N/A

Spokesperson

Abstract

The ep->e'pρ⁰ reaction has been measured, using the 5.754 GeV electron beam of Jefferson Lab and the CLAS detector. This represents the largest ever set of data for this reaction in the valence region. Integrated and differential cross sections are presented. The W, Q² and t dependences of the cross section are compared to theoretical calculations based on t-channel meson-exchange Regge theory on the one hand and on quark handbag diagrams related to Generalized Parton Distributions (GPDs) on the other hand. The Regge approach can describe at the ~30% level most of the features of the present data while the two GPD calculations that are presented in this article which succesfully reproduce the high energy data strongly underestimate the present data. The question is then raised whether this discrepancy originates from an incomplete or inexact way of modelling the GPDs or the associated hard scattering amplitude or whether the GPD formalism is simply inapplicable in this region due to higher-twists contributions, incalculable at present.

Publication

S.A.Morrow, M.Guidal, M.Garcon, J.M.Laget, E.S.Smith, and CLAS Collaboration Exclusive ρ⁰ electroproduction on the proton at CLAS // Eur.Phys.J.A39,5-31(2009)

Quantities

σ σ_L σ_T σ_TT σ_TL dσ/dt dσ_L/dt dσ_T/dt R_ρ dσ/dφ r₀₀⁰⁴ r_1-1⁰⁴ r₁₁¹ b σ_T + εσ_L dσ/dcos(θ_HS^π⁺)

Measurements

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ID	Quantity	Beam	Target	Final state	Q²_min, GeV²	Q²_max, GeV²	W_min, GeV	W_max, GeV
E46M101	σ_TL	e	p	ρ⁰ p	5.353	5.353	None	None
E46M102	r₀₀⁰⁴	e	p	ρ⁰ p	1.725	5.353	None	None
E46M103	r₀₀⁰⁴	e	p	ρ⁰ p	1.725	1.725	None	None
E46M104	r₀₀⁰⁴	e	p	ρ⁰ p	1.752	2.32	None	None
E46M105	r₀₀⁰⁴	e	p	ρ⁰ p	1.785	2.639	None	None
E46M106	r₀₀⁰⁴	e	p	ρ⁰ p	2.05	3.295	None	None
E46M107	r₀₀⁰⁴	e	p	ρ⁰ p	2.35	3.807	None	None
E46M108	r₀₀⁰⁴	e	p	ρ⁰ p	2.95	4.307	None	None
E46M109	r₀₀⁰⁴	e	p	ρ⁰ p	3.85	4.35	None	None
E46M110	r₀₀⁰⁴	e	p	ρ⁰ p	4.352	4.85	None	None
E46M111	r₀₀⁰⁴	e	p	ρ⁰ p	5.353	5.353	None	None
E46M112	r_1-1⁰⁴	e	p	ρ⁰ p	1.725	5.353	None	None
E46M113	r_1-1⁰⁴	e	p	ρ⁰ p	1.725	1.725	None	None
E46M114	r_1-1⁰⁴	e	p	ρ⁰ p	1.752	2.32	None	None
E46M115	r_1-1⁰⁴	e	p	ρ⁰ p	1.785	2.639	None	None
E46M116	r_1-1⁰⁴	e	p	ρ⁰ p	2.05	3.295	None	None
E46M117	r_1-1⁰⁴	e	p	ρ⁰ p	2.35	3.807	None	None
E46M118	r_1-1⁰⁴	e	p	ρ⁰ p	2.95	4.307	None	None
E46M119	r_1-1⁰⁴	e	p	ρ⁰ p	3.85	4.35	None	None
E46M120	r_1-1⁰⁴	e	p	ρ⁰ p	4.352	4.85	None	None
E46M121	r_1-1⁰⁴	e	p	ρ⁰ p	5.353	5.353	None	None
E46M122	r₁₁¹	e	p	ρ⁰ p	1.725	5.353	None	None
E46M123	r₁₁¹	e	p	ρ⁰ p	1.725	1.725	None	None
E46M124	r₁₁¹	e	p	ρ⁰ p	1.752	2.32	None	None
E46M125	r₁₁¹	e	p	ρ⁰ p	1.785	2.639	None	None
E46M126	r₁₁¹	e	p	ρ⁰ p	2.05	3.295	None	None
E46M127	r₁₁¹	e	p	ρ⁰ p	2.35	3.807	None	None
E46M128	r₁₁¹	e	p	ρ⁰ p	2.95	4.307	None	None
E46M129	r₁₁¹	e	p	ρ⁰ p	3.85	4.35	None	None
E46M130	r₁₁¹	e	p	ρ⁰ p	4.352	4.85	None	None
E46M131	r₁₁¹	e	p	ρ⁰ p	5.353	5.353	None	None
E46M132	dσ/dcos(θ_HS^π⁺)	e	p	ρ⁰ p	1.725	1.725	None	None
E46M133	dσ/dcos(θ_HS^π⁺)	e	p	ρ⁰ p	1.752	1.752	None	None
E46M134	dσ/dcos(θ_HS^π⁺)	e	p	ρ⁰ p	2.042	2.042	None	None
E46M135	dσ/dcos(θ_HS^π⁺)	e	p	ρ⁰ p	2.32	2.32	None	None
E46M136	dσ/dcos(θ_HS^π⁺)	e	p	ρ⁰ p	1.785	1.785	None	None
E46M137	dσ/dcos(θ_HS^π⁺)	e	p	ρ⁰ p	2.05	2.05	None	None
E46M138	dσ/dcos(θ_HS^π⁺)	e	p	ρ⁰ p	2.35	2.35	None	None
E46M139	dσ/dcos(θ_HS^π⁺)	e	p	ρ⁰ p	2.639	2.639	None	None
E46M140	dσ/dcos(θ_HS^π⁺)	e	p	ρ⁰ p	2.05	2.05	None	None
E46M141	dσ/dcos(θ_HS^π⁺)	e	p	ρ⁰ p	2.35	2.35	None	None
E46M142	dσ/dcos(θ_HS^π⁺)	e	p	ρ⁰ p	2.65	2.65	None	None
E46M143	dσ/dcos(θ_HS^π⁺)	e	p	ρ⁰ p	2.95	2.95	None	None
E46M144	dσ/dcos(θ_HS^π⁺)	e	p	ρ⁰ p	3.295	3.295	None	None
E46M145	dσ/dcos(θ_HS^π⁺)	e	p	ρ⁰ p	2.35	2.35	None	None
E46M146	dσ/dcos(θ_HS^π⁺)	e	p	ρ⁰ p	2.65	2.65	None	None
E46M147	dσ/dcos(θ_HS^π⁺)	e	p	ρ⁰ p	2.95	2.95	None	None
E46M148	dσ/dcos(θ_HS^π⁺)	e	p	ρ⁰ p	3.35	3.35	None	None
E46M149	dσ/dcos(θ_HS^π⁺)	e	p	ρ⁰ p	3.807	3.807	None	None
E46M150	dσ/dcos(θ_HS^π⁺)	e	p	ρ⁰ p	2.95	2.95	None	None
E46M151	dσ/dcos(θ_HS^π⁺)	e	p	ρ⁰ p	3.35	3.35	None	None
E46M152	dσ/dcos(θ_HS^π⁺)	e	p	ρ⁰ p	3.85	3.85	None	None
E46M153	dσ/dcos(θ_HS^π⁺)	e	p	ρ⁰ p	4.307	4.307	None	None
E46M154	dσ/dcos(θ_HS^π⁺)	e	p	ρ⁰ p	3.85	3.85	None	None
E46M155	dσ/dcos(θ_HS^π⁺)	e	p	ρ⁰ p	4.35	4.35	None	None
E46M156	dσ/dcos(θ_HS^π⁺)	e	p	ρ⁰ p	4.352	4.352	None	None
E46M157	dσ/dcos(θ_HS^π⁺)	e	p	ρ⁰ p	4.85	4.85	None	None
E46M158	dσ/dcos(θ_HS^π⁺)	e	p	ρ⁰ p	5.353	5.353	None	None
E46M159	R_ρ	e	p	ρ⁰ p	1.725	5.353	None	None
E46M160	R_ρ	e	p	ρ⁰ p	1.725	1.725	None	None
E46M161	R_ρ	e	p	ρ⁰ p	1.752	2.32	None	None
E46M162	R_ρ	e	p	ρ⁰ p	1.785	2.639	None	None
E46M163	R_ρ	e	p	ρ⁰ p	2.05	3.295	None	None
E46M164	R_ρ	e	p	ρ⁰ p	2.35	3.807	None	None
E46M165	R_ρ	e	p	ρ⁰ p	2.95	4.307	None	None
E46M166	R_ρ	e	p	ρ⁰ p	3.85	4.35	None	None
E46M167	R_ρ	e	p	ρ⁰ p	4.352	4.85	None	None
E46M168	R_ρ	e	p	ρ⁰ p	5.353	5.353	None	None
E46M169	σ_L	e	p	ρ⁰ p	1.725	5.353	1.88157	2.76629
E46M170	σ_L	e	p	ρ⁰ p	1.6	1.9	2.2114	2.76629
E46M171	σ_L	e	p	ρ⁰ p	1.9	2.2	2.09055	2.63458
E46M172	σ_L	e	p	ρ⁰ p	2.2	2.5	1.99874	2.70454
E46M173	σ_L	e	p	ρ⁰ p	2.5	2.8	2.09586	2.58305
E46M174	σ_L	e	p	ρ⁰ p	2.8	3.1	1.98752	2.42957
E46M175	σ_L	e	p	ρ⁰ p	3.1	3.6	2.08964	2.51033
E46M176	σ_L	e	p	ρ⁰ p	3.6	4.1	2.00745	2.21065
E46M177	σ_L	e	p	ρ⁰ p	4.1	4.6	1.91371	2.10688
E46M178	σ_L	e	p	ρ⁰ p	4.6	5.1	1.99516	1.99516
E46M179	σ_L	e	p	ρ⁰ p	5.1	5.6	1.88157	1.88157
E46M180	dσ_L/dt	e	p	ρ⁰ p	1.725	1.725	None	None
E46M181	dσ_L/dt	e	p	ρ⁰ p	1.752	1.752	None	None
E46M182	dσ_L/dt	e	p	ρ⁰ p	2.042	2.042	None	None
E46M183	dσ_L/dt	e	p	ρ⁰ p	2.32	2.32	None	None
E46M184	dσ_L/dt	e	p	ρ⁰ p	1.785	1.785	None	None
E46M185	dσ_L/dt	e	p	ρ⁰ p	2.05	2.05	None	None
E46M186	dσ_L/dt	e	p	ρ⁰ p	2.35	2.35	None	None
E46M187	dσ_L/dt	e	p	ρ⁰ p	2.639	2.639	None	None
E46M188	dσ_L/dt	e	p	ρ⁰ p	2.05	2.05	None	None
E46M189	dσ_L/dt	e	p	ρ⁰ p	2.35	2.35	None	None
E46M190	dσ_L/dt	e	p	ρ⁰ p	2.65	2.65	None	None
E46M191	dσ_L/dt	e	p	ρ⁰ p	2.95	2.95	None	None
E46M192	dσ_L/dt	e	p	ρ⁰ p	3.295	3.295	None	None
E46M193	dσ_L/dt	e	p	ρ⁰ p	2.35	2.35	None	None
E46M194	dσ_L/dt	e	p	ρ⁰ p	2.65	2.65	None	None
E46M195	dσ_L/dt	e	p	ρ⁰ p	2.95	2.95	None	None
E46M196	dσ_L/dt	e	p	ρ⁰ p	3.35	3.35	None	None
E46M197	dσ_L/dt	e	p	ρ⁰ p	3.807	3.807	None	None
E46M198	dσ_L/dt	e	p	ρ⁰ p	2.95	2.95	None	None
E46M199	dσ_L/dt	e	p	ρ⁰ p	3.35	3.35	None	None
E46M200	dσ_L/dt	e	p	ρ⁰ p	3.85	3.85	None	None

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CLAS Physics Database

N/A

Measurements