This White Paper aims at highlighting the important benefits in the science reach of the EIC. High luminosity operation is generally desirable, as it enables producing and harvesting scientific ...results in a shorter time period. It becomes crucial for programs that would require many months or even years of operation at lower luminosity.
Tomographic image of the proton Dupré, R.; Guidal, M.; Vanderhaeghen, M.
Physical review. D,
01/2017, Volume:
95, Issue:
1
Journal Article
Peer reviewed
Open access
We have carried out a phenomenological analysis of the latest deep virtual Compton scattering experimental data based on the generalized parton distribution formalism. This allows us to extract the ...dependence of the spatial size of the proton on the quark’s longitudinal momentum. This results in the first continuous two-dimensional momentum-space image and tomography of the proton based on experimental data.
Electron-Ion Collider: The next QCD frontier Accardi, A.; Albacete, J. L.; Anselmino, M. ...
The European physical journal. A, Hadrons and nuclei,
2016/9, Volume:
52, Issue:
9
Journal Article
Peer reviewed
Open access
.
This White Paper presents the science case of an Electron-Ion Collider (EIC), focused on the structure and interactions of gluon-dominated matter, with the intent to articulate it to the broader ...nuclear science community. It was commissioned by the managements of Brookhaven National Laboratory (BNL) and Thomas Jefferson National Accelerator Facility (JLab) with the objective of presenting a summary of scientific opportunities and goals of the EIC as a follow-up to the 2007 NSAC Long Range plan. This document is a culmination of a community-wide effort in nuclear science following a series of workshops on EIC physics over the past decades and, in particular, the focused ten-week program on “Gluons and quark sea at high energies” at the Institute for Nuclear Theory in Fall 2010. It contains a brief description of a few golden physics measurements along with accelerator and detector concepts required to achieve them. It has been benefited profoundly from inputs by the users’ communities of BNL and JLab. This White Paper offers the promise to propel the QCD science program in the US, established with the CEBAF accelerator at JLab and the RHIC collider at BNL, to the next QCD frontier.
The feedback mechanism presented in the paper published by Dwyer (2003) is examined in the context of runaway breakdown and thunderstorm electrical conditions. A detailed comparison between previous ...kinetic and Monte Carlo simulations performed by the authors and others and those of Dwyer are presented. The role of positrons and bremsstrahlung photons in contributing to the runaway avalanche rate is discussed. An alternative and simplified treatment of the feedback mechanism is presented. Our preliminary results are in basic agreement with Dwyer and indicate that positron feedback is more important. In addition, we find that there is a temporal ‘stepping’ effect associated with the feedback process and that this effect could also lead to a spatial stepping reminiscent of stepped leaders.
Carbon wire chamber at sub-atmospheric pressure Charles, G.; Audouin, L.; Bettane, J. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2017, Volume:
855
Journal Article
Peer reviewed
Present in many experiments, wire and drift chambers have been used in a large variety of shapes and configurations during the last decades. Nevertheless, their readout elements has not evolved much: ...tungsten, sometimes gold-plated or aluminum, wires. By taking advantage of the developments in the manufacture of conducting carbon fiber, we could obtain interesting improvements for wire detectors. In this article, we present recent tests and simulations using carbon fibers to readout signal in place of traditional tungsten wires. Unlike metallic wires, their low weight guaranties a reduced quantity of material in the active area.
The HPS electromagnetic calorimeter Balossino, I.; Baltzell, N.; Battaglieri, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2017, Volume:
854, Issue:
C
Journal Article
Peer reviewed
Open access
The Heavy Photon Search experiment (HPS) is searching for a new gauge boson, the so-called “heavy photon.” Through its kinetic mixing with the Standard Model photon, this particle could decay into an ...electron-positron pair. It would then be detectable as a narrow peak in the invariant mass spectrum of such pairs, or, depending on its lifetime, by a decay downstream of the production target. The HPS experiment is installed in Hall-B of Jefferson Lab. This article presents the design and performance of one of the two detectors of the experiment, the electromagnetic calorimeter, during the runs performed in 2015–2016. The calorimeter's main purpose is to provide a fast trigger and reduce the copious background from electromagnetic processes through matching with a tracking detector. The detector is a homogeneous calorimeter, made of 442 lead-tungstate (PbWO4) scintillating crystals, each read out by an avalanche photodiode coupled to a custom trans-impedance amplifier.
Risk assessment for RGBD scans in real time Dupre, R.; Argyriou, V.; Greenhill, D.
2016 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP),
03/2016
Conference Proceeding, Journal Article
Open access
In this paper we address the notion of risk assessment of three dimensional scenes. Furthermore through the use of local feature recognition techniques and machine learning we perform this analysis ...on real time point cloud recordings. We provide a definition of risk and potential hazards that incorporates different elements but mainly focuses on intrinsic risk related properties of an object (e.g sharpness). A 3D Voxel HOG descriptor is utilised that aims to classify and recognise the presence of hazardous characteristics and features of objects present in a given scene. Additionally we utilise and extend the 3D Risk Scenes Dataset (3DRS) designed for risk evaluation in scene analysis. The effectiveness of our method is tested on captured point cloud sequences containing hazardous and non hazardous data with a high degree of accuracy across all tested data.
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