arXiv subjects

Diego Casadei

Publications and source records attributed to Diego Casadei.

21 records · Page 2Linked to original sources

arXiv2006

Searches for Cosmic Antimatter

We know from experimental high energy physics that whenever matter is created, an equal amount of antimatter is also created. However, we live in a large region of the universe where the antimatter can not constitute more than a very small fraction of the total mass. The cosmic antimatter problem has been addressed since the beginning of modern cosmology, but no definite answer has been formulated despite of the several approaches that can be found in the literature. In this paper we will make a historical review and we will focus on the experimental techniques that has been proposed to reveal directly and indirectly the presence of cosmic antimatter in the universe. Indirect searches can be carried on with the measurements of the electromagnetic radiation in the microwave and gamma-ray range, and of the neutrino flavour, whereas direct searches lay on the measurement of the cosmic rays and probe shorter distances. Finally, the current limits on the cosmic antimatter to matter ratio are compared to the sensitivity of future experiments.

astro-ph↗

arXiv2004

The Local Interstellar Spectrum of Cosmic Ray Electrons

The direct measurements of electrons and positrons over the last 30 years, corrected for the solar effect in the force-field approximation, are considered. The resulting overall electron spectrum may be fitted with a single power law above few GeV with spectral index ($γ_{-} = 3.41 \pm 0.02$), consistent with the spectral index of the positron spectrum ($γ_{+} = 3.40 \pm 0.06$), therefore suggesting a common acceleration process for both species. We propose that the engine was a shock wave originating from the last supernova explosion among those that formed the local bubble. In addition, at low energy, the electron spectrum measured during the last $A+$ solar phase is damped, whereas the positron spectrum is well represented by a single power law down to the lowest inferred local interstellar energy (0.8 GeV). We suggest that this difference arises from a time- and charge-dependent effect of the solar modulation that is not taken into account by the force-field approximation.

astro-ph↗

arXiv2004

Cosmic Ray Astrophysics with AMS-02

The Alpha Magnetic Spectrometer (AMS) is a cosmic ray (CR) experiment that will operate on the International Space Station for three years, measuring the particle spectra in the rigidity range from 0.2 GV to 2 TV. The AMS-02 detector will provide measurements with unprecedented statistics of the hadronic and leptonic cosmic rays, allowing for a better study of the Earth magnetosphere through the secondaries produced by CR interactions in the atmosphere; of the solar system environment through the measurement of the solar modulation over a long period; of the solar system neighborhood through the measurement of the ratio between unstable isotopes and stable elements; of the interstellar medium of our Galaxy through the ratio between secondary and primary isotopes and the measurement of proton and helium spectra.

astro-ph↗