DJ_RES: the results container for DJANGOH program

The DJANGOH program is a powerful tool for radiative corrections computation for HERA. It's the only program that allows to operate with arbitrary measurable variables.

It's very efficient when the leptonic variables are used. But the single calculation in hadronic variables with DJANGOH may takes several hours or days. Therefore the simple container of precalculated DJANGOH results is created.

The container (Fortran or ROOT) function reads precalculated data and returns the value of relative correction ratio for specified point.

See also the definitions section and example plots below.

See manual and comments in file headers for more details.

Definitions

Delta:delta
ZEUS variables:vars
The sum here covers all the hadronic remnants and radiative photon, if it's not escaped into the beam pipe:
vars

The ThetaPipe angle is set to 5o by default and can be changed at recalculation stage.

Variables with ThetaPipe=0o are leptonic.
Variables with ThetaPipe=90o are Jacquet-Blondel (JB).

TDjRes example #1

Location: DjResExampleYPlots() function in TDjRes.C file.
Creates the set of 1-dim plots for Delta at fixed 'x'.
Compares Delta plots for 3 various ".dat" files (djangoh_r_1.dat,djangoh_r_2.dat and djangoh_r_3.dat).

Let's test it on JB, leptonic and ZEUS (same link as above) variable data sets.
Result (green=leptonic, blue=ZEUS, red=JB):
example1
We can see that ZEUS-variables plot is usually between leptonic and JB ones. And radiative correction in ZEUS variables is mostly close to zero (in contrast to Lept. and JB plots).

TDjRes example #2

Location: DjResExample2D() function in TDjRes.C file.
Creates the 2D diagrams in {x,Q2} axes.
The plots are composed for delta, error and 2 separated plots for statistical and systematical errors.
For ZEUS-variable data set we have:
example2

TDjResEvt examples

Note: TDjResEvt class is used for debug only. It operates with number-of-events files (".evts"). And provides the same functions as TDjRes. It can also convert events data to djangoh_r_200.dat file (to counter-check Djangoh User procedure). See TDjResEvt.C file header for further comments.

TDjResEvt example #1

Location: DjResEvtExample() function in TDjResEvt.C file.
Same to TDjRes.C example #1, but deals with events file.
Creates 1D plots for ZEUS, JB and leptonic Delta (or number of events) values. The 'x' is fixed to 0.01,0.03,0.1 and 0.4. See function header to change parameters.
Uses djangoh_r.evts (e.g. djangoh_r_1.evts from the table above) and djangoh_r_200.born files.
Result (green=leptonic, blue=ZEUS, red=JB):
evt example 1
Next, the number-of-events plots produced by same example function. Colors: green=leptonic, blue=ZEUS, red=JB events.
Black line is the Born events estimation.
evt example 1b
The 'Delta' value is a ratio of blue and black lines here (minus unit).
One can see sufficient fluctuations of the blue line. That's the origin of huge errors for 'Delta' at x>0.3 region.

TDjResEvt example #2

Location: DjResEvtExampleConvert() function in TDjResEvt.C file.
Combines several ".evts" files into the single ".dat" file.
Note: the same procedure for ZEUS variables is performed automatically in Djangoh User procedure.
The leptonic and JB result files were created using this example and all the event files from the table above.
The djangoh_r_200.born file was also used.

Please contact me in case of any problem/question: Vladimir.Makarenko@desy.de

Last updated on 14.04.2009.