229 research outputs found
The Orbifold and the SUSY Flavor Problem
The characteristic property of the orbifold is its cyclic
permutation symmetry. It is argued that this property may be instrumental in
explaining simultaneously the fermion mass hierarchy and the squark mass
degeneracy. Detailed studies in free fermionic models that preserve the cyclic
permutation symmetry of anomalous U(1) charges of the three generations are
discussed.Comment: 9 pages. Standard Late
On the origin of three generation free fermionic superstring models
The three generation superstring models in the free fermionic models have had
remarkable success in describing the real--world. The most explored models use
the NAHE set to obtain three generations and to separate the hidden and
observable sectors. It is of course well known that the full NAHE set is not
required in order to construct three generation free fermionic models. I argue
that all the semi--realistic free fermionic models that have been constructed
to date correspond to orbifolds. Thus, the successes of the
semi--realistic free fermionic models, if taken seriously, suggest that the
true string vacuum is a orbifold with nontrivial background
fields and quantized Wilson lines.Comment: 12 pages, phyzzx.tex, tables.te
Phenomenological aspects of M-theory
The Standard Model data suggests the realization of grand unification
structures in nature, in particular that of SO(10). A class of string vacua
that preserve the SO(10) embedding, are the three generation free fermion
heterotic-string models, that are related to Z2xZ2 orbifold compactification.
Attempts to use the M-theory framework to explore further this class of models
are discussed. Wilson line breaking of the SO(10) GUT symmetry results in
super-heavy meta-stable states, which produce several exotic dark matter and
UHECR candidates, with differing phenomenological characteristics. Attempts to
develop the tools to study the properties of these states in forthcoming UHECR
experiments are discussed. It is proposed that quantum mechanics arises from an
equivalence postulate, that may lay the foundations for the rigorous
formulation of quantum gravity.Comment: 25 pages. 6 figures. Standard Latex & iopart.cls. To appear in the
proceedings of Beyond the Desert 02 - Accelerator and non Accelerator
Approaches, Oulu, Finland, 2-7 June 200
Cosmological and phenomenological implications of Wilsonian matter in realistic superstring derived models
Superstring phenomenology aims at achieving two goals. The first is to
reproduce the observed physics of the Standard Model. The second is to identify
experimental signatures of superstring unification which, if observed, will
provide further evidence for the validity of superstring theory. I discuss such
potential signatures of superstring unification. I propose that proton lifetime
constraints imply that the Standard Model gauge group must be obtained directly
at the string level. In this case the unifying gauge group, for example
, is broken to the Standard Model gauge group by ``Wilson lines''. The
symmetry breaking by ``Wilson line'' has important implications. It gives rise
to exotic massless states which cannot fit into multiplets of the original
unifying gauge group. This is an important feature because it results in
conservation laws which forbid the interaction of the exotic ``Wilsonian''
states with the Standard Model states. The ``Wilsonian'' matter states then
have important phenomenological implications. I discuss two such implications:
exotic ``Wilsonian'' states as dark matter candidates and ``Wilsonian'' matter
as the messenger sector in gauge mediated dynamical SUSY breaking scenarios.Comment: 22 pages. Standard Latex. 4 figures. epsf.te
Deriving The Standard Model From Superstring Theory
I outline a program to derive the Standard Model directly from superstring
theory. I present a class of three generation superstring standard--like models
in the free fermionic formulation. I discuss some phenomenological properties
of these models. In particular these models suggest an explanation for the top
quark mass hierarchy. A numerical estimate yielded . The
general texture of fermion mass matrices was obtained from analysis of
nonrenormalizable terms up to order .I argue that the realistic features
of these models are due to the underlying orbifold, with
standard embedding, at the free fermionic point in toroidal compactification
space.Comment: IASSNS--HEP--94/21, 11 page
The Equivalence Postulate of Quantum Mechanics, Dark Energy and The Intrinsic Curvature of Elementary Particles
The equivalence postulate of quantum mechanics offers an axiomatic approach
to quantum field theories and quantum gravity. The equivalence hypothesis can
be viewed as adaptation of the classical Hamilton-Jacobi formalism to quantum
mechanics. The construction reveals two key identities that underly the
formalism in Euclidean or Minkowski spaces. The first is a cocycle condition,
which is invariant under --dimensional Mobius transformations with Euclidean
or Minkowski metrics. The second is a quadratic identity which is a
representation of the D-dimensional quantum Hamilton--Jacobi equation. In this
approach, the solutions of the associated Schrodinger equation are used to
solve the nonlinear quantum Hamilton-Jacobi equation. A basic property of the
construction is that the two solutions of the corresponding Schrodinger
equation must be retained. The quantum potential, which arises in the
formalism, can be interpreted as a curvature term. I propose that the quantum
potential, which is always non-trivial and is an intrinsic energy term
characterising a particle, can be interpreted as dark energy. Numerical
estimates of its magnitude show that it is extremely suppressed. In the
multi--particle case the quantum potential, as well as the mass, are
cumulative.Comment: 19 pages. Standard LaTe
Phenomenological survey of free fermionic heterotic-string models
A glossary overview of the phenomenological studies of quasi-realistic free
fermionic heterotic string models is presented. I elaborate on the
correspondence of these models with Z2XZ2 orbifolds.Comment: 14 pages. Standard LaTe
Superstring Phenomenology - A Personal Perspective
In the first part of this paper I review the construction of the realistic
free fermionic models, as well as current attempts to study aspects of these
models in the nonperturbative framework of M- and F-theories. I discuss the
recent demonstration of a Minimal Superstring Standard Model, which contains in
the observable sector, below the string scale, solely the MSSM charged
spectrum, and provides further support to the assertion that the true string
vacuum is connected to the Z_2 X Z_2 orbifold in the vicinity of the free
fermionic point in the Narain moduli space. In the second part I review the
recent formulation of quantum mechanics from an equivalence postulate, which
offers a new perspective on the synthesis of gravity and quantum mechanics, and
contemplate possible relations with string theory and beyond.Comment: 25 pages. Standard Latex & iopconf1.sty. To appear in the proceedings
of Beyond the Desert 99 - Accelerator and non Accelerator Approaches, Castle
Ringberg, Tegernsee, Germany, 6-12 June 199
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