References - Bogoliubov Laboratory of Theoretical Physics - JINR

Dependence of the AA fit parameters on the kinematical variables are shown in Figs.
3-7.
h
=Ad
0
/D
const
a
0.3
0.25
0.2
0.15
0.1
0.05
0
COMPASS 2002-4
HADRON ASYMMETRY
from L-POLARIZED D-TARGET
-
h
+ THIS WORK
h
-
h+ h
A
h d
P R E L I M I N A R Y
-2
10
-1
10
x
const
a
0.03
0.02
0.01
0
-0.01
COMPASS 2002-4
HADRON ASYMMETRY
from L-POLARIZED D-TARGET
P R E L I M I N A R Y
-0.02 -
h
+
h
-0.03
0.1 0.2 0.3 0.4 0.5 0.6 0.7
z
const
a
0.03
0.02
0.01
0
-0.01
COMPASS 2002-4
HADRON ASYMMETRY
from L-POLARIZED D-TARGET
P R E L I M I N A R Y
-0.02 -
h
+
h
-0.03
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
T
ph,GeV/c
Figure 3: Dependence of the AA fit parameters a const on kinematical variables.
The parameters aconst (x), being divided by the virtual photon depolarization factor D0,
are equal (by definition) to the asymmetry Ah d (x), already published by COMPASS [13].
Agreement of these data and data of the present analysis has demonstrated internal
consistency of the results.
φ
sin
a
0.06
0.04
0.02
0
-0.02
-0.04
-0.06
COMPASS 2002-4
HADRON ASYMMETRY
from L-POLARIZED D-TARGET
-
h
+ COMPASS
h
-
π+
π HERMES
-2
10
P R E L I M I N A R Y
-1
10
x
φ
sin
a
0.03
0.02
0.01
0
-0.01
COMPASS 2002-4
HADRON ASYMMETRY
from L-POLARIZED D-TARGET
-0.02
I I N A R Y
-
M
h -
+
h P R E L
π
COMPASS HERMES + π
-0.03
0.1 0.2 0.3 0.4 0.5 0.6 0.7
z
φ
sin
a
0.03
0.02
0.01
0
-0.01
COMPASS 2002-4
HADRON ASYMMETRY
from L-POLARIZED D-TARGET
P R E L I M I N A R Y
-0.02 -
h
+
h COMPASS
-
π
HERMES + π
-0.03
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
pT,GeV/c
h
Figure 4: Dependence of the AA fit parameters a sin φ on kinematical variables and similar data of
HERMES [8] for identified leading pions.
The x-dependence of the sin(φ) modulations of the AA, observed by HERMES, is less
pronounced at COMPASS. This modulation is due to pure twist-3 PDF’s entering from
the dσ0L contribution to the AA with a factor Mx/Q.
φ
sin2
a
0.06
0.04
0.02
0
−0.02
−0.04
−0.06
COMPASS 2002−4
HADRON ASYMMETRY
from L−POLARIZED D−TARGET
−
h +
h
−
π + π
−2
10
COMPASS
HERMES
P R E L I M I N A R Y
−1
10
x
φ
sin2
a
0.03
0.02
0.01
0
-0.01
COMPASS 2002-4
HADRON ASYMMETRY
from L-POLARIZED D-TARGET
-0.02 -
h
+
h
-0.03
0.1 0.2 0.3 0.4 0.5 0.6 0.7
P R E L I M I N A R Y
z
φ
sin2
a
0.03
0.02
0.01
0
-0.01
COMPASS 2002-4
HADRON ASYMMETRY
from L-POLARIZED D-TARGET
P R E L I M I N A R Y
-0.02 -
h
+
h
-0.03
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
pT,GeV/c
h
Figure 5: Dependence of the AA fit parameters a sin 2φ on kinematical variables compared to the data
of HERMES and calculations by H.Avakian et al. [14]: dashed line – h − , solid line – h + .
The amplitudes of the sin(2φ) modulations are small, consistent with zero within the
errors. They could be caused by PDF h⊥ 1L in dσ0L.
335