Study of a high intensity positron source based on oriented crystals

Positron sources are a key element for present and future lepton colliders, such as FCC-ee and ILC, which impose stringent requirements on electron and positron beams: they must have high intensity and low emittance in order to achieve high luminosity. The conventional method for making a positron source is to use a tungsten target hit by a high energy primary electron beam, generating photons by Bremsstrahlung that subsequently convert to e+e− pairs. However, the high thermal load and high energy density deposited in the target limits the intensity achievable with this technology. A possible way to overcome these limitations is to exploit the radiation processes that occur when charged particles pass through oriented crystals. A concrete proposal for an intense positron source with parameters of interest to FCC-ee based on this method has been advanced in the e+BOOST project. In this work, the proposal will be described in detail together with simulation results based on Geant4

Detector IDEA (Innovative Detector for Electron-positron Accelerators) designed for future accelerators e+e−

The Innovative Detector for Electron-positron Accelerators (IDEA) is designed for future e+e− colliders like the FCC-ee. This detector leverages advanced technologies to achieve high precision in measuring Standard Model particles. This paper provides an overview of the FCC-ee’s capabilities at various center-of mass energies and details the IDEA detector’s design and features, highlighting its potential for groundbreaking discoveries in high-energy physics

In-medium effects in ϕ-meson production in heavy ion collisions from subthreshold to relativistic energies

We investigate the hidden strange φ meson production in heavy-ion collisions from subthreshold (Ekin ∼ 1AGeV) to relativistic (Ekin ∼ 21ATeV) energies as well as its coupling to the open strange mesons (kaons, antikaons) and their productions. Our study is based on the off-shell microscopic Parton-Hadron-String Dynamics (PHSD) transport approach. Implementing novel meson-baryon and meson-hyperon production channels for φ mesons, calculated within a T-matrix coupled channel approach based on the extended SU(6) chiral effective Lagrangian model, along with the collisional broadening of the φ-meson in-medium spectral function, we find a substantial enhancement of φ meson production in heavy-ion collisions, especially at sub- and near-thresholds. This allows to describe the experimentally observed strong enhancement of the φ/K− ratio at low energies without including hypothetical decays of heavy baryonic resonances to φ as in alternative approaches

Stato dell'Unione: Quali prospettive per un mondo migliore?

Il 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

Quantifying neutron-proton equilibration using molecular dynamics codes

Previous studies have quantified neutron-proton equilibration experimentally in dynamically deformed nuclei in heavy ion collisions (Jedele A. et al., Phys. Rev. Lett., 118 (2017) 062501; Rodriguez Manso A. et al., Phys. Rev. C, 95 (2017) 044604). The results showed the composition of the two heaviest fragments from the excited projectile-like fragment evolve exponentially with respect to its angle of rotation. Simulations using constrained molecular dynamics and anti-symmetrized molecular dynamics were utilized for different slope parameterizations to compare the experimental results. The results indicate better agreement with a softer interaction

Dynamics of cluster production in Xe+Sn collisions between 65 and 150 MeV/nucleon

Characterization of the participant zone (PZ) in the 129,124Xe+112,124Sn reaction at the energy range 65–150 MeV/nucleon reveals copious cluster production. A detailed study of the chemical composition as a function of the impact parameter shows that heavier clusters (6He, 6−8Li, 7−10Be,...)are most likely produced for central collisions. A hierarchy of the cluster production with the neutron richness of the total system is observed, suggesting a full mixing of the projectile and target in the PZ. An estimate of the maximum density in central collisions has been deduced from the kinetic energy of the emitted fragments, reaching almost 2 times the normal density (2ρ0) at 150 MeV/nucleon

Evolution of an effective Hubble constant in ff modified gravity

We investigate the Hubble constant tension within f(R) modified gravity in the Jordan frame, focusing on its application to the dynamics of an isotropic Universe. A scalar field, non-minimally coupled to the metric, provides an extra degree of freedom compared to General Relativity. We analyze the impact of such a scalar field on the cosmic expansion, leading to an effective Hubble constant Heff 0 (z), dependent on redshift z. We show that our f(R) model might mimic dark energy and provide an apparent variation of the Hubble constant. Our results align with recent cosmological data analysis in redshift bins, indicating a decreasing trend of the Hubble constant. The redshift dependence of Heff 0 (z) might potentially reconcile measurements of the Hubble constant from probes at different redshifts

A novel optical imaging system for the LAr detector GRAIN

The Deep Underground Neutrino Experiment will be a next generation neutrino oscillation long-baseline accelerator experiment exploiting Liquid Argon Time Projection Chambers with the aim of determining the still unknown neutrino oscillation parameters, observing proton decay and detecting supernova neutrinos. GRAIN (GRanular Argon for Interactions of Neutrinos) is the Liquid Argon detector of SAND (System for on-Axis Neutrino Detection), which is part of the DUNE Near Detector complex. SAND is expected to significantly decrease uncertainties related to neutrino flux and cross-sections, to monitor the beam stability, and to investigate various neutrino interactions models, constraining at the same time nuclear effects. GRAIN will serve as a Liquid Argon target for detecting neutrinos and low-energy particles, ensuring cross-calibration with the other Near Detector components. The novel GRAIN system is designed to reconstruct charged particle tracks using the detection of LAr scintillation light by an optical system optimised for the Vacuum Ultra-Violet. Two options for the optical system are currently being studied: coded aperture masks and optical lenses, both coupled to a SiPM matrix. The readout, which is currently under development, will be performed through a 1024-channel ASIC, able to read 32x32 SiPM matrices in LAr

Searching for light Dark Matter with NA64-e and POKER at CERN

Light dark matter (LDM) is a theoretically well motivated model providing an attractive explanation for the observed relic dark matter density. In this scenario, LDM is composed of sub-GeV particles, feebly interacting with ordinary matter via a new force. NA64-e is a missing energy experiment at CERN Super Proton Synchrotron (SPS), aiming to produce LDM particles using the 100-GeV SPS electron beam impinging on a thick, active target (electromagnetic calorimeter). Each impinging electron is tagged and its momentum is measured; the LDM production signature consists in a large difference between the initial electron energy and the measured energy deposition in the calorimeter. In last years, NA64-e collected data also with a positron beam, in order to exploit the e+−e− resonant annihilation process for the Aproduction, synergistically with the POKER (POsitron resonant annihilation into darK mattER) project. POKER is an ERC-funded effort, whose aim is to perform a preliminary missing-energy measurement with a multi-energy positron beam. POKER will exploit the NA64−e experimental setup, using a new high-resolution PbWO4 electromagnetic calorimeter as an active target. This document presents the status of the NA64-e experiment, its latest results and future prospects. Advances in the POKER program are reported, with a focus on the analysis of the latest positron data-takings performed during 2022 and 2023

20th ISEC - International Stirling Engine Conference: Neaples 25th-27th June 2024

The meeting encompasses and welcomes both basic and applied research, as well as contributions on technical and economical aspects on Stirling Engine adoption for renewable energy generation, refrigeration and specialized applications as adoption in space and extra-terrestrial ones