arXiv subjects

Alberto Tonero

Publications and source records attributed to Alberto Tonero.

21 records · Page 2Linked to original sources

arXiv2015

Computing the Effective Action with the Functional Renormalization Group

The "exact" or "functional" renormalization group equation describes the renormalization group flow of the effective average action $Γ_k$. The ordinary effective action $Γ_0$ can be obtained by integrating the flow equation from an ultraviolet scale $k=Λ$ down to $k=0$. We give several examples of such calculations at one-loop, both in renormalizable and in effective field theories. We use the results of Barvinsky, Vilkovisky and Avramidi on the non-local heat kernel coefficients to reproduce the four point scattering amplitude in the case of a real scalar field theory with quartic potential and in the case of the pion chiral lagrangian. In the case of gauge theories, we reproduce the vacuum polarization of QED and of Yang-Mills theory. We also compute the two point functions for scalars and gravitons in the effective field theory of scalar fields minimally coupled to gravity.

hep-th↗

arXiv2015

A renormalization group improved computation of correlation functions in theories with non-trivial phase diagram

We present a simple and consistent way to compute correlation functions in interacting theories with non-trivial phase diagram. As an example we show how to consistently compute the four-point function in three dimensional $\mathbb{Z}_2$-scalar theories. The idea is to perform the path integral by weighting the momentum modes that contribute to it according to their renormalization group (RG) relevance, i.e. we weight each mode according to the value of the running couplings at that scale. In this way, we are able encode in a loop computation the information regarding the RG trajectory along which we are integrating. We show that depending on the initial condition, or initial point in the phase diagram, we obtain different behaviors of the four-point function at the end point of the flow.

hep-th↗

arXiv2014

Dipole-induced anomalous top quark couplings at the LHC

We consider direct bounds on the coefficients of higher dimensional top quark dipole operators from their contributions to anomalous top couplings that affect some related processes at the LHC. Several observables are studied. In particular, we incorporate for the first time in this type of analysis the recently measured associated $t \bar{t} V$ production, which is currently the only measured direct observable sensitive to the dipole operator involving the hypercharge field. We perform a Bayesian analysis to derive the $1(2)σ$ confidence level (CL) intervals on these coefficients.

hep-ph↗