The problem is that one will have to go to dimension 8 or higher.

# Loop-induced ZZ production at the LHC: an improved description by matrix-element matching
Congqiao Li

Q: What is going in the 8-minutes evaluation?
A: This is the matching and the generation of unweighted event.

Q: Why rule number 2 does not lead to gauge-dependent result?
A: This rule should define only the loop-induced diagrams of the full amplitude.