1 / 21

The status of SVD-2 experiment on the search of charm production in pA -interactions at 70 GeV/c

The status of SVD-2 experiment on the search of charm production in pA -interactions at 70 GeV/c. V.Popov for SVD-2 collaboration (SINP Moscow, IHEP Protvino, JINR Dubna). SVD-2 experiment. Physics motivation : Measurement of total cross sections and comparison with QCD predictions

thuy
Download Presentation

The status of SVD-2 experiment on the search of charm production in pA -interactions at 70 GeV/c

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The status of SVD-2 experiment on the search of charm production in pA-interactions at 70 GeV/c V.Popov for SVD-2 collaboration (SINP Moscow, IHEP Protvino, JINR Dubna)

  2. SVD-2 experiment • Physics motivation: • Measurement of total cross sections and comparison with QCD predictions • Differences in the fragmentation ( D°, D±,) • Search for the "intrinsic charm" • Experimental goals: • total cross sections • differential cross sections over xF and pt • A-dependence

  3. SVD-2 experiment • Current estimate ofpp cc + X cross section • (E-161 experiment, 5 events) :( 1.6+1.1-0.7 )b • Expected number of charm events within a total of • 5107 hadronic events (current experiment statistics) • For (c,c) ~A113,000 events • For (c,c) ~ A0.75,300 events

  4. SVD-2 experiment • Charm creation cross sections for different energies

  5. SVD-2 experiment • Beam: • (Protvino U-70 accelerator): p, 70 GeV/c • (x,y): 1 ... 1.25 mm • Intensity: 0.5×106 protons/spill • Target • 5 active(trigger) Si planes, 1 Pb plane and 1 C plane • Total "hadronic" thickness ~ 0.5%

  6. SVD-2 experiment Active Target layout

  7. SVD-2 experiment • Trigger-I • Based on energy depositions in 58 Si active target strips • Basic idea:to look for the >2...3 MIPs depositions in consecutive planes • Decision time: 220 ns • "Non-hadronic" events contamination: < 10% • Trigger-II • Not implemented yet... • Basic idea - a search of "secondary" activity • A simplified "fast" information from vertex tracking detector to be used

  8. K-     P-beam K-    1.a p+  1 2 3 5 4 1 High precision microstrip vertex detector. 1a Active target with Si, C and Pb planes 2 Multiwire proportional chambers. 3 Magnet ( 1.18 T over 3m long region). 4 Multicell threshold Cherenkov counter. 5 Gamma detector.

  9. SVD-2 detector • Vertex detector • beam telescope • tracking detector: • MIP/noise ratio ~ 10:1, registration threshold ~ 3.5 noise • Dead/noisy channels : < 5% • Planes configuration: • Orientation Strip pitch Number of strips • X,Y 25 640 • X,Y 50 640 • X,Y 50 1024 • X+10.5 50 1024 • X 50 1024 • Y+10.5 50 1024 • Y 50 1024

  10. SVD-2 detector • Spectrometer • Magnet: • Length : 3m (along the beam) • Field in the centre: up to 1.18 Tl • MWPC: • Number of planes - 18 (15 inside the magnet) • Acceptance: 220 mrad(X) * 170 mrad(Y) • Wires orientation: Y-10.5, Y, Y+10.5 • Wires step: 2 mm • Average efficiency: 80%

  11. SVD-2 detector • Cherenkov detector: • Measured efficiency: 70% for the  withp>5 GeV • Gamma-detector (DEGA): • 1500 channels, Cherenkov glass • Energy resolution for 15 GeV electrons • ~ 12% • mass resolution ~ 13% (preliminary)

  12. SVD-2 detector • Monitoring and data collection • 5 “detector component” PCs • read information from CAMAC electronics of sub-detectors • The “Collector” PC • synchronizing data within a spill, • creating and saving the unified data file • The monitor workstation • Partial reading of data file • Analyzing beam, detector and readout state • Simplified vertexing (also to check the trigger state)

  13. SVD-2 run - April '2002 • 80 “accelerator shifts” • > 50,000,000 triggers • Suggesting that… • 20% of events are discarded, • pp(cc) = 1.6b, • A-dependence as A1, • Identification efficiency is 10%, • gives an estimate for the number of charms to be identified: 1500…

  14. SVD-2 data analysis • Preliminaries: • General analysis of the formal events quality and the “indexing” • Amplitude analysis of the vertex detector data • Checks of the readout consistency • Geodetic analysis and alignment • Evaluation and testing of different algorithms for tracks and vertex reconstruction • Defining the methods of tracks selection by impact parameter • Different methods of momentum reconstruction.

  15. SVD-2 data analysis • Current status of reconstruction software: • FORTRAN code • Based on vertex+spectrometer data • Track finding starts in the vertex detector • Pre-generated tables for the momentum calculations • GEANT3 detector simulations • detailed geometry • geometry configuration file is the same as for reconstruction software (alignment…) • interfaces to • Pythia(…) at input • Raw data file format at output

  16. SVD-2 data analysis • Estimates of accuracies: • X,Y-resolutions for >3 hits tracks fitted: 8…10 m • Z-resolution • for the primary vertex: 70… 130 m • for the secondary vertex: 200… 300 m • Impact parameter resolution: ~ 17 m • Momentum resolution for the beam tracks (70 GeV): 3% • Effective mass resolution: • For K0: 3.9 MeV • For : 1.6 MeV

  17. SVD-2 data analysis Run I (april 2002) ~ 53 millions of inelastic pN-events on Si, C and Pb targets. Si – 300m; Pb – 220 m; С12 – 500 m Pb C12 Si Si Si Si Si sz = 70÷130µm, sx,y = 7÷10µm Fig 2. Primary vertex Z-coordinate in SVD-2 active target.

  18. Effective masses K0 

  19. Plans for the next run (fall ’2004) Vertex detector – changes in configuration and electronics to rise the efficiency and lower the multiple scattering effects Installation of 9 double planes of drift chambers (straw tubes 6mm, resolution <200m) 3 more chambers in the spectrometer  Better tracking and effective mass resolution Better magnetic field screening for Cherenkov detector PMTs  Rising the efficiency (up to 90%) New electronics in gamma detector  no event losses, 0 mass resolution 6…7% Level-II trigger and moving beam intensity to 2*107 p/spill  Increasing statistics 5-10 times Reconstruction software: moving to ROOT/C++  A nice trick to attract students

  20. A new project (with JINR) • The study of high multiplicities in hadronic events • Ncharged = 21…35? • H2 target to be used • SVD-2 modifications (+trigger) • Multiplicity distributions and different + , -, 0 correlations • Beam intensity up to 107 p/spill •  = 10 pb

  21. SVD-2 April '2002 run Number of events Number of charged particles

More Related