2,718 research outputs found
Quantum anomaly of the transverse Ward-Takahashi relation for the axial-vector vertex
We study the possible quantum anomaly for the transverse Ward-Takahashi
relations in four dimensional gauge theories based on the method of computing
the axial-vector and the vector current operator equations. In addition to the
well-known anomalous axial-vector divergence equation (the Adler-Bell-Jackiw
anomaly), we find the anomalous axial-vector curl equation, which leads to the
quantum anomaly of the transverse Ward-Takahashi relation for the axial-vector
vertex. The computation shows that there is no anomaly for the transverse
Ward-Takahashi relation for the vector vertex.Comment: 6 pages, LaTe
The frizzled pathway regulates the development of arista laterals.
BACKGROUND: The frizzled pathway in Drosophila has been studied intensively for its role in the development of planar polarity in wing hairs, thoracic bristles and ommatidia. Selected cells in the arista (the terminal segment of the antenna) elaborate a lateral projection that shares characteristics with both hairs and bristles. RESULTS: We found that mutations in putative downstream members of the frizzled pathway, such as inturned resulted in multipled and split laterals, but no obvious polarity defects. Mutations in upstream genes such as frizzled did not show an adult arista phenotype. When we examined lateral development in the mutants we found that, as is the case on the wing for hair development the frizzled pathway regulated the subcellular location for lateral initiation. However, on the arista an altered location for lateral initiation did not result in altered polarity, as did an altered site for hair initiation. The regulation of lateral development involved the preferential accumulation of Frizzled protein at the distal edges of lateral cells much as is seen on the wing. In contrast to the situation in wing cells, in arista cells the location for lateral initiation was close to but did not overlap the region of preferential Frizzled accumulation. CONCLUSION: Our data indicates that a modified version of the frizzled pathway regulates arista development. We conclude that the lack of a polarity defect in mutant aristae is likely to be a consequence of inherent differences in the cell biology of wing hair and lateral forming cells
Di-hadron azimuthal correlation and Mach-like cone structure in parton/hadron transport model
In the framework of a multi-phase transport model (AMPT) with both partonic
and hadronic interactions, azimuthal correlations between trigger particles and
associated scattering particles have been studied by the mixing-event
technique. The momentum ranges of these particles are
GeV/ and GeV/ (soft), or 4
GeV/ and GeV/ (hard) in Au + Au collisions at
= 200 GeV. A Mach-like structure has been observed in
correlation functions for central collisions. By comparing scenarios with and
without parton cascade and hadronic rescattering, we show that both partonic
and hadronic dynamical mechanisms contribute to the Mach-like structure of the
associated particle azimuthal correlations. The contribution of hadronic
dynamical process can not be ignored in the emergence of Mach-like correlations
of the soft scattered associated hadrons. However, hadronic rescattering alone
cannot reproduce experimental amplitude of Mach-like cone on away-side, and the
parton cascade process is essential to describe experimental amplitude of
Mach-like cone on away-side. In addition, both the associated multiplicity and
the sum of decrease, whileas the increases, with the impact
parameter in the AMPT model including partonic dynamics from string melting
scenario.Comment: 9 pages, 5 figures; Physics Letters B 641, 362-367 (2006
Application of SH and Lamb Wave Emat’s for Evaluation of Adhesive Joint in Thin Plate
The applicability of SH wave for the evaluation of adhesive joint in thin plate was studied. The advantages of the SH guided wave is that its displacement and stress are oriented parallel to the adhesive-adherent interface, and therefore, it can be used to evaluate interface properties. The experimental studies are focused on the relations between acoustic parameters and geometry conditions, the comparison of ultrasonic data and strength data of the joint, and the attenuation in different cases. The experiments were done on lap-shear samples and long samples. For excitation and reception of SH waves, non-contact electromagnetic transducers were used. An additional investigation was carried out using Lamb waves for the same sample parameters
Neutrino mass induced radiatively by supersymmetric leptoquarks
We show how nonzero Majorana neutrino masses can be radiatively generated by
extending the MSSM with leptoquark chiral multiplets without violating
R-parity. It is found that, with these particles, the R-parity conservation
does not imply lepton number conservation. Neutrino masses generated at a
one-loop level are closely related to the down quark mass matrix. The ratio of
neutrino mass-squared splittings obtained is naturally close to which is in the right region required to explain both
the atmospheric neutrino data and the MSW solutions for the solar neutrino
data.Comment: 13 pages, one figure, more constraints added. To appear in Phys.
Lett.
Collapse models with non-white noises II: particle-density coupled noises
We continue the analysis of models of spontaneous wave function collapse with
stochastic dynamics driven by non-white Gaussian noise. We specialize to a
model in which a classical "noise" field, with specified autocorrelator, is
coupled to a local nonrelativistic particle density. We derive general results
in this model for the rates of density matrix diagonalization and of state
vector reduction, and show that (in the absence of decoherence) both processes
are governed by essentially the same rate parameters. As an alternative route
to our reduction results, we also derive the Fokker-Planck equations that
correspond to the initial stochastic Schr\"odinger equation. For specific
models of the noise autocorrelator, including ones motivated by the structure
of thermal Green's functions, we discuss the qualitative and qantitative
dependence on model parameters, with particular emphasis on possible
cosmological sources of the noise field.Comment: Latex, 43 pages; versions 2&3 have minor editorial revision
A Note on Transverse Axial Vector and Vector Anomalies in U(1) Gauge Theories
The transverse axial vector and vector anomalies in four-dimensional U(1)
gauge theories studied in [10] is reexamined by means of perturbative methods.
The absence of transverse anomalies for both axial vector and vector current is
verified. We also show that the Pauli-Villars regularization and dimensional
regularization give the same result on the transverse anomaly of both axial
vector and vector current.Comment: Revtex4, 8 pages, two figures. Largely revised, using the
Pauli-Villars regularization instead of dimensional regularization in the
main proof. Final form to be published in Physics Letters
Additional symmetries of constrained CKP and BKP hierarchies
The additional symmetries of the constrained CKP (cCKP) and BKP (cBKP)
hierarchies are given by their actions on the Lax operators, and their actions
on the eigenfunction and adjoint eigenfunction are
presented explicitly. Furthermore, we show that acting on the space of the wave
operator, forms new centerless and
-subalgebra of centerless respectively. In
order to define above symmetry flows of the cCKP and cBKP
hierarchies, two vital operators are introduced to revise the additional
symmetry flows of the CKP and BKP hierarchies.Comment: 14 pages, accepted by SCIENCE CHINA Mathematics(2010
Should SUSY Yang-Mills be Reconsidered as a Family Unification Model?
We review earlier proposals for family unification, and discuss why
recent work of Kovner and Shifman on condensates in supersymmetric Yang-Mills
theories suggests the reconsideration of supersymmetric Yang-Mills as a
family unification theory.Comment: TeX 16
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