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Natura e ricerca: pratiche, narrazioni e visioni
Full text linkSi può voler bene a un lago che si studia? È possibile dedicarsi alla ricerca scientifica sui cetacei e, al tempo stesso, battersi attivamente per la loro protezione? Che ruolo hanno la meraviglia e il mistero nella ricerca sugli orsi? Sono queste alcune delle domande all’origine di “Natura e ricerca: pratiche, narrazioni e visioni”, secondo numero della collana editoriale Scienziatinaffanno? Il volume raccoglie le voci di ricercatrici e ricercatori provenienti da varie discipline, principalmente in ambito ecologico, che raccontano i molteplici modi di stare in relazione con il vivente nelle pratiche di ricerca, di educazione e di comunicazione
Search for collective behavior in very small and in large systems
Full text linkSigns of collectivity were initially seen in AuAu collisions at RHIC through measurements of two-particle long-range correlations in (pseudorapidity) Δη, within small (azimuthal) Δφ angles. In 2010 a similar ridge-like behavior was observed in high multiplicity pp collisions at 7 TeV at the LHC by CMS, extended afterwards also to pPb and PbPb collisions. In addition, several orders of anisotropic flow Fourier harmonics were measured later, showing a collective behavior compatible with hydrodynamic expectations. This posed the question about the threshold on system size and conditions for collectivity to arise. Signs of possible collectivity were then searched for in e+e− and ep at LEP, in γpandγAattheLHC,but usually limited to lower multiplicity ranges (< 40 particles per event), where collectivity was not expected, with negative results. However, more recent investigations with higher multiplicity data collected with the ALEPH experiment at LEP II energies seem to indicate a different picture. This talk shows recent results from the CMS Collaboration for two extreme sizes of colliding systems. On the lowest side, the results focus on the search for a ridge-like behavior in high multiplicity pp collisions
at 13 TeV inside a single jet, originated from a highly energetic parton. On the other extreme, PbPb collisions at
√ sNN = 5.02 TeV are employed to probe deeper into the quark-gluon plasma formed in such collisions, by measuring the speed of sound and the effective temperature in this medium
Forward-backward correlations with the Σ quantity in the wounded-constituent framework at LHC energies
Full text linkThis paper discusses the forward-backward (FB) correlations studied with the Σ quantity, which, defined as a strongly intensive quantity, is expected to be independent of system volume and volume fluctuations. The study compares the Σ observable calculated in the wounded nucleon model (WNM) and wounded quark model (WQM) with the most commonly used heavy-ion physics Monte Carlo generators and finds that the wounded-constituent approach performs better in describing experimental data. However, in this framework, the quantity Σ is no longer strongly intensive. The findings also show that Σ can be used to determine the fragmentation function of a wounded constituent with a novel method that is also
applicable in symmetric nucleus-nucleus collisions
Stato dell'Unione: Quali prospettive per un mondo migliore?
Full text linkIl volume “Stato dell’Unione: quali prospettive per un mondo migliore?”, con cui prende avvio la collana Finestre sull’Europa, è il risultato di una progettualità di formazione condivisa dalla rete dei Centri di documentazione europea (CDE) italiani, in collaborazione con la Rappresentanza
in Italia della Commissione europea, avviata nel 2023 sui
temi prioritari degli ultimi discorsi annuali sullo Stato dell’Unione1 presentati dalla Presidente della Commissione europea dinanzi al Parlamento europeo. A partire dalle relazioni sui risultati conseguiti durante l’ultimo anno e dalle priorità per l’anno successivo, il gruppo di lavoro
formazione dei CDE2 ha realizzato da febbraio a dicembre 2023 una rassegna di diciassette incontri on-line, indirizzati a un pubblico non solo accademico, sulle priorità politiche della Commissione europea e sulle relative fonti documentali
The OSCAR correlator for low energy nuclear reactions and heavy-ion collisions
Full text linkThe OSCAR array (hOdoscope of Silicons for Correlations and
Analysis of Reactions) is a modular detector designed to perform two- and multi-particle correlation measurements in heavy-ion collisions and direct nuclear reactions at low beam energies. The main features of the OSCAR detector will be presented in this manuscript, including its present and future scientific programs. Correlation measurements with OSCAR allow to study the decay of resonances produced during
nuclear reactions, providing information about the structure of unbound particle states in both stable and exotic light nuclei. As an example, the reconstruction of the Hoyle state in 12Cvia3-α particle correlations and invariant mass spectroscopy is shown. Possible applications on Femtoscopy studies of low energy heavy-ion collisions are also discussed
Isospin transport phenomena in heavy ion collisions at Fermi energies: An overview on the most recent results from the first INDRA-FAZIA experiment
Full text linkThecoupled INDRA-FAZIA apparatus is operating in GANIL since
2019, when its first experiment has been carried out. In this experiment, the four reactions 58,64Ni+58,64Ni at 32 and 52MeV/nucleon have been investigated in order to highlight the isospin transport effects on the neutron content of light and heavy fragments, particularly those belonging to the QP phase space which are collected by FAZIA. Here, we give an overview of the characteristics and performances of the coupled apparatus, as well as a summary of the most recent results and observations on this first rich dataset
Nuclear EoS with finite range interaction and the Constrained Dynamics
Full text linkThe effects of the many-body correlations with respect to a MF description characterizing the Constrained Molecular Dynamics are discussed in the case of finite and zero range effective microscopic interactions. In particular, for the system 64Ni+48Ca fusion-fission cross-sections, IMF production and transversal flow have been evaluated in the framework of the CoMD model at different incident energies. The results obtained significantly depend on whether or not the effects of the above-mentioned correlations are taken into account in the corresponding EoS
A crystallographic method to investigate the presence of cluster states in 12C ground state
Full text linkThis work explores the investigation of medium-energy angular distribution literature data for p + 12C elastic scattering. The goal is to highlight the possible existence of α-cluster structures in the ground state of the carbon nucleus; this matter is approached via Coupled-Channel (CC) calculations, which describe the 12C nucleus through a classic spheroidal-like structure, along with a further
contribution, which explicitly takes into account the possible existence of a triangular α-cluster structure for the nucleus, treated similarly to the X-ray diffraction by molecules. The results point towards a rather small cluster component in the ground state of the carbon nucleus: an upper limit of ≃ 1% is shown with a 99.75% confidence level and an inter-cluster distance of ≃ 3.9fm, compared, in the end, with various theoretical predictions reported in the literature
HERD: An innovative detector for new energy horizons in direct detection of cosmic rays
Full text linkThe HERD (High Energy cosmic-Radiation Detection facility)
experiment is a future experiment for the direct detection of cosmic rays, that will be installed on the Chinese space station in 2027. It is based on a calorimeter with an innovative geometry: it is indeed composed of about 7500 LYSO cubic scintillating crystals assembled in a spheroidal shape. Thanks to this specific geometry and to the equipment of sub-detectors on five sides around the calorimeter, HERD
will be capable to detect particles entering from five sides. This will lead to an increment in the geometric factor of more than one order of magnitude compared to the current in-orbit calorimetric experiments. Thanks to its enormous geometric factor HERD will extend cosmic-ray direct measurements more than one order of magnitude in energy. Indeed, it will directly detect for the first time the proton and helium knee. In addition, it will measure electron+positron flux up to tens of TeV looking for local sources of high energy leptons and for indirect signals of dark matter. Finally, HERD will also be a gamma-ray observatory. It is designed to be a new instrument for multi-messenger astronomy, study cosmic-ray acceleration
sources and look for indirect signals of dark matter. In this article we will introduce the HERD experiment with its scientific objectives and its detector
Development of a pattern-matching algorithm for the L0Muon Barrel Trigger for the muon spectrometer of the ATLAS experiment
Full text linkThe ATLAS Level-0 Muon trigger for the Phase-2 upgrade will use powerful Field-Programmable Gate Arrays (FPGAs) to perform fast trigger algorithms. In particular, the Barrel Sector Logic board will receive data from the RPC detectors and the Tile Calorimeter and provide muon candidates within a latency of a few hundred nanoseconds. Different approaches, such as geometrical methods, neural networks, and pattern matching, can be used to implement the trigger algorithms in the FPGA firmware. We discuss the development and optimization of a pattern-matching algorithm and present the preliminary results of our study