CLAS Physics Database

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Measurement E179M16

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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−φ_R}),
Beam spin asymmetry sin(2φ_h−φ_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−φ_R})	Data errors	Systematic errors
3.534	0.309	0.501	0.591	0.169	0.0119641	0.00929926	0.00112912752822237
3.429	0.284	0.493	0.568	0.311	-0.0069775	0.00885382	0.00210464234362806
3.221	0.259	0.481	0.553	0.426	0.00841837	0.00791197	0.00111633517525679
3.123	0.244	0.474	0.541	0.533	0.00645107	0.00743461	0.000593191636870149
3.027	0.231	0.464	0.532	0.653	-0.00808863	0.00622936	0.00119201844721155
2.759	0.204	0.454	0.531	0.864	-0.00813169	0.00488579	0.00059034487496621
2.897	0.226	0.946	0.56	0.16	-0.000679581	0.00454374	0.000355601079716604
2.865	0.221	0.915	0.566	0.306	-0.00864188	0.00498138	0.00108591581576447
2.837	0.217	0.894	0.57	0.422	0.00088889	0.00546824	0.00193810035697358
2.752	0.207	0.876	0.57	0.53	-0.0258545	0.00665779	0.00323050017561236
2.677	0.199	0.858	0.574	0.648	-0.00920303	0.00561535	0.00191950978156441
2.528	0.182	0.832	0.586	0.852	-0.0283835	0.00873555	0.00190544030508124