One loop predictions for the pion VFF in Resonance Chiral Theory

A calculation for the one-loop pion vector form-factor in Resonance Chiral Theory is provided in this talk. The amplitude is computed up to next-to-leading order in 1/Nc and, by means of high-energy constraints, we are able to produce a prediction for the corresponding O(p4) Chiral Perturbation Theory low energy constant L9(mu)=(7.6+- 0.6) 10^{-3} at the scale mu=770 MeV.Comment: 6 pages. Talk given at QCD@Work 2010 -International Workshop on QCD: Theory and Experiment-, 20-23 June 2010, Martina Franca, Valle d'Itria (Italy

QCD Correlators at Large NC

This talk explores the spin--1 correlators up to O(alpha_s) through a large NC resonance theory. The phenomenological analyses of this kind must take these corrections into account since they produce a larger impact than the first OPE condensates. It is also necessary to separate low and high energy regimes; fixing the parameters of the lightest multiplets through perturbative QCD arguments is unfair and introduces errors in the determination of the condensates and resonance parameters. This separation of regimes improves our understanding of the Minimal Hadronical Approximation. The study at O(alpha_s) already allows discerning between different hadronical models, where the Regge-like mass spectrum shows the best agreement to phenomenology.Comment: 4 pages, 1 table and 2 figures. Proceedings of the talk given at the International Conference on Quantum Chromodynamics, 2-9 July (2005), Montpellier (France). To be published in Nucl. Phys. B (Proc. Suppl.

V+A and V-A Correlators at Large NC: From OPE to Resonance Theory

The spin-1 correlators are analysed in this talk through a large NC resonance theory. The matching to perturbative QCD and the first terms in the OPE constrains the hadronic parameters. A further sum-rule analysis shows the wider range of validity of the resonance description, which can help to discern the proper structure of the QCD mass spectrum.Comment: 6 pages, 2 figures, proceedings of the talk given at HSQCD 2005, St. Petersburg, Russia, September 20-24 200

Electroweak chiral Lagrangians and the Higgs properties at the one-loop level

In these proceedings we explore the use of (non-linear) electroweak chiral Lagrangians for the description of possible beyond the Standard Model strong dynamics in the electroweak sector. Experimentally one observes an approximate electroweak symmetry breaking pattern $SU(2)_L\times SU(2)_R/SU(2)_{L+R}$. Quantum Chromodynamics shows a similar chiral structure and, in spite of the differences (in the electroweak theory $SU(2)_L\times U(1)_Y$ is gauged), it has served for years as a guide for this type of studies. Examples of one-loop computations in the low-energy effective theory and the theory including the first vector and axial-vector resonances are provided, yielding, respectively, predictions for $\gamma\gamma\to Z_LZ_L,W^+_LW^-_L$ and the oblique parameters $S$ and $T$.Comment: 6 pages, 2 eps figures. Proceedings of the 7th Edition of the International Workshop on Quantum Chromodynamics -QCD@Work: Interantional Workshop on QCD, Theory and Experiment- (16-19 June 2014, Giovinazzo, Italy