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About the need of the UFO stream. Biagio Di Micco. Motivations. In the study of radiative decays EVCL efficiency is computed by MC. This is a source of large uncertainty:. From Di Donato's talk (Capri) EVCL is one of the main experimental systematic.
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About the need of the UFO stream Biagio Di Micco
Motivations • In the study of radiative decays EVCL efficiency is computed by MC. This is a source of large uncertainty: From Di Donato's talk (Capri) EVCL is one of the main experimental systematic. • Absolutely needed for the measurement of h and h' branching ratios with 2 fb-1.
Present situation At the moment the EVCL is estimated by using a different selection that, anyway, doesn't include the full EVCL selection. This algorithm is already present in DATAREC. The efficiency of the algorithm using 2004 data has been computed.
“Minimum” biased sample 2004 DATA (idem until April 2005) DRN DRC evaluated using bit 18 in eclword (LSB bit 0) Stream occupancy 61% 0% Efficiency 43.7% 64% Due to several bugs in eclsfilt.kloe and dstradA.uic the whole minimum bias sample is in DRN. The minimum bias sample is not a minimum bias sample.
Alternative strategies 1) Downscale of a factor 10 all the events in input to event classification, reconstruct them according to the “rad” path (the same of “ksl”,”rpi”,”clb”), and put it in a different stream. (es. “UFO”) 2) Take all the events not selected by (“rad” or “ksl” or ”rpi” or ”clb”), downscale them of a factor 10 and put them in the UFO stream.
Advantage and disadvantage Very simple and time saving at analysis level. One gets EVCL efficiency simply by running the analysis code on the UFO stream. 1) 2) Painful from the analysis point of view. One should run on all the 5 streams, (rad, rpi, ksl,clb,ufo), avoid double counting, apply the downscale factor. TAPE occupancy in the case 1) (sum of all EVCL streams + ufo) = +19%. TAPE occupancy in the case 2) (sum of all EVCL streams + ufo) = +14%. The occupancy has been estimated by reconstructing from raw files and rebuilding the streams (run nr. 36461)
MC energy correction The correction is applied at cluster level. From Gauzzi's study |xcl| < 26.5 cm 26.5 < |xcl| < 163 cm |xcl| > 163 cm DATA MC = 1003 MC MC corr. = 1028 MC corr. DATA 2002 = 1020 Total prompt energy