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Charged Pion Photoproduction from Hydrogen and Deuterium at Jefferson Lab.

DE2004829599

Publication Date	2002
Personal Author	Gao, H.
Page Count	14
Abstract	The (gamma)n (yields) (pi)(sup -)p and (gamma)p (yields) (pi)(sup +)n reactions are essential probes of the transition from meson-nucleon degrees of freedom to quark-gluon degrees of freedom in exclusive processes. The cross sections of these processes are also, advantageous, for the investigation of oscillatory behavior around the quark counting prediction, since they decrease relatively slower with energy compared with other photon-induced processes. Moreover, these photoreactions in nuclei can probe the QCD nuclear filtering and color transparency effects. In this talk, I discuss the preliminary results on the (gamma)p (yields) (pi)(sup +)n and (gamma)n (yields) (pi)(sup -)p processes at a center-of-mass angle of 90(sup o) from Jefferson Lab experiment E94-104. I also discuss a new experiment in which singles (gamma)p (yields) (pi)(sup +)n measurement from hydrogen, and coincidence (gamma)n (yields) (pi)(sup -)p measurements at the quasifree kinematics from deuterium and (sup 12)C for photon energies between 2.25 GeV to 5.8 GeV in fine steps at a center-of-mass angle of 90(sup o) are planned. The proposed measurement will allow a detailed investigation of the oscillatory scaling behavior in photopion production processes and the study of the nuclear dependence of rather mysterious oscillations with energy that previous experiments have indicated. The various nuclear and perturbative QCD approaches, ranging from Glauber theory, to quark-counting, to Sudakov-corrected independent scattering, make dramatically different predictions for the experimental outcomes.
Keywords	Pions Photoproduction Hydrogen Deuterium Quantum chromodynamics Gluons Cross sections Kinematics Scattering Physics
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Jefferson Lab., Newport News, VA.; Massachusetts Inst. of Tech., Cambridge. Lab. for Nuclear Science.; Massachusetts Inst. of Tech., Cambridge. Dept. of Physics.; Department of Energy, Washington, DC.
Supplemental Notes	Prepared in cooperation with Massachusetts Inst. of Tech., Cambridge. Dept. of Physics. and Massachusetts Inst. of Tech., Cambridge. Lab. for Nuclear Science. Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200511

Charged Pion Photoproduction from Hydrogen and Deuterium at Jefferson Lab.

Charged Pion Photoproduction from Hydrogen and Deuterium at Jefferson Lab.
DE2004829599

Publication Date	2002
Personal Author	Gao, H.
Page Count	14
Abstract	The (gamma)n (yields) (pi)(sup -)p and (gamma)p (yields) (pi)(sup +)n reactions are essential probes of the transition from meson-nucleon degrees of freedom to quark-gluon degrees of freedom in exclusive processes. The cross sections of these processes are also, advantageous, for the investigation of oscillatory behavior around the quark counting prediction, since they decrease relatively slower with energy compared with other photon-induced processes. Moreover, these photoreactions in nuclei can probe the QCD nuclear filtering and color transparency effects. In this talk, I discuss the preliminary results on the (gamma)p (yields) (pi)(sup +)n and (gamma)n (yields) (pi)(sup -)p processes at a center-of-mass angle of 90(sup o) from Jefferson Lab experiment E94-104. I also discuss a new experiment in which singles (gamma)p (yields) (pi)(sup +)n measurement from hydrogen, and coincidence (gamma)n (yields) (pi)(sup -)p measurements at the quasifree kinematics from deuterium and (sup 12)C for photon energies between 2.25 GeV to 5.8 GeV in fine steps at a center-of-mass angle of 90(sup o) are planned. The proposed measurement will allow a detailed investigation of the oscillatory scaling behavior in photopion production processes and the study of the nuclear dependence of rather mysterious oscillations with energy that previous experiments have indicated. The various nuclear and perturbative QCD approaches, ranging from Glauber theory, to quark-counting, to Sudakov-corrected independent scattering, make dramatically different predictions for the experimental outcomes.
Keywords	Pions Photoproduction Hydrogen Deuterium Quantum chromodynamics Gluons Cross sections Kinematics Scattering Physics
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Jefferson Lab., Newport News, VA.; Massachusetts Inst. of Tech., Cambridge. Lab. for Nuclear Science.; Massachusetts Inst. of Tech., Cambridge. Dept. of Physics.; Department of Energy, Washington, DC.
Supplemental Notes	Prepared in cooperation with Massachusetts Inst. of Tech., Cambridge. Dept. of Physics. and Massachusetts Inst. of Tech., Cambridge. Lab. for Nuclear Science. Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200511