E99-107 CLAS experiment

Spokespersons: V. D. Burkert, R. Minehart
Year: 2005
Abstract: An extensive program is currently underway at the Jefferson Laboratory to study the excitation of nucleon resonances with electromagnetic probes. The CEBAF Large Acceptance spectrometer (CLAS) is well suited for the study of a broad rang of kinematics in the invariant mass W, photon virtuality Q^2, and has nearly complete angular coverage for the hadronic resonance decays. Until recently most of the resonance studies using electron beams have employed the single pi0 or eta channels to study the lower mass states, especially the Delta(1232) and the S_11(1535). Many of the higher mass resonances are isospin 1/2 states and couple more strongly to the n pi+ channel. The extraction of resonance information requires the analysis of the angular distribution in the hadronic center-of-mass system. With CLAS this channel becomes now fully accessible as the pi+ is measured in nearly the full azimuthal and polar angular ranges. High statistics data have been taken with a variety of beam energies ranging from 1.5 GeV to 5.75 GeV covering a Q^2 range from 0.3 to 3 GeV^2, and the full resonance mass range. The electron beam was polarized at about 70%. Data on invariant mass distributions for e p -> e' pi+ n is presented in this thesis. Three resonant enhancement can clearly be identified in all data sets belonging to the Delta(1232), D_13(1520), and F_15(1680) resonances. The latter two exhibit Q^2-dependences which are quite different from the Delta(1232).
Quantities: dσ/dΩ

Measurements

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ID	Quantity	Beam	Target	Final state	Q²_min, GeV²	Q²_max, GeV²	W_min, GeV	W_max, GeV
E14M101	dσ/dΩ	e	p	π⁺n	2.91	2.91	1.47	1.47
E14M102	dσ/dΩ	e	p	π⁺n	2.91	2.91	1.49	1.49
E14M103	dσ/dΩ	e	p	π⁺n	2.91	2.91	1.51	1.51
E14M104	dσ/dΩ	e	p	π⁺n	2.91	2.91	1.53	1.53
E14M105	dσ/dΩ	e	p	π⁺n	2.91	2.91	1.55	1.55
E14M106	dσ/dΩ	e	p	π⁺n	2.91	2.91	1.57	1.57
E14M107	dσ/dΩ	e	p	π⁺n	2.91	2.91	1.59	1.59
E14M108	dσ/dΩ	e	p	π⁺n	2.91	2.91	1.61	1.61
E14M109	dσ/dΩ	e	p	π⁺n	2.91	2.91	1.63	1.63
E14M110	dσ/dΩ	e	p	π⁺n	2.91	2.91	1.65	1.65
E14M111	dσ/dΩ	e	p	π⁺n	2.91	2.91	1.67	1.67
E14M112	dσ/dΩ	e	p	π⁺n	2.91	2.91	1.69	1.69
E14M113	dσ/dΩ	e	p	π⁺n	3.48	3.48	1.15	1.15
E14M114	dσ/dΩ	e	p	π⁺n	3.48	3.48	1.17	1.17
E14M115	dσ/dΩ	e	p	π⁺n	3.48	3.48	1.19	1.19
E14M116	dσ/dΩ	e	p	π⁺n	3.48	3.48	1.21	1.21
E14M117	dσ/dΩ	e	p	π⁺n	3.48	3.48	1.23	1.23
E14M118	dσ/dΩ	e	p	π⁺n	3.48	3.48	1.25	1.25
E14M119	dσ/dΩ	e	p	π⁺n	3.48	3.48	1.27	1.27
E14M120	dσ/dΩ	e	p	π⁺n	3.48	3.48	1.29	1.29
E14M121	dσ/dΩ	e	p	π⁺n	3.48	3.48	1.31	1.31
E14M122	dσ/dΩ	e	p	π⁺n	3.48	3.48	1.33	1.33
E14M123	dσ/dΩ	e	p	π⁺n	3.48	3.48	1.35	1.35
E14M124	dσ/dΩ	e	p	π⁺n	3.48	3.48	1.37	1.37
E14M125	dσ/dΩ	e	p	π⁺n	3.48	3.48	1.39	1.39
E14M126	dσ/dΩ	e	p	π⁺n	3.48	3.48	1.41	1.41
E14M127	dσ/dΩ	e	p	π⁺n	3.48	3.48	1.43	1.43
E14M128	dσ/dΩ	e	p	π⁺n	3.48	3.48	1.45	1.45
E14M129	dσ/dΩ	e	p	π⁺n	3.48	3.48	1.47	1.47
E14M130	dσ/dΩ	e	p	π⁺n	3.48	3.48	1.49	1.49
E14M131	dσ/dΩ	e	p	π⁺n	3.48	3.48	1.51	1.51
E14M132	dσ/dΩ	e	p	π⁺n	3.48	3.48	1.53	1.53
E14M133	dσ/dΩ	e	p	π⁺n	3.48	3.48	1.55	1.55
E14M134	dσ/dΩ	e	p	π⁺n	3.48	3.48	1.57	1.57
E14M135	dσ/dΩ	e	p	π⁺n	3.48	3.48	1.59	1.59
E14M136	dσ/dΩ	e	p	π⁺n	3.48	3.48	1.61	1.61
E14M137	dσ/dΩ	e	p	π⁺n	3.48	3.48	1.63	1.63
E14M138	dσ/dΩ	e	p	π⁺n	3.48	3.48	1.65	1.65
E14M139	dσ/dΩ	e	p	π⁺n	3.48	3.48	1.67	1.67
E14M140	dσ/dΩ	e	p	π⁺n	3.48	3.48	1.69	1.69
E14M141	dσ/dΩ	e	p	π⁺n	4.16	4.16	1.15	1.15
E14M142	dσ/dΩ	e	p	π⁺n	4.16	4.16	1.17	1.17
E14M143	dσ/dΩ	e	p	π⁺n	4.16	4.16	1.19	1.19
E14M144	dσ/dΩ	e	p	π⁺n	4.16	4.16	1.21	1.21
E14M145	dσ/dΩ	e	p	π⁺n	4.16	4.16	1.23	1.23
E14M146	dσ/dΩ	e	p	π⁺n	4.16	4.16	1.25	1.25
E14M147	dσ/dΩ	e	p	π⁺n	4.16	4.16	1.27	1.27
E14M148	dσ/dΩ	e	p	π⁺n	4.16	4.16	1.29	1.29
E14M149	dσ/dΩ	e	p	π⁺n	4.16	4.16	1.31	1.31
E14M150	dσ/dΩ	e	p	π⁺n	4.16	4.16	1.33	1.33
E14M151	dσ/dΩ	e	p	π⁺n	4.16	4.16	1.35	1.35
E14M152	dσ/dΩ	e	p	π⁺n	4.16	4.16	1.37	1.37
E14M153	dσ/dΩ	e	p	π⁺n	4.16	4.16	1.39	1.39
E14M154	dσ/dΩ	e	p	π⁺n	4.16	4.16	1.41	1.41
E14M155	dσ/dΩ	e	p	π⁺n	4.16	4.16	1.43	1.43
E14M156	dσ/dΩ	e	p	π⁺n	4.16	4.16	1.45	1.45
E14M157	dσ/dΩ	e	p	π⁺n	4.16	4.16	1.47	1.47
E14M158	dσ/dΩ	e	p	π⁺n	4.16	4.16	1.49	1.49
E14M159	dσ/dΩ	e	p	π⁺n	4.16	4.16	1.51	1.51
E14M160	dσ/dΩ	e	p	π⁺n	4.16	4.16	1.53	1.53
E14M161	dσ/dΩ	e	p	π⁺n	4.16	4.16	1.55	1.55
E14M162	dσ/dΩ	e	p	π⁺n	4.16	4.16	1.57	1.57
E14M163	dσ/dΩ	e	p	π⁺n	4.16	4.16	1.59	1.59
E14M164	dσ/dΩ	e	p	π⁺n	4.16	4.16	1.61	1.61
E14M165	dσ/dΩ	e	p	π⁺n	4.16	4.16	1.63	1.63
E14M166	dσ/dΩ	e	p	π⁺n	4.16	4.16	1.65	1.65
E14M167	dσ/dΩ	e	p	π⁺n	4.16	4.16	1.67	1.67
E14M168	dσ/dΩ	e	p	π⁺n	4.16	4.16	1.69	1.69

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CLAS Physics Database

E99-107 CLAS experiment

Measurements