Pseudoscalar production in electromagnetic fields by a Schwinger-like mechanism

In this talk I report on some recent calculations on the production of pseudoscalars from intense electromagnetic fields.Comment: 5 pages, Invited talk at QED2000, 2nd Workshop on Frontier Tests of Quantum Electrodynamics and Physics of the Vacuum, Trieste (October 2000

An Effective Guide to Beyond the Standard Model Physics

Effective Lagrangians with dimension-six operators are widely used to analyse Higgs and other electroweak data. We show how to build a basis of operators such that each operator corresponds to a coupling which is well measured or will be in the future. We choose a set of couplings such that the correspondence is one-to-one. In our framework, some important features of the Lagrangian are transparent. For example, one can clearly see the presence or absence of correlations among measurable quantities. This may be a useful guide when searching for physics beyond the Standard Model.Comment: Discussion expanded and tables added. Conclusions unchanged. 28 pa

Physics and Cosmology : the Milli-Electron-Volt Scale

A short review about vacuum energy and the cosmological constant is presented. The observed acceleration of the universe introduces a new meV energy scale. The problem is that, theoretically, the predicted vacuum energy is many orders of magnitude larger than $10^{-3}$ eV. The problem is a link between two Standard Models, namely the Standard Model of Particles and their Interactions (where the vacuum energy appears) and the Standard Cosmological Model (where a cosmological constant is a good fit to data), and perhaps it is a clue in our search for new physics.Comment: 5 pag

New Constraints on a Light Spinless Particle Coupled to Photons

We obtain new stringent constraints on a light spinless particle phi coupled only to photons at low energies, considering its effects on the extragalactic photon background, the blackbody spectrum of the CMBR and the cosmological abundance of deuterium.Comment: 7 pages, 1 postscript figur

Axion results: what is new?

The PVLAS collaboration has obtained results that may be interpreted in terms of a light axion-like particle, while the CAST collaboration has not found any signal of such particles. Moreover, the PVLAS results are in gross contradiction with astrophysical bounds. We develop a particle physics model with two paraphotons and with a low energy scale in which these apparent inconsistencies are circumvented.Comment: 10 pages, 4 figures. Based on two talks given at the International Workshop "The dark side of the Universe", Madrid, June 2006: "Evading astrophysical bounds on axion-like particles in paraphoton models" by J. Redondo and "Axion results: what is new?" by E. Masso. To be published in the Proceeding