void Boost_To_Stop_Rest_Frame(TLorentzVector& stop4, TLorentzVector& chargino4, TLorentzVector& b4, TLorentzVector& neutralino4, TLorentzVector& W4, TLorentzVector& up4, TLorentzVector& down4, TLorentzVector& s4)
{
    TVector3 betaV(-stop4.Px()/stop4.Energy(),-stop4.Py()/stop4.Energy(),-stop4.Pz()/stop4.Energy());
    stop4.Boost(betaV);
    chargino4.Boost(betaV);
    b4.Boost(betaV);
    neutralino4.Boost(betaV);
    W4.Boost(betaV);
    up4.Boost(betaV);
    down4.Boost(betaV);
    s4.SetE(chargino4.P()/chargino4.M());
    s4.SetVect(chargino4.Vect().Unit()*chargino4.Gamma());
}