Search results for "Field Theory"
showing 10 items of 1188 documents
Vector Mesons and Dence Skyrmion Matter
2004
In our continuing effort to understand hadronic matter at high density, we have developed a unified field theoretic formalism for dense skyrmion matter using a single Lagrangian to describe simultaneously both matter and meson fluctuations and studied in-medium properties of hadrons. Dropping the quartic Skyrme term, we incorporate into our previous Lagrangian the vector mesons rho and omega in a form which is consistent with the symmetries of QCD. The results that we have obtained, reported here, expose a hitherto unsuspected puzzle associated with the role the omega meson plays at short distance. Since the omega meson couples to baryon density, it leads to a pseudo-gap scenario for the ch…
LOW-ENERGY QCD II — STATUS OF LATTICE CALCULATIONS
2013
The current status of lattice calculations is reviewed, with a particular emphasis on the question whether lattice simulations have matured to a stage where there is full interaction with experiment. Particular examples include the hadron spectrum, mesonic form factors and decay constants, the axial charge of the nucleon, and the hadronic vacuum polarization contribution to the muon (g-2).
Model discriminating power ofμ→econversion in nuclei
2009
13 pages, 12 figures, 1 table.-- PACS nrs.: 13.35.Bv; 11.30.Hv.-- ArXiv pre-print available at: http://arxiv.org/abs/0904.0957
Constituent-quark model description of triply heavy-baryon nonperturbative lattice QCD data
2015
This paper provides results for the spectra of triply charmed and bottom baryons based on a constituent quark model approach. We take advantage of the assumption that potential models are expected to describe triply heavy baryons to a similar degree of accuracy as the successful results obtained in the charmonium and bottomonium sectors. The high precision calculation of the ground state and positive and negative parity excited states recently reported by nonperturbative lattice QCD provides us with a unique opportunity to confront model predictions with data. This comparison may also help to build a bridge between two difficult to reconcile lattice QCD results, namely, the lattice SU(3) QC…
Next-to-next-to-leading order prediction for the photon-to-pion transition form factor
2003
We evaluate the next-to-next-to-leading order corrections to the hard-scattering amplitude of the photon-to-pion transition form factor. Our approach is based on the predictive power of the conformal operator product expansion, which is valid for a vanishing $\beta$-function in the so-called conformal scheme. The Wilson--coefficients appearing in the non-forward kinematics are then entirely determined from those of the polarized deep-inelastic scattering known to next-to-next-to-leading accuracy. We propose different schemes to include explicitly also the conformal symmetry breaking term proportional to the $\beta$-function, and discuss numerical predictions calculated in different kinemati…
Brodsky-Lepage-Mackenzie scale for the pion transition form factor
2002
The next-to-leading order (NLO) Brodsky-Lepage-Mackenzie (BLM) scale for the pion transition form factor is determined. To achieve that, a consistent calculation up to ${n}_{f}$-proportional next-to-next-to-leading order contributions to both the hard-scattering amplitude and the perturbatively calculable part of the pion distribution amplitude is performed. By combining and matching the results obtained for these two amplitudes, a proper cancellation of collinear singularities is established and the ${\ensuremath{\gamma}}_{5}$ ambiguity problem (related to the use of the dimensional regularization method) is resolved by using the naive-${\ensuremath{\gamma}}_{5}$ as well as the 't Hooft--V…
Pinched weights and duality violation in QCD sum rules: A critical analysis
2010
We analyze the so-called pinched weights, that are generally thought to reduce the violation of quarkhadron duality in finite-energy sum rules. After showing how this is not true in general, we explain how to address this question for the left-right correlator and any particular pinched weight, taking advantage of our previous work [1], where the possible high-energy behavior of the left-right spectral function was studied. In particular, we show that the use of pinched weights allows to determine with high accuracy the dimension six and eight contributions in the operator-product expansion, O-6 = (-4.3(-0.7)(+0.9)) x 10(-3) GeV6 and O-8 = (-7.2(-5.3)(+4.2)) x 10(-3) GeV8.
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
Testing qcd with tau decays
1992
11 páginas, 2 tablas.-- CERN-TH-6422-92; LAL-92-10.
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 …