A search for the doubly charmed baryon $ \Xi_{cc}^{+} $ in the decay mode $ \Xi_{cc}^{+}\to \Lambda_c^{+}{K^{-}}{\pi^{+}} $ is performed with a data sample, corresponding to an integrated luminosity of 0.65 fb−1, of pp collisions recorded at a centre-of-mass energy of 7 TeV. No significant signal is found in the mass range 3300-3800 MeV/c 2. Upper limits at the 95% confidence level on the ratio of the $ \Xi_{cc}^{+} $ production cross-section times branching fraction to that of the $ \Lambda_c^{+} $ , R, are given as a function of the $ \Xi_{cc}^{+} $ mass and lifetime. The largest upper limits range from R < 1.5 × 10−2 for a lifetime of 100 fs to R < 3.9 × 10−4 for a lifetime of 400 fs.

We investigate the ratio of the branching fractions of the molecular candidates decaying into the ground and radially excited states within the quark-interchange model. Our numerical results suggest that these molecular candidates are more likely to decay into the radially excited states than into ground states. In particular, the ratio Γ½Z c ð4430Þ → πψð2SÞ=Γ½Z c ð4430Þ → πJ=ψ ∼ 9.9 is close to the experimental measurement, which supports the interpretation of Z c ð4430Þ as theDD Ã ð2SÞ molecular state. The ratios of the branching fractions of Z b ð10610Þ and Z b ð10650Þ to πϒð2S; 3SÞ and πϒð1SÞ agrees very well with the Belle Collaboration's measurement. We also predict the similar ratios for Z c ð3900Þ, Z c ð4020Þ, R Z c ð3900Þ ≈ 1.4, and R Z c ð4020Þ ≈ 4.8. Hopefully, the πψð2SÞ mode and the ratios R Z c ð3900Þ and R Z c ð4020Þ will be measured by the BESIII and Belle collaborations in the near future, which shall be very helpful for understanding the underlying dynamics of these exotic states.

An angular analysis of the B0 → K*0e+e− decay is performed using a data sample corresponding to an integrated luminosity of 9 fb−1 of pp collisions collected with the LHCb experiment. The analysis is conducted in the very low dielectron mass squared (q2) interval between 0.0008 and 0.257 GeV2, where the rate is dominated by the B0 → K*0γ transition with a virtual photon. The fraction of longitudinal polarisation of the K*0 meson, FL, is measured to be FL = (4.4 ± 2.6 ± 1.4)%, where the first uncertainty is statistical and the second systematic. The $$ {A}_{\mathrm{T}}^{\mathrm{Re}} $$ A T Re observable, which is related to the lepton forward-backward asymmetry, is measured to be $$ {A}_{\mathrm{T}}^{\mathrm{Re}} $$ A T Re = −0.06 ± 0.08 ± 0.02. The $$ {A}_{\mathrm{T}}^{(2)} $$ A T 2 and $$ {A}_{\mathrm{T}}^{\mathrm{Im}} $$ A T Im transverse asymmetries, which are sensitive to the virtual photon polarisation, are found to be $$ {A}_{\mathrm{T}}^{(2)} $$ A T 2 = 0.11 ± 0.10 ± 0.02 and $$ {A}_{\mathrm{T}}^{\mathrm{Im}} $$ A T Im = 0.02 ± 0.10 ± 0.01. The results are consistent with Standard Model predictions and provide the world’s best constraint on the b → sγ photon polarisation.

No abstract