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System Test with MOKKA input. currently look at Z-peak results , using the sample Ben generated on the csf farm results look considerably different from the ones of Marlin with SGV input , due to effects only
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System Test with MOKKA input • currently look at Z-peak results, using the sample Ben generated on the csf farm • results look considerably different from the ones of Marlin with SGV input, due to effects only • simulated in the full MC (non-Gaussian tails on angular distributions from multiple scattering) • does not make much sense to compare to Marlin(SGV input), instead compare with BRAHMS • two BRAHMS results available, which differ due to different level of cheating, differences in • track selection etc: TESLA-TDR result and plots from LC-note LC-PHSM-2003-061 • MARLIN(Mokka input) uses same track selectionthat was used in LC-PHSM-2003-061 which was • derived from the BRAHMS sample – should be a good first approximation of what will be • needed for MOKKA, though this should be revisited after the release • in addition, in MARLIN we currently suppress K-shorts and Lambdas and switch off photon • conversions in GEANT4 • MOKKA detector has layer thickness 0.12% X0, known to considerably degrade performance
The two BRAHMS results in comparison b c (b-bkgr) open: TESLA-TDR full: LC-PHSM-2003-061 c • LC-note result uses more realistic tracking and track selection derived from the • sample used; performance slightly worse than previous TESLA-TDR result • results shown for nominal layer thickness at time of TESLA-TDR of 0.064% X0
MARLIN (MOKKA input) compared to BRAHMS b c (b-bkgr) c open: BRAHMS, LC-note full: MARLIN (Mokka) • compare to result from LC-note (same track selection used in MARLIN) • Marlin result falls significantly short of BRAHMS performance look at inputs
b full: MARLIN(MOKKA) line: MARLIN(SGV input) for some variables find excellent agreement for example momentum of most significant track in the jet c uds
b significant difference seen in joint probability (both in R-phi, see plots, and in z) uds jets “look like” heavy flavour c uds
b this is already seen at the level of the impact parameter significances that are used to calculate the joint probability c uds
b c uds
b also, ZVRES seems to find secondary vertices in light jets! (plots show number of tracks in non-primary vertices) c uds
b this is confirmed by the resulting M_Pt distributions c uds
Preliminary conclusions • confidence in the MARLIN code obtained from System Test with SGV input • continues through to System Test with MOKKA input, e.g. some input distributions • agree very well with MARLIN(SGV input) • some of the degradation seen wrt SGV-input is expected from full MC and from the • increased layer thickness used in the detector model • however there are some effects needing further investigation: • ZVRES finds larger fraction of light jets with secondary vertices compared to • cleaner SGV-events, • impact parameter significances could also give rise to confusion of light with • heavy flavour jets