Hard pT weighting in MC

 Here is the Comparison of event weighting of hard pT by using N_generated and N_tried.
The weighting for Lambda pT 3~4 GeV/c is used as the example.

The following table shows the weight comparison obtained from the number of generated and tried.
First, we calculate the absolutely weight(= xsection/nevents)
Then the relative weight to the lowest hard_pt bin is shown in the table.

Hard pT Weighting for Lambda pT 3~4 GeV/c
pt_hard cross section N_events relative weight W_generate / W_tried
    generated tried generated tried

 

3~4

2.921E+00

402,982,359

1,751,444,204

1.000E+00

1.000E+00

1.00

4~5

7.084E-01

131,118,743

602,943,376

7.453E-01

7.044E-01

0.95

5~6

2.212E-01

54,106,666

231,196,237

5.639E-01

5.735E-01

1.02

6~8

1.159E-01

29,195,821

173,647,879

5.478E-01

4.003E-01

0.73

8~15

3.190E-02

9,606,555

52,954,659

4.581E-01

3.612E-01

0.79

15+

7.960E-04

3,524,413

21,956,043

3.115E-02

2.173E-02

0.70

The source of numbers in the table is the log file:
This Statistics is shown the generation log file.
The numbers in the table are corresponding to the picture. 

The row of NUMBER OF EVENTS PROCESSED = 100 is the number passed the Lambda filter and stored in the output file.
Details of the Lambda filter can be found:
https://drupal.star.bnl.gov/STAR/blog/jcmei/lambda-filter-used-mc-sample-production

The sum of number in the position of "47792" from each log file is the number of N_events of generated in the table.
The sum of number in the position of "216434" from each log file is the number of N_events of tried in the table.
MC_genration log pic

 Then we did the testing with both of the two weights method.

The comparison shows that the hard pT distribution weighed by the weight_generated is better the the weight_tried.

Here, the weight estimated using the number of events generated will be used.