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EmcCalPi0 Overview

EmcCalPi0 Overview. historical overview current work planning. Why calibrate with pi0s?. know the mass plentiful produce photons in a wide range of energies useful for physics want to optimize resolution, linearity of calorimeter. Enrico Maly, ECP calibrations.

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EmcCalPi0 Overview

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  1. EmcCalPi0 Overview • historical overview • current work • planning

  2. Why calibrate with pi0s? • know the mass • plentiful • produce photons in a wide range of energies • useful for physics • want to optimize resolution, linearity of calorimeter

  3. Enrico Maly, ECP calibrations • both Ecor = E*f(E,theta) where f() is polynomial in ln(E) + polynomial in cos(theta) + ln(E)cos(theta) term • Enrico has 4 lnE coefficients, 2 cos(theta), 0 ln*cos • factorizable -> can extract theta terms for EmcCalPi0 • EmcCalPi0 has 3 lnE coeffs, 0 cos, 0 ln*cos • EmcCalPi0 is a rolling calibration - updates after 50k if change needed • runs on standard (unbeamspot corrected) lists • extracts constants with calculation, not fit (won't crash) • Enrico runs on blocks of collections (w/b.s.), does a fit

  4. Beamspot affects neutrals

  5. How EmcCalPi0 works • runs in Prompt Calibration farms • fills rolling histograms in ln(m(gg)/m(p)) • analytically calculates dependence of peak on parameters • produces A0, then A1, then A2 • updates constants if significant • settles • can have hysteresis - remembers start condition • has produced 200 sets of constants for current data set

  6. Constants not yet useful Early runs are not settled due to multiple restarts of PC, multiple PCs

  7. EmcCalPi0 recently • investigating run period around beam spot shift • ran EmcCalPi0 offline on small run blocks • allowed constants to settle • 0th order term changes at shift boundary • apply constants to selection in EScale package • compare to EScale using standard correction • with and without beamspot correction • looked at one energy bin • EmcCalPi0 compensates for bs - but m = 134 MeV

  8. Results for Eg>0.5 GeV

  9. But... • EScale package not suited for studying multiple calibrations, theta dependence • selection criteria seem to affect apparent linearity • So have made some ntuples with the relevant EMC (and DCH) info to do offline studies • as of yesterday

  10. Cubic term in fit? • EmcCalPi0 is not able to do a cubic fit for technical reasons (math is too hard, for one) • Enrico's constants have one • Steal it? ditto for theta terms?

  11. Plans • would like to try calibrating on beamspot-corrected lists • include some info from Maly calib. • improve selection • try to show resolution improvement using offline calibration • then import new constants into db • hopefully use this experience to implement improved rolling calibration

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