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Feasibility of the detection of D0 mesons in the NA61/SHINE experiment:
Vertex detector for NA61/SHINE
P. Staszel and Yasir AliJagiellonian University
Silicon Detector Workshop, Split, 8-10 October 2012
Silicon Detector Workshop, Split, 8-10 October 2
Outline
1. Current NA61/SHINE experimental setup
2. Motivations for vertex detector
3. Particle fluxes in Pb+Pb at 158 AGeV
4. Particle density in central Pb+Pb
5. Tentative idea
6. Some results for D0→ K+ π-
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Silicon Detector Workshop, Split, 8-10 October 3
NA61/SHINE detector
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Silicon Detector Workshop, Split, 8-10 October 4
NA61/SHINE detector – top view VTPC2
Silicon Detector Workshop, Split, 8-10 October 5
NA61/SHINE detector – top view VTPC2
Vertex Detector (VD)
Silicon Detector Workshop, Split, 8-10 October 6
Physics Motivations
1. No rare probes measurement below top SPS (158AGeV) energy
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Int. J. Mod. Phys. E17 1367
Silicon Detector Workshop, Split, 8-10 October 7
Physics Motivations
2. Measurement of J/Ψ at top SPS energy (NA50,NA60) was performed → anomalous suppression
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Silicon Detector Workshop, Split, 8-10 October 8
Physics Motivations
3. Statistics should allow for differential analysis: spectra, RAA
, v2
4. Measurement of Λ
c and improvement in the multi-strange hyperon
measurement
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Silicon Detector Workshop, Split, 8-10 October 9
Vertex detector in geant4
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VDS1 VDS1VDS2 VDS4
Helium Vessel
Silicon Detector Workshop, Split, 8-10 October 10
Vertex detector in geant4 – zoom in
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Pb target
Silicon Detector Workshop, Split, 8-10 October 11
Charged Particle Fluxes
1. Charged particles produced in Pb+Pb interactions. - during spill the anticipated beam intensity is 105 Pb ions per second. - for 200 μm Pb target interaction probability is 0.5% which leads to 500 Hz interaction rate - used AMPT to generate 100k min. bias Pb+Pb at 158 AGeV
2. Delta electrons produced mostly in target - study 10k Pb ions passing through the lead target - soft particles – surrounding material might be important - production threshold cut in geant4: minimum distance that produced particle will travel in a given material → translates to cut on energy If the distance is (too) small – a lot of soft particles is produced (CPU consumption) If the distance is (too) large – important component might not be described
→ the influence of the production threshold cut has to be studied
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Silicon Detector Workshop, Split, 8-10 October 12
AMPT Event: Pb+Pb at 158GeV
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Silicon Detector Workshop, Split, 8-10 October 13
Charged particles produced in Pb+Pb interactions
1.
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Silicon Detector Workshop, Split, 8-10 October 14
Charged particles produced in Pb+Pb interactions
1.
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Silicon Detector Workshop, Split, 8-10 October 15
Charged particles produced in Pb+Pb interactions
1.
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Silicon Detector Workshop, Split, 8-10 October 16
Charged particles produced in Pb+Pb interactions
1.
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Silicon Detector Workshop, Split, 8-10 October 17
Pb electromagnetic interaction
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Silicon Detector Workshop, Split, 8-10 October 18
Pb electromagnetic interaction – zoom in
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Silicon Detector Workshop, Split, 8-10 October 19
Delta electrons: results (averaged over 10k Pb events)
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Silicon Detector Workshop, Split, 8-10 October 20
Delta electrons: results II
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Hadronic interactions:flux = (105 * 0.005) event/s * 1.6 particles/mm2/event == 800 particles/mm2/s = 800 Hz/mm2
Electromagnetic interactions (δ-electrons):flux = 105 event/s * 0.04 particles/mm2/event == 4000 Hz/mm2
Silicon Detector Workshop, Split, 8-10 October 21
1.
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Charged particles produced in Pb+Pb 0-10% central interactions
Silicon Detector Workshop, Split, 8-10 October 22
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Charged particles produced in Pb+Pb 0-10% central interactions
13mm
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1. Pixels cover area where hits/mm2 > 0.5
2. some overlap between pixels and MicroMegas
3. Inner (pixel) structure is composed of detectors equipped with a single Timepix chip - active dimension 14x14 mm2
Preliminary drawing of the 1-st station
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D0→ K+ π- , 200k 0-10% cent. Pb+Pb at 158 AGeV
S/B=13For 50M events:SNR = 19340k D0+D0bar
S/B=15For 50M events:SNR = 17834k D0+D0bar
S/B=6.6For 50M events:SNR = 16331k D0+D0bar
S/B=9.6For 50M events:SNR = 15526k D0+D0bar
Silicon Detector Workshop, Split, 8-10 October 25
Backup Slides
Silicon Detector Workshop, Split, 8-10 October 26
Delta electrons: study effect of production threshold cuts
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Silicon Detector Workshop, Split, 8-10 October 27
Delta electrons: study effect of production threshold cuts
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