Estimate of META efficiency Estimate of META efficiency in NOV02in NOV02

Aim: check of META efficiency implemented in digitizers in order to get proper efficiency correction of yields

Needed: noise free sample of tracks from MDC spline tracks - only 66% match with TOF hit RK tracks - 90% match with TOF hit

Result: estimate of lower limit of META efficiency crosscheck needed

P. Tlustý Krakow, March 4, 2006

HistoryHistory Smolenice 2002TOF efficiency

no mag. field - all tracks

no tracking -

matching of inner and outer mdc segments by hand

Conclusion -

TOF efficiency as expected

MethodMethod Nov. 2002 gen4 dst’s -> “pdf ntuples” from PidTrackCandidate data - 20 M events (days 348-350)UrQMD simulations - 30 M events

selection of tracks:

• inner mdc segment 2 > -1, RK 2 > 1000, SplineAccepted=1, RKAccepted=1

• 3 types of tracks - 1) negative with mom>400 MeV/C „pi-“ 2) positive with mom>400 MeV/c „p“ 3) tracks matched to RICH „e“

MethodMethod efficiency calculated as ratio

NMETAmatched/Nall

in theta-momentum space

ResultsResults EXP data - yields vs theta

black - all tracks

red - matched with META

efficiency

ResultsResults EXP data - yields vs phi

black - all tracks

red - matched with META

efficiency

ResultsResults SIM data - yields vs theta

black - all tracks

red - matched with META

green - „good“ tracks

efficiency

ResultsResults SIM data - yields vs phi

black - all tracks

red - matched with META

green - „good“ tracks

efficiency

Results - Results - -- META efficiency vs theta

black - EXP

red - SIM

green - Shower eff (Jurek)

Results - Results - -- TOF efficiency in 50 < theta < 80 region

sector 0 0.893 ± 0.003sector 3 0.922 ± 0.004

SIM 0.967 ± 0.003

ConclusionsConclusions Negative tracks with reasonably high momenta can be used forsuch kind of study, we can get at least relative numbers of METAefficiency (sector comparison etc.).

Any absolute correction should be done carefully.

Results AUG04 - Results AUG04 - -- META efficiency vs theta

black - EXP

red - SIM

TOF efficiency

sector 0 0.930 ± 0.005 1 0.919 ± 0.004 3 0.920 ± 0.005 4 0.940 ± 0.005SIM 0.963 ± 0.005

NOV02 gen4 - negative tracks vs phi

much better than Nov02 gen3SYS 0

SYS 1

NOV02 gen4 - negative tracks vs theta

differences between sectors SEC 0

SEC 3

Hadron acceptance and Hadron acceptance and efficiency calculationefficiency calculation

November 2002 hadron analysis UrQMD simulations - 54 M events (gen4 dst) used

selection of particles: GeantKine id, parent_id=0

selection of tracks: PidTrackCandidate, id, correlation flag: mdc0,mdc1,meta

•RK tracks matched to META

• inner mdc segment 2 > -1, RK 2 > 1000, SplineAccepted=1, RKAccepted=1

• tracks with TOFINO paddle multiplicity =1

all particles written to tree, histogramms filled as the 2nd step for each sector independently

HADES acceptanceHADES acceptance acceptance calculated from SIM

data as ratio

Nrectracks/Nprimary

for p, +,- in theta vs momentum

Binning: theta 2 deg,

momentum 25 MeV/c

Range: theta 0-100 deg,

momentum 0-2000MeV/c

Corrected particle yieldsCorrected particle yields

),( ),(),( ),(

),(pEpA

pPpNpN identified

corr