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Kinematic variables

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Andrey edited this page Oct 6, 2021 · 3 revisions

To calculate Q2, W, xB and -t

    auto vqq = beam - ele
    double Q2 = -vqq.M2()
    double W = (beam+targ-ele).M()
    double xB = Q2/(W*W - Mpro*Mpro + Q2);
    double mt = -(pro-targ).M2()

To calculate Trento phi

using proton

    auto lnorm = vqq.Vect().Cross(beam.Vect());
    auto hnorm = pro.Vect().Cross(vqq.Vect());
    double phistar = lnorm.Angle(hnorm)*TMath::RadToDeg();
    if( lnorm.Dot(pro.Vect()) > 0 ) phistar = 360 - phistar;

using meson

    auto lnorm = vqq.Vect().Cross(beam.Vect());
    auto hnorm = vqq.Vect().Cross(gg.Vect());
    double phistar = lnorm.Angle(hnorm)*TMath::RadToDeg();
    if( lnorm.Dot(gg.Vect()) < 0 ) phistar = 360 - phistar;