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Title: Isobar channels in the production of π+π- pairs on a proton by virtual photons

Abstract

A new approach is developed for evaluating contributions of various isobar channels to the double charged-pion production in the reactions γ r,v p → π + π - p. This approach makes it possible to determine both respective cross sections and amplitudes for quasi-two-particle channels from a fit to data on cross sections for a three-particle final state. The diffractive anzatz, which is widely used to describe rho-meson production, is modified to meet the purpose of the description of data in the near-threshold and subthreshold regions. The cross sections for rho-meson electroproduction in the energy region of nucleon-resonance excitation are determined for the first time on the basis of the latest data of the CLAS Collaboration.

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Thomas Jefferson National Accelerator Facility, Newport News, VA
Sponsoring Org.:
USDOE - Office of Energy Research (ER)
OSTI Identifier:
908800
Report Number(s):
JLAB-PHY-07-642; DOE/ER/40150-4284
Journal ID: ISSN 1063-7788; PANUEO; TRN: US0703772
DOE Contract Number:
AC05-84ER40150
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Atomic Nuclei; Journal Volume: 70
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; AMPLITUDES; CROSS SECTIONS; ELECTROPRODUCTION; EXCITATION; PHOTONS; PRODUCTION; PROTONS

Citation Formats

Burkert, V D, Mokeev, V I, Shvedunov, N V, Boluchevskii, A A, Battaglieri, M, Golovach, E N, Elouardrhiri, L, Joo, K, Isupov, E L, Ishkhanov, B S, Markov, N S, Ripani, M, Ricco, J, Sapunenko, V V, Taiuti, M, and Fedotov, G V. Isobar channels in the production of π+π- pairs on a proton by virtual photons. United States: N. p., 2007. Web. doi:10.1134/S1063778807030027.
Burkert, V D, Mokeev, V I, Shvedunov, N V, Boluchevskii, A A, Battaglieri, M, Golovach, E N, Elouardrhiri, L, Joo, K, Isupov, E L, Ishkhanov, B S, Markov, N S, Ripani, M, Ricco, J, Sapunenko, V V, Taiuti, M, & Fedotov, G V. Isobar channels in the production of π+π- pairs on a proton by virtual photons. United States. doi:10.1134/S1063778807030027.
Burkert, V D, Mokeev, V I, Shvedunov, N V, Boluchevskii, A A, Battaglieri, M, Golovach, E N, Elouardrhiri, L, Joo, K, Isupov, E L, Ishkhanov, B S, Markov, N S, Ripani, M, Ricco, J, Sapunenko, V V, Taiuti, M, and Fedotov, G V. Thu . "Isobar channels in the production of π+π- pairs on a proton by virtual photons". United States. doi:10.1134/S1063778807030027. https://www.osti.gov/servlets/purl/908800.
@article{osti_908800,
title = {Isobar channels in the production of π+π- pairs on a proton by virtual photons},
author = {Burkert, V D and Mokeev, V I and Shvedunov, N V and Boluchevskii, A A and Battaglieri, M and Golovach, E N and Elouardrhiri, L and Joo, K and Isupov, E L and Ishkhanov, B S and Markov, N S and Ripani, M and Ricco, J and Sapunenko, V V and Taiuti, M and Fedotov, G V},
abstractNote = {A new approach is developed for evaluating contributions of various isobar channels to the double charged-pion production in the reactions γ r,v p → π + π - p. This approach makes it possible to determine both respective cross sections and amplitudes for quasi-two-particle channels from a fit to data on cross sections for a three-particle final state. The diffractive anzatz, which is widely used to describe rho-meson production, is modified to meet the purpose of the description of data in the near-threshold and subthreshold regions. The cross sections for rho-meson electroproduction in the energy region of nucleon-resonance excitation are determined for the first time on the basis of the latest data of the CLAS Collaboration.},
doi = {10.1134/S1063778807030027},
journal = {Physics of Atomic Nuclei},
number = ,
volume = 70,
place = {United States},
year = {Thu Mar 01 00:00:00 EST 2007},
month = {Thu Mar 01 00:00:00 EST 2007}
}
  • A new approach is developed for evaluating contributions of various isobar channels to the double charged-pion production in the reactions {gamma}{sub r,v}p {sup {yields}} {pi}{sup +}{pi}{sup -}p. This approach makes it possible to determine both respective cross sections and amplitudes for quasi-two-particle channels from a fit to data on cross sections for a three-particle final state. The diffractive anzatz, which is widely used to describe rho-meson production, is modified to meet the purpose of the description of data in the near-threshold and subthreshold regions. The cross sections for rho-meson electroproduction in the energy region of nucleon-resonance excitation are determined formore » the first time on the basis of the latest data of the CLAS Collaboration.« less
  • The target and double spin asymmetries of the exclusive pseudoscalar channel e→p→→epπ0 were measured for the first time in the deep-inelastic regime using a longitudinally polarized 5.9 GeV electron beam and a longitudinally polarized proton target at Jefferson Lab with the CEBAF Large Acceptance Spectrometer (CLAS). The data were collected over a large kinematic phase space and divided into 110 four-dimensional bins of Q2, xB, -t and Φ. Large values of asymmetry moments clearly indicate a substantial contribution to the polarized structure functions from transverse virtual photon amplitudes. The interpretation of experimental data in terms of generalized parton distributions (GPDs)more » provides the first insight on the chiral-odd GPDs H˜T and ET, and complement previous measurements of unpolarized structure functions sensitive to the GPDs HT and E¯T. These data provide a crucial input for parametrizations of essentially unknown chiral-odd GPDs and will strongly influence existing theoretical calculations based on the handbag formalism.« less
  • The target and double spin asymmetries of the exclusive pseudoscalar channelmore » $$\vec e\vec p\to ep\pi^0$$ were measured for the first time in the deep-inelastic regime using a longitudinally polarized 5.9 GeV electron beam and a longitudinally polarized proton target at Jefferson Lab with the CEBAF Large Acceptance Spectrometer (CLAS). The data were collected over a large kinematic phase space and divided into 110 four-dimensional bins of $Q^2$, $$x_B$$, $-t$ and $$\phi$$. Large values of asymmetry moments clearly indicate a substantial contribution to the polarized structure functions from transverse virtual photon amplitudes. The interpretation of experimental data in terms of generalized parton distributions (GPDs) provides the first insight on the chiral-odd GPDs $$\tilde{H}_T$$ and $$E_T$$, and complement previous measurements of unpolarized structure functions sensitive to the GPDs $$H_T$$ and $$\bar E_T$$. Finally, these data provide necessary constraints for chiral-odd GPD parametrizations and will strongly influence existing theoretical handbag models.« less
  • The target and double spin asymmetries of the exclusive pseudoscalar channelmore » $$\vec e\vec p\to ep\pi^0$$ were measured for the first time in the deep-inelastic regime using a longitudinally polarized 5.9 GeV electron beam and a longitudinally polarized proton target at Jefferson Lab with the CEBAF Large Acceptance Spectrometer (CLAS). The data were collected over a large kinematic phase space and divided into 110 four-dimensional bins of $Q^2$, $$x_B$$, $-t$ and $$\phi$$. Large values of asymmetry moments clearly indicate a substantial contribution to the polarized structure functions from transverse virtual photon amplitudes. The interpretation of experimental data in terms of generalized parton distributions (GPDs) provides the first insight on the chiral-odd GPDs $$\tilde{H}_T$$ and $$E_T$$, and complement previous measurements of unpolarized structure functions sensitive to the GPDs $$H_T$$ and $$\bar E_T$$. Finally, these data provide necessary constraints for chiral-odd GPD parametrizations and will strongly influence existing theoretical handbag models.« less