999 research outputs found
Nonet Classification of Scalar/Isoscalar Resonances in the Mass Region below 1900 MeV: Observation of the Lightest Scalar Glueball
We summarize the results of the investigation of the wave
which is devoted to the search for the lightest scalar glueball. In the
framework of the K-matrix formalism, the -nonet classification of the
scalar/isoscalar states is performed in the mass region below 1900 MeV basing
on the following data: GAMS data for , ,
; CERN-M\"unich data for ; Crystal Barrel
data for , , ; BNL
data for . It is shown the existence of an extra state
for classification: this state is a good candidate for the lightest
scalar glueball. Analysis of the glueball/ mixing shows that the
glueball state has mainly dispersed over three real resonances: ,
and . The broad resonance with complex mass
MeV is descendant of the pure glueball. The
restored mass of the pure glueball is equal to 1695 MeV. This value agrees well
with the results of lattice gluodynamics.Comment: LaTex, 5 pages and 7 figures. Talk given by V.V.Anisovich at LEAP96,
Dinkelsbuhl, German
A model for A=3 antinuclei production in proton-nucleus collisions
A simple coalescence model based on the same diagrammatic approach of
antimatter production in hadronic collisions as used previously for
antideuterons is used here for the hadroproduction of mass 3 antinuclei. It is
shown that the model is able to reproduce the existing experimental data on
Tbar and 3hebar production without any additional parameter.Comment: 7 figures. submitted to Eur. Phys. J.
Parameters of scalar resonances from the combined analysis of data on processes and decays
A combined analysis of data on isoscalar S-wave processes
and on decays
from the DM2, Mark III and BESIII
collaborations is performed to study mesons. The method of analysis is
based on analyticity and unitarity and uses an uniformization procedure. In the
analysis limited only to the multi-channel -scattering data, two
possible sets of parameters of the were found: in both cases the
mass was about 700 MeV but the total width was either about 600 or 930 MeV. The
extension of the analysis using only the DM2 and Mark III data on the
decays does not allow to choose between these sets. However, the data from
BESIII on the di-pion mass distribution in the decay
clearly prefers the wider state. Spectroscopic implications from
results of the analysis are also discussed.Comment: the formalism is also described (text overlap) in arXiv:1108.3725;
new extended analysis of data; revised PRD versio
Search for the radiative decay in the SND experiment at VEPP-2M
The decay was investigated by the SND detector
at VEPP-2M collider in the reaction .
Here we present the results and some details of this study. We report an upper
limit (90% c.l.) as our
final result. Our upper limit does not contradict the earlier measurement by
GAMS spectrometer. To facilitate future studies a rather detailed review of the
problem is also given.Comment: 24 pages, 6 figures, LaTex. To be published in Nucl. Phys.
-Glueball/-State Mixing in the Mass Region near 1500 MeV
Basing on the results of the K-matrix fit of wave, we
analyze the analytic structure of the amplitude and /glueball content
of resonances in the mass region 1200-1900 MeV, where an extra state for -systematics exists being a good candidate for the lightest scalar
glueball. Our analysis shows that the pure glueball state dispersed over three
resonances: , and , while the
glueball admixture in is small. The broad resonance
is the descendant of the lightest pure glueball. The
mass of pure glueball is MeV, in agreement with Lattice
calculation results.Comment: LaTex, 12 pages, 2 figure
On nature of the scalar-isoscalar mesons in the uniformizing-variable method based on analyticity and unitarity
The experimental data on the processes
in the
channel have been jointly analyzed to study the status
and nature of the . The method of analysis is based on analyticity and
unitarity and uses an uniformization procedure. Some spectroscopic implications
from results of the analysis are discussed.Comment: 18 pages, 5 figures, 9 table
Nonet Classification of Scalar/Isoscalar Resonances below 1900 MeV: the Existence of an Extra Scalar State in the Region 1200-1600 MeV
A classification of the mesons is performed on the basis of
the K-matrix analysis of meson spectra in the reactions: (i) GAMS data on , , ; (ii) Crystal Barrel data on
, , ;
(iii) CERN-M\"unich data on ; (iiii) BNL data on . The analysis points to the existence of four comparatively
narrow scalar resonances which correspond to the following poles of the
scattering amplitude (in MeV): , , and .
The scattering amplitude also has a fifth pole at the
complex mass . The masses of the K-matrix
poles (bare states) are at MeV, MeV,
MeV, MeV and MeV. The quark content of the bare
states is analyzed using the values of their couplings to the , , and . It is shown that one of the bare states in the
mass region 1200-1600 MeV is superfluous for the classification and
should be considered as the lightest glueball.Comment: LaTex 26 pages and 8 figure
Masses and Internal Structure of Mesons in the String Quark Model
The relativistic quantum string quark model, proposed earlier, is applied to
all mesons, from pion to , lying on the leading Regge trajectories
(i.e., to the lowest radial excitations in terms of the potential quark
models). The model describes the meson mass spectrum, and comparison with
measured meson masses allows one to determine the parameters of the model:
current quark masses, universal string tension, and phenomenological constants
describing nonstring short-range interaction. The meson Regge trajectories are
in general nonlinear; practically linear are only trajectories for light-quark
mesons with non-zero lowest spins. The model predicts masses of many new
higher-spin mesons. A new meson is predicted with mass 1910 Mev. In
some cases the masses of new low-spin mesons are predicted by extrapolation of
the phenomenological short-range parameters in the quark masses. In this way
the model predicts the mass of to be MeV, and
the mass of to be MeV (the potential model predictions
are 100 Mev lower). The relativistic wave functions of the composite mesons
allow one to calculate the energy and spin structure of mesons. The average
quark-spin projections in polarized -meson are twice as small as the
nonrelativistic quark model predictions. The spin structure of reveals an
80% violation of the flavour SU(3). These results may be relevant to
understanding the ``spin crises'' for nucleons.Comment: 30 pages, REVTEX, 6 table
Some indication for a missing chiral partner eta_4 around 2 GeV
The high-lying mesons in the light quark sector previously obtained from the
partial wave analysis of the proton-antiproton annihilation in flight at 1.9 -
2.4 GeV region at CERN reveal a very high degree of degeneracy. This degeneracy
can be explained as due to an effective restoration of both SU(2)_L * SU(2)_R
and U(1)_A symmetries combined with a principal quantum number n + J. In this
case there must be chiral partners for the highest spin states in the 2 and 2.3
GeV bands presently missing in the data. Here we reanalyze the Crystal Barrel
data and show an indication for existence of the missing state around
2 GeV. This result calls for further experimental search of the missing states
both in the proton-antiproton annihilation and in the production reactions.Comment: 4 pp. A fit with the energy-dependent width has been added that
agrees with the previous analysis. Accepted by PR
- …