CLAS Physics Database

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Measurement E179M20

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Experiment: SIDIS Dihadron Beam Spin Asymmetry, 2020

Spokespersons: C. Dilks, T. Hayward, A. Vossen

Experiment comment:
Process: ep→eπ⁺π^-X
Data tables have the following columns:

mean Q²
mean x
mean M_h, the dihadron invariant mass
mean z, of the pion pair
mean P_T, more commonly written P_h^⊥, is the component of the total dihadron momentum, transverse to q
A_LU amplitude, for a particular modulation
statistical uncertainty
systematic uncertainty

For each of the 7 asymmetry modulations, there are 4 tables, one for each binning scheme: (1) binned by x, (2) binned by M_h, (3) binned by z and M_h, and (4) binned by P_T and M_h.

Measurement comment: Binning scheme: bins of P_T, for M_h below and above 0.63 GeV

Publication:

T.B. Hayward, C. Dilks, A. Vossen, H. Avakian Observation of Beam Spin Asymmetries in the Process ep→eπ+π-X with CLAS12 // (submitted to PRL)

Quantity measured: A_LU^{sin (2φ_h−2φ_R}),
Beam spin asymmetry sin(2φ_h−2φ_R) moment
Beam: e, polarization: longitudinal
Target: p (Z=1, A=1), polarization: none
Final state: π π + X, polarization: none

Q² :	1 — 10.6 GeV²
W :	2 — 4 GeV
x_b :	0.06 — 0.77
E_beam :	10.6041 GeV

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Click here to get data in text file, delimited with tabs.

Measured data:

Q², GeV²	x	M(π⁺,π⁻), GeV	z	P_T, GeV	A_LU^{sin (2φ_h−2φ_R})	Data errors	Systematic errors
3.534	0.309	0.501	0.591	0.169	-0.0177303	0.0102352	0.00177072995995776
3.429	0.284	0.493	0.568	0.311	0.015255	0.0119629	0.00371389574113833
3.221	0.259	0.481	0.553	0.426	-0.00581823	0.0113189	0.000938669377404864
3.123	0.244	0.474	0.541	0.533	-0.0226012	0.0106563	0.00180172826721089
3.027	0.231	0.464	0.532	0.653	-0.0315085	0.00872679	0.00196043242315797
2.759	0.204	0.454	0.531	0.864	-0.022665	0.00637935	0.00105257285899213
2.897	0.226	0.946	0.56	0.16	0.0123849	0.00386825	0.0011971099478378
2.865	0.221	0.915	0.566	0.306	0.0187867	0.00431815	0.00169945006679322
2.837	0.217	0.894	0.57	0.422	0.0107962	0.00472372	0.00218951796532407
2.752	0.207	0.876	0.57	0.53	0.0366156	0.0059609	0.00281525607024257
2.677	0.199	0.858	0.574	0.648	0.0492061	0.00618709	0.00300940020594935
2.528	0.182	0.832	0.586	0.852	0.0813171	0.00737058	0.00504975317509508