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Probably nothing profound …

Probably nothing profound … It’s basically what I said in my email to cnipol-l mailing list on Sept. 16 &23, 2010 where I tried some ideas that have been thrown out.  For me, I’d like to see what are the differences … Wednesday, October 14, 2010 Kin Yip. Alpha calibration changing with time.

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Probably nothing profound …

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  1. Probably nothing profound … It’s basically what I said in my email to cnipol-l mailing list on Sept. 16 &23, 2010 where I tried some ideas that have been thrown out.  For me, I’d like to see what are the differences … Wednesday, October 14, 2010 Kin Yip

  2. Alpha calibration changing with time Jun 17, 2009 Jan. 15, 2010

  3. Normally, we have banana bands to veto the background. Just a random example:

  4. After plotting using E = 0.5m (L/t)2 Realized that, we can’t give up the energy scale from ADC’s.

  5. Polarization = asymmetry/AN  • I use the same calibration constants (energy and time scales)(done at the very beginning of the run, putting in some more exact distances etc.) • After using TOF only, E = 0.5m (L/t)2 100% event accepted  stupid ! Of course, we need the ADC-energy scale to get rid of backgrounds. • For example, for the run 47046, from our nominal way to using TOF only, AN doesn’t change much (from 0.011571 to 0.011616, < 0.4%). • But overall, from the nominal way to using TOF only (which we accept 100% of events), the polarization would change from 59.2% to 54.6% for the run 47046 with statistical error of 2.5%.

  6. Slicing E (due to my existing binning, 340 – 1140 keV as we use ~ 400-1000 keV • Divided into 20 bins  20 fits (ns) • Found the TOF for each E bin; • New energy scale = 0.5m (L/t)2 ; (but we still use the ADC energy scale to do the banana cut) • In doing so, I’ve realized that • NOT just AN needs to be calculated using this new energy scale • To be consistent, the energy cuts ( 0.09 –t  0.022 ) needs to use the same energy scale.

  7. Then, it’s a shift in the different sets of events to calculate both asymmetries and AN’s • (which seems to cancel out …)

  8. Statistical error is always ~2.5% If I apply the TOF found from slicing done for 46009 : NEW If I do the slicing and find the TOF’s for 47046 and 47047 respectively: OLD

  9. Not sure what conclusion to draw exactly … • except probably that, if things are done consistently, the changes are small.

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