Recent results on the invisible Higgs analysis in tth Checks against old results and kinematical constraints on t->bjj reconstruction
Comparison with old results • Some plots from Eur.Phys.J. C29 (2003) 54, hep-ph/0207014 were reproduced • Checked old plots • Results shown for tth and its main background, tt • Histograms normalized by /N = 1/L to correspond to ~1fb-1 • Cuts applied as in paper
Comparison with old results Main problem in background acceptance comes from tau events
Results of the kinematic fit • Running over 100k tth events • Pt resolution of the Higgs around 80GeV • But!….
Results of the kinematic fit • Neutrino reconstruction totally off • Chi2 way too low
Results of the kinematic fit Correlation between Higgs azimuthal direction and pTmiss directions very high This may be useable in event reconstruction Fit results agree with expectations on this point
Reconstruction of t->Wb->jjb • A simple kinematic relation exists between the W and the b jet • This may be useable to either: • Reject wrong bjj combinations • Correct the b-jet energy scale (Pedro’s suggestion)
Reconstruction of t->Wb->jjb Even after detector smearing with ATLFAST, reconstruction of t->bjj decay may benefit from kin.constraint Plots below made by requiring right bjj combinations MC truth: kinematical constraint clearly shown in plots below Constraints not so useful in t->bl case
Reconstruction of t->Wb->jjb • Can we use this to correct for the b-jet energy scale on a event-by-event basis?