4,506 research outputs found
Towards a unitary Dalitz plot analysis of three-body hadronic B decays
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
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
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 400 km\s). We found
emission of CO, SiO, SO, SO (in all three red novae), HS (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 10 M 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 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
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
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
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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