Precision Measurement of the Branching Fraction of $D^{+}\to \mu^{+}\nu_{\mu}$

Ablikim, Medina; Achasov, Mikhail N.; Adlarson, Patrik Adlarsson; Afedulidis, Orestis; Ai, Xiaocong; Aliberti, Riccardo; Amoroso, Antonio; An, Qi; Bai, Yu; Bakina, Olga

Precision Measurement of the Branching Fraction of $D^{+}\to \mu^{+}\nu_{\mu}$

BESIII

Collaboration

Oct 10, 2024

9 pages

e-Print:

2410.07626 [hep-ex]

Experiments:

BEPC-BES-III

View in:

ADS Abstract Service

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Abstract: (arXiv)

Using

20.3~\mathrm{fb}^{-1}

of

e^+e^-

collision data collected at a center-of-mass energy of

E_{\rm cm}=3.773

GeV with the BESIII detector operating at the BEPCII collider, we determine the branching fraction of the leptonic decay

D^+\to\mu^+\nu_\mu

to be

(3.981\pm0.079_{\rm stat}\pm0.040_{\rm syst})\times10^{-4}

. Interpreting our measurement with knowledge of the Fermi coupling constant

G_F

, the masses of the

D^+

and

\mu^+

as well as the lifetime of the

D^+

, we determine

f_{D^+}|V_{cd}|=(47.53\pm0.48_{\rm stat}\pm0.24_{\rm syst}\pm0.12_{\rm input})~\mathrm{MeV}

. This result is a factor of 2.3 more precise than the previous best measurement. Using the value of the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element

|V_{cd}|

given by the global standard model fit, we obtain the

D^+

decay constant

f_{D^+}=(211.5\pm2.3_{\rm stat}\pm1.1_{\rm syst}\pm0.8_{\rm input})

MeV. Alternatively, using the value of

f_{D^+}

from a precise lattice quantum chromodynamics calculation, we extract

|V_{cd}|=0.2242\pm0.0023_{\rm stat}\pm0.0011_{\rm syst}\pm0.0009_{\rm input}

.

Note:

9 pages, 2 figures

References(0)

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Precision Measurement of the Branching Fraction of D+→μ+νμD^{+}\to \mu^{+}\nu_{\mu}D+→μ+νμ​

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Precision Measurement of the Branching Fraction of $D^{+}\to \mu^{+}\nu_{\mu}$