87 research outputs found
Extensions of the Poincare group
We construct an extension of the Poincare group which involves a mixture of
internal and space-time supersymmetries. The resulting group is an extension of
the superPoincare group with infinitely many generators which carry internal
and space-time indices. It is a closed algebra since all Jacobi identities are
satisfied and it has therefore explicit matrix representations. We investigate
the massless case and construct the irreducible representations of the extended
symmetry. They are divided into two sets, longitudinal and transversal
representations. The transversal representations involve an infinite series of
integer and half-integer helicities. Finally we suggest an extension of the
conformal group along the same line.Comment: 13 pages, LaTex fil
Algebras, Derivations and Integrals
In the context of the integration over algebras introduced in a previous
paper, we obtain several results for a particular class of associative algebras
with identity. The algebras of this class are called self-conjugated, and they
include, for instance, the paragrassmann algebras of order , the
quaternionic algebra and the toroidal algebras. We study the relation between
derivations and integration, proving a generalization of the standard result
for the Riemann integral about the translational invariance of the measure and
the vanishing of the integral of a total derivative (for convenient boundary
conditions). We consider also the possibility, given the integration over an
algebra, to define from it the integral over a subalgebra, in a way similar to
the usual integration over manifolds. That is projecting out the submanifold in
the integration measure. We prove that this is possible for paragrassmann
algebras of order , once we consider them as subalgebras of the algebra of
the matrices. We find also that the integration over the
subalgebra coincides with the integral defined in the direct way. As a
by-product we can define the integration over a one-dimensional Grassmann
algebra as a trace over matrices.Comment: 23 pages, few typos corrected. Final version to be published in
International Journal of Modern Physic
Modeling missing transverse energy in V+jets at CERN LHC
I discuss a method to model the instrumental response of the CMS and ATLAS
detectors at high transverse missing energies to dominant standard model V+jets
backgrounds, where V is a Z, gamma or W, using multi-jet QCD events. The method
is developed for new physics searches in early data at the Large Hadron
Collider (LHC) with minimal recourse to simulation.Comment: Replaced with the published versio
Enhanced Worldvolume Supersymmetry and Intersecting Domain Walls in N=1 SQCD
We study the worldvolume dynamics of BPS domain walls in N=1 SQCD with N_f=N
flavors, and exhibit an enhancement of supersymmetry for the reduced moduli
space associated with broken flavor symmetries. We provide an explicit
construction of the worldvolume superalgebra which corresponds to an N=2 Kahler
sigma model in 2+1D deformed by a potential, given by the norm squared of a
U(1) Killing vector, resulting from the flavor symmetries broken by unequal
quark masses. This framework leads to a worldvolume description of novel
two-wall junction configurations, which are 1/4-BPS objects, but nonetheless
preserve two supercharges when viewed as kinks on the wall worldvolume.Comment: 35 pages, 3 figures; v2: minor corrections and a reference added, to
appear in Phys. Rev.
New Einstein-Hilbert-type Action and Superon-Graviton Model(SGM) of Nature
A nonlinear supersymmetric(NLSUSY) Einstein-Hilbert(EH)-type new action for
unity of nature is obtained by performing the Einstein gravity analogue
geomtrical arguments in high symmetry spacetime inspired by NLSUSY. The new
action is unstable and breaks down spontaneously into E-H action with matter in
ordinary Riemann spacetime. All elementary particles except graviton are
composed of the fundamental fermion "superon" of Nambu-Goldstone(NG) fermion of
NLSUSY and regarded as the eigenstates of SO(10) super-Poincar\'e (SP) algebra,
called superon-graviton model(SGM) of nature. Some phenomenological
implications for the low energy particle physics and the cosmology are
discussed. The linearization of NLSUSY including N=1 SGM action is attempted
explicitly to obtain the linear SUSY local field theory, which is equivalent
and renormalizable.Comment: 37 pages, Latex, Based on a talk by K. Shima at International
Conference on Mathematics and Nucler Physics for the 21st Century, March
8-13, 2003, Atomic Energy Authority, Cairo, Egyp
Exact Results in Gauge Theories: Putting Supersymmetry to Work. The 1999 Sakurai Prize Lecture
Powerful methods based on supersymmetry allow one to find exact solutions to
certain problems in strong coupling gauge theories. The inception of some of
these methods (holomorphy in the gauge coupling and other chiral parameters, in
conjunction with instanton calculations) dates back to the 1980's. I describe
the early exact results -- the calculation of the beta function and the gluino
condensate -- and their impact on the subsequent developments. A brief
discussion of the recent breakthrough discoveries where these results play a
role is given.Comment: Based on the talk at the Centennial Meeting of The American Physical
Society, March 20-26, Atlanta, GA. LaTex (uses sprocl.sty), 36 pages, 5 eps
figures include
Grand Unification as a Bridge Between String Theory and Phenomenology
In the first part of the talk, I explain what empirical evidence points to
the need for having an effective grand unification-like symmetry possessing the
symmetry SU(4)-color in 4D. If one assumes the premises of a future predictive
theory including gravity--be it string/M theory or a reincarnation--this
evidence then suggests that such a theory should lead to an effective grand
unification-like symmetry as above in 4D, near the string-GUT-scale, rather
than the standard model symmetry. Advantages of an effective supersymmetric
G(224) = SU(2) SU(2) SU(4) or SO(10) symmetry in 4D
in explaining (i) observed neutrino oscillations, (ii) baryogenesis via
leptogenesis, and (iii) certain fermion mass-relations are noted. And certain
distinguishing tests of a SUSY G(224) or SO(10)-framework involving CP and
flavor violations (as in , , edm's of the
neutron and the electron) as well as proton decay are briefly mentioned.
Recalling some of the successes we have had in our understanding of nature so
far, and the current difficulties of string/M theory as regards the large
multiplicity of string vacua, some comments are made on the traditional goal of
understanding {\em vis a vis} the recently evolved view of landscape and
anthropism.Comment: A chart showing some insights gained in the world of the very small
and that of the very large is included. A few relevant references are added.
Some clarification is made in the last section as regards the question of
understanding versus landscape and anthropis
Pre - Inflationary Clues from String Theory ?
"Brane supersymmetry breaking" occurs in String Theory when the only
available combinations of D-branes and orientifolds are not mutually BPS and
yet do not introduce tree-level tachyon instabilities. It is characterized by
the emergence of a steep exponential potential, and thus by the absence of
maximally symmetric vacua. The corresponding low-energy supergravity admits
intriguing spatially-flat cosmological solutions where a scalar field is forced
to climb up toward the steep potential after an initial singularity, and
additional milder terms can inject an inflationary phase during the ensuing
descent. We show that, in the resulting power spectra of scalar perturbations,
an infrared suppression is typically followed by a pre-inflationary peak that
reflects the end of the climbing phase and can lie well apart from the
approximately scale invariant profile. A first look at WMAP9 raw data shows
that, while the chi^2 fits for the low-l CMB angular power spectrum are clearly
compatible with an almost scale invariant behavior, they display nonetheless an
eye-catching preference for this type of setting within a perturbative string
regime.Comment: 34 pages, LaTeX, 16 eps figures. Relative displacement in fig. 14 and
some typos corrected, references and acknowledgments updated. To appear in
JCA
Quadratic pseudosupersymmetry in two-level systems
Using the intertwining relation we construct a pseudosuperpartner for a
(non-Hermitian) Dirac-like Hamiltonian describing a two-level system
interacting in the rotating wave approximation with the electric component of
an electromagnetic field. The two pseudosuperpartners and pseudosupersymmetry
generators close a quadratic pseudosuperalgebra. A class of time dependent
electric fields for which the equation of motion for a two level system placed
in this field can be solved exactly is obtained. New interesting phenomenon is
observed. There exists such a time-dependent detuning of the field frequency
from the resonance value that the probability to populate the excited level
ceases to oscillate and becomes a monotonically growing function of time
tending to 3/4. It is shown that near this fixed excitation regime the
probability exhibits two kinds of oscillations. The oscillations with a small
amplitude and a frequency close to the Rabi frequency (fast oscillations) take
place at the background of the ones with a big amplitude and a small frequency
(slow oscillations). During the period of slow oscillations the minimal value
of the probability to populate the excited level may exceed 1/2 suggesting for
an ensemble of such two-level atoms the possibility to acquire the inverse
population and exhibit lasing properties.Comment: 5 figure
Cosmology and New Physics
A comparison of the standard models in particle physics and in cosmology
demonstrates that they are not compatible, though both are well established.
Basics of modern cosmology are briefly reviewed. It is argued that the
measurements of the main cosmological parameters are achieved through many
independent physical phenomena and this minimizes possible interpretation
errors. It is shown that astronomy demands new physics beyond the frameworks of
the (minimal) standard model in particle physics. More revolutionary
modifications of the basic principles of the theory are also discussed.Comment: 37 pages, 5 figures; lectures presented at 9th International Moscow
School of Physics (34th ITEP Winter School
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