31,967 research outputs found
Normalization of the covariant three-body bound state vertex function
The normalization condition for the relativistic three nucleon Bethe-Salpeter
and Gross bound state vertex functions is derived, for the first time, directly
from the three body wave equations. It is also shown that the relativistic
normalization condition for the two body Gross bound state vertex function is
identical to the requirement that the bound state charge be conserved, proving
that charge is automatically conserved by this equation.Comment: 24 pages, 9 figures, published version, minor typos correcte
The stability of the spectator, Dirac, and Salpeter equations for mesons
Mesons are made of quark-antiquark pairs held together by the strong force.
The one channel spectator, Dirac, and Salpeter equations can each be used to
model this pairing. We look at cases where the relativistic kernel of these
equations corresponds to a time-like vector exchange, a scalar exchange, or a
linear combination of the two. Since the model used in this paper describes
mesons which cannot decay physically, the equations must describe stable
states. We find that this requirement is not always satisfied, and give a
complete discussion of the conditions under which the various equations give
unphysical, unstable solutions
An Exact Prediction of N=4 SUSYM Theory for String Theory
We propose that the expectation value of a circular BPS-Wilson loop in N=4
SUSYM can be calculated exactly, to all orders in a 1/N expansion and to all
orders in g^2 N. Using the AdS/CFT duality, this result yields a prediction of
the value of the string amplitude with a circular boundary to all orders in
alpha' and to all orders in g_s. We then compare this result with string
theory. We find that the gauge theory calculation, for large g^2 N and to all
orders in the 1/N^2 expansion does agree with the leading string theory
calculation, to all orders in g_s and to lowest order in alpha'. We also find a
relation between the expectation value of any closed smooth Wilson loop and the
loop related to it by an inversion that takes a point along the loop to
infinity, and compare this result, again successfully, with string theory.Comment: LaTeX, 22 pages, 3 figures. Argument corrected and two new sections
adde
More on Phase Structure of Nonlocal 2D Generalized Yang-Mills Theories (nlgYM's)
We study the phase structure of nonlocal two dimensional generalized Yang -
Mills theories (nlgYM) and it is shown that all order of model
of these theories has phase transition only on compact manifold with (on
sphere), and the order of phase transition is 3. Also it is shown that the
model of nlgYM has third order phase
transition on any compact manifold with ,
and has no phase transition on sphere.Comment: 11 pages, no figure
Interacting Higher Spins and the High Energy Limit of the Bosonic String
In this note, we construct a BRST invariant cubic vertex for massless fields
of arbitrary mixed symmetry in flat space-time. The construction is based on
the vertex given in bosonic Open String Field Theory. The algebra of gauge
transformations is closed without any additional, higher than cubic, couplings
due to the presence of an infinite tower of massless fields. We briefly discuss
the generalization of this result to a curved space-time and other possible
implications.Comment: Published Version; typos corrected, references added; (v3) Some typos
corrected and a minor clarification about eq. (3.29
- …