Goals for pp 200 GeV

1
Goals for pp 200 GeV

• 80pb-1 recorded with longitudinal pp for DG
  measurement (20082009) ¼ in 2008
• Sensitivity from 0.002ltxlt0.3
• Inclusive jets extend pT reach
• Di-jets and p0p0 statistical precision less
  selectivity
• g-jets-drives lumi req. 20pb-1(slow) qg
  selectivity
• Transverse 30pb-1(fast) 10pb-1(slow)
• Extend SSA to 6 GeV
• Extend dijet Sivers to high h1h2 (FMSEEMC)
• Explore transversity

2
BUR Assumptions to get 80pb-1 Long. (recorded)
between 20082009 and include transverse running

• 85 pb-1 delivered in 2008 (geom. mean of
  55-135pb-1)
• 35 dead in 2008
• Recorded lumi 1/3delivered in 2008
• DAQ1000 in 2009
• Run transverse early since 2 spin gains more
  quickly than SSA from incr. in pol.

Propose 1/3 2/3 T/L split of 90pb-1 del.
3
Mid-rapidity DG

• Rate limited by dijets
• select those with one xpartongt0.2
• pTgt6 GeV in BEMC 4 GeV EEMC-EEMC L0
• Total rate to L2 260 Hz (goal 200us/evt 5DT)
• Select dijets, gammas and incl jets in L2
• L2 dijet sample
• Select dijets in L2 virtually 100 purity
  offline
• Graded thresholds for coincident regions (details
  next slide) to get xpartongt0.2
• Rate details 3rd slide down 5.8(B)9.4 Hz(EE) 16
  dead time

4

• We will be rate limited for dijets - must
  prescale and/or raise pT
• Raising pT increases minimum x_gluon we can reach
• We have access to low x in asymmetric collisions
  endcapbarrel endcapendcap and
  FMSbarrel.or.endcap
• Requiring one partonic xgt.3 enhances qg and the
  polarization of that parton what good do a lot
  of gg dijets do us at this point?

pT necessary so maximum x0.2 vs eta3 and eta4 If
trigger on calorimeter at this value then should
have good accpetance for jet pT 50 higher
corresponding to x.3

• L0 thr 4 GeV in EEMC, 8 GeV in BEMC, 2GeV in
  FMS large cryst.
• L2 thr region dependent
• EEMCEEMC 4GeV2GeV opp f
• EEMCWestB 6GeV3GeV
• EEMCEastB 8GeV4GeV
• EBEB,WBWB 10GeV5GeV
• EBWB 15GeV7.5 GeV

May want finer division or actual
thrf(eta3,eta4)
FMSEMCs 2GeV1GeV
5
Each combination of detectors covers different x
regions
Endcap-West Barrel
Endcap-East Barrel
Endcap-Endcap
FMS- endcap
Barrel-Barrel
6
1.1pb-1 int lumi expect x20 2M sec/10 wks data
acq.
Estimated L2 rates from 2006 L2 2nd iteration
Lower L0 and match rates to min 1
Hz http//www.star.bnl.gov/protected/spin/balewski
/2008-trigger/2_rateFrom2006diJets/
From rate plots
L2 in
L2 out
Use random to avoid conflicting L2 condition else
L2 dijet
g trig options, others?
overlaps
20x100 L x ps
x2 for removing Etot
20x1 L x ps
7
First estimates of dijet results for 2008
20 pb-1 and 65 polarization Uniform pTgt5GeV
(should be optimized by region) Separated by calo
region coinc. to emphasize x ranges
8
Inclusive jets

• Continue measurements to higher pT
• Goal to take best available stats 15 GeV and up
• Requires trigger to fully turn on so thr11GeV
• L2 rate out is 5 Hz 5 DT
• Expected results next page

9
Inclusive Jets at high pT
Need justification for other physics and trigs
Murad 2008 projection 2006 Stat errs/2.5
Dave 2006
Tai 2006
Want turned on fully by 15GeV maybe little
higher?
30 pb-1 recorded vs 6 x5 Pol .65 vs .60
x1.4 A_LL error bars 1/2.5 smaller Red
bars account for higher trig. thr. Could gain at
high pT from lower dead time
10
Direct photon DG

• Also want to start 6 GeV. Compensate for 80pb-1
  vs orig. 320pb-1
• If awayside jet meets L2 dijet criteria will be
  in that sample
• Need to add gamma trigger to account for away
  side jets that fragment charged
• L2 HT.TP output 8 Hz (considering overlaps) 8 DT
  

11
Expected DG Results based on simulations
Eventually gives best determ. of Dg(x) for
existing experiments.
500 GeV data not in plot
But 1/4 L expected at 200 GeV Go lower in pT
500 GeV important for low x
Comparison to competing expmts.
Fit integral of DG(x) determined to 60.5
Potential for constraints on DG(x)
12
Trigger rate summary Long.
At L0 into L2 Etot-L2 100 Hz
2 DT -2 JP-l2
160 Hz 3 DT HighEtJet
1 Hz 0 DT
mb,zb,MonJP0(1) 4 Hz 0 DT Out of
L2 di-jets 5.8(B)9.4 Hz(EE) 16 DT
-1 -7 incl. jets 5 Hz
overlap 5 DT -2.5? g-jet
8 Hz 8 DT -3
HighEtJet 1 Hz 1
DT mb,zb,MonJP0(1) 4 Hz 4 DT
-1.5(-3.5) Forward
12 DT -7
total 51 DT
-24
Add fast det only ht.tp to get g-jet while slow
det are dead Run fastBSMD during slow det. dead
13

• Forward Long.
• p0-p0 correlations between FMS and EMCs
• Neutral dijet correlations between FMS and EMCs
• BSMD needed for p0-p0 correlations
• Integrated luminosity of 60 pb-1 for longitudinal
  two-spin measurements (same as mid-rapidity)
• fast-detector mode (FMS, bEMC, eEMC, eSMD) rate
  100 Hz assume minimal dead time
• fast-detector mode bSMD (FMS, bEMC, eEMC,
  eESMD, bSMD) rate 20 Hz 2DT (20 Hz/950Hz BSMD
  full dead rate)May top out at 700Hz(650?)
• slow-detector mode rate lt 10 Hz lt10DT

14
Transverse program Extend forward p0 SSA
asymmetries to 6 GeV g-jet SSA for color charge
interaction Extend dijet Sivers to FMS-EEMC
coinc. Mid-rapidity dijets ATT, AS , explore
transversity g-jet ATT, AS Same trigger setups
as Long.
15
Progress in Theory/Experiment - I

• Precise measurements of the xF dependence of AN
  were completed in run 6 with the FPD/FPD from
  data obtained with Lint6.8 pb-1 and 60 beam
  polarization.
• An assumed factorized calculation is in fair
  agreement with the data. It uses the Sivers
  function extracted from semi-inclusive deep
  inelastic scattering, related to orbital motion
  of the quarks within the proton.
• A proven factorized twist-3 calculation is also
  in fair agreement with data. It use quark-gluon
  correlators, shown to be related to moments of
  the Sivers function.

• Is this evidence that the Sivers function is
  universal?
• Can further measurement conclusively identify
  attraction between unlike color charge and
  repulsion between like color charges? (Color
  charge interactions are required by the Sivers
  effect to make a non-zero AN.)

References v1.0 of paper intended for
publication in PRL http//star.star.bnl.gov/protec
ted/spin/larisa/PRL07/v1.1/text.v1.1.pdf and
references therein
16
Progress in Theory/Experiment - II

• First measurements of the pT dependence of AN at
  fixed xF were completed in run 6 with the
  FPD/FPD from data obtained with Lint6.8 pb-1
  and 60 beam polarization.
• Both pQCD calculations expect a decrease of AN
  with increasing pT.
• Are there other contributions? (e.g., Collins
  effect)
• What happens at higher pT?
• What happens at lower pT?

References v1.0 of paper intended for
publication in PRL http//star.star.bnl.gov/protec
ted/spin/larisa/PRL07/v1.0/text.v1.0.pdf and
references therein
17
Transverse Spin and FMS

• Acceptance of FMS and projected RHIC performance
  will enable
• further reach for inclusive p0 and heavy mesons
• spin-dependent near-side correlations (p0-p0) ?
  separation of Sivers and Collins effects
• spin-dependent away-side correlations (p0-jet) ?
  isolation of Sivers effect
• embark on spin-dependent inclusive g and gjet
• Note that entire delivered luminosity is useful
  for measurements based on run-6 operations.

Projections for run-8, assuming split of
longitudinaltransverse21
18
Transverse Spin Direct g
Theory expects repulsive color charge
interactions to result in an opposite sign to
spin-correlated momentum imbalance for gjet.
Magnitude of effect requires gt105 events to see
significant effect.
Bacchetta et al. arXivhep-ph/0703153
Comparison of run-6 data to simulation provides
indication that prompt g can be extracted. The
large acceptance and dynamic range of the FMS is
needed to veto daughter g from p0,h,
decays. Expect gt0.5M g events into small fiducial
volume in 30 pb-1 sample with Eggt25 GeV.
19
Request for Time/Bandwidth in ppFMS Triggered
Readout

• Integrated luminosity of 30 pb-1 for p?p
  collisions
• Fast-detector mode (FMS, bEMC, eEMC, BSMD, ESMD)
  rate 100 Hz for p?p collisions 10 DT (100
  Hz/950Hz BSMD full dead rate) 700/650?
• Slow-detector mode (FMS, bEMC, eEMC, BSMD, ESMD
  slow detectors) rate gt10 Hz for p?p collisions
  10DT

20
Trigger rate summary Trans.
At L0 into L2 Etot-L2 100 Hz
2 DT -2 JP-l2 ps4
40Hz 160 Hz 3 DT -2 ht.tp EEMC
lt10 Hz 0DT HighEtJet
1 Hz 0 DT
mb,zb,MonJP0(1) 4 Hz 0 DT Out of
L2 di-jets 5.8(B)9.4 Hz(EE) 16 DT
-1 -7 -4 incl. jets 5 Hz
overlap 5 DT -2.5? g-jet
8 Hz 8 DT -3
HighEtJet 1 Hz 1
DT mb,zb,MonJP0(1) 4 Hz 4 DT
-1.5(-3.5) Forward
20 DT
total 59 DT
36
Allow 50 live