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CFT Occupancy dependence on Beam Luminosity

CFT Occupancy dependence on Beam Luminosity. David Lam Oct 2003. CFT Occupancy vs. Luminosity. Choose 3 classes of events for the study: Zero-biased triggered Minimum-biased triggered Jet triggered – JT_45TT specifically

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CFT Occupancy dependence on Beam Luminosity

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  1. CFT Occupancy dependence on Beam Luminosity David Lam Oct 2003

  2. CFT Occupancy vs. Luminosity • Choose 3 classes of events for the study: • Zero-biased triggered • Minimum-biased triggered • Jet triggered – JT_45TT specifically • Events with delivered luminosity range from 6E30 to ~40E30 (cm-2 s-1) • Two set of events: • Set 1: 10 events between Feb and Mar 2003 • Set 2: 11 events in August (just before the shutdown)

  3. Method • Use a modified version of cft_offline_mon • Use D0TriggerFilter to pick out the desired events • Since most of the reconstructed events are still generated using p13, we used raw data instead to get rid of the 20 ADC cut • Plot average occupancy vs. the middle point of the delivered luminosity range.

  4. Occupancy distribution

  5. Results • Fitting results show occupancies increased with luminosity as expected • Top line: Jet triggered • Middle line: Min-biased triggered • Bottom line: Zero-biased triggered • MC min-biased and zero-biased events are also included. • When extrapolated, at 200E30, jet triggered occupancy is approximately: 0.233 (CFTX 1)

  6. Events between Feb. and Mar.

  7. Events in Aug (before shutdown)

  8. Result • Zero-biased events triggered on beam crossing: • Contain mostly electronic background “noise” • Occupancy variation due to p/anti-p halo • Min-based events triggered on collision: • Signal in luminosity monitors above threshold on both ends • Number of collision increases with luminosity – Poisson distribution • Supposedly, occupancies increase faster with luminosity compared to zero-biased event. • But, slopes for the fits of min-biased events are lower than zero-biased and jet triggered – so dig deeper….

  9. Trigger luminosity • Look into the recorded luminosity for each event • Recorded luminosity are stored by luminosity block (lbn), which usually corresponds to time interval of 1 minute. • Plot occupancy vs. record luminosity for each trigger

  10. Zero-biased Events (Set 1)

  11. Zero-biased Events (Set 2)

  12. Result (cont.) • Both set of zero-biased events have positive dependencies on luminosity • However, for set 1 min-biased events, some funny looking structure in the plot • Set 2 min-biased events have occupancies DECREASE with increasing luminosity

  13. Min-biased Events (Set 1)

  14. Min-biased Events (Set 2)

  15. Jet triggered Events (Set 1)

  16. Jet triggered Events (Set 2)

  17. Jet-triggered events recorded luminosity distribution Set 2 Set 1

  18. Jet triggered result • Set 1 jet triggered occupancies increase with increasing luminosity in range 0 – 900 ub-1 • But set 2 occupancies DECREASE with increasing luminosity in range 0 – 150 ub-1 • Why the range of recorded luminosity differed? Given that the delivered luminosity range are the same in both sets. • Comments? Suggestions?

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