Using a 3.19 fb-1 data sample collected at an e+e- center-of-mass energy of Ecm=4.178 GeV with the BESIII detector, we measure the branching fraction of the leptonic decay Ds+→μ+νμ to be BDs+→μ+νμ=(5.49±0.16stat±0.15syst)×10-3. Combining our branching fraction with the masses of the Ds+ and μ+ and the lifetime of the Ds+, we determine fDs+|Vcs|=246.2±3.6stat±3.5syst MeV. Using the c→s quark mixing matrix element |Vcs| determined from a global standard model fit, we evaluate the Ds+ decay constant fDs+=252.9±3.7stat±3.6syst MeV. Alternatively, using the value of fDs+ calculated by lattice quantum chromodynamics, we find |Vcs|=0.985±0.014stat±0.014syst. These values of BDs+→μ+νμ, fDs+|Vcs|, fDs+ and |Vcs| are each the most precise results to date. © 2019 authors. Published by the American Physical Society.

Jim Libby

Department Of Physics

quantum theory

BRANCHING FRACTIONS

Data sample

DECAY CONSTANTS

Global standards

LATTICE QUANTUM CHROMODYNAMICS

LEPTONIC DECAY

PSEUDOSCALAR DECAY CONSTANTS

QUARK-MIXING MATRIX

Germanium compounds

Fulltext

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Physical Review Letters

Using e+e- annihilation data corresponding to an integrated luminosity of 3.19 fb-1 collected at a center-of-mass energy of 4.178 GeV with the BESIII detector, we measure the absolute branching fractions BDs+→ηe+νe=(2.323±0.063stat±0.063syst)% and BDs+→η′e+νe=(0.824±0.073stat±0.027syst)% via a tagged analysis technique, where one Ds is fully reconstructed in a hadronic mode. Combining these measurements with previous BESIII measurements of BD+→η(′)e+νe, the η-η′ mixing angle in the quark flavor basis is determined to be φP=(40.1±2.1stat±0.7syst)°. From the first measurements of the dynamics of Ds+→η(′)e+νe decays, the products of the hadronic form factors f+η(′)(0) and the Cabibbo-Kobayashi-Maskawa matrix element |Vcs| are determined with different form factor parametrizations. For the two-parameter series expansion, the results are f+η(0)|Vcs|=0.4455±0.0053stat±0.0044syst and f+η′(0)|Vcs|=0.477±0.049stat±0.011syst. © 2019 authors. Published by the American Physical Society.

Measurement of the Dynamics of the Decays Ds+ →η (′)e+νe

Determination of the Pseudoscalar Decay Constant f Ds+ via Ds+ →μ+νμ

Using e+e- annihilation data of 2.93 fb-1 collected at center-of-mass energy s=3.773 GeV with the BESIII detector, we measure the absolute branching fraction of D0→K-μ+νμ with significantly improved precision: BD0→K-μ+νμ=(3.413±0.019stat±0.035syst)%. Combining with our previous measurement of BD0→K-e+νe, the ratio of the two branching fractions is determined to be BD0→K-μ+νμ/BD0→K-e+νe=0.974±0.007stat±0.012syst, which agrees with the theoretical expectation of lepton flavor universality within the uncertainty. A study of the ratio of the two branching fractions in different four-momentum transfer regions is also performed, and no evidence for lepton flavor universality violation is found with current statistics. Taking inputs from global fit in the standard model and lattice quantum chromodynamics separately, we determine f+K(0)=0.7327±0.0039stat±0.0030syst and |Vcs|=0.955±0.005stat±0.004syst±0.024LQCD. © 2019 authors. Published by the American Physical Society.

Study of the D0 →k-μ+νμ Dynamics and Test of Lepton Flavor Universality with D0 →k- +ν Decays

We present a measurement of angular observables and a test of lepton flavor universality in the B→K∗ℓ+ℓ- decay, where ℓ is either e or μ. The analysis is performed on a data sample corresponding to an integrated luminosity of 711 fb-1 containing 772×106 BB pairs, collected at the (4S) resonance with the Belle detector at the asymmetric-energy e+e- collider KEKB. The result is consistent with standard model (SM) expectations, where the largest discrepancy from a SM prediction is observed in the muon modes with a local significance of 2.6σ. © 2017 American Physical Society.

Lepton-Flavor-Dependent Angular Analysis of B →k∗ℓ+ℓ-

Advances in Astrophysics

The Computational Cosmic Brain

TH Open

10.1055/s-009-42224

Journal	Data powered by TypesetPhysical Review Letters
Publisher	Data powered by TypesetAmerican Physical Society
ISSN	00319007
Open Access	No