def S(wc_obj, par, meson, amplitude, etaCP): M12, G12 = get_M12_G12(wc_obj, par, meson) qp = common.q_over_p(M12, G12) DM = common.DeltaM(M12, G12) if DM < 0: qp = -qp # switch the sign of q/p to keep DeltaM > 0 A = amplitude(par) A_bar = amplitude(conjugate_par(par)) xi = etaCP * qp * A / A_bar return -2*xi.imag / ( 1 + abs(xi)**2 )
def DeltaGamma_B(wc_obj, par, meson): r"""Decay width difference defined as $\Delta\Gamma = \Gamma_1 - \Gamma_2$ in the convention where $\Delta M = M_2 - M_1$ is positive (and the mass eigenstate 1 is CP-even in the absence of CP violation), as often used in the $B$ system.""" M12, G12 = get_M12_G12(wc_obj, par, meson) DM = common.DeltaM(M12, G12) if DM > 0: return common.DeltaGamma(M12, G12) else: return -common.DeltaGamma(M12, G12)
def DeltaM_positive(wc_obj, par, meson): r"""Mass difference defined to be strictly positive""" M12, G12 = get_M12_G12(wc_obj, par, meson) return abs(common.DeltaM(M12, G12))
def DeltaM_12(wc_obj, par, meson): r"""Mass difference defined to be $M_1 - M_2$, where the mass eigenstate 1 is CP-even in the absence of CP violation.""" M12, G12 = get_M12_G12(wc_obj, par, meson) return -common.DeltaM(M12, G12)
def DeltaM(wc_obj, par, meson): M12, G12 = get_M12_G12(wc_obj, par, meson) return common.DeltaM(M12, G12)