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NCC Task Force

Richard SetoNCC Task Force Meeting

Nov 20, 2007BNL

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Updates on Agenda

Bugs pi0 folks – goal R_AA, pi0, direct photon, Delta

G chic folks – goal R_AA Trigger Dec 4 –asses whether Dec 20 is a reasonable

goal for completion. Report from Dave/Stefan – pi0, dir photon Carla/Sky - chic Ken – delta G

Some software docs for my code and cross sections in https://www.phenix.bnl.gov/WWW/p/draft/seto/meet/NCC_taskforce_Nov_20_2007/nccinstruction.pdf

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Comments continue to make progress cleaning up bugs – Bug in

SF(1) figured out Need to clear up more bugs – e.g. zebra bank size in

pisa Mickey has a DST ready – I have not tried it yet Edouard is done optimizing the NCC code Would like to see for pi0’s

pi0’s single track (Stefan and Dave) then turned over to takao to make the direct photon

spectrum and then to the spin folks to produce delta G then turn to heavy ion to produce R_AA

For chic – barbara would like to see more manpower on this

T-28 days and counting FVTX review went well. Need to have HW clearly done

– Ed/Barbara tell me I should work on the management plan and not on simulations….

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Comments on mixed bkgd I realized out mixed bkg for both the

pi0 and chic was being done incorrectly Steps

we take signal embed it in bkg

This assumes ALL events have a signal. But most of the time (for pi0) and often (for chic) in a mixed event we are mixing one signal event with a non-signal event, or two non-signal events

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The problemwhat we do real life

event with signalevent without signal

events mixed pairs events mixed pairs

assume4x mix

i.e. mix depth=4

1 12

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3

456

5

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skip some

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Solution - chic I believe the group Sky+Carla always mix a j/psi

in the main event with photons in previous events we trigger on the j/psi mix J/psi and chic into signal in a 6 to 4 ratio (please

check this number) This may be enough if the j/psi signal is very clean –

(which I don’t think it will be even with the DCA cuts on the FVTX)

Find the bkg under J/psi, these will be events in which there is neither a J/psi or chic – we will have to find the fraction of these.

then in the mixed events we will (according to the fraction) keep only the bkg in the mix stack, and not the merged event

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solution – two track pi0 pi0

Calculate fraction of events which really have a pi0 of the relevant pt and y

keep bkg in mix stack usually. For the small fraction which does have the relevant pi0, keep the merged event

The question is when we have TWO such events in the range of the mix depth

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two track pi0’svs pt and y, new code, cuts, a first look at dAu

richard seto

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comparing old and new NCC code The next few plots compare the old and new NCC code. 1 pi0

at the specified energy is embedded into 1 hijing pp min bias event. I then look for a two track pi0 in that bin. The new NCC code uses SF(0), i.e. just a constant sampling fraction. When Ondrej manages to debug SF(1) it should get better.

No cuts (e.g. chisq/assym/energy etc) have been applied. They will help of course

Plots on the upper left have black – all events, red- mixed bkg using events with embedded pi0, blue-mixed bkg without the embedded pi0

The statistics here are 10K, pi0’s embedded into 10K hijing At the higher pt the background (bottom right in blue shows

the background in events without the embedded pi0. I am running out of statistics here. I will need to run lots more background events. (perhaps a factor x10)

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y 1-1.5 pt 1.5-2

new code (Nov 16) SF(0) old code (oct 11)

similar result – slightly better S/B, much better eff

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y 1-1.5 pt 6.5-7

new code (Nov 16) SF(0) old code (oct 11)

red – bkg with signal in itblue – bkg w/o signal pi0better eff, better S/B

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y 1.5-2 pt 1.5-2

new code (Nov 16) SF(0) old code (oct 11)

red – bkg with signal in itblue – bkg w/o signal pi0higher y bins not possible with old code – low pt

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y1.5-2 pt5.5-6

new code (Nov 16) SF(0) old code (oct 11)

red – bkg with signal in itblue – bkg w/o signal pi0higher y bins not possible with old code – higher pt

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y 2-2.5 pt 2-2.5

new code (Nov 16) SF(0) old code (oct 11)

red – bkg with signal in itblue – bkg w/o signal pi0higher y bins not possible with old code –low pt

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y 2-2.5 pt 5-5.5

new code (Nov 16) SF(0) old code (oct 11)

red – bkg with signal in itblue – bkg w/o signal pi0higher y bins not possible with old code – higher pt

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extremes the next few slides are the highest and

lowest I could go with the new ncc code. The plots on the left are the lowest (1-1.5 is the lowest I threw) and the ones on the right are the highest. At the higher pt my pisa jobs crashed so I didn’t have any data there, hence I don’t think these plots are really the highest I can go. I did not bother to figure out why they crashed since I didn’t think I could do two track pi0’s that high.

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y=1-1.5 – new code SF(0)

pt=1-1.5 pt=9.5-10

red – bkg with signal in itblue – bkg w/o signal pi0

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y=1.5-2 new code SF(0)

pt=8.5-9pt=1-1.5 ran out of simulation data

red – bkg with signal in itblue – bkg w/o signal pi0

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y=2-2.5 new code SF(0)

pt=5.5-6pt=2-2.5 ran out of simulation data

red – bkg with signal in itblue – bkg w/o signal pi0

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cross section eta = 1-1.5 two track

pt (GeV)

old code new code

better error bars (better eff and S/B)

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efficiency eta=1-1.5 pp min bias

in pt bin thrown

in 0.5 GeV low bin in 0.5 GeV high bin

pt (GeV)

pt (GeV)pt (GeV)

pt (GeV)

Nfou

nd/n

thro

wn old code new code

eff toteff higher

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other stuff

pi0 mass (GeV) pi0 sigma (GeV)

pt (GeV)

pt (GeV)pt (GeV)

pt (GeV)

signal to background

signal toback in merged events

old code new code

S/B looks better now

pi0 mass low

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compare hits in EMC to NCC

this is the cluster energy distribution, d^2N/dE/dy, for one PbSc sector

(W1) in Run-3 p+p:

https://www.phenix.bnl.gov/WWW/p/draft/bathe/ncc/dN_dEdy.gif

This is a physics quantity, fully normalized:

- N_evt, 25e6 - bin size, 16./320. - azimuthal acceptance,

22.5/360. - pseudorapidity

acceptance, 0.7 - dead towers, ~1.

Is this what you were looking for?

Best regards, Stefan

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3.5

from 1-4 GeV central arms drops 3.5 OM and NCC drops 2.0 OM

PbSC W1

E GeV

E GeV eta

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pp cross section - new code–all rapidities

y=1.0-1.5 y=2.0-2.5y=1.5-2.0

pisa crashes for pi0 signal

remember I assume the phenix y=0 crosssection for this. I need to update that withsome hijing-like or brahms data

in pp all rapidities possible - for 500 GeV good, Delta G coverage

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Eff all y

y=1.0-1.5 y=2.0-2.5y=1.5-2.0

in pt bin thrown

in 0.5 GeV low bin in 0.5 GeV

high bin

Nfou

nd/n

thro

wn

eff tottot

eff drops offat low ptat higher eta

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other all, y

y=1.0-1.5 y=2.0-2.5y=1.5-2.0

pi0 mass (GeV) pi0 sigma (GeV)

signal to background

signal toback in merged events

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dAu – first look

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dAu mb y=1.0-1.5 – new code

pt 1.0-1.5pt 7.5-8.0

red – bkg with signal in itblue – bkg w/o signal pi0

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Now try cuts to increase S/B

Come back to question of why S/B gets worse at higher pt

Does extra stuff in NCC shown before do this?Answer I think- what I am missing is cuts on assym, which would require TWO showers at relatively high energy jobs are running now to get final answer

A first look

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Cuts pp y=1.0-1.5 pt=1.5-2.0

No cutsAssym>0.8E_photon>0.3 GeVpt_photon >0.2 GeVY_photon<2.5 (in good part of NCC)

small sample – 2K events

with Cuts : cleaner signal, better S/B

red – bkg with signal in itblue – bkg w/o signal pi0

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My Plans Next –look cross sections for dAu (have to

put data in) cuts with cross sections for pp, dAu (running) SF(1) with cuts for pp, dAu Move on to central dAu, AuAu

running time a problem – my priority has dropped Adopt DST’s run at ISU (will transfer bkg and signal files and

use disk space) help the chic folks