[Theory-seminars] TODAY's seminar: J.J. Sanz Cillero. 2pm. Room L102.

[Cesar Fernandez-Ramirez]

Dear all,

please find enclosed the information on TODAY's seminar.


Place: Room L102
Time: 2pm (coffee at 1.45pm)

Speaker: Juan José Sanz Cillero (Universidad Autónoma de Madrid/Instituto de Física Teórica, Madrid, Spain)
Title: "EW chiral Lagrangians and the Higgs properties at the one-loop level"

Abstract: So far LHC has found only a relatively light Higgs boson with mass 
mh=126 GeV and no  beyond-SM particle has appeared yet below the TeV.  
Likewise,  there have been no significant deviations in the interaction 
couplings  with respect  to the expected SM values. EW chiral 
Lagrangians are found to be, therefore, a natural and systematic 
approach for the study of this type of scenarios. However,  due to the 
tight constraints from LHC data, one needs to go beyond the leading 
order approximation in order to disentangle possible new physics. This 
is,  full one-loop effects must be computed and handled in a systematic 
way; tree-level phenomenological estimates are simply not accurate 
enough and miss crucial contributions.
More specifically, I will discuss the one-loop calculation of the 
photon-photon transition into longitudinal ZZ and W+W-, and related 
observables like e.g. the oblique parameter S, at the one-loop level. 
The renormalization and running of the relevant chiral couplings are 
analyzed and a joined analysis of several observables (photon-photon 
transitions, decay rates, oblique parameters and form-factors) is 
proposed for the extraction of the corresponding EW Lagrangian parameters.
In the last part of the talk, I will look at the particular predictions 
that arise in strongly-coupled models with resonances. Strongly coupled 
EW models with massive resonances are found not in conflict with the 
experimental S and T as far as the masses of the new vector and 
axial-vector resonance lie above the TeV scale and the hWW coupling 
remains  close to the Standard Model one.
All through the talk we will employ usual QCD tools such as effective 
chiral Lagrangians, Weinberg's EFT dimensional power counting and 
dispersion relations.

-- 
César Fernández-Ramírez

Theory Center -- Jefferson Lab
12000 Jefferson Ave., Newport News, VA 23606, USA

Phone: (+1) 757-269-7844
Fax: (+1) 757-269-7002
E-mail: cesar at jlab.org