arXiv subjects

Ruben Gargiulo

Publications and source records attributed to Ruben Gargiulo.

5 recordsLinked to original sources

arXiv2025

MUSIC: A Multi-Purpose Detector Concept for Physics at the 10 TeV Muon Collider

This work presents a proof of concept for MUSIC, a multi-purpose detector conceived for high-precision and ultra-high-energy physics studies in the challenging environment of $\sqrt{s}=10$ TeV muon-antimuon collisions. The detector features a central tracking system, electromagnetic and hadronic calorimeters, and dedicated muon detectors. This paper outlines the main design elements of each subdetector, with an emphasis on the effects of machine-induced backgrounds and the reconstruction strategies employed for key physics objects. Performance results for electrons, photons, muons, and jets are reported, and studies of jet flavour identification are discussed.

hep-ex↗

arXiv2025

Feasibility study of true muonium observation with the existing Belle-II dataset

True muonium ($\mu^+\mu^-$) is one of the cleanest bound states, being composed only of leptons, along with true tauonium and positronium. Unlike the latter, true muonium and true tauonium have not been observed so far. This article shows that the spin-0 state of true muonium (para-TM), decaying into two photons, can be observed at a discovery level of significance in the dataset already collected by the Belle-II experiment at the $\Upsilon (4S)$ peak, with certain assumptions on systematic uncertainties. Para-TM is produced via photon-photon fusion, and its observation is based on the detection of the photon pair resulting from its decay, on top of the continuum background due predominantly to light-by-light scattering. Trigger, acceptance and isolation cuts, along with calorimeter resolution and reconstruction efficiency, are taken into account during the Monte Carlo simulation of both signal and background. In order to separate signal and background, a machine learning method, based on extremely randomized trees, is trained on simulated events. Finally, the expected statistical significance of TM observation is evaluated, taking into account systematic uncertainties in a parametric fashion.

hep-ph↗

arXiv2024

Feasibility study of True Muonium discovery with CERN-SPS H4 positron beam

True muonium ($\mu^+\mu^-$) is one of the heaviest and smallest electromagnetic bound states not containing hadrons, and has never been observed so far. In this work it is shown that the spin-1 TM state (ortho-TM) can be observed at a discovery level of significance in three months at the CERN SPS North-Area H4A beam line, using 43.7 GeV secondary positrons. In this way, by impinging the positrons on multiple thin low-Z targets, ortho-TM, which decays predominantly to $e^+e^-$, can be produced from $e^+e^- \to TM$ interactions on resonance ($\sqrt{s} \sim 2m_{\mu}$).

hep-ex↗

arXiv2024

The Mu2e crystal and SiPM calorimeter: construction status

The Mu2e experiment at Fermilab searches for the neutrino-less conversion of a negative muon into an electron, with a distinctive signature of a mono-energetic electron with energy of 104.967 MeV. The calorimeter is made of two disks of pure CsI crystals, each read out by two custom large area UV-extended SiPMs. It plays a fundamental role in providing excellent particle identification capabilities and an online trigger filter while improving the track reconstruction, requiring better than 10% energy and 500 ps timing resolutions for 100 MeV electrons. In this paper, we present the status of construction and the Quality Control (QC) performed on the produced crystals and photosensors, the development of the rad-hard electronics, and the most important results of the irradiation tests. Construction of the mechanics is also reported. Status and plans for the calorimeter assembly and its first commissioning are described.

physics.ins-det↗

arXiv2023

True muonium resonant production at $e^+e^-$ colliders with standard crossing angle

True muonium ($\mu^+\mu^-$) is the heaviest and smallest bound state not involving quantum chromodynamics, after true tauonium ($\tau^+\tau^-$) and mu-tauonium ($\mu^\pm\tau^\mp$). Unlike atoms containing $\tau$ particles, the muon lifetime is long enough to allow observation of true muonium (TM) decays and transitions. One of the proposed methods to observe the spin 1 fundamental state of TM, which has the smallest lifetime among TM spin 1 states, was to build an $e^+e^-$ collider with a large crossing angle ($\theta \sim 30^\circ$) in order to provide TM with a large boost and detect its decay vertex in $e^+ e^-$. The following paper will instead show that TM excited states ($n\geq2$) can be observed in relatively large quantities ($\mathcal{O}$(10)/month) at a feasible $e^+e^-$ collider with standard crossing angles, after setting their center-of-mass energy to the TM mass ($\sim2m_{\mu}=211.4$ MeV).

hep-ph↗