题  目：Electroweak Chiral Lagrangian with a Light Higgs and the gamma gamma -> WL+ WL−, ZL ZL at the One-Loop Level

报告人：Juan Jose Sanz-Cillero博士  马德里自治大学理论物理研究所

时  间：03月19日(周四) 15:00-16:00

地  点：理科二号楼B404

报告摘要：The gamma gamma scattering into longitudinal electroweak gauge bosons can be used to discern new physics in present and future collider experiments. We take an effective field theory approach where we consider the  electroweak chiral Lagrangian including a light Higgs-like scalar (ECLh) as a dynamical light field together with a non-linear realziation of the would-be-Goldstone bosons associated to the electroweak symmetry breaking. This description assumes the existence of a mass gap between mh, mW, mZ and the potential new emergent resonances, setting an intermediate energy region (above mh,mW,mZ and below the resonance masses) where the use of the ECLh is the most appropriate tool to compute the relevant observables.  
We analize in detail the proper chiral counting rules for the present case, the photon-photon scattering. The amplitude is computed within this effective theory framework up to next-to-leading order, i.e., up to the one-loop level (only bosonic loop contributions are accounted so far). The distinctive signal we found in our theoretical prediction leads to interesting implications both theoretically and experimentally. After extremely subtle cancellations the final amplitudes happen to UV finite, being determined by a set of renormalization group invariant combinations of effective couplings. We finally propose a joint analysis of our results for the photon-photon scattering amplitudes together with other photonic processes and electroweak precission observables for a future comparison with data. This could help to disantangle the nature of the light Higgs-like particle.

报告人简介：Dr. Sanz-Cillero obtained his Ph.D from University of Valencia in 2004 and worked as postdoc researcher in IPN at Orsay in Paris, Peking University, University Autonoma of Barcelona, INFN at Bari.He is working at IFT in University Autonoma of Madrid and CSIC. He is currently a visitor of the Beijing Center for Future High Energy Physics.His research topics covers a broad range in particle physics, including chiral effective field theory and related phenomenology, holographic QCD, Higgs physics, etc.