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Author

W. Meyer

Bio: W. Meyer is an academic researcher from Ruhr University Bochum. The author has contributed to research in topics: Meson & Nucleon. The author has an hindex of 54, co-authored 278 publications receiving 9583 citations. Previous affiliations of W. Meyer include Argonne National Laboratory & University of Liverpool.
Topics: Meson, Nucleon, Muon, Pion, Proton


Papers
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Journal ArticleDOI
TL;DR: The authors report the results of the experiment E142 which measured the spin dependent structure function of the neutron, which confirms the fundamental Bjorken sum rule with O({alpha}{sub s}{sup 3}) corrections to within one standard deviation, a major success for perturbative Quantum Chromodynamics.
Abstract: The authors report the results of the experiment E142 which measured the spin dependent structure function of the neutron, g{sub 1}{sup n}(x, Q{sup 2}). The experiment was carried out at the Stanford Linear Accelerator Center by measuring an asymmetry in the deep inelastic scattering of polarized electrons from a polarized {sup 3}He target, at electron energies from 19 to 26 GeV. The structure function was determined over the kinematic range 0.03 < BJorken x < 0.6 and 1.0 < Q{sup 2} < 5.5 (GeV/c){sup 2}. An evaluation of the integral {integral}{sub 0}{sup 1} g{sub 1}{sup n}(x,Q{sup 2})dx at fixed Q{sup 2} = 2 (GeV/c){sup 2} yields the final result {Lambda}{sub 1}{sup n} = -0.032 {+-} 0.006 (stat.) {+-} 0.009 (syst.). This result, when combined with the integral of the proton spin structure function measured in other experiments, confirms the fundamental Bjorken sum rule with O({alpha}{sub s}{sup 3}) corrections to within one standard deviation. This is a major success for perturbative Quantum Chromodynamics. Some ancillary results include the findings that the Ellis-Jaffe sum rule for the neutron is violated at the 2 {sigma} level, and that the total contribution of the quarks to the helicity of the nucleon is 0.36 {+-}more » 0.10. The strange sea polarization is estimated to be small and negative, {Delta}s = -0.07 {+-} 0.04.« less

330 citations

Journal ArticleDOI
Koji Abe1, T. Akagi2, P.L. Anthony2, R. Antonov3, R. G. Arnold4, T. Averett5, T. Averett6, H. R. Band7, J. M. Bauer8, J. M. Bauer9, H. Borel, P. E. Bosted4, Vincent Breton, J. Button-Shafer8, J. P. Chen10, J. P. Chen6, Timothy Chupp10, J. Clendenin2, C. Comptour, K. P. Coulter10, G. Court2, G. Court11, D. Crabb6, M. Daoudi2, Donal Day6, F. S. Dietrich12, J. A. Dunne4, J. A. Dunne13, H. Dutz2, H. Dutz14, R. Erbacher2, J. Fellbaum4, A. Feltham15, H. Fonvieille, Emil Frlez6, D. Garvey16, R. Gearhart2, J. Gomez13, P. Grenier, K. A. Griffioen17, K. A. Griffioen3, S. Hoibraten6, E. W. Hughes5, E. W. Hughes2, Ch. Hyde-Wright18, J. R. Johnson7, D. Kawall2, Avraham Klein18, S. E. Kuhn18, M. Kuriki1, R. A. Lindgren6, T. J. Liu6, R. M. Lombard-Nelsen, J. Marroncle, T. Maruyama2, X.K. Maruyama16, J. S. McCarthy6, W. Meyer2, W. Meyer14, Z. E. Meziani2, Z. E. Meziani19, R. C. Minehart6, John C. Mitchell13, J. Morgenstern, G. G. Petratos20, G. G. Petratos2, R. Pitthan2, Dinko Pocanic6, C. Y. Prescott2, R. Prepost7, P. Raines3, B. Raue21, B. Raue18, D. Reyna4, A. Rijllart22, A. Rijllart2, Y. Roblin, L. S. Rochester2, S. E. Rock4, O. Rondon6, Ingo Sick15, L. C. Smith6, Timothy B. Smith10, M. Spengos4, M. Spengos3, F. Staley, Pascal Steiner15, S.St. Lorant2, L. M. Stuart2, F. Suekane, Z. M. Szalata4, H. Tang2, Y. Terrien, T. L. Usher2, D. Walz2, F.R. Wesselmann18, James L. White4, James L. White2, K. Witte2, C. C. Young2, B. Youngman2, H. Yuta, G. H. Zapalac7, B. Zihlmann15, D. Zimmermann6 
TL;DR: In this paper, the authors reported measurements of the proton and deuteron spin structure functions at beam energies of 29.1, 16.2, and 9.7 GeV.
Abstract: Measurements are reported of the proton and deuteron spin structure functions ${g}_{1}^{p}$ and ${g}_{1}^{d}$ at beam energies of 29.1, 16.2, and 9.7 GeV, and ${g}_{2}^{p}$ and ${g}_{2}^{d}$ at a beam energy of 29.1 GeV. The integrals ${\ensuremath{\Gamma}}_{p}={\ensuremath{\int}}_{0}^{1}{g}_{1}^{p}{(x,Q}^{2})dx$ and ${\ensuremath{\Gamma}}_{d}={\ensuremath{\int}}_{0}^{1}{g}_{1}^{d}{(x,Q}^{2})dx$ were evaluated at fixed ${Q}^{2}=3(\mathrm{GeV}{/c)}^{2}$ using the full data set to yield ${\ensuremath{\Gamma}}_{p}=0.132\ifmmode\pm\else\textpm\fi{}0.003(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.009(\mathrm{syst})$ and ${\ensuremath{\Gamma}}_{d}=0.047\ifmmode\pm\else\textpm\fi{}0.003\ifmmode\pm\else\textpm\fi{}0.006.$ The ${Q}^{2}$ dependence of the ratio ${g}_{1}{/F}_{1}$ was studied and found to be small for ${Q}^{2}g1(\mathrm{GeV}{/c)}^{2}.$ Within experimental precision the ${g}_{2}$ data are well described by the twist-2 contribution, ${g}_{2}^{\mathrm{WW}}.$ Twist-3 matrix elements were extracted and compared to theoretical predictions. The asymmetry ${A}_{2}$ was measured and found to be significantly smaller than the positivity limit $\sqrt{R}$ for both proton and deuteron targets. ${A}_{2}^{p}$ is found to be positive and inconsistent with zero. Measurements of ${g}_{1}$ in the resonance region show strong variations with $x$ and ${Q}^{2},$ consistent with resonant amplitudes extracted from unpolarized data. These data allow us to study the ${Q}^{2}$ dependence of the integrals ${\ensuremath{\Gamma}}_{p}$ and ${\ensuremath{\Gamma}}_{n}$ below the scaling region.

295 citations

Journal ArticleDOI
V.Yu. Alexakhin1, W. Wislicki, F. Kunne, J. Ehlers  +200 moreInstitutions (1)
TL;DR: First measurements of the Collins and Sivers asymmetries of charged hadrons produced in deep-inelastic scattering of muons on a transversely polarized 6LiD target are presented.
Abstract: First measurements of the Collins and Sivers asymmetries of charged hadrons produced in deep-inelastic scattering of muons on a transversely polarized {sup 6}LiD target are presented. The data were taken in 2002 with the COMPASS spectrometer using the muon beam of the CERN SPS at 160 GeV/c. The Collins asymmetry turns out to be compatible with zero, as does the measured Sivers asymmetry within the present statistical errors.

264 citations

Journal ArticleDOI
TL;DR: For the kinematic range of $0.014lxl0.7$ and $1l{Q}^{2}l17(\mathrm{GeV}/c{)}^{2] 2, this article reported a precision measurement of the neutron spin structure function using deep inelastic scattering of polarized electrons.
Abstract: We report on a precision measurement of the neutron spin structure function ${g}_{1}^{n}$ using deep inelastic scattering of polarized electrons by polarized ${}^{3}\mathrm{He}$. For the kinematic range $0.014lxl0.7$ and $1l{Q}^{2}l17(\mathrm{GeV}/c{)}^{2}$, 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 ${Q}^{2}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}5(\mathrm{GeV}/c{)}^{2}$. We find relatively large negative values for ${g}_{1}^{n}$ at low $x$. The results call into question the usual Regge theory method for extrapolating to $x\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0$ to find the full neutron integral $\ensuremath{\int}{1}^{}{g}_{1}^{n}(x)\mathrm{dx}$, needed for testing the quark-parton model and QCD sum rules.

259 citations

Journal ArticleDOI
Bernardo Adeva1, Taylan Akdogan2, E. Arik2, A. Arvidson3  +196 moreInstitutions (43)
TL;DR: In this article, the spin asymmetries A1 and the spin structure functions g1 of the proton and the deuteron in the kinematic range 0.0008
Abstract: We present the final results of the spin asymmetries A1 and the spin structure functions g1 of the proton and the deuteron in the kinematic range 0.0008

250 citations


Cited by
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Journal ArticleDOI
01 Apr 1988-Nature
TL;DR: In this paper, a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) is presented.
Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

9,929 citations

Journal ArticleDOI
TL;DR: The Nambu-Jona-Lasinio (NJL) model as mentioned in this paper is a low-energy effective theory of QCD, and it has been applied to the system at finite temperature (T ) and density (ϱ) relevant to the early universe, interior of the neutron stars and the ultrarelativistic heavy ion collisions.

1,142 citations

Journal ArticleDOI
TL;DR: Recently, the LHCb Collaboration discovered two hidden-charm pentaquark states, which are also beyond the quark model as discussed by the authors, and investigated various theoretical interpretations of these candidates of the multiquark states.

1,083 citations

Journal ArticleDOI
TL;DR: The authors give an exposition of Shor's algorithm together with an introduction to quantum computation and complexity theory, and discuss experiments that may contribute to its practical implementation.
Abstract: Current technology is beginning to allow us to manipulate rather than just observe individual quantum phenomena. This opens up the possibility of exploiting quantum effects to perform computations beyond the scope of any classical computer. Recently Peter Shor discovered an efficient algorithm for factoring whole numbers, which uses characteristically quantum effects. The algorithm illustrates the potential power of quantum computation, as there is no known efficient classical method for solving this problem. The authors give an exposition of Shor's algorithm together with an introduction to quantum computation and complexity theory. They discuss experiments that may contribute to its practical implementation. [S0034-6861(96)00303-0]

1,079 citations

Journal ArticleDOI
TL;DR: In this article, the authors present a review of the application of atomic physics to address important challenges in physics and to look for variations in the fundamental constants, search for interactions beyond the standard model of particle physics and test the principles of general relativity.
Abstract: Advances in atomic physics, such as cooling and trapping of atoms and molecules and developments in frequency metrology, have added orders of magnitude to the precision of atom-based clocks and sensors. Applications extend beyond atomic physics and this article reviews using these new techniques to address important challenges in physics and to look for variations in the fundamental constants, search for interactions beyond the standard model of particle physics, and test the principles of general relativity.

1,077 citations