E895 JTF Multiplicity Cuts
|
1.85 AGeV |
3.91 AGeV |
6.0 AGeV |
8.0 AGeV |
| 2 fm
(1.8 %) |
190 |
260 |
285 |
320 |
| 3 fm
(4.2 %) |
175 |
235 |
260 |
290 |
| 4 fm
(7.4 %) |
160 |
210 |
230 |
260 |
| 5 fm
(12 %) |
140 |
180 |
200 |
225 |
| 6 fm
(17 %) |
125 |
155 |
170 |
190 |
| 7 fm
(23 %) |
105 |
120 |
135 |
145 |
| 8 fm
(30 %) |
85 |
90 |
95 |
105 |
| 9 fm
(38 %) |
60 |
60 |
60 |
60 |
Notes:
(1) The percent cross section indicated within the parentheses relates
to the measured total reaction cross section for Au+Au at 10.6 AGeV which
is 6.78 barns, and not to a geometric cross section for two 7.1 fm gold
nuclei which would be 6.33 barns.
(2) The Mcuts for 2 AGeV-9 fm, and for 4 AGeV-8,9 fm are estimated by
extrapolating the systematics. The effective trigger bias for the min bias
runs for these two energies are 8.1 and 7.7 fm respectively.
(3) The statistical uncertainty in determining the precise location of for
the cuts is about 4 units (determined by calculating cuts for adjacent
runs independently). This poor resolution is because of the low number of
runs used for the trigger bias study. The Mcuts have been rounded to the
nearest five so as not imply any greater precision of these cuts.
(4) The precision of the trigger bias determination is about 0.4 fm for
the most peripheral bin. The effective precision of the low impact
parameter bins would be greater, but the correlation between Multiplicity
and impact parameter may get worse. We suggest that the error in the
estimated impact parameter should be quoted at 0.5 fm although a study of
the dispersion in Multiplcity from RQMD events should be done to properly
estimate this systematic error.
(5) These Mcuts were determined using a track quality criterium of DCA <
2.5 cm. When using these Mcuts no other track quality cuts should be used
when determining event multiplicity for the purpose of centrality
selection.
Mulitiplicity Distributions (with a DCA < 2.5 cm track quality cut):
GIF
PS
JTF/BTF Comparison:
GIF
PS
