46 research outputs found
QCD/String holographic mapping and high energy scattering amplitudes
We find a one to one mapping between low energy string dilaton states in AdS
bulk and high energy glueball states on the corresponding boundary. This
holographic mapping leads to a relation between bulk and boundary scattering
amplitudes. From this relation and the dilaton action we find the appropriate
momentum scaling for high energy QCD amplitudes at fixed angles.Comment: Minor changes in text. Version accepted for publication in PL
AdS space compactification and holographic mapping in the AdS/CFT correspondence
Physical consistency of quantum fields in anti-de Sitter space time requires
that the space must be compactified by the inclusion of a boundary where
appropriate conditions are imposed. An interpretation for the presence of this
boundary is found taking AdS as a limiting case of the space generated by a
large number of coincident branes. The compactification of AdS leads to a
discretization of the spectrum of bulk fields. As a consequence, we find a one
to one mapping between the quantum states of scalar fields in AdS bulk and
boundary. Using this mapping as an approximation for the dual relation between
string dilaton field and scalar QCD glueballs the high energy QCD scaling is
reproduced. We also use this map to estimate the ratio of scalar glueball
masses.Comment: 5 pages, talk presented at "Renormalization Group and Anomalies in
Gravity and Cosmology", Ouro Preto, Brazil, March 200
Deep Inelastic Scattering in Holographic AdS/QCD Models
We review the description of deep inelastic scattering using some AdS/QCD
phenomenological models.Comment: Talk presented by NRFB at Light Cone 2009: Relativistic Hadronic and
Particle Physics, 8-13 Jul 2009, Sao Jose dos Campos, Brazi
Local renormalizable gauge theories from nonlocal operators
The possibility that nonlocal operators might be added to the Yang-Mills
action is investigated. We point out that there exists a class of nonlocal
operators which lead to renormalizable gauge theories. These operators turn out
to be localizable by means of the introduction of auxiliary fields. The
renormalizability is thus ensured by the symmetry content exhibited by the
resulting local theory. The example of the nonlocal operator is analysed in detail. A few remarks on the possible role
that these operators might have for confining theories are outlined.Comment: 16 page
Vector mesons in a relativistic point-form approach
We apply the point form of relativistic quantum mechanics to develop a
Poincare invariant coupled-channel formalism for two-particle systems
interacting via one-particle exchange. This approach takes the exchange
particle explicitly into account and leads to a generalized eigenvalue equation
for the Bakamjian-Thomas type mass operator of the system. The coupling of the
exchange particle is derived from quantum field theory. As an illustrative
example we consider vector mesons within the chiral constituent quark model in
which the hyperfine interaction between the confined quark-antiquark pair is
generated by Goldstone-boson exchange. We study the effect of retardation in
the Goldstone-boson exchange by comparing with the commonly used instantaneous
approximation. As a nice physical feature we find that the problem of a too
large - splitting can nearly be avoided by taking the dynamics of
the exchange meson explicitly into account.Comment: 14 pages, 1 figur
Independence of , Poincare Invariance and the Non-Conservation of Helicity
A relativistic constituent quark model is found to reproduce the recent data
regarding the ratio of proton form factors, . We show that
imposing Poincare invariance leads to substantial violation of the helicity
conservation rule, as well as an analytic result that the ratio
for intermediate values of .Comment: 13 pages, 7 figures, to be submitted to Phys. Rev. C typos corrected,
references added, 1 new figure to show very high Q^2 behavio
Poincare Invariant Algebra From Instant to Light-Front Quantization
We present the Poincare algebra interpolating between instant and light-front
time quantizations. The angular momentum operators satisfying SU(2) algebra are
constructed in an arbitrary interpolation angle and shown to be identical to
the ordinary angular momentum and Leutwyler-Stern angular momentum in the
instant and light-front quantization limits, respectively. The exchange of the
dynamical role between the transverse angular mometum and the boost operators
is manifest in our newly constructed algebra.Comment: 21 pages, 3 figures, 1 tabl
Modeling quark-hadron duality for relativistic, confined fermions
We discuss a model for the study of quark-hadron duality in inclusive
electron scattering based on solving the Dirac equation numerically for a
scalar confining linear potential and a vector color Coulomb potential. We
qualitatively reproduce the features of quark-hadron duality for all potentials
considered, and discuss similarities and differences to previous models that
simplified the situation by treating either the quarks or all particles as
scalars. We discuss the scaling results for PWIA and FSI, and the approach to
scaling using the analog of the Callan-Gross relation for y-scaling.Comment: 38 pages, 21 figure
Prospects for e+e- physics at Frascati between the phi and the psi
We present a detailed study, done in the framework of the INFN 2006 Roadmap,
of the prospects for e+e- physics at the Frascati National Laboratories. The
physics case for an e+e- collider running at high luminosity at the phi
resonance energy and also reaching a maximum center of mass energy of 2.5 GeV
is discussed, together with the specific aspects of a very high luminosity
tau-charm factory. Subjects connected to Kaon decay physics are not discussed
here, being part of another INFN Roadmap working group. The significance of the
project and the impact on INFN are also discussed. All the documentation
related to the activities of the working group can be found in
http://www.roma1.infn.it/people/bini/roadmap.html.Comment: INFN Roadmap Report: 86 pages, 25 figures, 9 table