muons from /k csc samples vs generator predictions: preliminary comparisons
TRANSCRIPT
Muons from /K
CSC samples vs generator predictions: preliminary
comparisons
Minimum bias• 124k events
simulated with PionDecayer
• Selected one light meson forced to decay
• Muon mother decay before calorimeter
CSC SamplesSingle
• pT vs distribution extracted from min bias and J1-J8 di-jets PYTHIA generated sample
– csc11.005001.pythia_minbias– csc11.005010.J1_pythia_jetjet– …– csc11.005017.J8_pythia_jetjet
• Get all pions coming from interaction point
• pT>2.5GeV
• ||<2.7
• Average multiplicity per event <n> = 0.38
• 1M events simulated with PionDecayer at various pT
• Differential cross-sections
typically used to compute rates for kaons, , from generators:
– PYTHIA 5.7 (JETSET 7.4)– DPMJET II.3 and II.4
from Oren Y. and Nisati L.
• Assumed cross-section from minimum bias only=80 mbarn
Old predictions
∂∂
∂
Tp
2
Decay weight for CSC samples
Ratio of pT distribution for unweighted and
weighted events
Events reweighted for probability of
decaying into a
cp
m
τl
=w
l maximum pathm masspmomentumτ life timec light speed
Cross-sections (barn)
τot()PYTHIA(*) DPMJET (*)
Minimum bias ( only)
Single (all) ( only) (all) ( only)
3<pT<45 GeV
38.4 22.8 81.2 38.1 18.3 35.1
36.7 21.9 77.8 36.6 17.0 32.6
4<pT<45 GeV
10.3 5.98 20.3 9.48 4.80 11.0
9.85 5.73 19.5 9.10 4.50 10.2
5<pT<45 GeV
3.56 2.04 6.51 3.04 1.58 4.32
3.42 1.96 6.25 2.92 1.48 4.0
6<pT<45 GeV
1.48 0.83 2.59 1.21 0.63 1.96
1.42 0.79 2.49 1.16 0.60 1.81
(*) Oren Y. and Nisati L.||<2.7
||<2.4DPMJET default for rates computation (more conservative)
pT and projections
DPMJET
PYTHIA
Single
pT
Min bias
In the following we will restrict to:
4000<pT<45000 MeV(min bias: pT<20000 MeV)
||<2.4
4000<pT<45000 MeV
||<2.4
PYTHIA / DPMJET all light hadrons
PYTHIA / DPMJET
pT
pT
PYTHIA / single
DPMJET / single
pT
pT
PYTHIA / min bias, only
DPMJET / min bias, only
pT
pT
Conclusions
• There are differences between old predictions from PYTHIA and DPMJET (within a factor 1.5)
• New samples give cross-section predictions in agreement within a factor of 2– We have good samples suitables for studying
rejection of muons from light mesons