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Monte Carlo simulation of the background for the Drell-Yan
reaction @ COMPASS
Monte Carlo simulation of the background for the Drell-Yan
reaction @ COMPASS
Marialaura Colantoni
Laboratory of Nuclear Problems
Dubna 14-12-2006
Marialaura Colantoni
Laboratory of Nuclear Problems
Dubna 14-12-2006
14-12-2006 M. Colantoni - JIRN Dubna 2
Aim of the simulationsAim of the simulations
+ A (+-) + X
Very small cross section (~ nbarn)�many from the beam and the
secondary interactions
+ A (+-) + X
Very small cross section (~ nbarn)�many from the beam and the
secondary interactions
14-12-2006 M. Colantoni - JIRN Dubna 3
Setup: muon_2006(*)Setup: muon_2006(*)
(*) + small modifications
Transverse polarized target magnet
14-12-2006 M. Colantoni - JIRN Dubna 4
Target regionTarget region
some more modifications possible: absorber to be inserted : detectors position around target
14-12-2006 M. Colantoni - JIRN Dubna 5
Simulation chainSimulation chain
Comgeant version 0.0.7.2 Internal generator Gheisha
100 GeV - beam all interactions activated
Coral 25 oct 2006 check-out Phast.7.28 root 4.03
Everything already installed on the Turin farmEverything already installed on the Turin farm
Comgeant version 0.0.7.2 Internal generator Gheisha
100 GeV - beam all interactions activated
Coral 25 oct 2006 check-out Phast.7.28 root 4.03
Everything already installed on the Turin farmEverything already installed on the Turin farm
14-12-2006 M. Colantoni - JIRN Dubna 6
Very preliminary results on background studies
Very preliminary results on background studies
14-12-2006 M. Colantoni - JIRN Dubna 7
Selection criteriaSelection criteria
Looking for every reconstructed vertex with: at least 2 or more tracks a definite momentum for each tracks a pair +-
No cut on vertex position or on kinematical
variables was applied (not yet)
Looking for every reconstructed vertex with: at least 2 or more tracks a definite momentum for each tracks a pair +-
No cut on vertex position or on kinematical
variables was applied (not yet)
14-12-2006 M. Colantoni - JIRN Dubna 8
StatisticsStatistics
Background events generated 2·106 Events reconstructed 105
Background events generated 2·106 Events reconstructed 105
14-12-2006 M. Colantoni - JIRN Dubna 9
StatisticsStatistics
Wall1 P & Wall1 N 309
Wall1 P & Wall2 N 318
Wall1 N & Wall2 P 0
Wall2 P & Wall2 N 0
Wall1-2 P & Wall1 N 0
Wall1-2 P & Wall2 N 0
Wall1-2 N & Wall1 P 0
Wall1-2 N & Wall2 P 0
Wall1-2 P & Wall1-2 N 0
14-12-2006 M. Colantoni - JIRN Dubna 10
no Wall requestedno Wall requested
14-12-2006 M. Colantoni - JIRN Dubna 11
no Wall requestedno Wall requested
E+ [GeV]
E-
[GeV
]
q2 [GeV]2
pT [GeV]
14-12-2006 M. Colantoni - JIRN Dubna 12
Wall requestedWall requestedWall1 p + Wall1 n Wall1 p + Wall2 n
vz [cm] vz
[cm]
q2 [GeV]2 q2 [GeV]2
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x1 x2 distributionsx1 x2 distributions
wall1 p-wall1 nwall1 p-wall2 n
no request
14-12-2006 M. Colantoni - JIRN Dubna 14
Only Drell-Yan eventsOnly Drell-Yan events
Events generated: 500 Events reconstructed: 246
Just for test
Events generated: 500 Events reconstructed: 246
Just for test
14-12-2006 M. Colantoni - JIRN Dubna 15
StatisticsStatistics
Wall1 P & Wall1 N 108
Wall1 P & Wall2 N 93
Wall1 N & Wall2 P 0
Wall2 P & Wall2 N 0
Wall1-2 P & Wall1 N 0
Wall1-2 P & Wall2 N 0
Wall1-2 N & Wall1 P 0
Wall1-2 N & Wall2 P 0
Wall1-2 P & Wall1-2 N 0
14-12-2006 M. Colantoni - JIRN Dubna 16
no Wall requestedno Wall requested
vz [cm]
vy [c
m]
vx [cm]
14-12-2006 M. Colantoni - JIRN Dubna 17
no Wall requestedno Wall requested
E+ [GeV]
E+
[GeV
]
q2 [GeV]2
pT [GeV] xf
14-12-2006 M. Colantoni - JIRN Dubna 18
Wall requestedWall requestedWall1 p + Wall1 n Wall1 p + Wall2 n
vz [cm]
vz [cm]
q2 [GeV]2 q2 [GeV]2
14-12-2006 M. Colantoni - JIRN Dubna 19
Conclusions & OutlookConclusions & Outlook
preliminary test of the simulation chain much more statistics to generate up to now no big problems found a lot of work to be done but…
preliminary test of the simulation chain much more statistics to generate up to now no big problems found a lot of work to be done but…
… the work is in progress
