Production of the Y(4260) State in B Meson Decay

We calculate the branching ratio for the production of the meson $Y(4260)$ in the decay $B^- \to Y(4260)K^-$. We use QCD sum rules approach and we consider the $Y(4260)$ to be a mixture between charmonium and exotic tetraquark, $[\bar{c}\bar{q}][qc]$, states with $J^{PC}=1^{--}$. Using the value of the mixing angle determined previously as: $\theta=(53.0\pm0.5)^\circ$, we get the branching ratio $\mathcal{B}(B\to Y(4260)K)=(1.34\pm0.47)\times10^{-6}$, which allows us to estimate an interval on the branching fraction $3.0 \times 10^{-8} < {\mathcal B}_{_Y} < 1.8 \times 10^{-6}$ in agreement with the experimental upper limit reported by Babar Collaboration.Comment: 5 pages, 2 figures, 1 table. arXiv admin note: text overlap with arXiv:1105.134

Distance-Preserving Subgraphs of Interval Graphs

We consider the problem of finding small distance-preserving subgraphs of undirected, unweighted interval graphs that have k terminal vertices. We show that every interval graph admits a distance-preserving subgraph with O(k log k) branching vertices. We also prove a matching lower bound by exhibiting an interval graph based on bit-reversal permutation matrices. In addition, we show that interval graphs admit subgraphs with O(k) branching vertices that approximate distances up to an additive term of +1

Study of the process e+e- -> omega pi0 in the phi-meson mass region with the KLOE detector

We have studied the e+e- -> omegapi0 cross section in the sqrt(s) interval 1000-1030 MeV using the pi+pi-pi0pi0 and pi0pi0gamma final states with a sample of ~600 pb^-1 collected with the KLOE detector at DAFNE. By fitting the observed interference pattern around M_phi for both final states, we extract the ratio of the decay widths Gamma(omega->pi0gamma)/Gamma(omega->pi+pi-pi0) = 0.0897 +- 0.0016 and derive the branching fractions BR(omega -> pi+pi-pi0)= (90.24 +- 0.19)%, BR(omega -> pi0gamma) = (8.09 +- 0.14)%. The parameters describing the e+e- -> omegapi0 reaction around M_\phi are also used to extract the branching fraction for the OZI and G-parity violating phi -> omegapi0 decay: BR(phi->omegapi0) = (4.4 +- 0.6)x10^-5.Comment: 12 Pages, 4 figures, submitted to Physics Letter

Interval exchanges, admissibility and branching Rauzy induction

We introduce a definition of admissibility for subintervals in interval exchange transformations. Using this notion, we prove a property of the natural codings of interval exchange transformations, namely that any derived set of a regular interval exchange set is a regular interval exchange set with the same number of intervals. Derivation is taken here with respect to return words. We characterize the admissible intervals using a branching version of the Rauzy induction. We also study the case of regular interval exchange transformations defined over a quadratic field and show that the set of factors of such a transformation is primitive morphic. The proof uses an extension of a result of Boshernitzan and Carroll