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NCC Task ForceRichard Seto

NCC Task Force MeetingJan 8, 2007

BNL

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Agenda Assessment of where we are and time

schedule - plans for work over the holiday.

I would like to hear reports from everyone as usual.

1) Dave/stefan - pi0's - could I get a plot or something to show (or a slide)to the DC and an update

2) Ken/Paul/Todd - same for spin 3) Takao - plan for the direct photon. (a slide

or so for summary to the DC)

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The Document The goals in simplest terms for the NCC task force is to

produce the following figure of merit (FOM) plots from realistic physics simulations. Realistic means a full simulation using PISA with detector response, reconstruction, and data analysis.

a) R_AA for pi0 as a function of pt for various centralities in AuAu and dAu collisions

b) Direct photons cross sections, and likewise R_AA. c) R_AA for the Chi_C via its decay to J/psi photon as a function of

pt for various centralities. Very likely we will limit this to rapidity 1-1.5

d) A_LL(pt) for direct photons in 500 GeV polarized pp collisions d') Because we already have jet reconstruction going in pp

collisions we should easily be able to use this information to get A_LL(x) giving a greater sensitivity to low-x

e) a demonstration that we can we can extract pi0's at various angles in various centrality collisions with a known efficiency - This should answer the projective Geometry question.

Schedule To collaboration – Jan 20 To DOE – End of Jan

HI

HI

spin

answer to committee

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comments from axel What is missing all together are slides

addressing b) the direct photons and more specifically e). For e) one more technical slide explaining that the

NCC has "tracking capability" and showing reconstruction efficiencies as function of function of impact angle for different pt and maybe vertex positions should be sufficient to address the issue.

For the next two the single track pi0 is critical b) you might consider, and I do not know how much

work that is, comparing a MC input spectrum for single photons with the reconstructed one plus and R_AA plot.

Spin (RKS added this)

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Status of simulation effort Full GEANT based simulation (PISA) Full reconstruction and PID

pattern recognition of showers in PADS (stripixels have not been incorporated into pattern recongnition stage)

energy and rapidity dependent calibrations of sampling fraction and energy corrections

Particle Identification using longitudinal and transverse shower shapes – also function of energy and rapidity – transverse shower shapes using both pads and stripixels

Single track pi0 using stripixels done generation of signal and underlying event – with

signal being embedded into underlying event when necessary.

Analysis of events. Mixed event technique used to extract backgrounds

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Critical simulation analysis goals reconstruction pi0’s in pp to AuAu

From this projective geometry question can be answered R_AA can be formed From this direct photons can be extracted

for heavy ion direct photon analysis for Delta G from direct photon A_LL

status: 2 gamma complete – this will take us to pt~4 GeV single gamma is running at RCF

reconstruct chic pp to AuAu R_AA for chic

status: complete to mid-central AuAu central AuAu running at RCF

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π0 2γ pp to central AuAu10K events simulated for AuAu (real data ~109 events)

AuAu 40-50% AuAu 20-30% AuAu 10-20%AuAu 0-10%

AuAu 60-80%

y=1-1.5 pt=2-2.5

dAu mb

dAu cent 20%

y=1-1.5 pt=1.5-2

ppmb 200 GeV

ppmb 200 GeV

y=2.0-2.5 pt=1.0-1.5

y=1-1.5 pt=1.5-2

pp mb 500 GeV

pp mb 500 GeV

y=1.5-2 pt=1.0-1.5

pp mb

y=1-1.5 pt=2-2.5

y=1-1.5 pt=2.5-3

y=1-1.5pt=2.5-3

y=1-1.5 pt=2.5-3

y=1-1.5 pt=2-2.5

y=1-1.5 pt=2-2.5

y=1-1.5 pt=2-2.5

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Single track pi0’s

Jobs running at RCF

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R_AA stat error only – 2 gamma y=1-1.5

AuAu 50-60% pi0 NCC

0.0000

0.1000

0.2000

0.3000

0.4000

0.5000

0.6000

0.7000

0.8000

0.9000

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5

PT

R_A

A

single track takes over

Assumed AuAu – 10B min bias events (since 50-60 is 10% of cross section) scale error bars by 3 for 1B

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χC pp to AuAu 40-50% central

Embed χC and J/ in appropriate ratio where χC J/ +γ in pp min bias

Dimuon decay of J/ measured in muon arms

plot J/ +γ mass – J/ mass

Mixed bkg: J/+γ mass – J/+γ mass mixed event, normalized above 1.6 MeV

mixed bkgforeground

All y – (jobs for lower pt, y bins, and most central AuAu running at RCF)

pt=5-6 pt=7-8 pt=9-10

pt=5-6 pt=7-8 pt=9-10pt=5-6 pt=7-8 pt=9-10

pt=5-6 pt=7-8 pt=9-10

ppmbdAu mb

dAu 0-20% AuAu 40-50%

M(J/+γ)-M(J/) M(J/+γ)-M(J/)

M(J/+γ)-M(J/)M(J/+γ)-M(J/)

subtracted

χC

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Chi_C R_AA should be

straightforward once RCF jobs complete

latest erroron this point (stat)is 8% using pt>3i.e old prediction is unchanged

R_AA of chic

present J/psir_AA data

50-60% central

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sweet spot

note change in scale

for GSC pi0 ~ little asymmetry

Done Weight scheme to input spin info

implemented Prompt photon events generated

and made to be consistent with NLO pQCD calculations.

ALL vs. pT done for PYTHIA and in agreement with earlier calculations.

Error bars assuming no background

GRSV models added to weighting scheme

Note: for pi0 we find very little asymmetry (consistent with Volgesang) pi0 background will not contaminate direct photon asymmetry

To do Calculate error bars with

background using reconstructed direct photons

Plot vs reconstructed pT

Spin update