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)
