A N DY Status Commissioning with colliding beams (p +p at s=500 GeV)
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Transcript of A N DY Status Commissioning with colliding beams (p +p at s=500 GeV)
ANDY StatusCommissioning with colliding beams (p+p at s=500 GeV)
L.C.Bland, for AnDY
12 April 2011
Time Meeting, BNL
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Local PolarimetryEvent data analysis to tune parameters for scaler board
• Events that pass a ZDC trigger (Blue-facing OR Yellow-facing) are analyzed. Similar information is available on scaler board (acquiring data at 9.38 MHz), although final tuning is required.
• Uses ZDC shower maximum detector to reconstruct azimuth () for event. is spin sorted, based on 7-bit bunch counter and polarization pattern.
• N±() and N±() are combined in a cross ratio analysis and then fit by sin().
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Higher Intensity for IP2 Collisions
IP2 collisions have begun <3 hours after physics ON
Minimal impact on STAR,PHENIX
Fri. 8 April
1.501011/bunch
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Integrated Luminosity Estimate to Date
• Presently, no accidentals correction (found to be large for ZDC). All rates are now scaled on bunch-crossing scalers, following 20110330 access and subsequent timing adjustments.
• Requires calibration of effective cross section for BBC via vernier scan.
• Jet analyzing power measurement sets goal of 10 / pb for run 11.
• Establishing luminosity capability in run 11 is important for Drell Yan attempt in runs 12,13 (150 / pb in each run)
~2mr crossing angle~1.6mr crossing angle
~0mr crossing angle
Many thanks to C-A for increasing the threshold for IP2 collisions
systematically increased thresholds
for IP2 collisions
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We are in “production” with a jet trigger >660M jet events recorded.
• Further increase per bunch intensity for IP2 bump removal? Present criteria couples IP2 collision start with CNI measurement move CNI measurement earlier?
• Vernier scan at IP2?
• Reduce IP2 * during APEX?
• Demonstrate reproducibility
• Complete ECal gain matching Not much progress in past week.
• Begin local polarimetry production. Scaler board and FPGA configurations in production. Final tuning required
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Issues and Plans
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Backup
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Reminder of GoalsLong-term and run-11
Goals of ANDY project:
• Establish that large-xF low-mass dileptons from the Drell-Yan process can be discriminated from background in s=500 GeV p+p collisions
• Measure the analyzing power for Drell-Yan production with sufficient statistical precision to test the theoretical prediction of a sign change for DY in relation to semi-inclusive deep inelastic scattering
• Establish if robust detection of Drell-Yan dileptons at large xF and low mass requires magnetic analysis critical for future facilities at RHIC
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ANDY Prioritiesfor remainder of RHIC run-11
Run-11 goals:
• Establish the impact of a third IR on RHIC performance for p+p collisions at s=500 GeV - Demonstrate luminosity at IP2, as required for Drell-Yan sample in runs 12 (without magnet),13 (with magnet). Estimate that 150 / pb gives 104 large-rapidity di-electrons with M>4 GeV/c2 for p+p at s=500 GeV. Is this possible in a 10-week run?
• Demonstrate calibration of HCal
• Measure analyzing power for large xF jet production. Non-zero AN required for jets if Drell-Yan production has an analyzing power. Complete the measurement of the analyzing power for jet production. A non-zero AN for jets is a requirement for Drell-Yan to have non-zero analyzing power. Recent theoretical work establishes intrinsic interest in the jet analyzing power measurement.
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Run11 AN(Jet)
arXiv:1011.2692v1
200GeV
Non-zero jet analyzing power essentially a prerequisite before proceeding to Drell Yan
arXiv:1103.1591 jet AN measurements are required to clarify signs of quark/gluon correlators related to Sivers functions.
from p+p
“old” Sivers function
“new” Sivers function
s=200 GeV
• Siver’s effect only (no collin’s effect contribution)
• Need AN(Jet) measurements before DY
• With ~10/pb & P=50%, AnDY run11 can measure AN(Jet)
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Estimates
• At present threshold for IP2 collisions (average intensity < 0.901011/bunch), integrate ~200 / nb / fill
• 2 fills/day has been achieved
• Consequently, 12.5 days are required to get 5 / pb
• Maximum possible integrated luminosity (IP2 collisions for entire fill) would yield ~700 nb/fill
One week at 2 fills/day would provide 5 / pb
Two weeks at 2 fills/day would provide 10 / pb
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Schematic of detector for Run-11Equipment in place:
• HCal is two existing 9x12 modules from E864 (NIM406,227)
• ECal are two small lead-glass modules from BigCal at JLab
• BBC (from PHOBOS) and ZDC
• Preshower is newly constructed scintillator arrays
Goals:
• Establish impact of 3IR operation on PHENIX/STAR luminosity
• Calibrate HCal
• relative gain via cosmic-ray
• absolute energy scale via ,KS…
• Measure hadronic backgrounds to benchmark simulations
• Measure jet analyzing power (Lint~10 / pb, P=50%)
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IP2 in January, 2011Run-11 Staging of ANDY
See http://hena.lbl.gov/IP2/Business/status/<date> for pictures of progress
Left/right symmetric HCal
Left/right symmetric ECal
Left/right symmetric preshower
Trigger/DAQ electronics
Blue-facing BBC
Beryllium vacuum pipe