53 research outputs found
On the Parameters of the QCD-Motivated Potential in the Relativistic Independent Quark Model
In the framework of the relativistic independent quark model the parameters
of the QCD-motivated static potential and the quark masses are calculated on
the basis of the meson mass spectra. The value of the confining
potential coefficient is found to be ({}^2q\bar qe^+e^-$ decay widths are estimated with the help of relativistic
modification of the Van Royen-Weisskopf formula.Comment: 10 pages, LaTex; added references for the beginning, changed the last
paragraph at the end, made a few stylistic correction
Tensor extension of the Poincar\'e algebra
A tensor extension of the Poincar\'e algebra is proposed for the arbitrary
dimensions. Casimir operators of the extension are constructed. A possible
supersymmetric generalization of this extension is also found in the dimensions
.Comment: 1+7 pages, LaTe
The Stabilized Poincare-Heisenberg algebra: a Clifford algebra viewpoint
The stabilized Poincare-Heisenberg algebra (SPHA) is the Lie algebra of
quantum relativistic kinematics generated by fifteen generators. It is obtained
from imposing stability conditions after attempting to combine the Lie algebras
of quantum mechanics and relativity which by themselves are stable, however not
when combined. In this paper we show how the sixteen dimensional Clifford
algebra CL(1,3) can be used to generate the SPHA. The Clifford algebra path to
the SPHA avoids the traditional stability considerations, relying instead on
the fact that CL(1,3) is a semi-simple algebra and therefore stable. It is
therefore conceptually easier and more straightforward to work with a Clifford
algebra. The Clifford algebra path suggests the next evolutionary step toward a
theory of physics at the interface of GR and QM might be to depart from working
in space-time and instead to work in space-time-momentum.Comment: 14 page
Some consequences of a noncommutative space-time structure
The existence of a fundamental length (or fundamental time) has been
conjecture in many contexts. Here one discusses some consequences of a
fundamental constant of this type, which emerges as a consequence of
deformation-stability considerations leading to a non-commutative space-time
structure. This mathematically well defined structure is sufficiently
constrained to allow for unambiguous experimental predictions. In particular
one discusses the phase-space volume modifications and their relevance for the
calculation of the GZK sphere. Corrections to the spectrum of the Coulomb
problemb are also computed.Comment: 17 pages Latex, 3 figure
Soft singularity and the fundamental length
It is shown that some regular solutions in 5D Kaluza-Klein gravity may have
interesting properties if one from the parameters is in the Planck region. In
this case the Kretschman metric invariant runs up to a maximal reachable value
in nature, i.e. practically the metric becomes singular. This observation
allows us to suppose that in this situation the problems with such soft
singularity will be much easier resolved in the future quantum gravity then by
the situation with the ordinary hard singularity (Reissner-Nordstr\"om
singularity, for example). It is supposed that the analogous consideration can
be applied for the avoiding the hard singularities connected with the gauge
charges.Comment: 5 page
Scalar and vector form factors of the in-medium nucleon
Using the quark-meson coupling model, we calculate the form factors at sigma-
and omega-nucleon strong-interaction vertices in nuclear matter. The
Peierls-Yoccoz projection technique is used to take account of center of mass
and recoil corrections. We also apply the Lorentz contraction to the internal
quark wave function. The form factors are reduced by the nuclear medium
relative to those in vacuum. At normal nuclear matter density and Q^2 = 1
GeV^2, the reduction rate in the scalar form factor is about 15%, which is
almost identical to that in the vector one. We parameterize the ratios of the
form factors in symmetric nuclear matter to those in vacuum as a function of
nuclear density and momentum transfer.Comment: 13 pages, 2 figures, references are up date
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