H. Fonvieille
A5046750815- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- Nuclear physics research studies
- High-Energy Particle Collisions Research
- Atomic and Subatomic Physics Research
- Advanced NMR Techniques and Applications
- Particle Accelerators and Free-Electron Lasers
- Dark Matter and Cosmic Phenomena
- Nuclear Physics and Applications
- Superconducting Materials and Applications
- Atomic and Molecular Physics
- Quantum, superfluid, helium dynamics
- Radiation Detection and Scintillator Technologies
- Medical Imaging Techniques and Applications
- Particle accelerators and beam dynamics
- Particle Detector Development and Performance
- X-ray Spectroscopy and Fluorescence Analysis
- Neutrino Physics Research
- Physics of Superconductivity and Magnetism
- Electron and X-Ray Spectroscopy Techniques
- Computational Physics and Python Applications
- Advanced Chemical Physics Studies
- Crystallography and Radiation Phenomena
- Photocathodes and Microchannel Plates
- Magnetic confinement fusion research
Clermont Université
2013-2024
Centre National de la Recherche Scientifique
2014-2024
Université Clermont Auvergne
2014-2024
Laboratoire de Physique Corpusculaire
2003-2022
Institut National de Physique Nucléaire et de Physique des Particules
1995-2017
Laboratoire d'Informatique, de Modélisation et d'Optimisation des Systèmes
1997-2008
Institut Pascal
1997-2008
University of Maryland, College Park
2004
William & Mary
2002
Williams (United States)
2002
The ratio of the proton's elastic electromagnetic form factors, G(E(p))/G(M(p)), was obtained by measuring P(t) and P(l), transverse longitudinal recoil proton polarization, respectively. For e-->p-->ep-->, G(E(p))/G(M(p)) is proportional to P(t)/P(l). Simultaneous measurement P(l) in a polarimeter provides good control systematic uncertainty. results for show decrease as Q2 increases from 0.5 3.5 GeV2, indicating first time definite difference spatial distribution charge magnetization...
The ratio of the electric and magnetic form factors proton, GEp/GMp, was measured at Thomas Jefferson National Accelerator Facility (JLab) using recoil polarization technique. is directly proportional to transverse longitudinal components proton in elastic $\vec ep \to e\vec p$ reaction. new data presented this article span range 3.5 < Q2 5.6 GeV2 are well described by a linear fit. Also, QF2p/F1p reaches constant value above Q2=2 GeV2.
The spin structure function of the neutron gn1 has been determined over range 0.03<x<0.6 at an average Q2 2 (GeV/c)2 by measuring asymmetry in deep inelastic scattering polarized electrons from a 3He target energies between 19 and 26 GeV. integral is found to be F10gn1(x)dx=-0.022±0.011. Earlier reported proton results together with Bjorken sum rule predict F10gn1(x)dx=-0.059±0.019.Received 1 April 1993DOI:https://doi.org/10.1103/PhysRevLett.71.959©1993 American Physical Society
New precise results of a measurement the elastic electron-proton scattering cross section performed at Mainz Microtron MAMI are presented. About 1400 sections were measured with negative four-momentum transfers squared up to Q^2=1 (GeV/c)^2 statistical errors below 0.2%. The electric and magnetic form factors proton extracted by fits large variety factor models directly sections. show some features scale pion cloud. charge radii determined be r_E=0.879(5)(stat.)(4)(syst.)(2)(model)(4)(group)...
Measurements are reported of the proton and deuteron spin structure functions ${g}_{1}^{p}$ ${g}_{1}^{d}$ at beam energies 29.1, 16.2, 9.7 GeV, ${g}_{2}^{p}$ ${g}_{2}^{d}$ a energy 29.1 GeV. The integrals ${\ensuremath{\Gamma}}_{p}={\ensuremath{\int}}_{0}^{1}{g}_{1}^{p}{(x,Q}^{2})dx$ ${\ensuremath{\Gamma}}_{d}={\ensuremath{\int}}_{0}^{1}{g}_{1}^{d}{(x,Q}^{2})dx$ were evaluated fixed ${Q}^{2}=3(\mathrm{GeV}{/c)}^{2}$ using full data set to yield...
The ratio of the proton elastic electromagnetic form factors, ${G}_{\mathit{Ep}}/{G}_{\mathit{Mp}}$, was obtained by measuring ${P}_{t}$ and ${P}_{\ensuremath{\ell}}$, transverse longitudinal recoil polarization components, respectively, for $\stackrel{\ensuremath{\rightarrow}}{e}p\ensuremath{\rightarrow}e\stackrel{\ensuremath{\rightarrow}}{p}$reaction in four-momentum transfer squared range 0.5 to $3.5\phantom{\rule{0.3em}{0ex}}\text{GeV}{}^{2}$. In single-photon exchange approximation,...
This paper describes a precise measurement of electron scattering off the proton at momentum transfers $0.003\ensuremath{\lesssim}{Q}^{2}\ensuremath{\lesssim}1$ ${\mathrm{GeV}}^{2}$. The average point-to-point error cross sections in this experiment is $\ensuremath{\sim}0.37%$. These data are used for coherent new analysis together with all world unpolarized and polarized from very smallest to highest so far measured. extracted electric magnetic form factors provide insight into their exact...
A massive, but light, Abelian U(1) gauge boson is a well-motivated possible signature of physics beyond the standard model particle physics. In this Letter, search for signal such in electron-positron pair production at spectrometer setup A1 Collaboration Mainz Microtron described. Exclusion limits mass range 40 MeV/c2 to 300 MeV/c2, with sensitivity squared mixing parameter as little ε2=8×10−7 are presented. large fraction space has been excluded where discrepancy measured anomalous...
We report on a precision measurement of the neutron spin structure function ${g}_{1}^{n}$ using deep inelastic scattering polarized electrons by ${}^{3}\mathrm{He}$. For kinematic range $0.014<x<0.7$ and $1<{Q}^{2}<17(\mathrm{GeV}/c{)}^{2}$, we obtain $\ensuremath{\int}{0.014}^{0.7}{g}_{1}^{n}(x)dx\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\ensuremath{-}0.036\ifmmode\pm\else\textpm\fi{}0.004(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.005(\mathrm{syst})$ at an average...
We have measured the ratio $\frac{{g}_{1}^{p}}{{F}_{1}^{p}}$ over range $0.029<x<0.8$ and $1.3<{Q}^{2}<10$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{2}$ using deep-inelastic scattering of polarized electrons from ammonia. An evaluation integral $\ensuremath{\int}{0}^{1}{g}_{1}^{p}(x, {Q}^{2})\mathrm{dx}$ at fixed ${Q}^{2}=3$ yields 0.127\ifmmode\pm\else\textpm\fi{}0.004(stat)\ifmmode\pm\else\textpm\fi{}0.010(syst), in agreement with previous experiments, but well below Ellis-Jaffe sum...
The neutron longitudinal and transverse asymmetries A1n A2n have been extracted from deep inelastic scattering of polarized electrons by a He3 target at incident energies 19.42, 22.66, 25.51 GeV. measurement allows for the determination spin structure functions g1n(x, Q2) g2n(x, over range 0.03<x<0.6 an average Q2 2 (GeV/c)2. data are used evaluation Ellis-Jaffe Bjorken sum rules. function is small negative within our measurement, yielding integral ∫0.030.6g1n(x)dx=−0.028±0.006 (stat)±0.006...
We report on a high-statistics measurement of the deuteron spin structure function ${g}_{1}^{d}$ at beam energy 29 GeV in kinematic range $0.029<x<0.8$ and $1<{Q}^{2}<10$ (GeV $/c$${)}^{2}$. The integral ${\ensuremath{\gamma}}_{1}^{d}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\ensuremath{\int}{1}^{}{g}_{1}^{d}\mathrm{dx}$ evaluated fixed ${Q}^{2}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}3$ $/c$${)}^{2}$ gives...
A new exclusion limit for the electromagnetic production of a light $U(1)$ gauge boson ${\ensuremath{\gamma}}^{\ensuremath{'}}$ decaying to ${e}^{+}{e}^{\ensuremath{-}}$ was determined by A1 Collaboration at Mainz Microtron. Such bosons appear in several extensions standard model and are also discussed as candidates interaction dark matter with matter. In electron scattering from heavy nucleus, existing limits narrow state coupling were reduced nearly an order magnitude range lepton pair...
Precise measurements of the proton electromagnetic form factor ratio $R = \mu_p G_E^p/G_M^p$ using polarization transfer method at Jefferson Lab have revolutionized understanding nucleon structure by revealing strong decrease $R$ with momentum $Q^2$ for $Q^2 \gtrsim 1$ GeV$^2$, in disagreement previous extractions from cross section measurements. In particular, results exposed limits applicability one-photon-exchange approximation and highlighted role quark orbital angular structure. The...
We perform a systematic study of the α-particle excitation from its ground state 0_{1}^{+} to 0_{2}^{+} resonance. The so-called monopole transition form factor is investigated via an electron scattering experiment in broad Q^{2} range (from 0.5 5.0 fm^{-2}). precision new data dramatically supersedes that older sets data, each covering only portion range. allow determination two coefficients low-momentum expansion, leading puzzle. By confronting state-of-the-art theoretical calculations, we...
New measurements are reported on the deuteron spin structure function g_1^d. These results were obtained from deep inelastic scattering of 48.3 GeV electrons polarized deuterons in kinematic range 0.01 < x 0.9 and 1 Q^2 40 (GeV/c)^2. first high dose electron data using lithium deuteride (6Li2H) as target material. Extrapolations performed to obtain moments g_1^d, including Gamma_1^d, net quark polarization Delta Sigma.
We have measured proton and deuteron virtual photon-nucleon asymmetries ${A}_{2}^{p}$ ${A}_{2}^{d}$ structure functions ${g}_{2}^{p}$ ${g}_{2}^{d}$ over the range $0.03<x<0.8$ $1.3<{Q}^{2}<10(\mathrm{GeV}/c{)}^{2}$ by inelastically scattering polarized electrons off ammonia targets. Results for ${A}_{2}$ are significantly smaller than positivity limit $\sqrt{R}$ both Within experimental precision ${g}_{2}$ data well described twist-2 contribution, ${g}_{2}^{\mathrm{WW}}$. Twist-3 matrix...
This paper was published online on 20 May 2005 without several of the authors’ corrections incorporated. Equation (13) has been replaced. The captions Figs. 16–18 have also Typographical errors pages 4, 6, 14, 15, 18, 19, 22, and 24 all corrected. corrected as 8 June 2005. text is correct in printed version journal.Received 6 2005DOI:https://doi.org/10.1103/PhysRevC.71.069902©2005 American Physical Society
We report on a new experimental method based initial-state radiation (ISR) in e–p scattering, which exploits the radiative tail of elastic peak to study properties electromagnetic processes and extract proton charge form factor (GEp) at extremely small Q2. The ISR technique was implemented an experiment three-spectrometer facility Mainz Microtron (MAMI). This led precise validation corrections far away from line provided first measurements GEp for 0.001≤Q2≤0.004(GeV/c)2.