320 research outputs found
The new analysis of the KLOE data on the phi->eta pi0 gamma decay
In this paper we present the fit to the recent high-statistical KLOE data on
the phi -> eta pi^0 gamma decay. This decay mainly goes through the a_0 gamma
intermediate state. The obtained results differ from those of the previous
fits: data prefer a high a_0 mass and a considerably large a_0 coupling to the
K\bar K}.Comment: 11 pages, 2 figure
Search for and mesons in
We study the decay taking into account the scalar
mesons production and the final state
radiation. We note that the relative sign between the final state radiation
amplitude and the scalar meson production amplitude is fixed in the
loop model which describes data on the and
decays. As consequence this model predicts
the definite interference between the final state radiation and the scalar
resonance production amplitudes. We calculate the mass spectra of the
decay and the differential cross-sections for
and for
reactions.Comment: typos remove
Analysis of the nature of the and decays
We study interference patterns in the and reactions. Taking into account the interference, we fit the
experimental data and show that the background reaction does not distort the
spectrum in the decay everywhere over the
energy region and does not distort the spectrum in the decay
in the wide region of the system
invariant mass, MeV, or when the photon energy is less than
300 MeV. We discuss the details of the scalar meson production in the radiative
decays and note that there are reasonable arguments in favor of the one-loop
mechanism and . We
discuss also distinctions between the four-quark, molecular, and two-quark
models and argue that the Novosibirsk data give evidence in favor of the
four-quark nature of the scalar and mesons.Comment: 15 pages, 7 figures, title is changed, a few clarifying remarks are
added, accepted for publication in Physical Review
Study of the process in the energy region below 0.98 GeV
The cross section of the process was measured in
the Spherical Neutral Detector (SND) experiment at the VEPP-2M collider in the
energy region below 980 MeV. This measurement was based on about
selected events. The obtained cross section was analyzed
together with the SND and DM2 data in the energy region up to 2
GeV. The -meson parameters: MeV,
MeV and nb were obtained. It was found that the experimental data cannot be
described by a sum of only , , and
resonances contributions. This can be interpreted as a
manifestation of decay, suppressed by -parity, with relative
probability .Comment: 41 pages REVTEX and 34 figure
Electromagnetic form factors of charged and neutral kaons in an extended vector-meson-dominance model
A model is developed for electromagnetic form factors of the charged and
neutral K-mesons. The formalism is based on ChPT Lagrangians with vector
mesons. The form factors, calculated without fitting parameters, are in a good
agreement with experiment for space-like and time-like photon momenta.
Contribution of the two-kaon channels to the muon anomalous magnetic moment
a_\mu is calculated.Comment: 23 pages, 11 figures, accepted for publication in Eur. Phys. J.
Energy calibration of the NaI(Tl) calorimeter of the SND detector using cosmic muons
The general purpose spherical nonmagnetic detector (SND) is now taking data
at VEPP-2M collider in BINP (Novosibirsk) in the centre of mass energy
range of GeV. The energy calibration of the NaI(Tl) calorimeter
of the SND detector with cosmic muons is described. Using this method, the
energy resolution of for 500 MeV photons was achieved.Comment: 15 pages, Latex, 11 figures (.EPS
Energy calibration of the NaI(Tl) calorimeter of the SND detector using events
Calibration of the three layer NaI(Tl) spherical calorimeter of the SND
detector using electron -- positron scattering events is described. Energy
resolution of for 500 MeV photons was achieved.Comment: 12 pages, Latex, 8 figures (.EPS
The decays omega(782), phi(1020) to 5 pi in the hidden local symmetry approach
The decays omega -> 2pi^+ 2pi^- pi^0 and omega -> pi^+ pi^- 3pi^0 are
reconsidered in the hidden local symmetry approach (HLS) added with the
anomalous terms. The decay amplitudes are analyzed in detail, paying the
special attention to the Adler condition of vanishing the whole amplitude at
vanishing momentum of any final pion. Combining the Okubo-Zweig-Iizuka (OZI)
rule applied to the five pion final state, with the Adler condition, we
calculate also the phi -> 2pi^+ 2pi^-pi^0 and phi -> pi^+ pi^- 3pi^0 decay
amplitudes. The partial widths of the above decays are evaluated, and the
excitation curves in e^+e^- annihilation are obtained, assuming reasonable
particular relations among the parameters characterizing the anomalous terms of
the HLS Lagrangian. The evaluated branching ratios B(phi -> pi^+ pi^-
3pi^0)~2x10^{-7} and B(phi -> 2pi^+ 2pi^- pi^0)~7x10^{-7} are such that with
the luminosity L=500 pb^{-1} attained at DAFNE phi factory, one may already
possess about 1685 events of the decays phi -> 5pi.Comment: 15 pages text, 12 pages of figures. Typos corrected, clarifying
remarks added. Accepted for publication in Phys.Rev.
New Data from SND Detector in Novosibirsk
The current status of experiments with SND detector at VEPP-2M e^+e^-
collider in the energy range 2E_0=400-1400 MeV and recent results of data
analysis for , and decays and e^+e^- annihilation into
hadrons are presented.Comment: 7 pages, 8 figures, Latex2e, uses espcrc1.sty. Talk given at 8th
International Conference on Hadron Spectroscopy (HADRON 99), Beijing, China,
24-28 Aug 199
Study of the process in the energy region from 0.98 to 1.38 GeV.}
The cross section of the process was measured in
the Spherical Neutral Detector experiment at the VEPP-2M collider in the energy
region MeV. The measured cross section, together
with the and cross sections
obtained in other experiments, was analyzed in the framework of the generalized
vector meson dominance model. It was found that the experimental data can be
described by a sum of , mesons and two and
resonances contributions, with masses
, MeV and
widths , MeV. The analysis of the invariant mass spectra in the energy
region from 1100 to 1380 MeV has shown that for their
descriptionone should take into account the
mechanism also. The phase between the
amplitudes corresponding to the and
intermediate states was measured for the first time. The value of the phase is
close to zero and depends on energy.Comment: 29 pages REVTEX and 17 figures, accepted for publication in Physical
Review
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