TY - JOUR
T1 - Light-front quark model analysis of the exclusive rare Bc→D(s) (≤+≤, v≤ V-ν≤ν̄) decays
AU - Choi, Ho Meoyng
PY - 2010/3/8
Y1 - 2010/3/8
N2 - We investigate the exclusive rare Bc→D(s)ν≤ν̄≤ and B→D(s)≤+≤- (≤=e, μ, τ) decays within the standard model and the light-front quark model constrained by the variational principle for the QCD-motivated effective Hamiltonian. The form factors f±(q2) and fT(q2) are obtained from the analytic continuation method in the q+=0 frame. While the form factors f+(q2) and fT(q2) are free from the zero mode, the form factor f-(q2) is not free from the zero mode in the q+=0 frame. We discuss the covariance (i.e. frame independence) of our model calculation and quantify the zero-mode contributions to f-(q2) for Bc→D(s) decays. The branching ratios and the longitudinal lepton polarization asymmetries are calculated with and without the long-distance contributions. Our numerical results for the nonresonant branching ratios for Bc→D(Ds)ν≤ν̄ and Bc→D(Ds) ≤+≤- are in the order of 10-8 (10 -7) and 10-9 (10-8), respectively. The averaged values of the lepton polarization asymmetries obtained from the linear (harmonic oscillator) potential parameters are found to be -0.99 (-0.99) for Bc→Dμ+μ- and -0.16 (-0.15) for Bc→Dτ+τ-, and -0.98 (-0.98) for Bc→Dsμ+μ- and -0.14 (-0.12) for Bc→Dsτ+τ-, respectively.
AB - We investigate the exclusive rare Bc→D(s)ν≤ν̄≤ and B→D(s)≤+≤- (≤=e, μ, τ) decays within the standard model and the light-front quark model constrained by the variational principle for the QCD-motivated effective Hamiltonian. The form factors f±(q2) and fT(q2) are obtained from the analytic continuation method in the q+=0 frame. While the form factors f+(q2) and fT(q2) are free from the zero mode, the form factor f-(q2) is not free from the zero mode in the q+=0 frame. We discuss the covariance (i.e. frame independence) of our model calculation and quantify the zero-mode contributions to f-(q2) for Bc→D(s) decays. The branching ratios and the longitudinal lepton polarization asymmetries are calculated with and without the long-distance contributions. Our numerical results for the nonresonant branching ratios for Bc→D(Ds)ν≤ν̄ and Bc→D(Ds) ≤+≤- are in the order of 10-8 (10 -7) and 10-9 (10-8), respectively. The averaged values of the lepton polarization asymmetries obtained from the linear (harmonic oscillator) potential parameters are found to be -0.99 (-0.99) for Bc→Dμ+μ- and -0.16 (-0.15) for Bc→Dτ+τ-, and -0.98 (-0.98) for Bc→Dsμ+μ- and -0.14 (-0.12) for Bc→Dsτ+τ-, respectively.
UR - http://www.scopus.com/inward/record.url?scp=77950572122&partnerID=8YFLogxK
U2 - 10.1103/PhysRevD.81.054003
DO - 10.1103/PhysRevD.81.054003
M3 - Article
AN - SCOPUS:77950572122
SN - 1550-7998
VL - 81
JO - Physical Review D - Particles, Fields, Gravitation and Cosmology
JF - Physical Review D - Particles, Fields, Gravitation and Cosmology
IS - 5
M1 - 054003
ER -