Phenomenological test of the large N_c ChPT predictions for the pseudoscalar mixing parameters

Talk presented at the PHOTON2005 International Conference on the Structure and Interactions of the Photon, Warsaw, Poland, 31.8-4.9.2005Altres ajuts: work partially suportted by EU, HPRN-CT-2002-00311, EURIDICE networkA phenomenological analysis of various decay processes is performed in order to test the large Nc Chiral Perturbation Theory predictions for the octet and singlet pseudoscalar decay constants and mixing angles. The results obtained hint at a disagreement with the expectations of this theoretical framework although the statistical significance is still limite

η-η'mixing : overview

Participació en el workshop 'Light Meson Dynamics' held in Mainz from February 10th to 12th, 201

A first prediction of the electromagnetic rare decays η'→π0γγ and η'→ηγγ

Contribution to the proceedings of the 6th International Conference on Quarks and Nuclear Physics (QNP2012)- Session B, Ecole Polytechnique, Palaiseau, Paris, April 16-20, 2012The branching ratio of the electromagnetic rare decays η→π0γγ and η'→(π0,η)γγ are analysed in terms of scalar and vector meson exchange contributions using the frameworks of the Linear Sigma Model and Vector Meson Dominance, respectively. The measured η→π0γγ process serves as a test of our approach while the non yet measured η'→(π0,η)γγ reactions are predicted for the first time. Our prediction for the η→π0γγ decay agrees with recent experimental reported values, thus supporting the validity of our framework. Therefore, our predictions for the η'→π0γγ and η'→ηγγ decays should be taken as a first indication of the possible values of the associated branching ratios. We hope these predictions to be interesting and useful for experiments such as KLOE-2, Crystal Ball, WASA, and BES-III where these processes are expected to be measured in the next future

Two mixing angle description of radiative VPgamma decays

Talk presented at the 12th International High-Energy Physics Conference in Quantum Chromodynamics (QCD 2005), Montpellier, France, 4-8 July 2005Altres ajuts: work partially suportted by EU, HPRN-CT-2002-00311, EURIDICE networkAn analysis of various radiative VPγ decays is performed using the two mixing angle description of the η-η' system. The agreement is excellent. Our results are expressed both in the ''octet-singlet'' and in the ''quark-flavour'' basis. It turns out that at the present experimental accuracy, the two angles are significantly different in the former, but not in the latter basis

A rational approach to η AND η' transition form factors

Contribució a Proceedings of the International Workshop on e+e- Collisions from Phi to Psi 2013 (PHIPSI2013), Rome, Italy, 9-12 September 2013The η and η 0 transition form factors in the space-like region are analyzed at low and intermediate energies in a model-independent way through the use of rational approximants. The slope and curvature parameters of the form factors as well as their values at infinity are extracted from experimental data. The impact of these results on the mixing parameters of the η-η 0 system are also discussed

Statistical fluctuations of ground-state energies and binding energies in nuclei

The statistical fluctuations of the ground-state energy and of the binding energy of nuclei are investigated using both perturbation theory and supersymmetry. The fluctuations are induced by the experimentally observed stochastic behavior of levels in the vicinity of neutron threshold. The results are compared with a recent analysis of binding-energy fluctuations by Bohigas and Leboeuf, and with theoretical work by Feshbach et al.Comment: 8 pages, 2 figure

Quantum Energies of Solitons

For renormalizable models a method is presented to unambiguously compute the energy that is carried by localized field configurations (solitons). A variational approach for the total energy is utilized to search for soliton configurations. As an example a 1+1 dimensional model is considered. The quantum energy of configurations that are translationally invariant for a subset of coordinates is discussed.Comment: 6 pages LaTeX with ws-p8-50x6-00.cls (included). To appear in the proceedings of the 6th workshop on non-perturbative QCD, Paris, June 200

CEBAF at Higher Energies

This report summarizes topics in hadron spectroscopy and production which could be addressed at CEBAF with an energy upgrade to $E_\gamma=8$ GeV and beyond. The topics discussed include conventional meson and baryon spectroscopy, spectroscopy of exotica (especially molecules and hybrids), CP and CPT tests using $\phi$ mesons, and new detector and accelerator options.Comment: (A Workshop held at CEBAF, Newport News, Virginia, 14-16 April 1994): 11 pages and 1 figure (available as hard copy from the authors), ORNL/CCIP/94-15.Working Group Report on Hadron Spectroscopy and Productio