4,506 research outputs found

    Towards a unitary Dalitz plot analysis of three-body hadronic B decays

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    A unitary model of the final state kaon pion interaction amplitudes in the B --> K pi pi decays is constructed. The weak decay penguin amplitudes, derived in QCD factorization, are supplemented by phenomenological contributions. The strange kaon- pion scalar and vector form factors are used to calculate the kaon pion effective mass and helicity angle distributions, branching ratios, CP asymmetries and the phase difference between the B0 and anti B0 decay amplitudes to K*(892) pi. The fit on the phenomenological parameters leads to a good agreement with the experimental data, particularly for the B --> K*(892) pi decays. However, our predicted B+- --> K*0(1430) pi+-, K*0(1430)--> K+-pi-+ branching fraction is smaller than the results of the Belle and BaBar collaborations, obtained from isobar model analyses. A new parameterization of the S-wave kaon- pion effective mass distribution, which can be used in future experimental Dalitz plot analyses, is proposed.Comment: 5 pages, 1 figure, contribution to Proc. Int. Europhysics Conference on High Energy Physics (HEP2009), July 16-22, 2009, Krakow, Poland, PoS(HEP2009)20

    Final state interactions and CP violation in B decays to three pseudoscalars

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    We study CP violation and final state interactions between pions and kaons in B+, B-, B0 and bar B0 decays into K pi pi. The weak transition amplitudes consist of two terms: the first part is derived in QCD factorization approach and the second one is a phenomenological long-distance charming penguin contribution. The final state K pi interactions in S- and P-waves are described by strange scalar and vector form factors, respectively. These are determined using a unitary coupled channel model together with chiral symmetry and asymptotic QCD constraints. The final state interactions are dominated by presence of the scalar K*0(1430) and the vector K*(892) resonances. We show that additional charming penguin amplitudes are needed to reproduce the latest experimental K pi effective mass and helicity angle distributions, branching fractions and asymmetries obtained by Belle and BaBar collaborations.Comment: Talk given at XIII International Conference on Hadron Spectroscopy (Hadron 2009), Nov. 29 - Dec. 4 2009, Florida State Universit

    Submillimeter-wave emission of three Galactic red novae: cool molecular outflows produced by stellar mergers

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    Red novae are optical transients erupting at luminosities typically higher than those of classical novae. Their outbursts are believed to be caused by stellar mergers. We present millimeter/submillimeter-wave observations with ALMA and SMA of the three best known Galactic red novae, V4332 Sgr, V1309 Sco, and V838 Mon. The observations were taken 22, 8, and 14 yr after their respective eruptions and reveal the presence of molecular gas at excitation temperatures of 35-200 K. The gas displays molecular emission in rotational transitions with very broad lines (full width \sim400 km\s). We found emission of CO, SiO, SO, SO2_2 (in all three red novae), H2_2S (covered only in V838 Mon) and AlO (present in V4332 Sgr and V1309 Sco). No anomalies were found in the isotopic composition of the molecular material and the chemical (molecular) compositions of the three red novae appear similar to those of oxygen-rich envelopes of classical evolved stars (RSGs, AGBs, post-AGBs). The minimum masses of the molecular material that most likely was dispersed in the red-nova eruptions are 0.1, 0.01, and 104^{-4} M_{\odot} for V838 Mon, V4332 Sgr, and V1309 Sco, respectively. The molecular outflows in V4332 Sgr and V1309 Sco are spatially resolved and appear bipolar. The kinematic distances to V1309 Sco and V4332 Sgr are 2.1 and 4.2 kpc, respectively. The kinetic energy stored in the ejecta of the two older red-nova remnants of V838 Mon and V4332 Sgr is of order 104610^{46} erg, similar to values found for some post-AGB (pre-PN) objects whose bipolar ejecta were also formed in a short-duration eruption. Our observations strengthen the link between these post-AGB objects and red novae and support the hypothesis that some of the post-AGB objects were formed in a common-envelope ejection event or its most catastrophic outcome, a merger.Comment: 19 pages, 13 figures, accepted to A&

    CP violation and final state interactions in B --> K pi pi decays

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    Effects of CP violation and of final state interactions between pairs of pseudoscalar mesons are studied in three-body B+, B-, B0 and antiB0 decays into K pi pi. An alternative approach to the isobar model for three-body B decays is proposed. It is based on the QCD factorization approximation and the knowledge of the meson-meson form factors. Some phenomenological charming penguin amplitudes are needed to describe the branching fractions, direct CP asymmetries of the quasi-two-body B --> K*(892) pi and B --> K0*(1430) pi decays as well as the K pi effective mass and the helicity angle distributions. The experimental branching fractions for the B --> K0*(1430) pi decay, obtained by the Belle and BaBar collaborations using the isobar model, are larger than our predictions by about 52 per cent.Comment: 3 pages, contribution to International Europhysics Conference on High Energy Physics HEP 2007, Manchester (England), July 19-25, 200

    The Temperature Evolution of the Spectral Peak in High Temperature Superconductors

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    Recent photoemission data in the high temperature cuprate superconductor Bi2212 have been interpreted in terms of a sharp spectral peak with a temperature independent lifetime, whose weight strongly decreases upon heating. By a detailed analysis of the data, we are able to extract the temperature dependence of the electron self-energy, and demonstrate that this intepretation is misleading. Rather, the spectral peak loses its integrity above Tc due to a large reduction in the electron lifetime.Comment: 5 pages, revtex, 4 encapsulated postscript figure

    Towards new background independent representations for Loop Quantum Gravity

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    Recently, uniqueness theorems were constructed for the representation used in Loop Quantum Gravity. We explore the existence of alternate representations by weakening the assumptions of the so called LOST uniqueness theorem. The weakened assumptions seem physically reasonable and retain the key requirement of explicit background independence. For simplicity, we restrict attention to the case of gauge group U(1).Comment: 22 pages, minor change
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