ND Flux Normalization

1
ND Flux Normalization

• Mike Kordosky
• UCL
• Oct 13, 2005

2
Outline

• Measure CC flux in near detector
• One idea using two samples
• Flux shape QE sample 0ltElt20 GeV
• Flux normalization total-CC 10ltElt20 GeV
• QE sample flux shape M. Dorman
• Normalization
• Know generated flux
• NEUGEN provides cross section estimate
• interpret data/mc ratio as flux correction

3
X-section reminder
shape
normalization

• Shape of QE x-section reasonably well constrained
• s varies by 10 from 1-10 GeV
• Total CC x-section well measured above 30 GeV and
  on Fe
• constrains 10-20 GeV region

sCC/E
neutrino energy (GeV)
4
Data and MC samples

• Batch processed with R1.18
• Thanks batch processing and MC groups!
• LE-10 MC
• 239 files, 98188 snarls, 0.236e19 POT
• LE-10 data
• runs span 7860-8200, 8300-8432
• 2.428e19 POT (TORTGT) after beam quality cuts
• 10 times MC sample

5
Event Selection

• Fiducial Pitt (molded to ND shape)
• 0.6ltZlt3.56m, 0.3ltUlt1.8m, -1.8ltVlt-0.3m, Xgt2.4m,
  Rgt0.8m
• Track quality
• trk.fit.pass, chi2/ndflt20, U-V z-vertex lt 6
• Fit quality s(q/p)/(q/p) lt0.3
• Dave Petyt CC PID gt-0.4
• Cut on charge sign to select n

6
CC PDFs
reconstruction independent
7
Efficiency
10-20 GeV
0-20 GeV

• track quality 89.9 (90.1)
• fit quality 85.0 (82.6)
• cc PID 66.6 (66.5)
• charge 62.9 (64.5)

Denominator CC events reconstructed in fiducial
volume
8
Selected Sample MC
10-20 GeV
0-20 GeV

• events 18517 (2995)
• QE 18.7 (6.9)
• RES 27.7 (13.2)
• DIS 48.4 (75.7)
• NC 4.6 (3.0)
• nu-bar 0.4 (1.0)

Shower Energy Linear pulse-height scale
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Selected Sample Data
Tricky region RES/DIS overlap Focusing Edge
Z. Pavlovic
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10-20 GeV region
data/mc 1.01 /- 0.02 10ltElt20 GeV
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y-distribution

• reco y Ehad / En
• data/mc presented before was with no cut on y
• But, know QE sample concentrated at low-y
• NC bkgd. at high-y and doesn't represent flux

MC
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y-distribution

• reco y Ehad / En
• data/mc presented before was with no cut on y
• But, know QE sample concentrated at low-y and NC
  bkgd. at high-y.
• Accept 0.2 lt y lt 7.5
• Sample 93.4 DIS

data/mc 1.01 /- 0.03 10ltElt20 GeV
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DIS sample

• DIS sample (J. Morfin)
• Wgt2 , Qgt1 GeV
• 53.4 of original CC sample
• QE 0.7 (0.4)
• RES 4.7 (2.2)
• DIS 89.3 (92.4)
• NC 4.5 (3.9)
• nu-bar 0.6 (0.7)

0-20 GeV
10-20 GeV
data/mc 1.08 /- 0.03 10ltElt20 GeV
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DIS sample y-distribution

• 10 lt E lt 20 GeV
• reco y Ehad / En
• data/mc presented before was with no cut on y
• But, know QE sample concentrated at low-y
• NC bkgd. at high-y and doesn't represent flux

MC
15
DIS sample y-distribution

• 10 lt E lt 20 GeV
• reco y Ehad / En
• data/mc presented before was with no cut on y
• But, know QE sample concentrated at low-y
• NC bkgd. at high-y and doesn't represent flux

data/mc 1.06 /- 0.03 10ltElt20 GeV
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Conclusions

• Working toward measurement of absolute flux
• QE events shape
• CC events 10-20 GeV normalization
• Have measured the normalization ratio from 10-20
  GeV based on 2.43e19 POT in the LE-10 beam
• From inclusive CC sample
• data/mc 1.01 /- 0.02
• data/mc 1.01 /- 0.03 ( y selection to remove
  NC)
• From DIS sample (Wgt2, Qgt1)
• data/mc 1.08 /- 0.03
• data/mc 1.06 /- 0.03 (y selection to remove NC)

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Conclusions

• From inclusive CC sample
• data/mc 1.01 /- 0.02
• data/mc 1.01 /- 0.03 ( y selection to remove
  NC)
• From DIS sample (Wgt2, Qgt1 GeV)
• data/mc 1.08 /- 0.03
• data/mc 1.06 /- 0.03 (y selection to remove
  NC)
• Errors are statistical, dominated by size of MC
  sample
• No accound for x-section errors... NuValidator
  fitting?
• Assuming MC efficiency, resolution, backgrounds
  accurate
• closer study needed
• some evidence (y distribution) for decent
  agreement of backgrounds
• Unfold to estimate true energy distribution?