First observation of Î\u9b+ c â\u86\u92 Î\u9bK+ Ï\u800 and evidence of Î\u9b+ c â\u86\u92 Î\u9bK+ Ï\u80 + Ï\u80 -

We present the first observation of the singly Cabibbo-suppressed decay Lambda thorn c -&gt;Lambda K thorn pi 0with asignificance of5.7 sigma and the first evidence of Lambda thorn c -&gt;Lambda K thorn pi thorn pi-decay with a significance of3.1 sigma,basedone thorn e-annihilation data recorded by the BESIII detector at the BEPCII collider. The data correspond to anintegrated luminosity of6.4fb-1, in the center-of-mass energy range from 4.600 to 4.950 GeV. Wedetermine the branching fractions of Lambda thorn c -&gt;Lambda K thorn pi 0and Lambda thorn c -&gt;Lambda K thorn pi thorn pi-relative to their Cabibbo-favored counterparts to beBo Lambda thorn c -&gt;Lambda K thorn pi 0 thorn Bo Lambda thorn c -&gt;Lambda pi thorn pi 0 thorn 1/4o2.090.39stat0.07syst thorn x10-2andBo Lambda thorn c -&gt;Lambda K thorn pi thorn pi- thorn Bo Lambda thorn c -&gt;Lambda pi thorn pi thorn pi- thorn 1/4o1.130.41stat0.06syst thorn x10-2, respectively. Moreover, by combining our measured result with theworld average ofBo Lambda thorn c -&gt;Lambda pi thorn pi 0 thorn , we obtain the branching fractionBo Lambda thorn c -&gt;Lambda K thorn pi 0 thorn 1/4o1.490.27stat0.05syst0.08ref thorn x10-3. This result significantly departs from theoretical predictionsbased on quarkSUo3 thorn flavor symmetry, which is underpinned by the presumption of meson pairS-waveamplitude dominanceFor complete list of authors see http://dx.doi.org/10.1103/PhysRevD.109.032003</p

Tests of CP symmetry in entangled Î\u9e0- (Î\u9e)over-bar0 pairs

The J/psi -&gt; Xi(0)(Xi) over bar (0) process and subsequent decays are investigated using (10087 +/- 44) x 10(6) J/psi events collected at the BESIII experiment. The decay parameters of Xi(0) and (Xi) over bar (0) are simultaneously measured to be alpha(Xi) = -0.3750 +/- 0.0034 +/- 0.0016, (alpha) over bar (Xi) = 0.3790 +/- 0.0034 +/- 0.0021, phi(Xi) = 0.0051 +/- 0.0096 +/- 0.0018 rad, (phi) over bar (Xi) = -0.0053 +/- 0.0097 +/- 0.0019 rad with unprecedented accuracies, where the first and the second uncertainties are statistical and systematic, respectively. The most precise values for CP asymmetry observables of Xi(0) decay are obtained to be A(CP)(Xi) = (-5.4 +/- 6.5 +/- 3.1) x 10(-3) and Delta phi(Xi)(CP) = (-0.1 +/- 6.9 +/- 0.9) x 10(-3) rad. For the first time, the weak and strong phase differences are determined to be xi(P) - xi(S) = (0.0 +/- 1.7 +/- 0.2) x 10(-2) rad and delta(P) - delta(S) = (-1.3 +/- 1.7 +/- 0.4) x 10(-2) rad, which are the most precise results for any weakly decaying baryon. These results will play important roles in the studies of the CP violations and polarizations for the strange, charmed, and beauty baryons.For complete list of authors see http://dx.doi.org/10.1103/PhysRevD.108.L031106</p