CLAS Physics Database

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Measurement E179M23

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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 z, 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 (−φ_h+2φ_R}),
Beam spin asymmetry sin(−φ_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 (−φ_h+2φ_R})	Data errors	Systematic errors
3.129	0.22	0.464	0.4	0.598	0.0112874	0.00660137	0.00132443256354091
3.21	0.244	0.468	0.474	0.61	-0.000533796	0.00685607	0.000526779987874587
3.131	0.248	0.472	0.528	0.608	0.00127454	0.0064317	0.000699477978967493
3.107	0.254	0.47	0.579	0.59	-0.00246362	0.00688905	0.00158508342839829
3.021	0.253	0.478	0.638	0.556	0.00805179	0.00640232	0.00119632464972421
2.825	0.234	0.482	0.727	0.5	0.0150553	0.00746905	0.00166767103349953
2.764	0.192	0.821	0.404	0.386	-0.0244509	0.00577767	0.0007362834358267
2.847	0.209	0.859	0.474	0.427	-0.0186648	0.00553041	0.00136146518172065
2.862	0.218	0.88	0.528	0.451	-0.0282167	0.00452298	0.00103424171674529
2.85	0.223	0.9	0.58	0.466	-0.0292047	0.00544723	0.0011793807081504
2.785	0.221	0.921	0.638	0.467	-0.0228124	0.00501054	0.001301136465257
2.628	0.202	0.958	0.731	0.438	-0.0291538	0.00512626	0.00152798130881471