We explore the prospect of charged Higgs boson search in top quark decay at the Tevatron collider upgrade, taking advantage of the opposite states of $\tau$ polarization resulting from the $H^\pm$ and $W^\pm$ decays. Methods of distinguishing the two contr
events.Moreover,since the hadronicτand QCD jet events dominantly populate the1-prong and multi-prong channels respectively,the prong distribution of the narrow jets can be used to distinguish the two.This way the CDF experiment [11]has been able to identify the W→τνevents and test W universality as well as put modest constraints on t and H±masses from(3)using a data sample of integrated luminosity～4pb?1.In the present case,however,one would be looking for a few tens of hadronicτevents in a data sample of～500 times larger integrated luminosity,for which the QCD jet background cannot be controlled by the above method.Therefore one cannot use the singleτchannel for the charged Higgs search and even theττchannel may be at best marginal.The best charged Higgs signature is provided by the?τchannel. The largest background comes from W→?νaccompanied by QCD jets,which can be easily suppressed by the above mentioned jet angle and multiplicity cuts.Besides the hard isolated lepton?provides a more robust trigger than the missing-E T.Therefore in this work we shall concentrate mainly on the?τchannel;but similar analysis can be carried over in theττchannel as well.
The?τandττchannels correspond to the leptonic decay of both the charged bosons in(16),i.e.
H+H?,H+W?,H?W+,W+W?
↓↓↓↓↓↓↓↓
τ+Lτ?Rτ+Lτ?L,??τ?Rτ+R,?+τ+R,?+τ?L,??(17)
By convention,
Pτ≡Pτ?=?Pτ+,Pτ±=σ
τ±
R?
στ±L