content_image/366691.jpg
Higgs and W boson is following. 

<img src='content_image/366691.jpg'>

This is violated by loop corrections in the MSSM but the violation is very tiny. In BMSSM, the modification can be sizable depending on which operators are added, but still the charged Higgs will be at around the weak scale. Such a light Higgs might be dangerous. However, it was shown that it can be perfectly consistent with the charged Higgs search from the top decay at the Tevatron since the charged Higgs decays not only to τν (and cs ) but also decays to AW ±∗ [16]. 

If h and A production is kinematically allowed at the Z pole, it can provide a very interesting signature. For small ZZh coupling which is needed to keep h lighter than Z boson, ZAh coupling is almost maximal and hA associated production is possible. The branching ratio of Z to Higgs is typically a few percent of Z to b ¯ b . There are two possibilities. If h mainly decays to AA , Z → hA → 3 A → 6 τ puts a bound on h mass. If h is heavier than 70 GeV, the scenario is consistent with the current search bound. More interesting possibility is the case when h mainly decays to b ¯ b . Although it requires a fine tuning in the parameter choice since h coupling to A is of order one while it couples to b with a bottom Yukawa coupling which is smaller than one except at large tan β (tan β ∼ 60). In this case, Z → hA → b ¯ bτ $^{+}$τ − would be the main decay channel. For m$_{h}$ ≥ 70 GeV, h and A are produced with very small kinetic energy and two taus decayed from A would be very soft. Two tau jets carry about 15 GeV of energy (7.5 GeV each) and the measured energy of each tau jet will be typically smaller than 5 GeV since it emits at least one tau neutrino and can emit more in leptonic decays. If the energy of tau jet is less than 5 GeV, it is too soft to be identified as tau jet and the whole event will be recorded as hadron events. 

In this Letter, we focus on the scenario in which Z → hA is kinematically allowed at the Z pole and h mainly decays to b ¯ b . This happens for m$_{h}$ ∼ 70 GeV and m$_{A}$ ≤ 2 m$_{b}$ . To take into account the recent BaBar result on Upsilon decay, we take m$_{A}$ = 7 or 8 GeV as a representative value. The change of m$_{A}$ does not affect the result very much other than the light CP odd Higgs search bound. 

