PDG table

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sin2qW measurement in the World
PDG table
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KS CsI(Tl) Experiment Configuration
Multi-Disks Array (several Tb)
FADC Readout 16 ch., 20 MHz, 8 bit
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Period II Data Volume (186 kg in mass) Total
95 / 50 days ON/OFF Period III Data Volume (200
kg in mass) Total 190 / 40 days ON/OFF

• Energy resolution info
• ? 10 FWHM _at_ 660 keV
• Z-position resolution is
• ? ?(z) 2 cm _at_ 660 keV
• ? ?(z) lt2 cm _at_ higher energies

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Event Selection
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Data Analysing Techniques - Defining Cuts
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Data Analysing Techniques - Defining Cuts
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P-II and P-III OFF CsI Energy Spectra with
Various Cuts
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The Efficiency and Suppression Factors of
Various Cuts
Period-III
Period-II
CUTS (3 - 8 MeV) Suppression (cpd) raw 245.935 Efficiencies Live Time Eff. 93.53
CRV 28.824 (11.72 ) 94.04
SH 3.103 (10.76 ) 99.66
PSD 1.532 (49.37 ) 100
Z-Cut 0.5234 (34.16) 80
Total 0.213 74.98
CUTS (3 - 8 MeV) Suppression (cpd) raw 415.239 Efficiencies Live Time Eff. 88.78
CRV 26.672 (6.42 ) 92.67
SH 3.682 (15.64 ) 99.91
PSD 1.235 (33.54 ) 100
Z-Cut 0.447 (36.19 ) 80
Total 0.107 77.07
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The Stability Check
Period - II
Period - III
Cut Efficiency
Cut Efficiency
Data Stabilty
Data Stabilty
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The Stability Check 3-8 MeV
Period - II
Period - III
OFF
ON
OFF
ON
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P-II P-III CsI Energy Spectra
ON P-II and P-III
OFF P-II and P-III
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Background Understanding
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Efficiencies, Measured Half-Livesand
Contamination Level
Published Zhu Y. F., et al., Nucl. Instr. and
Meth. A 557 (2006) 490-500.
137Cs contamination level in CsI gt (1.55 0.02
) X 10-17 g/g
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Estimate the background due to Intrinsic 208Tl
3a, 3b
BR 36
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Environmental Background Understanding
Nearly all crystals including 2020 and 40 cm
crystals data was analyzed.
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Background Understanding via Multi Hit
External Source(s)
511 keV
605 keV
2100 keV
796 keV
1173 keV
1332 keV

• Co-60
• 1173.2 keV 99.86 accompanied with 1332.5 keV
  99.98
• The background related to reactor. Mostly come
  from the dust.
• Tl Pair Production One escape peaks
• ( 2105 511 keV)

• Cs-134 (n 133Cs g 134Cs)
• 605 keV 97.6
• 796 keV 85.5

510, 583 keV
External Source(s)
2614 keV
With the Q of beta decay at 2MeV
Internal Source(s)
2614 keV 99 accompanied with 583 keV 85 510.8
keV 23 860 keV with 13
860 keV

• Cosmic induced neutrons can be captured by the
  target nuclei 133Cs.

• Combination of Tl gammas can affect up to around
  4 MeV

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Background Understanding Due to Tl-208 and
Cosmic Inefficiency
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Background Understanding Due to Tl-208
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Tl-208 SH Estimation 3 - 3.5 MeV PIII-ON Period
583 keV g 2614 keV g
No z-cut
4 cm z-cut
Best fit 0.0444 0.00407 c2 8.59/(nof8)
SH 610.38 55.90
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SH Background Prediction Due to Cosmic

• ? ON - OFF
• ? ON - (SH)pred.

• ? ON - BKG

where T1 (SH)not cos (SH)cos and
T2 (MH)not cos (MH)cos
d(SH)pred lt dOFF we win
with this alternative approach

• Single Hit Prediction is made by using ON period
  data. We can improve accuracy profoundly since we
  have more than 100 days ON data in PII and 200
  days in PIII and more for other periods

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Background Expectation via PAIR PRODUCTION
3 - HIT
2 - HIT
q
p
q
q
p
SH
p
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Background Understanding via Multi-Hit
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Period - III
Period - II
OFF-(SH)pred.
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SH Prediction via Multi-Hit for ON Data
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sin2qW measurement for Period-II
ON-BKG
Sin2qW 0.294 0.0933
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sin2qW measurement for Period-III
ON-BKG
Sin2qW 0.225 0.113
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sin2qW measurement for Period-II Period-III
(ON-BKG)p2p3
Sin2qW 0.259 0.0724
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TEXONO Status
The Summary of cross section and Weinberg Angle
Measurements with various methods
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R (1.141 0.5181) RSM Sin2qW 0.259 0.0724
TEXONO
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Expected Accuracy with data size
For . sin2qW
For . cross-section
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Status of P-IV Data Very Preliminary
ON P-IV
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Conclusion
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