|V_{cd}| from D meson leptonic decays

Na, H., Davies, C.T.H. , Follana, E., Lepage, G.P. and Shigemitsu, J. (2012) |V_{cd}| from D meson leptonic decays. Physical Review D, 86(5), 054510. (doi: 10.1103/PhysRevD.86.054510)

Abstract

We present an update of the D meson decay constant fD using the highly improved staggered quark action for valence charm and light quarks on MILC Nf=2+1 lattices. The new determination incorporates HPQCD’s improved scale r1Nf=2+1=0.3133(23)  fm, accurately retuned bare charm quark masses and data from an ensemble that is more chiral than in our previous calculations. We find fD=208.3(3.4)  MeV. Combining the new fD with D→μνμ branching fraction data from CLEO-c, we extract the Cabibbo-Kobayashi-Maskawa matrix element |Vcd|=0.223(10)exp(4)lat. This value is in excellent agreement with |Vcd| from D semileptonic decays and from neutrino scattering experiments and has comparable total errors. We determine the ratio between semileptonic form factor and decay constant and find [f+D→π(0)/fD]lat=3.20(15)  GeV-1 to be compared with the experimental value of [f+D→π(0)/fD]exp=3.19(18)  GeV-1. Finally, we mention recent preliminary but already more accurate D→μνμ branching fraction measurements from BES III and discuss their impact on precision |Vcd| determinations in the future.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Follana, Dr Eduardo and Shigemitsu, Prof Junko and Davies, Professor Christine
• Authors: Na, H., Davies, C.T.H., Follana, E., Lepage, G.P., and Shigemitsu, J.
• College/School: College of Science and Engineering > School of Physics and Astronomy
• Journal Name: Physical Review D
• Publisher: American Physical Society
• ISSN: 1550-7998
• Published Online: 21 September 2012