arXiv subjects

Paolo Walter Cattaneo

Publications and source records attributed to Paolo Walter Cattaneo.

8 recordsLinked to original sources

arXiv2026

Letter Of Intent for a future $μ^+ \to \mathrm{e}^+ γ$ experiment at the High Intensity Muon Beam facility at PSI

Searches for charged lepton flavor violation in the muon sector stand out among the most sensitive and clean probes for physics beyond the Standard Model. Currently, $μ^+ \to \mathrm{e}^+ γ$ experiments provide the best constraints in this field for a wide range of models while, in the coming years, new experiments investigating the processes of $μ^+ \to \mathrm{e}^+ \mathrm{e}^+ \mathrm{e}^-$ and $μ\to \mathrm{e}$ conversion in the nuclear field are anticipated to reach comparable or higher sensitivities. The High-Intensity Muon Beam (HIMB) facility at PSI, which is expected to deliver muon beam intensities up to two orders of magnitude higher than the existing beam lines, offers a unique opportunity to significantly enhance the sensitivity of $μ^+ \to \mathrm{e}^+ γ$ searches. The discovery potential could be substantially boosted and a sensitivity comparable to that of all the other projects could be reestablished, which is essential for discriminating among competing new-physics scenarios should an observation occur in any of the channels. In this document, we express our interest in developing a $μ^+ \to \mathrm{e}^+ γ$ experimental program at HIMB, with the goal of improving, within the next decade, the sensitivity of the $μ^+ \to \mathrm{e}^+ γ$ search by more than one order of magnitude relative to the expected final result of the current leading experiment, MEG II. This effort would ensure that PSI retains its leadership in this field.

hep-ex↗

arXiv2025

Constraints on Lorentz invariance from the event KM3-230213A

Lorentz invariance is the cornerstone of relativity theory. Its implications have been verified experimentally with a variety of approaches. The detection of a muon at extremely high energy detected by the ARCA detector in the Mediterranean sea, the most energetic particle directly measured up to date, allows to put additional constraints on Lorentz non-invariant theories. The prediction of some of those theories is that the lifetimes of particles in the laboratory frame 'decrease' rather than 'increase' with increasing $γ$. In this frame the sheer fact that the muon traversed the whole ARCA detector puts a lower limit on the muon lifetime in the laboratory frame, that implies upper limits on Lorentz violating parameters.

hep-ph↗

arXiv2022

AGILE Observations of GRB 220101A: A "New Year's Burst" with an Exceptionally Huge Energy Release

We report the AGILE observations of GRB 220101A, which took place at the beginning of 1st January 2022 and was recognized as one of the most energetic gamma-ray bursts (GRBs) ever detected since their discovery. The AGILE satellite acquired interesting data concerning the prompt phase of this burst, providing an overall temporal and spectral description of the event in a wide energy range, from tens of keV to tens of MeV. Dividing the prompt emission into three main intervals, we notice an interesting spectral evolution, featuring a notable hardening of the spectrum in the central part of the burst. The average fluxes encountered in the different time intervals are relatively moderate, with respect to those of other remarkable bursts, and the overall fluence exhibits a quite ordinary value among the GRBs detected by MCAL. However, GRB 220101A is the second farthest event detected by AGILE, and the burst with the highest isotropic equivalent energy of the whole MCAL GRB sample, releasing E_iso=2.54x10^54 erg and exhibiting an isotropic luminosity of L_iso=2.34x10^52 erg/s (both in the 400 keV - 10 MeV energy range). We also analyzed the first 10^6 s of the afterglow phase, using the publicly available Swift XRT data, carrying out a theoretical analysis of the afterglow, based on the forward shock model. We notice that GRB 220101A is with high probability surrounded with a wind-like density medium, and that the energy carried by the initial shock shall be a fraction of the total E_iso, presumably near 50%.

astro-ph.HE↗

arXiv2012

Testing the Special Relativity Theory with Neutrino interactions

A recent measurement of neutrino velocity by the OPERA experiment and prediction of energy loss of superluminal neutrino via the pair creation process $ν\to νe^+e^-$ stimulated a search of isolated $e^+e^-$ pairs in detectors with good tracking capability traversed by a large flux of high energy neutrino like NOMAD. NOMAD has already searched for similar topologies. These results can be reinterpreted to provide stringent limits on special relativity violating parameters separately for each $ν$ species.

hep-ph↗

arXiv2009

Capacitances in micro-strip detectors: a conformal mapping approach

The knowledge of capacitance in semiconductor micro-strip detectors is important for a correct design, simulation and understanding of the detectors. Analytical approaches can efficiently complement numerical methods providing quick results in the design phase. The conformal mapping method has proved to be the most effective analytical approach providing many realistic models. In this paper improved analytical results are presented and compared with experimental data.

physics.ins-det↗

arXiv2009

The MEG Spectrometer at PSI

The MEG experiment is designed to search the Lepton Flavor Violating process $μ\to e^+γ$ \cite{mori-1999,meg2007-baldini}. This search requires a high intensity muon beam stopping in a thin target with the maximum rate compatible with the background from combinatorial events. The events are analyzed by a high resolution and fast liquid xenon calorimeter and by a spectrometer composed by an array of ultra-light drift chambers (DCH) for momentum measurement and a double layered timing counter (TC) for measuring the $e^+$ time. The design parameters and performance of the spectrometer during the 2008 physics run are described.

physics.ins-det↗

arXiv2009

Optical analysis of spherical mirrors of telescopes: the lens-less Schmidt case

The light distribution on the focal surface of spheric mirrors designed for telescopes in the lens-less Schmidt configuration is calculated analytically using geometrical optics. This analysis was motivated by considerations of the design the design of the AUGER fluorescence detector. Its geometrical parameters are used in the examples.

astro-ph.IM↗

arXiv2002

Critical review of the results of the Homestake solar neutrino experiment

The radiochemical experiment in the Homestake mine was designed to measure the solar neutrino flux through the detection of $^{37}Ar$ produced in the reaction $ν_e + ^{37}Cl \longrightarrow e^-+^{37}Ar$. The comparison between this measurement and the theoretical predictions from solar models evidences a substantial disagreement. I reanalyzed the data evidencing a bias with high statistical significance and suggesting a new interpretation of the data.

astro-ph↗