Study of the decay D0→K¯0π−e+νe

We report a study of the decay D0→K̄0π-e+νe based on a sample of 2.93 fb-1 e+e- annihilation data collected at the center-of-mass energy of 3.773 GeV with the BESIII detector at the BEPCII collider. The total branching fraction is determined to be B(D0→K̄0π-e+νe)=(1.434±0.029(stat.)±0.032(syst.))%, which is the most precise to date. According to a detailed analysis of the involved dynamics, we find this decay is dominated with the K∗(892)- contribution and present an improved measurement of its branching fraction to be B(D0→K∗(892)-e+νe)=(2.033±0.046(stat.)±0.047(syst.))%. We further access their hadronic form-factor ratios for the first time as rV=V(0)/A1(0)=1.46±0.07(stat.)±0.02(syst.) and r2=A2(0)/A1(0)=0.67±0.06(stat.)±0.01(syst.). In addition, we observe a significant K̄0π- S-wave component accounting for (5.51±0.97(stat.)±0.62(syst.))% of the total decay rate

Study of the h(c)(1(1)P(1)) meson via psi(2S) -> pi(0)h(c) decays at BESIII

Using 448 million psi(2S) events, the spin-singlet P-wave charmonium state h(c)(1(1)P(1)) is studied via the psi(2S) -> pi(0)h(c) decay followed by the h(c) -> gamma eta(c) transition. The branching fractions are measured to be B-Inc(psi(2S) -> pi(0)h(c)) x B-Tag (h(c) -> gamma eta(c)) = (4.22(-0.26)(+0.27) +/- 0.19) x 10(-4), B-Inc (psi(2S) -> pi(0)h(c)) = (7.32 +/- 0.34 +/- 0.41) x 10(-4) , and B-Tag (h(c) -> gamma eta(c)) = (57.66(-3.50)(+3.62) +/- 0.58)%, where the uncertainties are statistical and systematic, respectively. The h(c)(1(1)P(1)) mass and width are determined to be M = (3525.32 +/- 0.06 +/- 0.15) MeV/c(2) and Gamma = (0.78(-0.24)(+0.27)+/- 0.12) MeV. Using the center of gravity mass of the three chi(cJ) (1(3)P(J)) mesons [M(c.o.g.)], the 1P hyperfine mass splitting is estimated to be Delta(hyp) = M(h(c)) - M(c.o.g.) = (0.03 +/- 0.06 +/- 0.15) MeV/c(2), which is consistent with the expectation that the 1P hyperfine splitting is zero at the lowest order

Study of the decay D0→K¯0π−e+νe

We report a study of the decay D0→K̄0π-e+νe based on a sample of 2.93 fb-1 e+e- annihilation data collected at the center-of-mass energy of 3.773 GeV with the BESIII detector at the BEPCII collider. The total branching fraction is determined to be B(D0→K̄0π-e+νe)=(1.434±0.029(stat.)±0.032(syst.))%, which is the most precise to date. According to a detailed analysis of the involved dynamics, we find this decay is dominated with the K∗(892)- contribution and present an improved measurement of its branching fraction to be B(D0→K∗(892)-e+νe)=(2.033±0.046(stat.)±0.047(syst.))%. We further access their hadronic form-factor ratios for the first time as rV=V(0)/A1(0)=1.46±0.07(stat.)±0.02(syst.) and r2=A2(0)/A1(0)=0.67±0.06(stat.)±0.01(syst.). In addition, we observe a significant K̄0π- S-wave component accounting for (5.51±0.97(stat.)±0.62(syst.))% of the total decay rate

Measurement of A baryon polarization in e(+) e(-) -> Lambda(Lambda)over-bar at root s=3.773 GeV

Using a data sample of psi(3770) events collected with the BESIII detector at BEPCII corresponding to an integrated luminosity of 2.9 fb-1, we report a measurement of A spin polarization in e+ e- -> Lambda(Lambda) over bar at = root s = 3.773 GeV. The significance of polarization is found to be 2 sigma including the systematic uncertainty, which implies a zero phase between the transition amplitudes of the Lambda(Lambda) over bar helicity states. This phase can be interpreted in terms of psionic form factors, and is determined to be Delta Phi(Psi) = Phi(Psi)(E) - Phi(Psi)(M) = (71(-46)(+66) +/- 5)degrees. Similarly, the ratio between the form factors is found to be R-psi = vertical bar G(E)(Psi)/G(M)(Psi)vertical bar = 0.48(-0.35)(+0.21) +/- 0.03. The first uncertainties are statistical and the second systematic