Charged Higgs Boson Search at the Tevatron Upgrade Using Tau(7)

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

where v stands for the vector meson and L,T denote its longitudinal and trans-verse polarization states.The angleθmeasures the direction of the meson in theτrest frame relative to theτline of?ight,which de?nes its polarization axis.It is related to the fraction x of theτenergy-momentum carried by the meson in the laboratory frame,i.e.

2x?1?m2π,v/m2τ

cosθ=

.(29)

m2τ+2m2v

Consequently the e?ect ofτpolarization is reduced by a factor of～1/2in ρmomentum distribution and practically washed out in the case of a1.Thus the inclusive1-prongτjet resulting from(20-22)is expected to be harder for the H±signal compared to the W boson background;but the presence of the transverseρand a1contributions makes the size of this di?erence rather modest.We shall see below that it is possible to suppress the transverseρand a1contributions and enhance the di?erence between the signal and the background in the1-prong hadronicτchannel even without identifying the individual mesonic contributions to this channel.

The key feature of vector meson decay,relevant for the above purpose,is the correlation between its state of polarization and the energy sharing among

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