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Title: Quark-hadron duality in spin structure functions g{sub 1}{sup p} and g{sub 1}{sup d}

Abstract

New measurements of the spin structure functions of the proton and deuteron g{sub 1}{sup p}(x,Q{sup 2}) and g{sub 1}{sup d}(x,Q{sup 2}) in the nucleon resonance region are compared with extrapolations of target-mass-corrected next-to-leading-order (NLO) QCD fits to higher energy data. Averaged over the entire resonance region (W<2 GeV), the data and QCD fits are in good agreement in both magnitude and Q{sup 2} dependence for Q{sup 2}>1.7 GeV{sup 2}/c{sup 2}. This ''global'' duality appears to result from cancellations among the prominent ''local'' resonance regions: in particular strong {sigma}{sub 3/2} contributions in the {delta}(1232) region appear to be compensated by strong {sigma}{sub 1/2} contributions in the resonance region centered on 1.5 GeV. These results are encouraging for the extension of NLO QCD fits to lower W and Q{sup 2} than have been used previously.

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;  [1]
  1. Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States) (and others)
Publication Date:
OSTI Identifier:
20995162
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 75; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevC.75.035203; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; DELTA-1232 BARYONS; DEUTERONS; EXTRAPOLATION; GEV RANGE 01-10; PROTONS; QUANTUM CHROMODYNAMICS; QUARK-HADRON INTERACTIONS; RESONANCE; SPIN; STRUCTURE FUNCTIONS

Citation Formats

Bosted, P. E., Brooks, W. K., Burkert, V. D., Cords, D., Degtyarenko, P. V., Deur, A., Guo, L., Gyurjyan, V., Ito, M. M., Keith, C., Manak, J. J., Mecking, B. A., Mestayer, M. D., Niczyporuk, B. B., Nozar, M., Sharabian, Y. G., Smith, E. S., Thoma, U., Weygand, D. P., and Wolin, E. Quark-hadron duality in spin structure functions g{sub 1}{sup p} and g{sub 1}{sup d}. United States: N. p., 2007. Web. doi:10.1103/PHYSREVC.75.035203.
Bosted, P. E., Brooks, W. K., Burkert, V. D., Cords, D., Degtyarenko, P. V., Deur, A., Guo, L., Gyurjyan, V., Ito, M. M., Keith, C., Manak, J. J., Mecking, B. A., Mestayer, M. D., Niczyporuk, B. B., Nozar, M., Sharabian, Y. G., Smith, E. S., Thoma, U., Weygand, D. P., & Wolin, E. Quark-hadron duality in spin structure functions g{sub 1}{sup p} and g{sub 1}{sup d}. United States. doi:10.1103/PHYSREVC.75.035203.
Bosted, P. E., Brooks, W. K., Burkert, V. D., Cords, D., Degtyarenko, P. V., Deur, A., Guo, L., Gyurjyan, V., Ito, M. M., Keith, C., Manak, J. J., Mecking, B. A., Mestayer, M. D., Niczyporuk, B. B., Nozar, M., Sharabian, Y. G., Smith, E. S., Thoma, U., Weygand, D. P., and Wolin, E. Thu . "Quark-hadron duality in spin structure functions g{sub 1}{sup p} and g{sub 1}{sup d}". United States. doi:10.1103/PHYSREVC.75.035203.
@article{osti_20995162,
title = {Quark-hadron duality in spin structure functions g{sub 1}{sup p} and g{sub 1}{sup d}},
author = {Bosted, P. E. and Brooks, W. K. and Burkert, V. D. and Cords, D. and Degtyarenko, P. V. and Deur, A. and Guo, L. and Gyurjyan, V. and Ito, M. M. and Keith, C. and Manak, J. J. and Mecking, B. A. and Mestayer, M. D. and Niczyporuk, B. B. and Nozar, M. and Sharabian, Y. G. and Smith, E. S. and Thoma, U. and Weygand, D. P. and Wolin, E.},
abstractNote = {New measurements of the spin structure functions of the proton and deuteron g{sub 1}{sup p}(x,Q{sup 2}) and g{sub 1}{sup d}(x,Q{sup 2}) in the nucleon resonance region are compared with extrapolations of target-mass-corrected next-to-leading-order (NLO) QCD fits to higher energy data. Averaged over the entire resonance region (W<2 GeV), the data and QCD fits are in good agreement in both magnitude and Q{sup 2} dependence for Q{sup 2}>1.7 GeV{sup 2}/c{sup 2}. This ''global'' duality appears to result from cancellations among the prominent ''local'' resonance regions: in particular strong {sigma}{sub 3/2} contributions in the {delta}(1232) region appear to be compensated by strong {sigma}{sub 1/2} contributions in the resonance region centered on 1.5 GeV. These results are encouraging for the extension of NLO QCD fits to lower W and Q{sup 2} than have been used previously.},
doi = {10.1103/PHYSREVC.75.035203},
journal = {Physical Review. C, Nuclear Physics},
number = 3,
volume = 75,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}
  • New measurements of the spin structure functions of the proton and deuteron g{sub 1}{sup p}(x, Q{sup 2}) and g{sub 1}{sup d}(x, Q{sup 2}) in the nucleon resonance region are compared with extrapolations of target-mass-corrected next-to-leading-order (NLO) QCD fits to higher energy data. Averaged over the entire resonance region (W < 2 GeV), the data and QCD fits are in good agreement in both magnitude and Q{sup 2} dependence for Q{sup 2} > 1.7 GeV{sup 2}/c{sup 2}. This ''global'' duality appears to result from cancellations among the prominent ''local'' resonance regions: in particular strong {sigma}{sub 3/2} contributions in the {Delta}(1232) regionmore » appear to be compensated by strong {sigma}{sub 1/2} contributions in the resonance region centered on 1.5 GeV. These results are encouraging for the extension of NLO QCD fits to lower W and Q{sup 2} than have been used previously.« less
  • Jefferson Lab experiment E01-012 measured the {sup 3}He spin-structure functions and virtual photon asymmetries in the resonance region in the momentum transfer range 1.0<Q{sup 2}<4.0 (GeV/c){sup 2}. Our data, when compared with existing deep inelastic scattering data, were used to test quark-hadron duality in g{sub 1} and A{sub 1} for {sup 3}He and the neutron. In addition, preliminary results on the {sup 3}He spin-structure function g{sub 2}, on the Burkhardt-Cottingham sum rule and on higher twist effects through the x{sup 2}-weighted moment d{sub 2} of the neutron were presented.
  • The structure functions g{sub 1}{sup p} and g{sub 1}{sup n} have been measured over the range 0.014 < x < 0.9 and 1 < Q{sup 2} < 40 GeV{sup 2} using deep-inelastic scattering of 48 GeV longitudinally polarized electrons from polarized protons and deuterons. We find that the Q{sup 2} dependence of g{sub 1}{sup p} (g{sub 1}{sup n}) at fixed x is very similar to that of the spin-averaged structure function F{sub 1}{sup p} (F{sub 1}{sup n}). From a NLO QCD fit to all available data we find {Gamma}{sub 1}{sup p} - {Gamma}{sub 1}{sup n} = 0.176 {+-} 0.003 {+-}more » 0.007 at Q{sup 2} = 5 GeV{sup 2}, in agreement with the Bjorken sum rule prediction of 0.182 {+-} 0.005.« less
  • We present the spin-orbit (SO) and Renner-Teller (RT) quantum dynamics of the spin-forbidden quenching O({sup 1}D) + N{sub 2}(X{sup 1}{Sigma}{sub g}{sup +}){yields}O({sup 3}P) + N{sub 2}(X{sup 1}{Sigma}{sub g}{sup +}) on the N{sub 2}O X-tilde{sup 1}A{sup '}, a-tilde{sup 3}A', and b-tilde{sup 3}A{sup '} coupled PESs. We use the permutation-inversion symmetry, propagate coupled-channel (CC) real wavepackets, and compute initial-state-resolved probabilities and cross sections {sigma}{sub j0} for the ground vibrational and the first two rotational states of N{sub 2}, j{sub 0}= 0 and 1. Labeling symmetry angular states by j and K, we report selection rules for j and for the minimum Kmore » value associated with any electronic state, showing that a-tilde{sup 3}A' is uncoupled in the centrifugal-sudden (CS) approximation at j{sub 0}= 0. The dynamics is resonance-dominated, the probabilities are larger at low K, {sigma}{sub j0} decrease with the collision energy and increase with j{sub 0}, and the CS {sigma}{sub 0} is lower than the CC one. The nonadiabatic interactions play different roles on the quenching dynamics, because the X-tilde{sup 1}A{sup '}-b-tilde{sup 3}A{sup '} SO effects are those most important while the a-tilde{sup 3}A'-b-tilde{sup 3}A{sup '} RT ones are negligible.« less