Strong Interaction Physics at the Luminosity Frontier with 22 GeV Electrons at Jefferson Lab

This document presents the initial scientific case for upgrading the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab (JLab) to 22 GeV. It is the result of a community effort, incorporating insights from a series of workshops conducted between March 2022 and April 2023. With a track record of over 25 years in delivering the world's most intense and precise multi-GeV electron beams, CEBAF's potential for a higher energy upgrade presents a unique opportunity for an innovative nuclear physics program, which seamlessly integrates a rich historical background with a promising future. The proposed physics program encompass a diverse range of investigations centered around the nonperturbative dynamics inherent in hadron structure and the exploration of strongly interacting systems. It builds upon the exceptional capabilities of CEBAF in high-luminosity operations, the availability of existing or planned Hall equipment, and recent advancements in accelerator technology. The proposed program cover various scientific topics, including Hadron Spectroscopy, Partonic Structure and Spin, Hadronization and Transverse Momentum, Spatial Structure, Mechanical Properties, Form Factors and Emergent Hadron Mass, Hadron-Quark Transition, and Nuclear Dynamics at Extreme Conditions, as well as QCD Confinement and Fundamental Symmetries. Each topic highlights the key measurements achievable at a 22 GeV CEBAF accelerator. Furthermore, this document outlines the significant physics outcomes and unique aspects of these programs that distinguish them from other existing or planned facilities. In summary, this document provides an exciting rationale for the energy upgrade of CEBAF to 22 GeV, outlining the transformative scientific potential that lies within reach, and the remarkable opportunities it offers for advancing our understanding of hadron physics and related fundamental phenomena.Comment: Updates to the list of authors; Preprint number changed from theory to experiment; Updates to sections 4 and 6, including additional figure

Lattice QCD extraction of the ηc\eta_{c}-meson tt-dependent parton distribution function

International audienceThe formalism of short-distance factorization, conveyed through the pseudo-distribution approach, connects space-like and light-cone correlators and thus allows for the extraction in lattice QCD of a number of parton distributions. We compute the $t$-dependent parton distribution function of valence quarks in a $\eta_{c}$-meson. After reviewing the main ideas behind the pseudo-distribution formalism, and relying on the analytic structure of Ioffe-time distributions, we come up with a proposal for a model-independent extraction of $t$-dependent parton distribution functions. We present results for the $\eta_{c}$-meson Ioffe time valence $t$-dependent parton distribution function at a renormalization scale of $3~\textrm{GeV}$

Lattice QCD extraction of the ηc\eta_{c}-meson tt-dependent parton distribution function

International audienceThe formalism of short-distance factorization, conveyed through the pseudo-distribution approach, connects space-like and light-cone correlators and thus allows for the extraction in lattice QCD of a number of parton distributions. We compute the $t$-dependent parton distribution function of valence quarks in a $\eta_{c}$-meson. After reviewing the main ideas behind the pseudo-distribution formalism, and relying on the analytic structure of Ioffe-time distributions, we come up with a proposal for a model-independent extraction of $t$-dependent parton distribution functions. We present results for the $\eta_{c}$-meson Ioffe time valence $t$-dependent parton distribution function at a renormalization scale of $3~\textrm{GeV}$

Microstructure and properties of steel-aluminum Cold Metal Transfer joints

International audience1 mm thick sheets of 6016-T4 aluminum alloy and Zn coated steel were joined in a lap configuration using the Cold Metal Transfer (CMT) welding process with an Al-5Si filler metal and different powers and welding speeds. The formed reaction layer ensuring the bonding between the aluminum melting zone and the steel sheet doesn’t exceed 10 μm in thickness, and is composed of an iron-rich Fe-Al intermetallic on the steel side, and a Fe-Al-Si ternary compound on the aluminum weld side. The current waveform producing the lowest mean electrical power gives the most regular welds with lowest porosity in the melting zone. By optimizing the welding speed with this current waveform, the strength of the assembly under monotonic shear-tensile loading can reach 70% of that of the aluminum base material, and its lifetime under cyclic tensile loading exceeds 104 cycles for a maximal linear loading of 98 N mm−1 and 107 cycles for a maximal linear loading of 42 N mm−1

Low voltage switching cell for high density and modular 3D power module with integrated air-cooling

International audienceThis paper presents the TAPIR (compacT and modulAr Power modules with IntegRated cooling) power module technology based on dual side air-cooling, the heat sinks acting as electrodes of power devices. Used with a large number of power semiconductor devices, this technology improves the cooling performances while maintaining low stray inductances in switching cells. It is therefore suited to high-speed devices and allows increasing the density of power converters. A low-voltage switching cell is designed and electrically and thermally tested. The weight of the semiconductor and thermal management parts of a three-phase inverter made with TAPIR technology is estimated and compared with more classical packaging approaches

Low voltage switching cell for high density and modular 3D power module with integrated air-cooling

International audienceThis paper presents the TAPIR (compacT and modulAr Power modules with IntegRated cooling) power module technology based on dual side air-cooling, the heat sinks acting as electrodes of power devices. Used with a large number of power semiconductor devices, this technology improves the cooling performances while maintaining low stray inductances in switching cells. It is therefore suited to high-speed devices and allows increasing the density of power converters. A low-voltage switching cell is designed and electrically and thermally tested. The weight of the semiconductor and thermal management parts of a three-phase inverter made with TAPIR technology is estimated and compared with more classical packaging approaches