Search results for "effective field theory"
showing 10 items of 212 documents
Low energy structure of the nucleon from chiral effective field theory
2014
We present some updated results regarding the scalar and electromagnetic structure of the nucleon obtained by the relativistic formulation of chiral effective field theory with baryons. We compare them with previous determinations available in the literature, and show their relevance for searches of physics beyond the standard model in the low energy frontier. An accurate knowledge of the structure of the nucleon is important to improve our understanding of the funda- mental interactions and provide theoretical estimations of some important quantities with a small uncertainty. This is specially relevant for experiential searches of physics be- yond the standard model in the low energy front…
τ→πππντdecays in the resonance effective theory
2004
$\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\tau}}\ensuremath{\pi}\ensuremath{\pi}\ensuremath{\pi}{\ensuremath{\nu}}_{\ensuremath{\tau}}$ decays are analyzed within the framework of the resonance effective theory of QCD. We work out the relevant Lagrangian that describes the axial-vector current hadronization contributing to these processes, in particular the local ${a}_{1}(1260)\ensuremath{-}\ensuremath{\rho}(770)$-Goldstone interactions. The new coupling constants are constrained by imposing the asymptotic behavior of the corresponding spectral function within QCD. Hence we compare the theoretical framework with the experimental data, obtaining a good quality fit from the ALEPH spect…
Definition of theΔmass and width
2007
In the framework of effective field theory we show that, at two-loop order, the mass and width of the $\ensuremath{\Delta}$ resonance defined via the (relativistic) Breit-Wigner parametrization both depend on the choice of field variables. In contrast, the complex-valued position of the pole of the propagator is independent of this choice.
Factorization and N3LLp+NNLO predictions for the Higgs cross section with a jet veto
2013
We have recently derived a factorization formula for the Higgs-boson production cross section in the presence of a jet veto, which allows for a systematic resummation of large Sudakov logarithms of the form alpha_s^n ln^m(p_T^veto/m_H), along with the large virtual corrections known to affect also the total cross section. Here we determine the ingredients entering this formula at two-loop accuracy. Specifically, we compute the dependence on the jet-radius parameter R, which is encoded in the two-loop coefficient of the collinear anomaly, by means of a direct, fully analytic calculation in the framework of soft-collinear effective theory. We confirm the result obtained by Banfi et al. from a…
Odd-intrinsic-parity processes within the Resonance Effective Theory of QCD
2003
19 páginas, 4 figuras.-- arXiv:hep-ph/0306157v1
The hadronic cross-section in the resonance energy region
2004
Abstract We study the hadronic vacuum polarization in the resonance energy region, using the framework given bythe Resonance Effective Theory of QCD. We consider the incorporation of vector-pseudoscalar meson loops that give, inclusively, three and four pseudoscalar meson cuts. After resummation we achieve a QCD-based inclusive parameterization of the correlator, hence of the hadronic cross-section in the energy region populated by resonances.
Effective field theory description of the pion form factor
1997
7 páginas, 2 figuras.-- PACS: 14.40.Aq; 13.40.Gp; 13.6O.Fz; 12.39.Fe.-- arXiv:hep-ph/9707347v1
Sliding Vacua in Dense Skyrmion Matter
2003
In continuation of our systematic effort to understand hadronic matter at high density, we study dense skyrmion matter and its chiral phase structure in an effective field theory implemented with the trace anomaly of QCD applicable in the large $N_c$ limit. By incorporating a dilaton field $\chi$ associated with broken conformal symmetry of QCD into the simplest form of skyrmion Lagrangian, we simulate the effect of "sliding vacua" influenced by the presence of matter and obtain what could correspond to the ``intrinsic dependence" on the background of the system, i.e., matter density or temperature, that results when a generic chiral effective field theory of strong interactions is matched …
Effective field theory calculations in open charm and charmonium production in media
2019
Heavy quarkonium related observables are very useful to obtain information about the medium created in relativistic heavy ion collisions. The interaction of charmonium or bottomonium with the hot QCD medium created in these collisions can be efficiently described with the use of non-relativistic Effective Field Theories. In this proceedings, I will review recent progress in understanding quarkonium dynamics in a thermal medium with the use of potential non-relativistic QCD (pNRQCD). First, I will discuss the medium modifications of the decay width and the binding energy. Using pNRQCD power counting it is possible to identify in which temperature regimes a potential model can describe these mo…
Testing chiral effective theory with quenched lattice QCD
2008
We investigate two-point correlation functions of left-handed currents computed in quenched lattice QCD with the Neuberger-Dirac operator. We consider two lattice spacings a ~ 0.09, 0.12 fm and two different lattice extents L ~ 1.5, 2.0 fm; quark masses span both the p- and the epsilon-regimes. We compare the results with the predictions of quenched chiral perturbation theory, with the purpose of testing to what extent the effective theory reproduces quenched QCD at low energy. In the p-regime we test volume and quark mass dependence of the pseudoscalar decay constant and mass; in the epsilon-regime, we investigate volume and topology dependence of the correlators. While the leading order b…