ttbar 6 jets quick look at Optimal Jet

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t-tbar 6 jets quick look at Optimal Jet Finder jets LAPP, 28 Feb 2007

t-tbar 6 jets quick look at Optimal Jet Finder jets LAPP, 28 Feb 2007 Michel Lefebvre Physics and Astronomy University of Victoria British Columbia, Canada

Samples n Generated by Damir n Sample 5204 § MC@NLO ttbar 6 jets, full

Samples n Generated by Damir n Sample 5204 § [email protected] ttbar 6 jets, full simulation, Athena 11. 0. 42 n AOD produced using Athena 12. 0. 5 § 1050 events, ET > 7 Ge. V filter on jets § Particle. Jet. Container • each produced which its own H 1 weights – – Cone 4 Tower. Particle. Jets Cone. Tower. Particle. Jets Kt 4 Tower. Particle. Jets Kt 6 Tower. Particle. Jets Cone 4 Topo. Particle. Jets Cone. Topo. Particle. Jets Kt 4 Topo. Particle. Jets Kt 6 Topo. Particle. Jets § Jet. Collection using OJF • no proper H 1 weights available: use Cone weights • number of jets fixed to 6 • R parameter set to 0. 7 – Fuzzy. Tower. Jets Michel Lefebvre, 2007/02/28 Fuzzy. Cluster. Jets ttbar -> 6 jets and OJF 2

Jet-parton matching n Study events with “true” jet hypothesis n Matching criteria § For

Jet-parton matching n Study events with “true” jet hypothesis n Matching criteria § For each parton, look for a matching jet • restrict search in a region limited by Rmax = 0. 2 • keep the closest jet in this region § Demand that a jet be matched only once • matching efficiencies depends on interparton distances – same top combinations R(u-b) R(u-dbar) R(dbar-b) = 2. 220 ± 0. 002 = 2. 008 ± 0. 002 = 2. 037 ± 0. 002 R(ubar-bbar) = 2. 219 ± 0. 002 R(ubar-d) = 2. 010 ± 0. 002 R(d-bbar) = 2. 036 ± 0. 002 – other 9 combinations R Michel Lefebvre, 2007/02/28 2. 40 ttbar -> 6 jets and OJF 3

Parton matching efficiencies n no p. T jet cuts applied Michel Lefebvre, 2007/02/28 ttbar

Parton matching efficiencies n no p. T jet cuts applied Michel Lefebvre, 2007/02/28 ttbar -> 6 jets and OJF 4

Normalized distributions: towers Michel Lefebvre, 2007/02/28 ttbar -> 6 jets and OJF 5

Normalized distributions: towers Michel Lefebvre, 2007/02/28 ttbar -> 6 jets and OJF 5

Normalized distributions: topo clusters Michel Lefebvre, 2007/02/28 ttbar -> 6 jets and OJF 6

Normalized distributions: topo clusters Michel Lefebvre, 2007/02/28 ttbar -> 6 jets and OJF 6

Normalized p. T distributions: towers Michel Lefebvre, 2007/02/28 ttbar -> 6 jets and OJF

Normalized p. T distributions: towers Michel Lefebvre, 2007/02/28 ttbar -> 6 jets and OJF 7

Normalized E distributions: towers Michel Lefebvre, 2007/02/28 ttbar -> 6 jets and OJF 8

Normalized E distributions: towers Michel Lefebvre, 2007/02/28 ttbar -> 6 jets and OJF 8

Normalized p. T distributions: topo clusters Michel Lefebvre, 2007/02/28 ttbar -> 6 jets and

Normalized p. T distributions: topo clusters Michel Lefebvre, 2007/02/28 ttbar -> 6 jets and OJF 9

Normalized E distributions: topo clusters Michel Lefebvre, 2007/02/28 ttbar -> 6 jets and OJF

Normalized E distributions: topo clusters Michel Lefebvre, 2007/02/28 ttbar -> 6 jets and OJF 10

Comments n Very encouraging results for OFJ § here fixed number of jet mode!

Comments n Very encouraging results for OFJ § here fixed number of jet mode! § should try with number of jets not fixed • adjust parameter § more events would allow mass plots • requires 6 matched partons 1 to 1 Michel Lefebvre, 2007/02/28 ttbar -> 6 jets and OJF 11