Forward Neutral Pion Production in p+p and d+Au Collisions at sqrt(sNN)=200 GeV
J. Adams et al., Phys. Rev. Lett. 97 (2006) 152302.


Figure 1: Inclusive pi0 production cross section for p+p collisions.

The data were accumulated with the calorimeters in 3 separate positions. The <eta>=3.3 and <eta>=3.8 were taken with a prototype Forward Pi-zero Detector (PFPD), and the <eta>=4.00 data were taken with the complete FPD.

The normalization uncertainty for the data in Figure 1 is 16% (E_pi independent), and is uncorrelated between the different data sets.

Data from 3.7<eta<4.15 were selected, giving <eta>=4.00:
E_pi bin boundary (low) (GeV)
 E_pi bin boundary (high) (GeV)
 <E_pi> (GeV)
 <p_T,pi> (GeV/c)
 E*d^3sigma/dp^3 (microbarn*c^3/GeV^2)
 statistical error (microbarn*c^3/GeV^2)
 point-to-point systematic error (microbarn*c^3/GeV^2)
25
 30
 27.2
 1.01
 77.9
 0.9
 6.0
30
 35
 32.1
 1.19
 25.7
 0.4
 2.2
35
 40
 37.1
 1.37
 7.92
 0.10
 0.74
40
 45
 42.1
 1.56
 2.63
 0.05
 0.29
45
 50
 47.1
 1.73
 0.90
 0.03
 0.11
50
 55
 52.0
 1.94
 0.302
 0.025
 0.049


Data from 3.4<eta<4.0 were selected, giving <eta>=3.8:
E_pi bin boundary (low) (GeV)
 E_pi bin boundary (high) (GeV)
 <E_pi> (GeV)
 <p_T,pi> (GeV/c)
 E*d^3sigma/dp^3 (microbarn*c^3/GeV^2)
 statistical error (microbarn*c^3/GeV^2)
 point-to-point systematic error (microbarn*c^3/GeV^2)
30
 35
 32.2
 1.48
 10.8
 0.1
 2.4
35
 40
 37.1
 1.68
 3.68
 0.06
 0.66
40
 45
 42.1
 1.88
 1.00
 0.03
 0.16
45
 50
 47.1
 2.08
 0.342
 0.015
 0.066
50
 55
 51.9
 2.25
 0.084
 0.006
 0.021


Data from 3.05<eta<3.45 were selected, giving <eta>=3.3:
E_pi bin boundary (low) (GeV)
 E_pi bin boundary (high) (GeV)
 <E_pi> (GeV)
 <p_T,pi> (GeV/c)
 E*d^3sigma/dp^3 (microbarn*c^3/GeV^2)
 statistical error (microbarn*c^3/GeV^2)
 point-to-point systematic error (microbarn*c^3/GeV^2)
30
 35
 32.2
 2.34
 0.571
 0.018
 0.057
35
 40
 37.1
 2.74
 0.141
 0.008
 0.016
40
 45
 42.3
 3.01
 0.0422
 0.0043
 0.0052
45
 50
 46.9
 3.40
 0.0134
 0.0022
 0.0035




Figure 2: Inclusive pi0 production cross section for d+Au collisions.

The data were accumulated with the complete FPD. The data that are presented in Figure 2 were scaled by the number of binary collisions in order to facilitate comparison with the data in Figure 1. Here we present the data without and with this scale factor.

The normalization uncertainty for the data in Figure 2 is 16% (E_pi independent).

Data from 3.7<eta<4.15 were selected, giving <eta>=4.00:
E_pi bin boundary (low) (GeV)
 E_pi bin boundary (high) (GeV)
 <E_pi> (GeV)
 <p_T,pi> (GeV/c)
 E*d^3sigma/dp^3 (microbarn*c^3/GeV^2)
 statistical error (microbarn*c^3/GeV^2)
 point-to-point systematic error (microbarn*c^3/GeV^2)
25
 30
 27.1
 1.03
 9900
 100
 1500
30
 35
 32.2
 1.21
 2750
 40
 290
35
 40
 37.2
 1.38
 970
 20
 120
40
 45
 42.1
 1.55
 315
 11
 48
45
 50
 47.1
 1.72
 110
 6
 25
50
 55
 52.0
 1.91
 46
 4
 10


Data scaled by the number of binary collisions (as presented in Figure 2):
E_pi bin boundary (low) (GeV)
 E_pi bin boundary (high) (GeV)
 <E_pi> (GeV)
 <p_T,pi> (GeV/c)
 1/(2*197)*E*d^3sigma/dp^3 (microbarn*c^3/GeV^2)
 statistical error (microbarn*c^3/GeV^2)
 point-to-point systematic error (microbarn*c^3/GeV^2)
25
 30
 27.1
 1.03
 25.1
 0.3
 3.9
30
 35
 32.2
 1.21
 6.98
 0.10
 0.73
35
 40
 37.2
 1.38
 2.47
 0.05
 0.30
40
 45
 42.1
 1.55
 0.80
 0.03
 0.12
45
 50
 47.1
 1.72
 0.279
 0.014
 0.064
50
 55
 52.0
 1.91
 0.116
 0.011
 0.026




Figure 3: Nuclear modification factor for minimum-bias d+Au collisions.

These data are ratios of the data from figures 2 and 1. The p_T-dependent uncertainties have been added in quadrature. The normalization uncertainty for the data in Figure 3 is 17% (p_T independent).

STAR data for pi0 mesons at <eta>=4.00:
<p_T,pi> (GeV/c)
 R_dAu
 statistical error
 point-to-point systematic error
1.03
 0.322
 0.005
 0.056
1.21
 0.272
 0.006
 0.036
1.38
 0.311
 0.008
 0.048
1.55
 0.303
 0.012
 0.057
1.72
 0.309
 0.019
 0.081
1.91
 0.38
 0.05
 0.11

The data for negative hadrons at smaller values of eta come from the BRAHMS Collaboration website.



Figure 4: Coincidence probability versus azimuthal angle difference between the forward pi0 and a leading charged particle at midrapidity

The data are shown in two tables (bins) of pi0 meson energy. The data are the number of events as a function of azimuthal angle difference between a pi0 meson at <eta>=4.00 and the leading charged particle (LCP) at |eta|<0.75 with p_T>0.5 GeV/c, scaled by the number of pi0 mesons in that energy bin.

25<E_pi<30 GeV:
phi_pi - phi_LCP (radians)
 p+p coincidence probability (radians^-1)
 p+p statistical error (radians^-1)
 d+Au coincidence probability (radians^-1)
 d+Au statistical error (radians^-1)
0.35
 0.083
 0.003
 0.137
 0.007
1.05
 0.084
 0.003
 0.144
 0.007
1.75
 0.097
 0.003
 0.139
 0.007
2.44
 0.114
 0.004
 0.149
 0.007
3.14
 0.121
 0.004
 0.154
 0.007
3.84
 0.119
 0.004
 0.148
 0.007
4.54
 0.095
 0.003
 0.140
 0.007
5.24
 0.089
 0.003
 0.146
 0.007
5.93
 0.083
 0.003
 0.141
 0.007


30<E_pi<55 GeV:
phi_pi - phi_LCP (radians)
 p+p coincidence probability (radians^-1)
 p+p statistical error (radians^-1)
 d+Au coincidence probability (radians^-1)
 d+Au statistical error (radians^-1)
0.35
 0.079
 0.003
 0.127
 0.008
1.05
 0.085
 0.003
 0.139
 0.008
1.75
 0.096
 0.004
 0.141
 0.008
2.44
 0.119
 0.004
 0.155
 0.008
3.14
 0.128
 0.004
 0.156
 0.008
3.84
 0.117
 0.004
 0.169
 0.009
4.54
 0.105
 0.004
 0.138
 0.008
5.24
 0.085
 0.003
 0.131
 0.008
5.93
 0.075
 0.003
 0.131
 0.008


Last updated 14 February 2006
by G. Rakness (Gregory.Rakness@cern.ch)