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A N DY Status Commissioning with colliding beams

Status update on the commissioning of ANDY with colliding beams, including progress from 29 February to 5 March, IP2 access, and requests for upcoming demonstrations and measurements.

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A N DY Status Commissioning with colliding beams

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  1. ANDY StatusCommissioning with colliding beams L.C.Bland, for AnDY 6 March 2012 Time Meeting, BNL

  2. Progress29 February to 5 March • IP2 access on 29 February fixed most missing signals, restored LED operation for rebuilt run-11 ECal modules and sealed ECal. • ECal modules are now on rails (thanks C. Folz!) and are presently positioned to provide HCal an unobstructed view of collisions • Subsequent separated-beams test runs show that BBC and HCal are ready for collisions

  3. Requests • Complete IP2 DX training as required for s=510 GeV head-on collisions on 14 March access, as scheduled • Setup IP2 b* for s=510 GeV as needed for 10 pb-1/week demonstration • We ask that you reconsider s=200 GeV collisions at IP2 to deliver 1 pb-1 as needed for jet analyzing power measurement

  4. Backup

  5. GEANT model of proposed ANDY apparatus (run-13) Changes to ANDY for Run-12 Thanks to C.Folz, et al. • Proposed ANDY detector (left), as submitted, consists of annular ECal, annular HCal, preshower + tracking through the (modified) PHOBOS split-dipole • The HCal module pair used in run 11 was modified to become an annular 12-row x 20 column HCal for run 12. The picture to the right shows the phototube (PMT) end of HCal upon completion of its installation in December, before installing all PMT. • Separated-beams test on 20120225 and 20120227 shows most things are working, and identifies some things to fix (a few holes) on the 20120229 access.

  6. With run-12 test, becomes “measured to be” Critical Run-12 Tests…proposed... • (1) Finish HCal calibration with new annulus: correction for hadronic response • (2) Test operation of GEM prototype • (3) Demonstrate 10 pb-1/week at s=500 GeV, as required for runs 13,14 ANDY • Comments: • Corrections to run-11 HCal calibration for hadron showers expected to be ~20% • GEMs improve position resolution from ~5cm (run-11)  ~0.1mm for calorimeter/preshower association required for background discrimination and other trackings • Data from run-12 IP2 tests will improve run-11 J/ , enable B J/ +K and start on concurrent s=500 GeV ANp0 measurement required to determine sign of DY AN

  7. Dileptons from Run 11 Data • ANDY profiling methods were applied to a limited data sample (Lint=0.5 / pb) of run-11 ECal triggered data. • Dominant backgrounds are now from g, and are suppressed by using MIP response of beam-beam counters to tag clusters. • Individual detector p0ggcalibration for HCal was an essential step to reconstruct J/ • Limited granularity of BBC and poor position resolution of HCal-EM cluster results in less photon suppression than expected for final ANDY apparatus (project ~100x better suppression) • Hadron suppression is not yet required, but will be in going from dileptons to DY • J/e+e- peak has ~120 events with 5.4s statistical significance. PYTHIA 6.425 with NRQCD expects 420 events in the run-11 acceptance, approximately consistent with observation after crude efficiency correction. From PYTHIA 6.425, DY with M>4 GeV/c2 is 170x smaller in this acceptance. • J/ is a window to heavy flavor via BJ/ K and LbJ/ p p- that would help quantify intrinsic b from proton backgrounds to DY Run-11 data absolutely compared to fast-simulator used for DY estimates

  8. Recall from run-11…Jets arXiv:1103.1591 jet AN measurements are required to clarify signs of quark/gluon correlators related to Sivers functions. s=200 GeV from p+pp “new” Sivers function “old” Sivers function • As noted last year, jets and photons can discriminate betweeen quark-gluon correlators • s=500 GeV jets from run-11 ANDY will have 2.5x larger pT at the same xF, relative to these predictions. • The best way to test things is at s=200 GeV Non-zero jet analyzing power essentially a prerequisite before proceeding to Drell Yan 12/19/2019

  9. ProposalBest test of theory with jets… • We propose testing impact of IP2 collisions during ongoing s=200 GeV operation • If impact is small as expected from last year, then proceed to integrate 1 pb-1 of luminosity. • The data sample can likely be obtained with *=7.5m at IP2, although this is inefficient • We propose, contingent on impact test, a 6-bunch test ramp with IP2 *3m

  10. Schematic of detector for Run-11Polarized proton collisions at s=500 GeV from February to April 2011 • Beam-beam counter (BBC) for minimum-bias trigger and luminosity measurement from PHOBOS [NIM A474 (2001) 38] • Zero-degree calorimeter and shower maximum detector for luminosity measurement and local polarimetry (ZDC/ZDC-SMD, not shown) • Hadron calorimeter modules (HCal) are 9x12 modules from AGS-E864 (NIM406,227) • Small (~120 cells) ECal loaned from BigCal at JLab • Pre-shower detector

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