Configurational Entropy can disentangle conventional hadrons from exotica

We evaluate the Configurational Entropy (CE) for scalar mesons and for $J^P=\frac{1}{2}^+$ baryons in a holographic approach, varying the dimension of boundary theory operators and using the soft-wall dual model of QCD. We find that hybrid and multiquark mesons are characterized by an increasingly large CE. A similar behavior is observed for $J^P=\frac{1}{2}^+$ baryons, where the CE of pentaquarks is larger than for three-quark baryons, for same radial number. Configurational Entropy seems relevant in disentangling conventional hadrons from exotica.Comment: 13 pages, 4 figure

Unfolding spectral analysis of the Fermi-LAT data

The Large Area Telescope (LAT) onboard the Fermi satellite is observing the gamma-ray sky in the high energy region, above 20 MeV. We have developed a method to reconstruct the energy spectra of the gamma-rays detected by the Fermi LAT instrument based on a Bayesian unfolding approach, that takes into account the energy dispersion introduced by the instrument response. The method has been successfully applied to reconstruct the energy spectra of both steady and pulsating point sources. The analysis technique will be illustrated and the results obtained in some significant test cases will be discussed.Comment: 6 pages, 9 figure

Measurement of the ratio h/e with a photomultiplier tube and a set of LEDs

We propose a laboratory experience aimed at undergraduate physics students to understand the main features of the photoelectric effect and to perform a measurement of the ratio h/e, where h is the Planck's constant and e is the electron charge. The experience is based on the method developed by Millikan for his measurements on the photoelectric effect in the years from 1912 to 1915. The experimental setup consists of a photomultiplier tube (PMT) equipped with a voltage divider properly modified to set variable retarding potentials between the photocathode and the first dynode, and a set of LEDs emitting at different wavelengths. The photocathode is illuminated with the various LEDs and, for each wavelength of the incident light, the output anode current is measured as a function of the retarding potential applied between the cathode and the first dynode. From each measurement, a value of the stopping potential for the anode current is derived. Finally, the stopping potentials are plotted as a function of the frequency of the incident light, and a linear fit is performed. The slope and the intercept of the line allow respectively to evaluate the ratio h/e and the ratio W/e, where W is the work function of the photocathode.Comment: 14 pages, 4 figure

Measurements of the cosmic-ray electron and positron spectrum and anisotropies with the Fermi LAT

The Large Area Telescope (LAT) onboard the Fermi satellite is a pair-conversion telescope for high-energy gamma rays of astrophysical origin. Although it was designed to be a high-sensitivity gamma-ray telescope, the LAT has proved to be an excellent electron/positron detector. It has been operating in low Earth orbit since June 2008 and has collected more than 16 million cosmic-ray electron and positron (CRE) events in its first seven years of operation. The huge data sample collected by the LAT enables a precise measurement of the CRE energy spectrum up to the TeV region. A search for anisotropies in the arrival directions of CREs was also performed. The upper limits on the dipole anisotropy probe the presence of nearby young and middle-aged CRE sources

Hadronic interactions of primary cosmic rays with the FLUKA code

The measured fluxes of secondary particles produced by the interactions of cosmic rays with the astronomical environment represent a powerful tool to infer some properties of primary cosmic rays. In this work we investigate the production of secondary particles in inelastic hadronic interactions between several cosmic rays species of projectiles and different target nuclei of the interstellar medium. The yields of secondary particles have been calculated with the FLUKA simulation package, that provides with very good accuracy the energy distributions of secondary products in a large energy range. An application to the propagation and production of secondaries in the Galaxy is presented.Comment: 8 pages, 4 figures; Contribution to the 34th International Cosmic Ray Conference, July 30 to August 6, The Hague, Netherlands; fixing a typo in the y-axis label of Fig.

A Bayesian approach to evaluate confidence intervals in counting experiments with background

In this paper we propose a procedure to evaluate Bayesian confidence intervals in counting experiments where both signal and background fluctuations are described by the Poisson statistics. The results obtained when the method is applied to the calculation of upper limits will also be illustrated.Comment: 19 pages, 6 figure

The gamma-ray Moon seen by the Fermi LAT

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