arXiv subjects

G. Mandaglio

Publications and source records attributed to G. Mandaglio.

At least 37 records · Page 2Linked to original sources

arXiv2020

A simulation tool for MRPC telescopes of the EEE project

The Extreme Energy Events (EEE) Project is mainly devoted to the study of the secondary cosmic ray radiation by using muon tracker telescopes made of three Multigap Resistive Plate Chambers (MRPC) each. The experiment consists of a telescope network mainly distributed across Italy, hosted in different building structures pertaining to high schools, universities and research centers. Therefore, the possibility to take into account the effects of these structures on collected data is important for the large physics programme of the project. A simulation tool, based on GEANT4 and using GEMC framework, has been implemented to take into account the muon interaction with EEE telescopes and to estimate the effects on data of the structures surrounding the experimental apparata.A dedicated event generator producing realistic muon distributions, detailed geometry and microscopic behavior of MRPCs have been included to produce experimental-like data. The comparison between simulated and experimental data, and the estimation of detector resolutions is here presented and discussed.

physics.ins-det↗

arXiv2020

Characteristics and performance of the Multigap Resistive Plate Chambers of the EEE experiment

The Extreme Energy Events (EEE) experiment, dedicated to the study of secondary cosmic rays, is arguably the largest detector system in the world implemented by Multigap Resistive Plate Chambers. The EEE network consists of 60 telescopes distributed over all the Italian territory; each telescope is made of three MRPCs and allows to reconstruct the trajectory of cosmic muons with high efficiency and optimal angular resolution. A distinctive feature of the EEE network is that almost all telescopes are housed in High Schools and managed by groups of students and teachers, who previously took care of their construction at CERN. This peculiarity is a big plus for the experiment, which combines the scientific relevance of its objectives with effective outreach activities. The unconventional location of the detectors, mainly in standard classrooms of school buildings, with heterogeneous maintenance conditions and without controlled temperature and dedicated power lines, is a unique test field to verify the robustness, the low aging characteristics and the long-lasting performance of MRPC technology for particle monitoring and timing. Finally, it is reported how the spatial resolution, efficiency, tracking capability and stability of these chambers behave in time.

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arXiv2020

MRPC Telescope Simulation for the Extreme Energy Events Experiment

A simulation tool based on GEMC framework to describe the MRPC telescope of the Extreme Energy Events (EEE) Project is presented. The EEE experiment is mainly devoted to the study of the secondary cosmic muons by using MRPC telescope distributed in high schools and research centres in Italy and at CERN. This takes into account the muon interactions with EEE telescopes and the structures surrounding the experimental apparata; it consists of a dedicated event generator producing realistic muon distribution and a detailed geometry description of the detector. Microscopic behaviour of MRPCs has been included to produce experimental-like data. A method to estimate the chamber effciency directly from data has been implemented and tested by comparing the experimental and simulated polar angle distribution of muons.

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arXiv2020

Measurement of the branching fraction for the decay $K_S \to πμν$ with the KLOE detector

Based on a sample of 300 million $K_S$ mesons produced in $ϕ\to K_L K_S$ decays recorded by the KLOE experiment at the DA$Φ$NE $e^+e^-$ collider we have measured the branching fraction for the decay $K_S \to πμν$. The $K_S$ mesons are identified by the interaction of $K_L$ mesons in the detector. The $K_S \to πμν$ decays are selected by a boosted decision tree built with kinematic variables and by a time-of-flight measurement. Signal efficiencies are evaluated with data control samples of $K_L \to πμν$ decays. A fit to the reconstructed muon mass distribution finds $7223 \pm 180$ signal events. Normalising to the $K_S \to π^+ π^-$ decay events the result for the branching fraction is $\mathcal{B}(K_S \to πμν) = (4.56 \pm 0.11_{\rm stat} \pm 0.17_{\rm syst})\times10^{-4}$.

hep-ex↗

arXiv2020

The BGOOD experimental setup at ELSA

The BGOOD experiment at the ELSA facility in Bonn has been commissioned within the framework of an international collaboration. The experiment pursues a systematic investigation of non-strange and strange meson photoproduction, in particular $t$-channel processes at low momentum transfer. The setup uniquely combines a central almost $4π$ acceptance BGO crystal calorimeter with a large aperture forward magnetic spectrometer providing excellent detection of both neutral and charged particles, complementary to other setups such as Crystal Barrel, Crystal Ball, LEPS and CLAS.

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arXiv2019

New Eco-gas mixtures for the Extreme Energy Events MRPCs: results and plans

The Extreme Energy Events observatory is an extended muon telescope array, covering more than 10 degrees both in latitude and longitude. Its 59 muon telescopes are equipped with tracking detectors based on Multigap Resistive Plate Chamber technology with time resolution of the order of a few hundred picoseconds. The recent restrictions on greenhouse gases demand studies for new gas mixtures in compliance with the relative requirements. Tetrafluoropropene is one of the candidates for tetrafluoroethane substitution, since it is characterized by a Global Warming Power around 300 times lower than the gas mixtures used up to now. Several mixtures have been tested, measuring efficiency curves, charge distributions, streamer fractions and time resolutions. Results are presented for the whole set of mixtures and operating conditions, %. A set of tests on a real EEE telescope, with cosmic muons, are being performed at the CERN-01 EEE telescope. The tests are focusing on identifying a mixture with good performance at the low rates typical of an EEE telescope.

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arXiv2019

K$^-$ multi-nucleon absorption cross sections and branching ratios in $Λ$p and $Σ^0$p final states

The determination of low-energy cross sections and branching ratios of the K$^-$ multi-nucleon absorption processes in $Λ$p and $Σ^0$p final states performed by the AMADEUS collaboration is presented. Low momentum K$^-$ ($p_\mathrm{K} \simeq$ 127 MeV/c) produced at the DA$Φ$NE collider are impinged on a Carbon target within the KLOE detector and the two and three nucleon absorption processes are disentangled by comparing the experimental data to phenomenological calculations. The $Λ$p spectra are interpreted in terms of K$^-$ multi-nucleon absorption processes; the possible contribution of a K$^-$pp bound state is demonstrated to overlap with the two nucleon capture process, its absolute yield thus resulting indistinguishable.

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arXiv2018

The effect of the neutron and proton numbers ratio in colliding nuclei at formation of the evaporation residues in the $^{34}$S+$^{208}$Pb and $^{36}$S+$^{206}$Pb reactions

The difference between observed cross sections of the evaporation residues (ER) of the $^{34}$S+$^{208}$Pb and $^{36}$S+$^{206}$Pb reactions formed in the 2n and 3n channels has been explained by two reasons related with the entrance channel characteristics of these reactions. The first reason is that the capture cross section of the latter reaction is larger than the one of the $^{34}$S+$^{208}$Pb reaction since the nucleus-nucleus potential is more attractive in the $^{36}$S+$^{206}$Pb reaction due to two more neutrons in isotope $^{36}$S. The second reason is the difference in the heights of the intrinsic fusion barrier $B^*_{\rm fus}$ appearing on the fusion trajectory by nucleon transfer between nuclei of the DNS formed after the capture. The value of $B^*_{\rm fus}$ calculated for the $^{34}$S+$^{208}$Pb reaction is higher than the one obtained for the $^{36}$S+$^{206}$Pb reaction. This fact has been caused by the difference between the $N/Z$-ratios in the light fragments of the DNS formed during the capture in these reactions. The $N/Z$-ratio has been found by solution of the transport master equations for the proton and neutron distributions between fragments of the DNS formed at capture with the different initial neutron numbers $N=18$ and $N=20$ for the reactions with the $^{34}$S and $^{36}$S, respectively.

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arXiv2018

Role of charged particle emission on the evaporation residue formation in the $^{82}$Se+$^{138}$Ba reaction leading to the $^{220}$Th compound nucleus

We present detailed results of a theoretical investigation on the production of evaporation residue nuclei obtained in a heavy ion reaction when charged particles (proton and $α$-particle) are also emitted with the neutron evaporation along the deexcitation cascade of the formed compound nucleus. The almost mass symmetric $^{82}$Se+$^{138}$Ba reaction has been studied since there are many experimental results on individual evaporation residue (ER) cross sections after few light particle emissions along the cascade of the $^{220}$Th compound nucleus (CN) covering the wide 12--70 MeV excitation energy range. Our specific theoretical results on the ER cross sections for the $^{82}$Se+$^{138}$Ba are in good agreement with the available experimental measurements, but our overall theoretical results concerning all possible relevant contributions of evaporation residues are several times greater than the ERs measured in experiment. The discrepancy could be due to the experimental difficulties in the identification of ER nuclei after the emission of multiple neutral and charged particles, nevertheless the analysis of ER data is very important to test the reliability of the model and to stress the importance on the investigation of ER nuclei also obtained after charged particle emissions.

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arXiv2018

Effects of entrance channels on the deexcitation properties of the same compound nucleus formed by different pairs of collision partners

The properties of deexcitation of the same $^{220}$Th compound nucleus (CN) formed by different mass (charge) asymmetric reactions are investigated. It is demonstrated that the effective fission barrier $ $ value being a function of the excitation energy $E^*_{\rm CN}$ is strongly sensitive to the various orbital angular momentum $L=\ell\hbar$ distributions of CN formed with the same excitation energy $E^*_{CN}$ by the very different entrance channels $^{16}$O+$^{204}$Pb, $^{40}$Ar+$^{180}$Hf, $^{82}$Se+$^{138}$Ba and $^{96}$Zr+$^{124}$Sn. Consequently, the competition between the fission and evaporation of light particles (neutron, proton, and $α$-particle) processes along the deexcitation cascade of CN depends on the orbital angular momentum distribution of CN. Therefore, the ratio between the evaporation residue cross sections obtained after emission of neutral and charged particles and neutrons only for the same CN with a given excitation energy $E^*_{CN}$ is sensitive to the mass (charge) asymmetry of reactants in the entrance channel.

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arXiv2018

Measurement of the charge asymmetry for the $K_S \rightarrow πe ν$ decay and test of CPT symmetry with the KLOE detector

Using 1.63 fb$^{-1}$ of integrated luminosity collected by the KLOE experiment about $7\times 10^4$ $K_S \rightarrow π^{\pm}e^{\mp}ν$ decays have been reconstructed. The measured value of the charge asymmetry for this decay is $A_S = (-4.9 \pm 5.7_{stat} \pm 2.6_{syst}) \times 10^{-3}$, which is almost twice more precise than the previous KLOE result. The combination of these two measurements gives $A_S = (-3.8 \pm 5.0_{stat} \pm 2.6_{syst}) \times 10^{-3}$ and, together with the asymmetry of the $K_L$ semileptonic decay, provides significant tests of the CPT symmetry. The obtained results are in agreement with CPT invariance.

hep-ex↗

arXiv2018

Combined limit on the production of a light gauge boson decaying into $μ^+μ^-$ and $π^+π^-$

We searched for the $μ^+μ^-$ decay of a light vector gauge boson, also known as dark photon, in the $e^+ e^- \to μ^+ μ^- γ_{\rm ISR}$ process by means of the Initial State Radiation (ISR) method. We used 1.93~fb$^{-1}$ of data collected by the KLOE experiment at the DA$Φ$NE $ϕ$-factory. No structures have been observed over the irreducible $μ^+ μ^-$ background. A 90\% CL limit on the ratio $\varepsilon^2=α^{\prime}/α$ between the dark coupling constant and the fine structure constant of $ 3\times 10^{-6}-2\times 10^{-7}$ has been set in the dark photon mass region between 519 MeV and 973 MeV. This new limit has been combined with the published result obtained investigating the hypothesis of the dark photon decaying into hadrons in $e^+ e^- \to π^+ π^- γ_{\rm ISR}$ events. The combined 90\% CL limit increases the sensitivity especially in the $ρ-ω$ interference region and excludes $\varepsilon^2$ greater than $(13-2)\times 10^{-7}$. For dark photon masses greater than 600 MeV the combined limit is lower than 8~$\times\, 10^{-7}$ resulting more stringent than present constraints from other experiments.

hep-ex↗

arXiv2018

Performance of the Multigap Resistive Plate Chambers of the Extreme Energy Events Project

The muon telescopes of the Extreme Energy Events (EEE) Project are made of three Multigap Resistive Plate Chambers (MRPC). The EEE array is composed, so far, of 59 telescopes and is organized in clusters and single telescope stations distributed all over the Italian territory. They are installed in High Schools with the aim to join research and teaching activities, by involving researchers, teachers and students in the construction, maintenance, data taking and data analysis. The unconventional working sites, mainly school buildings with non-controlled environmental parameters and heterogeneous maintenance conditions, are a unique test field for checking the robustness, the low-ageing features and the long-lasting performance of the MRPC technology for particle tracking and timing purposes. The measurements performed with the EEE array require excellent performance in terms of time and spatial resolution, efficiency, tracking capability and stability. The data from two recent coordinated data taking periods, named Run 2 and Run 3, have been used to measure these quantities and the results are described, together with a comparison with expectations and with the results from a beam test performed in 2006 at CERN.

physics.ins-det↗

arXiv2018

First results from the upgrade of the Extreme Energy Events experiment

The Extreme Energy Events (EEE) experiment is the largest system in the world completely implemented with Multigap Resistive Plate Chambers (MRPCs). Presently, it consists of a network of 59 muon telescopes, each made of 3 MRPCs, devoted to the study of secondary cosmic rays. Its stations, sometimes hundreds of kilometers apart, are synchronized at a few nanoseconds level via a clock signal delivered by the Global Positioning System. The data collected during centrally coordinated runs are sent to INFN CNAF, the largest center for scientific computing in Italy, where they are reconstructed and made available for analysis. Thanks to the on-line monitoring and data transmission, EEE operates as a single coordinated system spread over an area of about $3 \times 10^5$ km$^2$. In 2017, the EEE collaboration started an important upgrade program, aiming to extend the network with 20 additional stations, with the option to have more in the future. This implies the construction, testing and commissioning of 60 chambers, for a total detector surface of around 80 m$^2$. In this paper, aspects related to this challenging endeavor are covered, starting from the technological solutions chosen to build these state-of-the-art detectors, to the quality controls and the performance tests carried on.

physics.ins-det↗

arXiv2018

Combination of KLOE $σ\big(e^+e^-\rightarrowπ^+π^-γ(γ)\big)$ measurements and determination of $a_μ^{π^+π^-}$ in the energy range $0.10 < s < 0.95$ GeV$^2$

The three precision measurements of the cross section $σ\big(e^+e^-\rightarrowπ^+π^-γ(γ)\big)$ using initial state radiation by the KLOE collaboration provide an important input for the prediction of the hadronic contribution to the anomalous magnetic moment of the muon. These measurements are correlated for both statistical and systematic uncertainties and, therefore, the simultaneous use of these measurements requires covariance matrices that fully describe the correlations. We present the construction of these covariance matrices and use them to determine a combined KLOE measurement for $σ\big(e^+e^-\rightarrowπ^+π^-γ(γ)\big)$. We find, from this combination, a two-pion contribution to the muon magnetic anomaly in the energy range $0.10 < s < 0.95$ GeV$^2$ of $a_μ^{π^+π^-} = (489.8 \pm 1.7_{\rm stat} \pm 4.8_{\rm sys} ) \times 10^{-10}$.

hep-ex↗

arXiv2018

The Extreme Energy Events experiment: an overview of the telescopes performance

Multigap Resistive Plate Chambers (MRPC). The EEE network is composed, so far, of 53 telescopes, each made of three MRPC detectors; it is organized in clusters and single telescope stations distributed all over the Italian territory and installed in High Schools, covering an area larger than $3\times10^{5}$ km$^{2}$. The study of Extensive Air Showers (EAS), that is one of the goal of the project, requires excellent performance in terms of time and spatial resolution, efficiency, tracking capability and long term stability. The data from two recent coordinated data taking periods, named Run 2 and Run 3, have been used to measure these quantities and the results are here reported, together with a comparison with expectations and with the results from a beam test performed in 2006 at CERN.

physics.ins-det↗

arXiv2017

Uncertainties and understanding of experimental and theoretical results regarding reactions forming heavy and superheavy nuclei

Experimental and theoretical results of the $P_{\mathrm{CN}}$ fusion probability of reactants in the entrance channel and the $W_{\mathrm{sur}}$ survival probability against fission at deexcitation of the compound nucleus formed in heavy-ion collisions are discussed. The theoretical results for a set of nuclear reactions leading to formation of compound nuclei (CNs) with the charge number $Z=102\text{--}122$ reveal a strong sensitivity of $P_{\mathrm{CN}}$ to the characteristics of colliding nuclei in the entrance channel, dynamics of the reaction mechanism, and excitation energy of the system. We discuss the validity of assumptions and procedures for analysis of experimental data, and also the limits of validity of theoretical results obtained by the use of phenomenological models. The comparison of results obtained in many investigated reactions reveals serious limits of validity of the data analysis and calculation procedures.

nucl-th↗

arXiv2017

Antikaon Interactions with Nucleons and Nuclei - AMADEUS At Da$Φ$ne

The aim of AMADEUS is to provide unprecedented experimental information on K$^-$ absorption in light nuclear targets, to face major open problems in hadron nuclear physics in the strangeness sector, namely the nature of the $Λ$(1405), strongly related to the possible existence of kaonic nuclear clusters, kaons and hyperon scattering cross sections on nucleons and nuclei. These issues are fundamental for a better understanding of the non-perturbative QCD in the strangeness sector. AMADEUS step 0 deals with the analysis of the 2004-2005 KLOE collected data. The interactions of the negative kaons produced by the DA$Φ$NE collider (a unique source of monochromatic low-momentum kaons) with the materials of the KLOE detector, used as active targets, provide samples of K$^-$ absorptions on H, ${}^4$He, ${}^{9}$Be and ${}^{12}$C, both at-rest and in-flight. A second step deals with the data from the implementation in the central region of the KLOE detector of a pure graphite target, providing a high statistic sample of K$^- \, {}^{12}$C nuclear captures at rest. For the future a new setup, with various dedicated gaseous and solid targets, is under preparation.

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