Separated Response Function Ratios in Exclusive, Forward π[superscript ±] Electroproduction
Author(s)
Huber, G. M.; Blok, H. P.; Butuceanu, C.; Gaskell, D.; Horn, T.; Mack, D. J.; Abbott, D.; Aniol, K.; Anklin, H.; Armstrong, C.; Arrington, J.; Assamagan, K.; Avery, S.; Baker, O. K.; Barrett, B.; Beise, E. J.; Bochna, C.; Boeglin, W.; Brash, E. J.; Breuer, H.; Chang, C. C.; Chant, N.; Christy, M. E.; Dunne, J.; Eden, T.; Ent, R.; Fenker, H.; Gibson, E. F.; Gilman, R.; Gustafsson, K.; Hinton, W.; Holt, R. J.; Jackson, H.; Jin, S.; Jones, M. K.; Keppel, C. E.; Kim, P. H.; Kim, W.; King, P. M.; Klein, A.; Koltenuk, D.; Kovaltchouk, V.; Liang, M.; Liu, J.; Lolos, G. J.; Lung, A.; Margaziotis, D. J.; Markowitz, P.; Matsumura, A.; McKee, D.; Meekins, D.; Mitchell, J.; Miyoshi, T.; Mkrtchyan, H.; Mueller, B.; Niculescu, G.; Niculescu, I.; Okayasu, Y.; Pentchev, L.; Perdrisat, C.; Pitz, D.; Potterveld, D.; Punjabi, V.; Qin, L. M.; Reimer, P. E.; Reinhold, J.; Roche, J.; Roos, P. G.; Sarty, A.; Shin, I. K.; Smith, G. R.; Stepanyan, S.; Tang, L. G.; Tadevosyan, V.; Tvaskis, V.; van der Meer, R. L. J.; Vansyoc, K.; Van Westrum, D.; Vidakovic, S.; Volmer, J.; Vulcan, W.; Warren, G.; Wood, S. A.; Xu, C.; Yan, C.; Zhao, W.-X.; Zheng, X.; Zihlmann, B.; ... Show more Show less
DownloadPhysRevLett.112.182501.pdf (286.2Kb)
PUBLISHER_POLICY
Publisher Policy
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
Terms of use
Metadata
Show full item recordAbstract
The study of exclusive π[superscript ±] electroproduction on the nucleon, including separation of the various structure functions, is of interest for a number of reasons. The ratio R[subscript L] = σ[π− over L]/σ[π+ over L] is sensitive to isoscalar contamination to the dominant isovector pion exchange amplitude, which is the basis for the determination of the charged pion form factor from electroproduction data. A change in the value of R[subscript T] = σ[π− over L]/σ[π+ over L] from unity at small −t, to 1/4 at large −t, would suggest a transition from coupling to a (virtual) pion to coupling to individual quarks. Furthermore, the mentioned ratios may show an earlier approach to perturbative QCD than the individual cross sections. We have performed the first complete separation of the four unpolarized electromagnetic structure functions above the dominant resonances in forward, exclusive π[superscript ±] electroproduction on the deuteron at central Q[superscript 2] values of 0.6, 1.0, 1.6 GeV[ superscript 2] at W = 1.95 GeV, and Q[superscript 2] = 2.45 GeV[superscript 2] at W=2.22 GeV. Here, we present the L and T cross sections, with emphasis on R[subscript L] and R[subscript T], and compare them with theoretical calculations. Results for the separated ratio R[subscript L] indicate dominance of the pion-pole diagram at low −t, while results for R[subscript T] are consistent with a transition between pion knockout and quark knockout mechanisms.
Date issued
2014-05Department
Massachusetts Institute of Technology. Department of PhysicsJournal
Physical Review Letters
Publisher
American Physical Society
Citation
Huber, G. M., et al. "Separated Response Function Ratios in Exclusive, Forward π[superscript ±] Electroproduction." Phys. Rev. Lett. 112 (May 2014), 182501. © 2014 American Physical Society
Version: Final published version
ISSN
0031-9007
1079-7114