11 february 2008 compass trigger meeting i. uman important reaction channels and the trigger...
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![Page 1: 11 February 2008 Compass Trigger Meeting I. Uman Important reaction channels and the trigger concepts of former experiments Proposed Reactions @ 190 GeV/c](https://reader036.vdocument.in/reader036/viewer/2022072015/56649ebb5503460f94bc376c/html5/thumbnails/1.jpg)
11 February 2008 Compass Trigger Meeting I. Uman
Important reaction channels and the trigger concepts of former experiments
Proposed Reactions @ 190 GeV/c with COMPASS: central Production:
diffractive Scattering: what can we learn from WA102?
and E852?
ηηX Xp,πpπ
ππX Xp,πpπ 22
ππX Xp,pπ 2ηπX Xp,pπ
sf Xpppp
Xppπ
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11 February 2008 Compass Trigger Meeting I. Uman
E852 Detector
![Page 3: 11 February 2008 Compass Trigger Meeting I. Uman Important reaction channels and the trigger concepts of former experiments Proposed Reactions @ 190 GeV/c](https://reader036.vdocument.in/reader036/viewer/2022072015/56649ebb5503460f94bc376c/html5/thumbnails/3.jpg)
11 February 2008 Compass Trigger Meeting I. Uman
E852 Detector
Max Beam of 2x106 99%
Target Cylindrical (TCYL)Prop. Wire Chambers (TPX)
CPVA,CPVB,CPVC,EV, BV
Downs. Endcup Array (DEA)
(LGD)}
TDX4
![Page 4: 11 February 2008 Compass Trigger Meeting I. Uman Important reaction channels and the trigger concepts of former experiments Proposed Reactions @ 190 GeV/c](https://reader036.vdocument.in/reader036/viewer/2022072015/56649ebb5503460f94bc376c/html5/thumbnails/4.jpg)
11 February 2008 Compass Trigger Meeting I. Uman
E852 Trigger
nπηpπ 0
• Pretrigger on
BV and EV
• Level 1 trigger on
DEA CPVB CPVC TCYL PWC
• Level 2 fast trigger processor total energy and effective
mass of the LGD photon system,
‘able to handle up to 104 events/s’ at 10% dead time’:
- (#TCYL tracks)-(#TPX1 hits)-(#TPX2 hits)-Level 2 trigger:
example: @18GeV/c:
0-0-0-TriggerProcessorenergy –TriggerProcessoreta
example: @18GeV/c: 0-2-2-TriggerProcessorenergy -TriggerProcessoreta
nππηpπ
![Page 5: 11 February 2008 Compass Trigger Meeting I. Uman Important reaction channels and the trigger concepts of former experiments Proposed Reactions @ 190 GeV/c](https://reader036.vdocument.in/reader036/viewer/2022072015/56649ebb5503460f94bc376c/html5/thumbnails/5.jpg)
11 February 2008 Compass Trigger Meeting I. Uman
E852 Trigger
from NIM A 387 (1997) 377:
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11 February 2008 Compass Trigger Meeting I. Uman
WA102 Detector
(Omega + GAMS)
![Page 7: 11 February 2008 Compass Trigger Meeting I. Uman Important reaction channels and the trigger concepts of former experiments Proposed Reactions @ 190 GeV/c](https://reader036.vdocument.in/reader036/viewer/2022072015/56649ebb5503460f94bc376c/html5/thumbnails/7.jpg)
11 February 2008 Compass Trigger Meeting I. Uman
WA102 Detector description
• “telescope” of ten microstrip detectors to measure beam direction
• 60 cm hydrogen target + box counter (TB)
• fifteen 2mm pitch (A and B) MWPC + one 1mm pitch MWPC + two drift chambers (DC) to measure medium momentum charged tracks
• sixteen (eight left+eight right) 2 mm pitch (C) MWPC to measure slow proton
• system of microstrip detector placed at 5 m and at 10 m downstream to measure the outgoing fast track (350-450 GeV/c)
• two Čerenkov detectors Č1 and Č2(not in 2006) + three scintillator hodoscopes HY1(not in 2006), HY2, HY3(not in 2006) for charged particle identification
• GAMS-4000 electromagnetic calorimeter for photons
![Page 8: 11 February 2008 Compass Trigger Meeting I. Uman Important reaction channels and the trigger concepts of former experiments Proposed Reactions @ 190 GeV/c](https://reader036.vdocument.in/reader036/viewer/2022072015/56649ebb5503460f94bc376c/html5/thumbnails/8.jpg)
11 February 2008 Compass Trigger Meeting I. Uman
WA102 Trigger
• fast particle crossing the microstrip telescope
• coincidence between two scintillator counters (A1+A2) placed close to the microstrip detectors at 5 m and 10 m (A2 split in two vertical direction A2L and A2R in order to determine the y-direction)
• slow particle left [right] defined by one hit on any of the fourteen slabs of the slow proton counter left (SPCL) [SPCR] + a hit in the left [right] element of the target box counter + >one hit in each of the two planes of the C MWPC on the left [right] side of the target
• zero hit in the other three sides of the TB to reduce backward diffraction or excitations events
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11 February 2008 Compass Trigger Meeting I. Uman
WA102 Trigger
ππXXpppp sf ,
• slow left proton and a hit in A2(L) (LL trigger) or slow right right proton in A2(R) (RR trigger) exclude elastic scattering
• elastic scattering were reduced in the LR and RL case by requiring one hit in the in the downstream hodoscope HY1
example: @450 GeV/c:
LR
• observation of higher and f2(1270) in the LL or RR case which cannot be due to the trigger or acceptance (Phys. Lett. B 388(1996) 853)
• enhancement of glueball candidates at high pT
LL LL
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11 February 2008 Compass Trigger Meeting I. Uman
Conclusion
• Care has to be taken to choose of a correct trigger logic which does not bias physics in central production
(maximize azimuthal acceptance)
• A choice of a common trigger which includes CP and diffractive scattering would reduce the beam time request