Study of dynamics ofD0→K−e+νe

Abstract

In an analysis of a 2.92 fb −1 data sample taken at 3.773 GeV with the BESIII detector operated at the BEPCII collider, we measure the absolute decay branching fractions B(D 0 → K − e + νe) = (3.505 ± 0.014 ± 0.033)% and B(D 0 → π − e + νe) = (0.295 ± 0.004 ± 0.003)%. From a study of the differential decay rates we obtain the products of hadronic form factor and the magnitude of the CKM matrix element f ), we determine the ratio |V cd |/|Vcs| = 0.238 ± 0.004 ± 0.002 ± 0.011, where the third error is from the uncertainty in the LCSR normalization. In addition, we measure form factor parameters for three different theoretical models that describe the weak hadronic charged currents for these two semileptonic decays. All of these measurements are the most precise to date.

Extraction of $$|V_{cd}|$$ | V cd |

“…Thus, each experiment provides results for the products |V cx | f D P + (q 2 ) in various q 2 -bins. The LQCD calculations of the semileptonic D → π(K ) form factors, fulfilling the quality criteria of the latest FLAG summary [3], provide the value of the vector form factor at zero 4-momentum transfer, f (q 2 ) at the physical pion mass and in the continuum and infinite volume limits has been calculated on the lattice by the European Twisted Mass Collaboration (ETMC), obtaining an overall agreement with the momentum dependence of the experimental data from BELLE [4], BABAR [5,6], CLEO [7] and BESIII [8]. Some deviations have been nevertheless observed at high values of q 2 .…”

“…The values of (q 2 i ) EXP measured for the D → π and D → K semileptonic decays by BABAR [5,6], CLEO [7] and BESIII [8] collaborations are collected in Tables 1, 2 Combining the BABAR, CLEO and BESIII data from Tables 1, 2, 3, 4 , 5 and 6 with the theoretical results for 0.14 ± 0.13 Fig. 1 for both |V cd | and |V cs |.…”

“…The analyses of the experimental data from BELLE [4], BABAR [5,6], CLEO [7] and BESIII [8,9] on D → π(K )e(μ)ν decays are based on a variety of parameterizations for the shape of the vector form factor f Dπ(K ) + (q 2 ), like effective pole models, inspired by either dispersion relations [10] or heavy-quark expansion arguments [11], the zexpansion method [12] or even relativistic quark model predictions [13]. Thus, each experiment provides results for the products |V cx | f D P + (q 2 ) in various q 2 -bins.…”

Analysis of D+→K¯0e

“…A binned extended maximum likelihood fit is used to determine the number of tagged D − events for each of the nine modes. We use the MC simulated signal shape convolved with a double-Gaussian resolution function to represent the beam-energy-constrained mass signal for the D − daughter particles, and an ARGUS function [11] multiplied by a third-order polynomial [12,13] to describe the background shape for the M BC distributions. In the fits all parameters of the double-Gaussian function, the ARGUS function, and the polynomial function are left free.…”

“…[13], we perform a binned extended maximum likelihood fit to the U miss distribution for each channel to separate the signal from the background component. The signal shape is constructed from a convolution of a MC determined distribution and a Gaussian function that accounts for the difference of the U miss resolutions between data and MC simulation.…”