154 research outputs found
A Note on the Supersymmetries of the Self-Dual Supermembrane
In this letter we discuss the supersymmetry issue of the self dual
supermembranes in (8+1) and (4+1)-dimensions. We find that all genuine
solutions of the (8+1)-dimensional supermembrane, based on the exceptional
group G_2, preserve one of the sixteen supersymmetries while all solutions in
(4+1)-dimensions preserve eight of them.Comment: Latex file, 12pages, no figure
Non-commutative Solitons in Finite Quantum Mechanics
We construct the unitary evolution operators that realize the quantization of
linear maps of SL(2,R) over phase spaces of arbitrary integer discretization N
and show the non-trivial dependence on the arithmetic nature of N. We discuss
the corresponding uncertainty principle and construct the corresponding
coherent states, that may be interpreted as non-commutative solitons.Comment: 3 pages LaTeX. Uses espcrc2.sty and amssymb.sty. Contribution to
Lattice 2002(theoretical
Non-Collapsing Membrane Instantons in Higher Dimensions
We introduce a particular embedding of seven dimensional self-duality
membrane equations in C^3\times R which breaks G_2 invariance down to SU(3).
The world-volume membrane instantons define SU(3) special lagrangian
submanifolds of C^3. We discuss in detail solutions for spherical and toroidal
topologies assuming factorization of time. We show that the extra dimensions
manifest themselves in the solutions through the appearance of a non-zero
conserved charge which prevents the collapse of the membrane. We find
non-collapsing rotating membrane instantons which contract from infinite size
to a finite one and then they bounce to infinity in finite time. Their motion
is periodic. These generalized complex Nahm equations, in the axially symmetric
case, lead to extensions of the continuous Toda equation to complex space.Comment: 14 pages, 2 figure
Gauge theories and non-commutative geometry
It is shown that a -dimensional classical SU(N) Yang-Mills theory can be
formulated in a -dimensional space, with the extra two dimensions forming
a surface with non-commutative geometry. In this paper we present an explicit
proof for the case of the torus and the sphere.Comment: 12 page
Low Scale Unification, Newton's Law and Extra Dimensions
Motivated by recent work on low energy unification, in this short note we
derive corrections on Newton's inverse square law due to the existence of extra
decompactified dimensions. In the four-dimensional macroscopic limit we find
that the corrections are of Yukawa type. Inside the compactified space of
n-extra dimensions the sub-leading term is proportional to the (n+1)- power of
the distance over the compactification radius ratio. Some physical implications
of these modifications are briefly discussed.Comment: 12pages, 2 figure
Octonionic Gravitational Instantons
We construct eight-dimensional gravitational instantons by solving
appropriate self-duality equations for the spin-connection. The particular
gravitational instanton we present has holonomy and, in a sense, it
is the eight-dimensional analog of the Eguchi-Hanson 4D space. It has a
removable bolt singularity which is topologically S^4 and its boundary at
infinity is the squashed S^7. We also lift our solutions to ten and eleven
dimensions and construct fundamental string and membrane configurations that
preserve 1/16 of the original supersymmetries.Comment: 17 pages, latex, no figures. References to earlier works adde
Determination of the anomalous dimension of gluonic operators in deep inelastic scattering at O(1/N_f)
Using large N_f methods we compute the anomalous dimension of the
predominantly gluonic flavour singlet twist-2 composite operator which arises
in the operator product expansion used in deep inelastic scattering. We obtain
a d-dimensional expression for it which depends on the operator moment n. Its
expansion in powers of epsilon = (4-d)/2 agrees with the explicit exact three
loop MSbar results available for n less than or equal to 8 and allows us to
determine some new information on the explicit n-dependence of the three and
higher order coefficients. In particular the n-dependence of the three loop
anomalous dimension gamma_{gg}(a) is determined in the C_2(G) sector at
O(1/N_f).Comment: 26 latex pages, 7 postscript figure
Octonionic Selfduality for SuperMembranes
In this work we study the recently introduced octonionic duality for
membranes. Restricting the self - duality equations to seven space dimensions,
we provide various forms for them which exhibit the symmetries of the
octonionic and quaternionic structure. These forms may turn to be useful for
the question of the integrability of this system. Introducing a consistent
quadratic Poisson algebra of functions on the membrane we are able to factorize
the time dependence of the self - duality equations. We further give the
general linear embeddings of the three dimensional system into the seven
dimensional one using the invariance of the self-duality equations under the
exceptional group G_2.Comment: Latex file, 21 page
Eight-Dimensional Self-Dual Spaces
We discuss higher-dimensional gravitational instantons by studying
appropriate self-duality equations for the spin connection. In seven and in
eight dimensions, the corresponding spaces admit a covariantly constant spinor
and have holonomies in G_2 and Spin(7), respectively. We find a non-compact
solution to the self-duality equations in eight dimensions in which the
self-dual space has an elliptically-fibered structure.Comment: 16 pages, late
Joint resummation in electroweak boson production
We present a phenomenological application of the joint resummation formalism
to electroweak annihilation processes at measured boson momentum Q_T. This
formalism simultaneously resums at next-to-leading logarithmic accuracy large
threshold and recoil corrections to partonic scattering. We invert the impact
parameter transform using a previously described analytic continuation
procedure. This leads to a well-defined, resummed perturbative cross section
for all nonzero Q_T, which can be compared to resummation carried out directly
in Q_T space. From the structure of the resummed expressions, we also determine
the form of nonperturbative corrections to the cross section and implement
these into our analysis. We obtain a good description of the transverse
momentum distribution of Z bosons produced at the Tevatron collider.Comment: 27 pages, LaTeX, 8 figures as eps files. Some additions to earlier
version, this version as published in Phys. Rev. D66 (2002) 01401
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