Feasibility of the detection of D0 mesons in the NA61 ...
Transcript of Feasibility of the detection of D0 mesons in the NA61 ...
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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NA61/SHINE detector
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NA61/SHINE detector – top view VTPC2
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NA61/SHINE detector – top view VTPC2
Vertex Detector (VD)
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Physics Motivations
1. No rare probes measurement below top SPS (158AGeV) energy
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Int. J. Mod. Phys. E17 1367
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Physics Motivations
2. Measurement of J/Ψ at top SPS energy (NA50,NA60) was performed → anomalous suppression
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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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Vertex detector in geant4
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VDS1 VDS1VDS2 VDS4
Helium Vessel
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Vertex detector in geant4 – zoom in
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Pb target
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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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AMPT Event: Pb+Pb at 158GeV
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Charged particles produced in Pb+Pb interactions
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Charged particles produced in Pb+Pb interactions
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Charged particles produced in Pb+Pb interactions
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Charged particles produced in Pb+Pb interactions
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Pb electromagnetic interaction
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Pb electromagnetic interaction – zoom in
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Delta electrons: results (averaged over 10k Pb events)
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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
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Charged particles produced in Pb+Pb 0-10% central interactions
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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
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Backup Slides
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Delta electrons: study effect of production threshold cuts
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Delta electrons: study effect of production threshold cuts
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