Separated response functions in exclusive, forward π [superscript ±] electroproduction on deuterium
dc.contributor.author | Huber, G. M. | |
dc.contributor.author | Blok, H. P. | |
dc.contributor.author | Butuceanu, C. | |
dc.contributor.author | Gaskell, D. | |
dc.contributor.author | Horn, T. | |
dc.contributor.author | Mack, D. J. | |
dc.contributor.author | Abbott, D. | |
dc.contributor.author | Aniol, K. | |
dc.contributor.author | Anklin, H. | |
dc.contributor.author | Armstrong, C. | |
dc.contributor.author | Arrington, J. | |
dc.contributor.author | Assamagan, K. | |
dc.contributor.author | Avery, S. | |
dc.contributor.author | Baker, O. K. | |
dc.contributor.author | Barrett, B. | |
dc.contributor.author | Beise, E. J. | |
dc.contributor.author | Bochna, C. | |
dc.contributor.author | Boeglin, W. | |
dc.contributor.author | Brash, E. J. | |
dc.contributor.author | Breuer, H. | |
dc.contributor.author | Chang, C. C. | |
dc.contributor.author | Chant, N. | |
dc.contributor.author | Christy, M. E. | |
dc.contributor.author | Dunne, J. | |
dc.contributor.author | Eden, T. | |
dc.contributor.author | Ent, R. | |
dc.contributor.author | Fenker, H. | |
dc.contributor.author | Gibson, E. F. | |
dc.contributor.author | Gilman, R. | |
dc.contributor.author | Gustafsson, K. | |
dc.contributor.author | Hinton, W. | |
dc.contributor.author | Holt, R. J. | |
dc.contributor.author | Jackson, H. | |
dc.contributor.author | Jin, S. | |
dc.contributor.author | Jones, M. K. | |
dc.contributor.author | Keppel, C. E. | |
dc.contributor.author | Kim, P. H. | |
dc.contributor.author | Kim, W. | |
dc.contributor.author | King, P. M. | |
dc.contributor.author | Klein, A. | |
dc.contributor.author | Koltenuk, D. | |
dc.contributor.author | Kovaltchouk, V. | |
dc.contributor.author | Liang, M. | |
dc.contributor.author | Liu, J. | |
dc.contributor.author | Lolos, G. J. | |
dc.contributor.author | Lung, A. | |
dc.contributor.author | Margaziotis, D. J. | |
dc.contributor.author | Markowitz, P. | |
dc.contributor.author | Matsumura, A. | |
dc.contributor.author | McKee, D. | |
dc.contributor.author | Meekins, D. | |
dc.contributor.author | Mitchell, J. | |
dc.contributor.author | Miyoshi, T. | |
dc.contributor.author | Mkrtchyan, H. | |
dc.contributor.author | Mueller, B. | |
dc.contributor.author | Niculescu, G. | |
dc.contributor.author | Niculescu, I. | |
dc.contributor.author | Okayasu, Y. | |
dc.contributor.author | Pentchev, L. | |
dc.contributor.author | Perdrisat, C. | |
dc.contributor.author | Pitz, D. | |
dc.contributor.author | Potterveld, D. | |
dc.contributor.author | Punjabi, V. | |
dc.contributor.author | Qin, L. M. | |
dc.contributor.author | Reimer, P. E. | |
dc.contributor.author | Reinhold, J. | |
dc.contributor.author | Roche, J. | |
dc.contributor.author | Roos, P. G. | |
dc.contributor.author | Sarty, A. | |
dc.contributor.author | Shin, I. K. | |
dc.contributor.author | Smith, G. R. | |
dc.contributor.author | Stepanyan, S. | |
dc.contributor.author | Tang, L. G. | |
dc.contributor.author | Tadevosyan, V. | |
dc.contributor.author | Tvaskis, V. | |
dc.contributor.author | van der Meer, R. L. J. | |
dc.contributor.author | Vansyoc, K. | |
dc.contributor.author | Van Westrum, D. | |
dc.contributor.author | Vidakovic, S. | |
dc.contributor.author | Volmer, J. | |
dc.contributor.author | Vulcan, W. | |
dc.contributor.author | Warren, G. | |
dc.contributor.author | Wood, S. A. | |
dc.contributor.author | Xu, C. | |
dc.contributor.author | Yan, C. | |
dc.contributor.author | Zhao, W.-X. | |
dc.contributor.author | Zheng, X. | |
dc.contributor.author | Zihlmann, B. | |
dc.date.accessioned | 2015-01-22T18:30:58Z | |
dc.date.available | 2015-01-22T18:30:58Z | |
dc.date.issued | 2015-01 | |
dc.date.submitted | 2014-08 | |
dc.identifier.issn | 0556-2813 | |
dc.identifier.issn | 1089-490X | |
dc.identifier.uri | http://hdl.handle.net/1721.1/93141 | |
dc.description.abstract | Background: Measurements of forward exclusive meson production at different squared four-momenta of the exchanged virtual photon, Q[superscript 2], and at different four-momentum transfer, t, can be used to probe QCD's transition from meson-nucleon degrees of freedom at long distances to quark-gluon degrees of freedom at short scales. Ratios of separated response functions in π [superscript −] and π [superscript +] electroproduction are particularly informative. The ratio for transverse photons may allow this transition to be more easily observed, while the ratio for longitudinal photons provides a crucial verification of the assumed pole dominance, needed for reliable extraction of the pion form factor from electroproduction data. Purpose: We perform the first complete separation of the four unpolarized electromagnetic structure functions L/T/LT/TT in forward, exclusive π [superscript ±] electroproduction on deuterium above the dominant resonances. Method: Data were acquired with 2.6–5.2-GeV electron beams and the HMS+SOS spectrometers in Jefferson Lab Hall C at central Q [superscript 2] values of 0.6, 1.0, and 1.6 GeV [superscript 2] at W=1.95 GeV, and Q [superscript 2] = 2.45 GeV [superscript 2] at W = 2.22 GeV. There was significant coverage in ϕ and ε, which allowed separation of σ [subscript L,T,LT,TT]. Results: σ [subscript L] shows a clear signature of the pion pole, with a sharp rise at small −t. In contrast, σ [subscript T] is much flatter versus t. The longitudinal/transverse ratios evolve with Q [superscript 2] and t and at the highest Q [superscript 2] = 2.45 GeV [superscript 2] show a slight enhancement for π [superscript −] production compared to π [superscript +]. The π [[superscript -] over π [superscript +]] ratio for transverse photons exhibits only a small Q [superscript 2] dependence, following a nearly universal curve with t, with a steep transition to a value of about 0.25, consistent with s-channel quark knockout. The σ [[subscript TT] over σ[subscript T]] ratio also drops rapidly with Q [superscript 2], qualitatively consistent with s-channel helicity conservation. The [π [superscript −] over π [superscript +]] ratio for longitudinal photons indicates a small isoscalar contamination at W = 1.95 GeV, consistent with what was observed in our earlier determination of the pion form factor at these kinematics. Conclusions: The separated cross sections are compared to a variety of theoretical models, which generally describe σ [subscript L] but have varying success with σ [subscript T]. Further theoretical input is required to provide a more profound insight into the relevant reaction mechanisms for longitudinal and transverse photons, such as whether the observed transverse ratio is indeed attributable to a transition from pion to quark knockout mechanisms and provide useful information regarding the twist-3 transversity generalized parton distribution, H [subscript T]. | en_US |
dc.description.sponsorship | United States. Dept. of Energy | en_US |
dc.description.sponsorship | National Science Foundation (U.S.) | en_US |
dc.description.sponsorship | United States. Dept. of Energy (Contract DE-AC05-84ER40150) | en_US |
dc.publisher | American Physical Society | en_US |
dc.relation.isversionof | http://dx.doi.org/10.1103/PhysRevC.91.015202 | en_US |
dc.rights | 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. | en_US |
dc.source | American Physical Society | en_US |
dc.title | Separated response functions in exclusive, forward π [superscript ±] electroproduction on deuterium | en_US |
dc.type | Article | en_US |
dc.identifier.citation | Huber, G. M. et al. “Separated Response Functions in Exclusive, Forward π [superscript ±] Electroproduction on Deuterium.” Physical Review C 91.1 (2015): 015202-1-015202-23. © 2015 American Physical Society | en_US |
dc.contributor.department | Massachusetts Institute of Technology. Department of Physics | en_US |
dc.contributor.mitauthor | Zhao, W.-X. | en_US |
dc.relation.journal | Physical Review C | en_US |
dc.eprint.version | Final published version | en_US |
dc.type.uri | http://purl.org/eprint/type/JournalArticle | en_US |
eprint.status | http://purl.org/eprint/status/PeerReviewed | en_US |
dc.date.updated | 2015-01-07T23:00:16Z | |
dc.language.rfc3066 | en | |
dc.rights.holder | American Physical Society | |
dspace.orderedauthors | 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. | en_US |
mit.license | PUBLISHER_POLICY | en_US |
mit.metadata.status | Complete |