Th. Walcher
A5040905799- Quantum Chromodynamics and Particle Interactions
- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Nuclear physics research studies
- Nuclear Physics and Applications
- Atomic and Subatomic Physics Research
- Particle Accelerators and Free-Electron Lasers
- Atomic and Molecular Physics
- Particle accelerators and beam dynamics
- X-ray Spectroscopy and Fluorescence Analysis
- Quantum, superfluid, helium dynamics
- Particle Detector Development and Performance
- Advanced X-ray Imaging Techniques
- Advanced NMR Techniques and Applications
- Advanced Chemical Physics Studies
- Medical Imaging Techniques and Applications
- Superconducting Materials and Applications
- Electron and X-Ray Spectroscopy Techniques
- Muon and positron interactions and applications
- Dark Matter and Cosmic Phenomena
- Radiation Detection and Scintillator Technologies
- Mass Spectrometry Techniques and Applications
- Crystallography and Radiation Phenomena
- Ion-surface interactions and analysis
- Inorganic Fluorides and Related Compounds
Johannes Gutenberg University Mainz
2009-2023
Max Planck Institute for Nuclear Physics
1987-2008
Heidelberg University
1984-2005
University of Maine
2003
Old Dominion University
1998
Institut Laue-Langevin
1998
University of Basel
1998
Bielefeld University
1997
Heidelberg University
1997
University of Warsaw
1997
Experimental results obtained at the CERN Super Proton Synchrotron on structure-function ratio F2n/F2p in kinematic range 0.004<x<0.8 and 0.4<Q2<190 GeV2, together with structure function F2d determined from a fit to published data, are used derive difference F2p(x)-F2n(x). The value of Gottfried sum F(F2p-F2n)dx/x=0.240±0.016 is below quark-parton-model expectation 1/3.Received 23 January 1991DOI:https://doi.org/10.1103/PhysRevLett.66.2712©1991 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)...
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...
Information on the size and shape of neutron skin (208)Pb is extracted from coherent pion photoproduction cross sections measured using Crystal Ball detector together with Glasgow tagger at MAMI electron beam facility. On exploitation an interpolated fit a theoretical model to sections, half-height radius diffuseness distribution are found be c(n)=6.70±0.03(stat.) fm a(n)=0.55±0.01(stat.)(-0.03)(+0.02)(sys.) fm, respectively, corresponding thickness...
The muon-proton and muon-deuteron inclusive deep inelastic scattering cross sections were measured in the kinematic range 0.002 < × 0.60 0.5 Q2 75 GeV2 at incident muon energies of 90, 120, 200 280 GeV. These results are based on full data set collected by New Muon Collaboration, including taken with a small angle trigger. extracted values structure functions F2p F2d good agreement those from other experiments. cover sufficient y to allow determination ratio longitudinally transversely...
Precise data on the neutron magnetic form factor G_{mn} have been obtained with measurements of ratio cross sections D(e,e'n) and D(e,e'p) up to momentum transfers Q^2 = 0.9 (GeV/c)^2. Data typical uncertainties 1.5% are presented. These allow for first time extract a precise value radius neutron.
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...
The electric form factor of the neutron ${G}_{E,n}$ has been measured in quasifree ${}^{2}\mathrm{H}(\stackrel{\ensuremath{\rightarrow}}{e}{,e}^{\ensuremath{'}}\stackrel{\ensuremath{\rightarrow}}{n})p$ reaction using 855 MeV polarized cw electron beam Mainz Microtron MAMI. polarization scattered neutrons was analyzed a polarimeter consisting two walls plastic scintillators. precession spin magnetic field used for first time to circumvent measurement effective analyzing power and...
The small electric quadrupole $E2$ amplitude of the predominantly magnetic dipole $M1$ $p\ensuremath{\rightarrow}\ensuremath{\Delta}(1232)$ transition has been measured using 270 to 420 MeV tagged linearly polarized photons in $p(\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\gamma}},p){\ensuremath{\pi}}^{o}$ reaction at Mainz Microtron MAMI. Differential cross sections and photon asymmetries were determined by measuring recoil proton cylindrically symmetric $4\ensuremath{\pi}$ detector...
We have measured the neutron electric form factor Gen via 3He→(e→,e′n)pp at Q2=0.67(GeV/c)2 using 3-spectrometer facility of A1 Collaboration Mainz Microtron and a dedicated detector. High pressure polarized 3He→ gas was used as target neutrons. is determined from ratio asymmetries A⊥/A∥ in quasifree kinematics with spin perpendicular parallel to momentum transfer. find Gen=0.052±0.011±0.005.Received 30 April 1999DOI:https://doi.org/10.1103/PhysRevLett.83.4257©1999 American Physical Society
Results are presented for F2d/F2p and Rd − Rp from simultaneous measurements of deep inelastic muon scattering on hydrogen deuterium targets, at 90, 120, 200 280 GeV. The difference Rp, determined in the range 0.002 < x 0.4 an average Q2 5 GeV2, is compatible with zero. dependence was measured kinematic 0.001 0.8 0.1 145 GeV2 small statistical systematic errors. For > ratio decreases Q2.