4,238 research outputs found
New correlations induced by nuclear supersymmetry
We show that the nuclear supersymmetry model (n-susy) in its extended
version, predicts correlations in the nuclear structure matrix elements which
characterize transfer reactions between nuclei that belong to the same
supermultiplet. These correlations are related to the fermionic generators of
the superalgebra and if verified experimentally can provide a direct test of
the model.Comment: Invited talk at "Nuclear Physics: Large and Small", April 19-22,
2004, Hacienda Cocoyoc, Mexic
Supersymmetric Contributions to Weak Decay Correlation Coefficients
We study supersymmetric contributions to correlation coefficients that
characterize the spectral shape and angular distribution for polarized muon-
and beta-decays. In the minimal supersymmetric Standard Model (MSSM), one-loop
box graphs containing superpartners can give rise to non-(V-A)x(V-A) four
fermion operators in the presence of left-right or flavor mixing between
sfermions. We analyze the present phenomenological constraints on such mixing
and determine the range of allowed contributions to the weak decay correlation
coefficients. We discuss the prospective implications for future muon- and
beta-decay experiments, and argue that they may provide unique probes of
left-right mixing in the first generation scalar fermion sector.Comment: Revised version - to appear in Phys.Rev.
Supersymmetric contributions to weak decay correlation coefficients
We study supersymmetric contributions to correlation coefficients that characterize the spectral shape and angular distribution for polarized µ- and beta-decays. In the minimal supersymmetric standard model (MSSM), one-loop box graphs containing superpartners can give rise to non-(V-A)[direct-product](V-A) four-fermion operators in the presence of left-right or flavor mixing between sfermions. We analyze the present phenomenological constraints on such mixing and determine the range of allowed contributions to the weak decay correlation coefficients. We discuss the prospective implications for future µ- and beta-decay experiments, and argue that they may provide unique probes of left-right mixing in the first generation scalar fermion sector
Implications of Gauge Unification for Time Variation of the Fine Structure Constant
Unification of the gauge couplings would imply that time variations of the
fine structure constant are accompanied by calculable and very significant time
variations in the QCD scale parameter . Since is
the dominant factor in setting the hadron masses, estimates made by simple
variations of the fine structure constant may not provide meaningful limits.
There may also be related variations in Yukawa couplings and the electroweak
scale. Implications for the 21 cm hyperfine transition, big bang
nucleosynthesis, and the triple alpha process are discussed. We find that the
first of these already provides strong constraints on the underlying theory. It
is emphasized more generally that time (and space) variations of fundamental
couplings and their correlations may be a significant probe of
ultra-high-energy physics.Comment: 13 pages, uses JHEP.cl
Neutron-Electron EDM Correlations in Supersymmetry and Prospects for EDM Searches
Motivated by recent progress in experimental techniques of electric dipole
moment (EDM) measurements, we study correlations between the neutron and
electron EDMs in common supersymmetric models. These include minimal
supergravity (mSUGRA) with small CP phases, mSUGRA with a heavy SUSY spectrum,
the decoupling scenario and split SUSY. In most cases, the electron and neutron
EDMs are found to be observable in the next round of EDM experiments. They
exhibit certain correlation patterns. For example, if d_n ~ 10^{-27} e cm is
found, d_e is predicted to lie in the range 10^{-28}-10^{-29} e cm.Comment: 16 pages,12 figures. To appear in JHEP. A note on stability of the
correlations added in Conclusions; refs. and footnotes adde
Indirect Signs of the Peccei-Quinn Mechanism
In the Standard Model, the renormalization of the QCD vacuum angle
is extremely tiny, and small is technically natural. In the general
Standard Model effective field theory (SMEFT), however, is
quadratically divergent, reflecting the fact that new sources of hadronic
CP-violation typically produce threshold corrections to
. The observation of such CP-violating interactions would therefore be
in tension with solutions to the strong CP problem in which is an
ultraviolet boundary condition, pointing to the Peccei-Quinn mechanism as the
explanation for why is small in the infrared. We study the quadratic
divergences in arising from dimension-6 SMEFT operators and discuss
the discovery prospects for these operators at electric dipole moment
experiments, the LHC, and future proton-proton colliders.Comment: 27 pages, 3 figures. Comments welcome
Random Matrix Theories in Quantum Physics: Common Concepts
We review the development of random-matrix theory (RMT) during the last
decade. We emphasize both the theoretical aspects, and the application of the
theory to a number of fields. These comprise chaotic and disordered systems,
the localization problem, many-body quantum systems, the Calogero-Sutherland
model, chiral symmetry breaking in QCD, and quantum gravity in two dimensions.
The review is preceded by a brief historical survey of the developments of RMT
and of localization theory since their inception. We emphasize the concepts
common to the above-mentioned fields as well as the great diversity of RMT. In
view of the universality of RMT, we suggest that the current development
signals the emergence of a new "statistical mechanics": Stochasticity and
general symmetry requirements lead to universal laws not based on dynamical
principles.Comment: 178 pages, Revtex, 45 figures, submitted to Physics Report
Grand unified theory constrained supersymmetry and neutrinoless double beta decay
We analyze the contributions to the neutrinoless double decay
(-decay) coming from the Grand Unified Theory (GUT) constrained
Minimal Supersymmetric Standard Model (MSSM) with trilinear R-parity breaking.
We discuss the importance of two-nucleon and pion-exchange realizations of the
quark-level -decay transitions. In this context, the questions
of reliability of the calculated relevant nuclear matrix elements within the
Renormalized Quasiparticle Random Phase Approximation (pn-RQRPA) for several
medium and heavy open-shell nuclei are addressed. The importance of gluino and
neutralino contributions to -decay is also analyzed. We review
the present experiments and deduce limits on the trilinear R-parity breaking
parameter from the non-observability of -decay
for different GUT constrained SUSY scenarios. In addition, a detailed study of
limits on the MSSM parameter space coming from the processes
by using the recent CLEO and OPAL results is performed. Some studies in respect
to the future -decay project GENIUS are also presented.Comment: 29 pages, 8 figure
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