Philip Hart, Manchester Emc Session Feb 2003 Coll. Meeting

EmcCalPi0 Overview

historical overview

current work

planning

Philip Hart, Manchester Emc Session Feb 2003 Coll. Meeting

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

Philip Hart, Manchester Emc Session Feb 2003 Coll. Meeting

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

Philip Hart, Manchester Emc Session Feb 2003 Coll. Meeting

Beamspot affects neutrals

Philip Hart, Manchester Emc Session Feb 2003 Coll. Meeting

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 A

1, then A

2

updates constants if significant

settles

can have hysteresis - remembers start condition

has produced 200 sets of constants for current data set

Philip Hart, Manchester Emc Session Feb 2003 Coll. Meeting

Constants not yet useful

Early runs are not settled due to multiple restarts of PC, multiple PCs

Philip Hart, Manchester Emc Session Feb 2003 Coll. Meeting

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

Philip Hart, Manchester Emc Session Feb 2003 Coll. Meeting

Results for Eg >0.5 GeV

chi**2 for 89 d.o.f.136.2 6.8 175135.7 6.9 204135.5 6.7 207135.5 6.8 237134.1 6.7 198134.2 6.8 193

mass (MeV) sigma (MeV)standard, no bs, preshiftstandard , no bs, postshiftstandard , nbs, preshiftstandard , nbs, postshiftECP, no bs, preshiftECP, no bs, posthift

Philip Hart, Manchester Emc Session Feb 2003 Coll. Meeting

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

Philip Hart, Manchester Emc Session Feb 2003 Coll. Meeting

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?

Philip Hart, Manchester Emc Session Feb 2003 Coll. Meeting

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