CLAS Physics Database

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Measurement E152M1

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Experiment: g11, 2016

Spokespersons: R. Dickson, R. A. Schumacher

Experiment comment:

The CLAS Collaboration at Thomas Jefferson National Accelerator Facility measured the reaction gamma + p--> f1(1285) + p over a wide range of W and meson production angles. The results summarized below are from the Ph.D. work of Ryan Dickson, in collaboration with Professor Reinhard A. Schumacher, at Carnegie Mellon University in Pittsburgh, Pennsylvania. The thesis work was completed in July 2011. The thesis was entitled "Photoproduction of the f1(1285)/eta(1295) Mesons Using CLAS at Jefferson Lab". The thesis is available at www.jlab.org/Hall-B/general/clas_thesis.html. There are two CLAS Analysis Notes associated with this work as well. The first is "Spin-Parity Determination of the f1(1285)/eta(1295) Meson Signal in the CLAS/g11 Data," Note 2015-102, dated 22-Sep-2015. The second is "Investigation of a Combinatoric Background Effect on the f1(1285) Cross Sections from the CLAS/g11 Data," Note 2016-102, dated 9-Apr-2016. The analysis notes are on the CLAS web site (collaboration-private documents).

All known corrections were applied to the yield extraction, normalization, and acceptance calculations in these data. The error bars are essentially statistical but include the fit uncertainties associated with background subtraction. The column headings below should be self-explanatory.

For each of five bins in W that are each 100 MeV wide (centered at 2.35, 2.45, ... , 2.75 GeV), the differential cross sections are tabulated at nine f1(1285) production angles. Note that the widths of the angle bins are 0.2 in cosine of the production angle, except for the most forward bin that is only 0.1 wide. Bin-to-bin systematic uncertainties are given below as well, and these represent mainly the level of consistency of the eta-prime cross sections extracted in this analysis in comparison to previous published CLAS cross sections. In addition, there are global systematic uncertainties, as discussed in the publication, of between 11% and 14%. The table below should be identical in content to the Appendix in the publication.

Publication:

R. Dickson, R. A. Schumacher et al. (CLAS Collaboration) Photoproduction of the $\f_1 (1285)$ Meson // Physical Review C 93, 065202 (2016) arXiv:1604.07425 [nucl-ex]

Quantity measured: dσ/dΩ, nb/sr
Differential cross section.
Beam: γ, polarization: none
Target: p (Z=1, A=1), polarization: none
Final state: f₁(1285), polarization: none

W :	2.35 — 2.75 GeV

Select data slice:
W = GeV

Observable quantity measured (Y axis): dσ/dΩ, nb/sr
Plot measurement data

Parameter (X axis): cos(θ),

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Measured data:

W, GeV	cos(θ)	dσ/dΩ, nb/sr	Data errors, nb/sr	Systematic errors, nb/sr
2.35	-0.7	5.96	0.57	1.57
2.35	-0.5	4.7	0.45	0.66
2.35	-0.3	6.42	0.54	0.9
2.35	-0.1	8.37	0.74	1.26
2.35	0.1	8.29	0.67	1.17
2.35	0.3	7.81	0.64	1.26
2.35	0.5	7.42	0.76	1.05
2.35	0.7	5.01	0.58	0.7
2.35	0.85	3.18	1	0.45
2.45	-0.7	2.8	0.4	0.93
2.45	-0.5	6.42	0.6	1.07
2.45	-0.3	6.39	0.63	1.32
2.45	-0.1	5.73	0.48	0.75
2.45	0.1	7.29	0.52	1.04
2.45	0.3	8.1	0.6	1.96
2.45	0.5	6.58	0.62	1.16
2.45	0.7	6.68	0.59	1.45
2.45	0.85	2.16	1.05	0.26
2.55	-0.7	4.22	0.49	0.88
2.55	-0.5	3.5	0.3	0.44
2.55	-0.3	4.38	0.51	1.46
2.55	-0.1	5.37	0.42	1.1
2.55	0.1	6.57	0.48	1.08
2.55	0.3	6.7	0.52	1.01
2.55	0.5	12.12	0.78	2.66
2.55	0.7	9.7	1.04	1.46
2.55	0.85	7.95	1.1	2.2
2.65	-0.7	2.21	0.35	0.37
2.65	-0.5	2.58	0.33	0.39
2.65	-0.3	2.85	0.37	0.4
2.65	-0.1	3.73	0.31	0.84
2.65	0.1	3.03	0.28	0.86
2.65	0.3	4.26	0.43	0.86
2.65	0.5	8.4	0.49	1.4
2.65	0.7	9.81	1.06	2.4
2.65	0.85	0.5	1.06	1.9
2.75	-0.7	2.49	0.28	0.32
2.75	-0.5	1.55	0.26	0.2
2.75	-0.3	1.7	0.18	0.3
2.75	-0.1	1.71	0.28	0.44
2.75	0.1	1.95	0.19	0.25
2.75	0.3	4.01	0.41	1
2.75	0.5	5.15	0.45	1.82
2.75	0.7	9.26	0.9	1.29
2.75	0.85	5.73	1.21	0.74