Module flavio.physics.bdecays.bvll.qcdf_interpolate

Functions for interpolated version of the QCDF spectator scattering corrections.

Rationale for this is that a) The QCDF corrections are very small, in fact smaller than hadronic uncertainties for most observables (except maybe isospin asymmetries) b) They are very costly computing-wise as they involve numerical integrals over light-cone distribution amplitudes.

Interpolating them leads to a drastic speed-up at the cost of some (unnecessary) precision.

Functions

def helicity_amps_qcdf(q2, par, B, V, cp_conjugate=False, contribution='all')

Expand source code

def helicity_amps_qcdf(q2, par, B, V, cp_conjugate=False, contribution='all'):
    if q2 > 6:
        warnings.warn("The QCDF corrections should not be trusted for q2 above 6 GeV^2")
    # ml = par['m_'+lep]
    # if lep == 'tau' or q2 < 4*ml**2 or q2 > 9:
    #     return {('0' ,'V'): 0, ('pl' ,'V'): 0, ('mi' ,'V'): 0}
    process = B + '->' + V # e.g. B0->K*0mumu
    if cp_conjugate:
        array_name = process + ' CP conjugate ' + contribution
    else:
        array_name = process + ' ' + contribution
    ha = {}
    ha_arr = interpolating_function_dict[array_name](q2).view(complex)
    # dividing the q^2 poles back in
    ha[('pl','V')] = ha_arr[0] / q2
    ha[('mi','V')] = ha_arr[1] / q2
    ha[('0','V')]  = ha_arr[2] / math.sqrt(q2)
    return ha