arXiv subjects

Javier Redondo

Publications and source records attributed to Javier Redondo.

101 records · Page 6Linked to original sources

arXiv2008

Helioscope Bounds on Hidden Sector Photons

The flux of hypothetical "hidden photons" from the Sun is computed under the assumption that they interact with normal matter only through kinetic mixing with the ordinary standard model photon. Requiring that the exotic luminosity is smaller than the standard photon luminosity provides limits for the mixing parameter down to 10^-14, depending on the hidden photon mass. Furthermore, it is pointed out that helioscopes looking for solar axions are also very sensitive to hidden photons. The recent results of the CAST collaboration are used to further constrain the mixing parameter at low masses m<1 eV where the luminosity bound is weaker. In this regime the solar hidden photon flux has a sizable contribution of longitudinally polarized hidden photons of low energy which are invisible for current helioscopes.

hep-ph↗

arXiv2006

Light scalars coupled to photons and non-newtonian forces

A particle $ϕ$ coupling to two photons couples also to charged particles, like protons, through a loop. If the particle is a light scalar this induced coupling to protons leads to non-newtonian forces. We show that the experimental constraints on exotic, fifth-type forces lead to stringent constraints on the $ϕγγ$ coupling.

hep-ph↗

arXiv2006

A model solving the PVLAS-CAST puzzle

Axion physics has received a boost with the recent claim of the PVLAS collaboration. Their results can be interpreted as due to a new axionlike particle but the CAST collaboration has not found trace of it. While the axionlike particle interpretation of the PVLAS signal is going to be probed by dedicated laboratory experiments, it is mandatory to find either alternatives to it or models in which the astrophysical bounds could be evaded. In this communication one of such models is presented. The new physics involved appears at a low energy scale $<$ eV.

hep-ph↗

arXiv2006

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.

hep-ph↗

arXiv2006

Compatibility of CAST search with axion-like interpretation of PVLAS results

The PVLAS collaboration has 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. We propose a particle physics model with paraphotons and with a low energy scale in which this apparent inconsistency is circumvented.

hep-ph↗

arXiv2006

New Results In Axion Physics

We comment on the recent experimental results from the PVLAS and CAST collaborations that search for axion-like particles. We propose a particle physics model in which their apparent inconsistency is circumvented.

hep-ph↗

arXiv2006

Nondiffractive sonic crystals

We predict theoretically the nondiffractive propagation of sonic waves in periodic acoustic media (sonic crystals), by expansion into a set of plane waves (Bloch mode expansion), and by finite difference time domain calculations of finite beams. We also give analytical evaluations of the parameters for nondiffractive propagation, as well as the minimum size of the nondiffractively propagating acoustic beams.

physics.flu-dyn↗

arXiv2006

We need lab experiments to look for axion-like particles

The PVLAS signal has renewed the interest in light bosons coupled to the electromagnetic field. However, astrophysical bounds coming from the lifetime of the sun and the CAST experiment are seemingly in conflict with this result. We discuss effective models that allow to suppress production of axion-like particles in the sun and thereby relax the bounds by some orders of magnitude. This stresses the importance of laboratory searches.

hep-ph↗

arXiv2005

Evading Astrophysical Constraints on Axion-Like Particles

Stellar energy loss arguments lead to strong constraints on the coupling $ϕγγ$ of a light axion-like particle to two photons. Helioscopes, like CAST, are able to put competitive bounds. The PVLAS experiment has recently observed a rotation of the polarization of a laser propagating in a magnetic field that can be interpreted as the effect of a quite strong $ϕγγ$ coupling. We present scenarios where the astrophysical and CAST bounds can be evaded, and we show that the PVLAS result can be accomodated in one of the models, provided the new physics scale is at very low energies.

hep-ph↗

arXiv2005

Nonlinear dynamics and chaos in parametric sound generation

A theoretical analysis of the subharmonic generation process in an acoustical resonator (interferometer) with plane walls is performed. It is shown that, when both the pumping wave and the generated subharmonic are detuned with respect to the resonator modes, the fields can display complex temporal behaviour such as self-pulsing and chaos. A discussion about the acoustical parameters required for the experimental observation of the phenomenon is given.

nlin.CD↗

arXiv2004

Systematic Approach to Gauge-Invariant Relations between Lepton Flavor Violating Processes

We analyze four-lepton contact interactions that lead to lepton flavor violating processes, with violation of individual family lepton number but total lepton number conserved. In an effective Lagrangian framework, the assumption of gauge invariance leads to relations among branching ratios and cross sections of lepton flavor violating processes. In this paper, we work out how to use these relations systematically. We also study the consequences of loop-induced processes.

hep-ph↗