fKK analysis in Run3 d Au collisions: Update

1
f?KK analysis in Run3 dAu collisions Update

• Dipali Pal Debsankar M.
• L/H PWG meeting
• March 16, 2006

2
Analysis after QM2005

• Fiducial cuts (presented on Feb 2, 2006 L/H
  meeting)
• - QM2005 preliminary data on dAu phi?KK
  includes only momentum independent zed vs phi
  fiducial cuts.(backup slides)
• - After QM2005 1/p vs phi fiducial regions
  have been studied for both data and MC. (backup
  slides)
• - Present data contain both momentum
  dependent and momentum independent fiducial cuts.
• Track matching cuts
• - phi ? KK analysis uses 3 sigma matching
  cuts at TOF and EMCAL.
• - Preliminary dAu data uses matching
  parameters at TOF and EMCAL simply from CNT
  files.
• - Checks on matching parameters have been
  done.
• - Tuned the matching parameters and applied
  to data and MC (showed in this presentation)
• PID cuts
• - phi?KK analysis uses 2 sigma kaon PID
  cuts at TOF and PbSc.
• - The PID nsigma parameters have been
  studied and tuned.
• - Applied tuned PID parameters to data and
  MC.
• A fresh set of mT spectra have been derived.

3
Tuning of the track matching parameters for K/-

• Expectation
• Distribution of z and phi matching parameters
  should have mean 0 and sigma 1
• Measured distributions are not consistent with
  expectations for both data and MC.
• Constructed z and phi residual distributions,
  fitted each of those with gaussian signal 2nd
  order polynomial background to determine mean and
  sigmas.
• Define subsystemsdz(phi) (Measured
  mean)/sigma
• Apply to data and MC.

4
Examples of before and after tuning effects on
track matching TOF K for data
f
Z

• After tuning (blue) data points are fitted with
  constant parameter.
• Improvements in matching parameters after tuning.

Mean
Mean
Z matching
Sigma
Sigma
5
Examples of before and after tuning effects on
track matching TOF K for monte-carlo
f
Z

• After tuning (blue) data points are fitted with
  constant parameter.
• Improvements in matching parameters after tuning.
• There is an offset in sigma after tuning.

6
How to apply 2nd order tuning to the matching
parameters?

• We apply the following cut
• tofsdR sqrt(tofsdz2 tofdsphi2) lt 3
• If we consider 1 sigma matching at z and f, then
  that is equivalent to v2 sigma in R.
• After tuning, subsystemsdz and subsystemsdphi
  distributions show some constant offsets with
  reference to 1.
• For tofsdz, this offset is 1.07, and for
  tofsdphi this is 0.97, so that
• for tofsdR, this is sqrt(1.072 0.972)
  1.44.
• We expect tofsdR to be sqrt(2) 1.41.
• ? Multiply, 1.41/1.44 0.98 with tofsdR and
  put a 3 sigma cut on that.

7
Tuning of PID parameters (isK)

• Expectation
• Distribution of isK matching parameters
  should show mean 0 and sigma 1
• Measured distributions are not consistent with
  expectations for both data.
• For MC, EMCAL isK distributions do exhibit
  mean 0 and sigma 1 but TOF doesnt.
• Constructed mass-squared distributions, fitted
  each of those with double gaussian function to
  determine mean and sigmas.
• Define isK (Measured mean)/sigma
• Apply to data and MC.

8
Examples of before and after tuning effects on
isK parameters TOF

• Improvements after tuning.
• After tuning data points have been fitted with
  constant parameter.
• Sigma shows some contant offset with reference to
  1.
• Same exercises have been done for EMCAL.

Mean
Mean
Data
MC
s
s
Data
MC
9
f? KK mT spectra after applying modified fiducial
cuts, matching and PID tuning
dN/dy
T TOF TOF 0.041 /- 0.008 397 /- 31 TOF
East 0.037 /- 0.005 404 /- 47 East East
0.038 /- 0.007 352 /- 57 West West 0.036
/- 0.004 393 /- 50
Comparison with QM05 results are shown in slide
11.
10
Subsystem consistency plots

• Yields from all subsystems are consistent with
  each other.

11
Comparison New and QM05 results
Ratios are consistent with 1 within error.
12
Summary

• Fine tuning of matching and PID parameters have
  been done.
• Application of matching and PID tuning, does not
  change yields and inverse slopes.

13
Backup slides
14
f?KK and f?ee
15
EMC East
16
f? KK mT spectra after applying modified fiducial
cuts, matching and PID tuning but no second
order tuning
Min bias yields and temperatures are
consistent for all subsystems.
17
Momentum independent fiducial studies (Next 3
slides)
Shown in L/H PWG on 12/02/2004
18
Zed vs phi distributions DC PC1 TOF
Rejected region -2 lt zed cm lt 1 186.0 lt
phideg lt 191.0 167.8 lt phideg lt 172.0

Shown in L/H PWG on 12/02/2004
19
Zed vs phi distributions DC PC1 PbSc(E)
Before fiducial cut
After fiducial cut
Rejected region -2 lt zed cm lt 1 173.6 lt
phideg lt 174.0 169.0 lt phideg lt 173.0 138.0 lt
phideg lt 146.0
Shown in L/H PWG on 12/02/2004
20
Zed vs phi distributions DC PC1 PbSc(W)
After fiducial cut
Before fiducial cut
Rejected region -2 lt zed cm lt 2 -10.0 lt
phideg lt -2.8 7.6 lt phideg lt 12.0 21.2
lt phideg lt 24.6
Shown in L/H PWG on 12/02/2004
21
Momentum dependent fiducial studies (Next 3
slides)Shown on February 2, 2006 L/H meeting
22
TOF
Charge/momentum
phiDC
23
PbSc-E
Before
After
Charge/momentum
phiDC
24
PbSc-W
After
phiDC