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-

VTPC2

Silicon Detector Workshop, Split, 8-10 October 3

NA61/SHINE detector

VTPC2

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

VTPC2

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

VTPC2

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

VTPC2

Silicon Detector Workshop, Split, 8-10 October 9

Vertex detector in geant4

VTPC1

VTPC2

VDS1 VDS1VDS2 VDS4

Helium Vessel

Silicon Detector Workshop, Split, 8-10 October 10

Vertex detector in geant4 – zoom in

VTPC1

VTPC2

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

VTPC2Sources of particles hitting VD:

Silicon Detector Workshop, Split, 8-10 October 12

AMPT Event: Pb+Pb at 158GeV

VTPC1

VTPC2

Silicon Detector Workshop, Split, 8-10 October 13

Charged particles produced in Pb+Pb interactions

1.

VTPC1

VTPC2

Silicon Detector Workshop, Split, 8-10 October 14

Charged particles produced in Pb+Pb interactions

1.

VTPC1

VTPC2

Silicon Detector Workshop, Split, 8-10 October 15

Charged particles produced in Pb+Pb interactions

1.

VTPC1

VTPC2

Silicon Detector Workshop, Split, 8-10 October 16

Charged particles produced in Pb+Pb interactions

1.

VTPC1

VTPC2

Silicon Detector Workshop, Split, 8-10 October 17

Pb electromagnetic interaction

VTPC1

VTPC2

Silicon Detector Workshop, Split, 8-10 October 18

Pb electromagnetic interaction – zoom in

VTPC1

VTPC2

Silicon Detector Workshop, Split, 8-10 October 19

Delta electrons: results (averaged over 10k Pb events)

VTPC1

VTPC2

Silicon Detector Workshop, Split, 8-10 October 20

Delta electrons: results II

VTPC1

VTPC2

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.

VTPC1

VTPC2

Charged particles produced in Pb+Pb 0-10% central interactions

Silicon Detector Workshop, Split, 8-10 October 22

1.

VTPC1

VTPC2

Charged particles produced in Pb+Pb 0-10% central interactions

13mm

VTPC1

VTPC2

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

VTPC1

VTPC2

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

VTPC1

VTPC2

Silicon Detector Workshop, Split, 8-10 October 27

Delta electrons: study effect of production threshold cuts

VTPC1

VTPC2