arXiv subjects

Carlo Rizzo

Publications and source records attributed to Carlo Rizzo.

27 records · Page 2Linked to original sources

arXiv2007

No light shining through a wall : new results from a photoregeneration experiment

Recently, axion-like particle search has received renewed interest. In particular, several groups have started ``light shining through a wall'' experiments based on magnetic field and laser both continuous, which is very demanding in terms of detector background. We present here the 2$σ$ limits obtained so far with our novel set-up consisting of a pulsed magnetic field and a pulsed laser. In particular, we have found that the axion-like particle two photons inverse coupling constant $M$ is $> 8\times 10^5$ GeV provided that the particle mass $m_\mathrm{a} \sim$ 1 meV. Our results definitively invalidate the axion interpretation of the original PVLAS optical measurements with a confidence level greater than 99.9%.

hep-ex↗

arXiv2007

The BMV experiment : a novel apparatus to study the propagation of light in a transverse magnetic field

In this paper, we describe in detail the BMV (Biréfringence Magnétique du Vide) experiment, a novel apparatus to study the propagation of light in a transverse magnetic field. It is based on a very high finesse Fabry-Perot cavity and on pulsed magnets specially designed for this purpose. We justify our technical choices and we present the current status and perspectives.

physics.optics↗

arXiv2007

Structure of the photon and magnetic field induced birefringence and dichroism

In this letter we show that the dichroism and ellipticity induced on a linear polarized light beam by the presence of a magnetic field in vacuum can be explained in the framework of the de Broglie's fusion model of a photon. In this model it is assumed that the usual photon is the spin 1 state of a particle-antiparticle bound state of two spin 1/2 fermions. The other S=0 state is referred to as the \emph{second} photon. On the other hand, since no charged particle neither particles having an electric dipole are considered, no effect is predicted in the presence of electric fields and this model is not in contradiction with star cooling data or solar axion search.

quant-ph↗

arXiv2006

Hyperspherical elliptic coordinates treatment of muon transfer from muonic hydrogen to atomic oxygen

Quantum-mechanical calculations of muon transfer between muonic hydrogen and an oxygen nuclei for $s$ waves and collision energies in the range $10^{-3} - 10^3$ eV, are presented. Close-coupling time-independent Schrödinger equations, written in terms of hyperspherical elliptic coordinates were integrated along the hyper-radius to obtain the partial and total muon-transfer probabilities. The results show the expected Wigner-Bethe threshold behavior up to collision energies of the order of $10^{-2}$ eV and pronounced maxima at $10^2$ eV which can be interpreted in terms of crossings between potential energy curves corresponding to the entrance channel state $(μp)_{1s} + \mO$ and two product channels which asymptotically correlate to $p + (\mOμ)_{n=5,6}$. The population of the final states with different orbital angular momenta is found to be essentially independent of energy in the range considered in this work. This can be attributed to a strong selection rule for the conservation of the quantum number associated to one of the elliptic hyperangles.

quant-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↗

arXiv2005

Looking for Light Pseudoscalar Bosons in the Binary Pulsar System J0737-3039

We present numerical calculations of the photon-light-pseudoscalar-boson conversion in the recently discovered binary pulsar system J0737-3039. Light pseudoscalar bosons (LPBs) oscillate into photons in the presence of strong magnetic fields. In the context of this binary pulsar system, this phenomenon attenuates the light beam emitted by one of the pulsars, when the light ray goes through the magnetosphere of the companion pulsar. We show that such an effect is observable in the gamma-ray band since the binary pulsar is seen almost edge-on, depending on the value of the LPB mass and on the strenght of its two-photon coupling. Our results are surprising in that they show a very sharp and significant (up to 50%) transition probability in the gamma-ray ($>$ tens of MeV) domain. The observations can be performed by the upcoming NASA GLAST mission.

astro-ph↗

arXiv2005

Observing Quantum Vacuum Lensing in Magnetized Neutron Star Binary System

In this letter we study the propagation of light in the neighbourhood of magnetised neutron stars. Thanks to the optical properties of quantum vacuum in the presence of a magnetic field, light emitted by background astronomical objects is deviated giving rise to a phenomenon of the same kind as the gravitational one. We give a quantitative estimation of this effect and we discuss the possibility of its observation. We show that this effect could be detected monitoring the evolution of the recently discovered double neutron star system J0737-3039.

quant-ph↗

arXiv2003

Proton Zemach radius from measurements of the hyperfine splitting of hydrogen and muonic hydrogen

While measurements of the hyperfine structure of hydrogen-like atoms are traditionally regarded as test of bound-state QED, we assume that theoretical QED predictions are accurate and discuss the information about the electromagnetic structure of protons that could be extracted from the experimental values of the ground state hyperfine splitting in hydrogen and muonic hydrogen. Using recent theoretical results on the proton polarizability effects and the experimental hydrogen hyperfine splitting we obtain for the Zemach radius of the proton the value 1.040(16) fm. We compare it to the various theoretical estimates the uncertainty of which is shown to be larger that 0.016 fm. This point of view gives quite convincing arguments in support of projects to measure the hyperfine splitting of muonic hydrogen.

quant-ph↗

arXiv2003

Muon transfer from muonic hydrogen to atomic oxygen

The muon transfer probabilities between muonic hydrogen and an oxygen atom are calculated in a constrained geometry one dimensional model for collision between 10^-6 and 10^3 eV. These estimated rates are discussed in the light of previous model calculations and available experimental data for this process.

quant-ph↗