975 research outputs found
Can a spontaneous collapse in flavour oscillations be tested at KLOE?
Why do we never see a table in a superposition of here and there? This
problem gets a solution by so called collapse models assuming the collapse as a
genuinely physical process. Here we consider two specific collapse models and
apply them to systems at high energies, i.e. flavour oscillating neutral meson
systems. We find on one hand a potentially new interpretation of the decay
rates introduced by hand in the standard formalism and on the other hand that
these systems at high energies constrain by experimental data the possible
collapse scenarios.Comment: To appear in the proceedings of the KLOE-2 Workshop on e+e- collision
physics at 1 GeV, 26-28 October 2016, INFN - Laboratori Nazionali di
Frascati, Ital
Dynamics of confined gluons
Propagation of gluons in the confining vacuum is studied in the framework of
the background perturbation theory, where nonperturbative background contains
confining correlators. Two settings of the problem are considered. In the first
the confined gluon is evolving in time together with static quark and antiquark
forming the one-gluon static hybrid. The hybrid spectrum is calculated in terms
of string tension and is in agreement with earlier analytic and lattice
calculations. In the second setting the confined gluon is exchanged between
quarks and the gluon Green's function is calculated, giving rise to the Coulomb
potential modified at large distances. The resulting screening radius of 0.5 fm
presents a serious problem when confronting with lattice and experimental data.
A possible solution of this discrepancy is discussed.Comment: 17 pages, no figures; v2: minor numerical changes in the tabl
The static interaction at small distances and OPE violating terms
Nonperturbative contribution to the one-gluon exchange produces a universal
linear term in the static potential at small distances . Its role in the resolution of long--standing
discrepancies in the fine splitting of heavy quarkonia and improved agreement
with lattice data for static potentials is discussed, as well as implications
for OPE violating terms in other processes.Comment: Latex, 5 pages, to be published in JETP Let
Glueballs, gluerings and gluestars in the d=2+1 SU(N) gauge theory
The 3d gluodynamics which governs the large T quark gluon plasma is studied
in the framework of the field correlator method. Field correlators and spacial
string tension are derived through the gluelump Green's functions. The glueball
spectrum is calculated both in C=-1 as well as in C=+1 sectors, and multigluon
bound states in the form of "gluon rings" and "gluon stars" are computed
explicitly. Good overall agreement with available lattice data is observed.Comment: 19 page
Current correlators in QCD: OPE versus large distance dynamics
We analyse the structure of current-current correlators in coordinate space
in large limit when the corresponding spectral density takes the form of
an infinite sum over hadron poles. The latter are computed in the QCD string
model with quarks at the ends, including the lowest states, for all channels.
The corresponding correlators demonstrate reasonable qualitative agreement with
the lattice data without any additional fits. Different issues concerning the
structure of the short distance OPE are discussed.Comment: LaTeX, 25 pages, 13 figure
Gluonic correlation length from spin-dependent potentials
The vacuum gluonic correlation length is extracted from recent lattice data
on spin-dependent interquark potentials in heavy quarkonia. It is shown that
the data are consistent with extremely small values of the correlation length,
Tg<0.1 fm.Comment: LaTeX2e, 6 pages, uses jetpl.cls (included), version to appear in
JETP Let
Baryon magnetic moments in the effective quark Lagrangian approach
An effective quark Lagrangian is derived from first principles through
bilocal gluon field correlators. It is used to write down equations for
baryons, containing both perturbative and nonperturbative fields. As a result
one obtains magnetic moments of octet and decuplet baryons without introduction
of constituent quark masses and using only string tension as an input. Magnetic
moments come out on average in reasonable agreement with experiment, except for
nucleons and . The predictions for the proton and neutron are shown
to be in close agreement with the empirical values once we choose the string
tension such to yield the proper nucleon mass. Pionic corrections to the
nucleon magnetic moments have been estimated. In particular, the total result
of the two-body current contributions are found to be small. Inclusion of the
anomalous magnetic moment contributions from pion and kaon loops leads to an
improvement of the predictions.Comment: 24 pages Revte
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