3,550 research outputs found
A Separate Higgs?
We investigate the possibility of a multi-Higgs doublet model where the
lightest neutral Higgs boson () decouples from the fermion sector. We are
partially motivated by the four events with
\,GeV recently observed by the L3 collaboration,
which could be a signal for .
Collider signatures for the additional physical Higgs bosons present in such
models are discussed.Comment: 8 pages (plus 2 figures, available by request), latex,
ANL-HEP-PR-92-10
Role of ABA Signaling in Regulation of Stem Sugar Metabolism and Transport under Post- Flowering Drought Stress in Sweet Sorghum
Sugar remobilization from vegetative to reproductive tissues is an important process that determines grain yield in crops. Sweet sorghum stems store sugar and introgression of Stay green1 (Stg 1) locus from the grain sorghum genotype B35 into the sweet sorghum genotype S35 was previously shown to bring about a 2-fold higher stem sugar accumulation in the near-isogenic line (NIL) S35SG06040. We hypothesized that remobilization of stem sugar augments grain yield on exposure to drought stress and that the phytohormone abscisic acid (ABA) has a role to play in this process. ABA levels were three times higher in the NIL as compared to those in S35 on drought stress exposure. Remobilization of stem sugars in the NIL was evident by the observed decrease in reducing sugar content in the stem but not in the peduncle in response to prolonged drought stress exposure. Drought-induced expression of some ABA response factors (ABFs) as well as invertase and sucrose transporter genes was seen to be higher in the NIL as compared to S35. An over-representation of ABA-responsive elements (ABREs) and sugar signaling motifs in the differentially expressed genes indicated the involvement of ABA and sugar signaling in regulation of their expression. Two ABF genes located on the Stg1 locus showed single nucleotide polymorphism, which possibly accounted for their differential regulation in S35 and the NIL. The results suggest that ABA signaling plays an important role in post-flowering drought-induced remobilization of sugars to the reproductive sinks
Left-Right Symmetry and Supersymmetric Unification
The existence of an SU(3) X SU(2)_L X SU(2)_R X U(1) gauge symmetry with g_L
= g_R at the TeV energy scale is shown to be consistent with supersymmetric
SO(10) grand unification at around 1O^{16} GeV if certain new particles are
assumed. The additional imposition of a discrete Z_2 symmetry leads to a
generalized definition of R parity as well as highly suppressed Majorana
neutrino masses. Another model based on SO(10) X SO(10) is also discussed.Comment: 11 pages, 2 figures not included, UCRHEP-T124, Apr 199
Page curves and typical entanglement in linear optics
Bosonic Gaussian states are a special class of quantum states in an infinite
dimensional Hilbert space that are relevant to universal continuous-variable
quantum computation as well as to near-term quantum sampling tasks such as
Gaussian Boson Sampling. In this work, we study entanglement within a set of
squeezed modes that have been evolved by a random linear optical unitary. We
first derive formulas that are asymptotically exact in the number of modes for
the R\'enyi-2 Page curve (the average R\'enyi-2 entropy of a subsystem of a
pure bosonic Gaussian state) and the corresponding Page correction (the average
information of the subsystem) in certain squeezing regimes. We then prove
various results on the typicality of entanglement as measured by the R\'enyi-2
entropy by studying its variance. Using the aforementioned results for the
R\'enyi-2 entropy, we upper and lower bound the von Neumann entropy Page curve
and prove certain regimes of entanglement typicality as measured by the von
Neumann entropy. Our main proofs make use of a symmetry property obeyed by the
average and the variance of the entropy that dramatically simplifies the
averaging over unitaries. In this light, we propose future research directions
where this symmetry might also be exploited. We conclude by discussing
potential applications of our results and their generalizations to Gaussian
Boson Sampling and to illuminating the relationship between entanglement and
computational complexity.Comment: 29 pages; 2 figures. Version 2: small updates to match journal
versio
Intermediate scale as a source of lepton flavor violation in SUSY SO(10)
In supersymmetric SO(10) grand unified models, we examine the lepton flavor
violation process from having the SU(2)U(1) gauge symmetry broken at an intermediate scale below the
SO(10) grand unification scale . Even in the case that supersymmetry is
broken by universal soft terms introduced at the scale , we find
significant rates for with GeV or
less. These rates are further enhanced if the universal soft terms appear at a
scale greater than .Comment: 12 pages (Latex), 3 PS Figures (uuencoded, epsf.tex), small addition
to discussion in the text, as to appear in Phys. Rev. D Rapid Communication
Texture of fermion mass matrices in partially unified theories
We investigate the texture of fermion mass matrices in theories with partial
unification (for example ) at a scale
GeV. Starting with the low energy values of the masses and the
mixing angles, we find only two viable textures with atmost four texture zeros.
One of these corresponds to a somewhat modified Fritzsch textures. A
theoretical derivataion of these textures leads to new interesting relations
among the masses and the mixing angles.Comment: 10 pages(Latex
Constraints from on gauge-mediated supersymmetry breaking models
We consider the branching ratio of in gauge mediated
supersymmetry breaking theories. Useful bounds on the parameter space of these
models are derived from the experimental bounds on . Constraints
on masses of NLSP are presented as a function of and for
.Comment: 12 pages(Latex), 3 PS Figures (uuencoded, epsf.tex); minor
modification in the introductory part of the tex
SUSY GUTs contributions and model independent extractions of CP phases
We consider the origin of new phases in supersymmetric grand unification
model, and show how significant new contributions arise from the gluino
mediated diagram. We then present a more general model independent analysis of
various modes of B-decays suggested previously for measurement of the CKM
phases and point out what they really measure. It is in principle possible to
separate out all the phases.Comment: 13 pages (Latex), 2 PS figures, a few remarks are added and a typo is
corrected. To appear in Phys. Rev. Let
Ab Initio Calculations of the Walls Shear Strength of Carbon Nanotubes
The dependence of the energy of interwall interaction in double-walled carbon
nanotubes (DWNT) on the relative position of walls has been calculated using
the density functional method. This dependence is used to evaluate forces that
are necessary for the relative telescopic motion of walls and to calculate the
shear strength of DWNT for the relative sliding of walls along the nanotube
axis and for their relative rotation about this axis. The possibility of
experimental verification of the obtained results is discussed.Comment: 4 pages, 1 figur
New physics effects to the lepton polarizations in the B -> K l^+ l^- decay
Using the general, model independent form of the effective Hamiltonian, the
general expressions of the longitudinal, normal and transversal polarization
asymmetries for (l^-) and (l^+) and combinations of them for the exclusive (B
-> K l^+ l^-) decay are found. The sensitivity of lepton polarizations and
their combinations on new Wilson coefficients are studied. It is found that
there exist regions of Wilson coefficients for which the branching ratio
coincides with the Standard Model result while the lepton polarizations differ
substantially from the standard model prediction. Hence, studying lepton
polarization in these regions of new Wilson coefficients can serve as a
promising tool for establishing new physics beyond the Standard Model.Comment: 18 pp, 14 figures (postscript formatted), LaTex formatte
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