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Published byShauna Edwards Modified over 8 years ago
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Processing large data sets Brad Abbott
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Now J/Psi Starting with root-tuples Add 4-momentum to look for candidates Pick events (raw) -> reconstruct event With reco code -> Vertex event if desired Ks V0 block in root-tuple
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Now Okay for near future but time consuming Cross section measurements: Root tuples have enough available information Many B analyses, we need to take reconstructed info and revertex to find candidates (how do we do this efficiently?)
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Vertexing in root See Suyong’s talk. Official vertexing in root? Will we need to go back to reco files to allow us to track with lower Pt cut/ DCA cuts?
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Vertexing in root We don’t want to vertex every event. Very time consuming 1 st pass of stripped data (2 leptons with Pt> n Gev) n to be determined. (Should satisfy many analyses except hadronic decay modes) Add 4-momentum to see if candidate exists
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General root-tuples Generate B “root-tuples” : standard root- tuples with additional info What root-tuples do we want?? J/Psi root-tuple J/Psi, Ks, Phi, K+,K*, etc. J/Psi cross section, CP violation, B+ lifetime, tagging studies, B->J/Psi, etc.
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General root-tuples Semileptonic root-tuple Bd->D* l nu Bd mixing Bs-> Ds l nu Bs mixing Hadronic root-tuple Bs-> Ds pi (Ds 3pi)….
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Root-tuples Rare decays ?? (B-> mu mu can add in new decay or increase mass window of J/Psi) Lambda b ?? Can these fit easily into the root-tuples Beneficial if few people responsible for generating root-tuple to make sure details correct
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Future Thumbnails. Should be able to vertex directly from thumbnails. Full track error matrix not available. Need to know effects of this on vertexing. Streaming-> implement special reco? (lower Pt/ different DCA cuts) Add in new reco analyze code which includes vertexing?.
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Vertexing all tracks Currently V0 in reco which vertexes all tracks. Too time consuming and turned off in MC. Vertexing Phi, Ds, B is time consuming so will most likely need pre-selection What pre-selection needed?
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Pre-selection Selecting on trigger enough? Add 4-momentum to search for candidates? (With low mass objects, almost all events have at least 1 candidate within mass window so very little rejection) For J/Psi 1st strip feasible, is it possible for semileptonic/hadronic decays.
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Efficiently re-vertexing tracks Need to think about how exactly we want to do this Feasible if we have intelligent pre-selection of events
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