1,769 research outputs found
Generalized top-spin analysis and new physics in collisions with beam polarization
A generalized top-spin analysis proposed some time ago in the context of
Standard Model and subsequently studied in varying contexts is now applied
primarily to the case of with transversely
polarized beams. This extends our recent work with new physics couplings of
scalar () and tensor () types. We carry out a comprehensive analysis
assuming only the electron beam to be transversely polarized, which is
sufficient to probe these interactions, and also eliminates any azimuthal
angular dependence due to standard model or new physics of vector () and
axial-vector () type interactions. We then consider new physics of general
four-Fermi type of and type with both beams transversely polarized and
discuss implications with longitudinal polarization as well. The generalized
spin bases are all investigated in the presence of either longitudinal or
transverse beam polarization to look for appreciable deviation from the SM
prediction in case of the new physics. 90% confidence level limits are obtained
on the interactions for the generalized spin bases with realistic integrated
luminosity. In order to achieve this we present a general discussion based on
helicity amplitudes and derive a general transformation matrix that enables us
to treat the spin basis. We find that beamline basis combined with transverse
polarization provides an excellent window of opportunity both for , and
, new physics, followed by the off diagonal basis. The helicity basis is
shown to be the best in case of longitudinal polarization to look for new
physics effectsdue to and .Comment: 21 pages using revtex4-
New Physics in at the ILC with polarized beams: Explorations beyond conventional anomalous triple gauge boson coupling
One of the most-studied signals for physics beyond the standard model in the
production of gauge bosons in electron-positron collisions is that due to the
anomalous triple gauge boson couplings in the final state. In this
work, we study the implications of this at the ILC with polarized beams for
signals that go beyond traditional anomalous triple neutral gauge boson
couplings. Here we report a dimension-8 CP-conserving vertex that
has not found mention in the literature. We carry out a systematic study of the
anomalous couplings in general terms and arrive at a classification. We then
obtain linear-order distributions with and without CP violation. Furthermore,
we place the study in the context of general BSM interactions represented by
contact interactions. We set up a correspondence between the
triple gauge boson couplings and the four-point contact interactions. We also
present sensitivities on these anomalous couplings, which will be achievable at
the ILC with realistic polarization and luminosity.Comment: 28 pages, 13 figure
Documentation and Analysis of Certain Macrofungal Traditional Practices from Western-India (Gujarat)
Traditional ethno-mycomedicinal practices involving macrofungi were documented using questionnaires from Jessore and Purna communities located in the Northern and Southern Gujarat. The quality of traditional knowledge within and in between the communities was compared by informant’s consensus index factor calculated for each ailment. The possibility of any relation between the traditional practices and informant’s consensus index factors was assessed as well. Alternately in order to classify the types of species usages, binary scores were allotted based on the presence or absence of species storage for later use, open sharing and specificity of the practices. Followed by this species scores were subjected to Euclidean distance dissimilarity matrix based hierarchical agglomerative clustering.
In totality 23 species were documented addressing various ailments, of which 9 species were used to treat general aspects like convalescence, whereas others (14 species) were used for specific ailments. In the Jessore community 5 of the 7 ailments (41.2%) were related to skin problems, whereas in Purna community only 7 of 18 ailments (38.9%) had similar usage. The total ailments addressed and species documented from the Purna community had a greater diversity and bore higher informant’s consensus index value in comparison to the Jessore community. Cause and effect of some abnormal informant’s consensus values, rendering it dubious, are also discussed. Hierarchical agglomerative clustering revealed the influence of all the three aspects scored as above. The corner-stone species are more important than other species because they are necessary for the survival of the traditional know-how and well being of the communities engaging them and have applications. Moreover, depletion due to rampant use of such species calls upon there identification and conservation. This could be achieved to an extent by simple binary scores based clustering. Certain corner-stone species with closed (absence of) knowledge sharing were found to withhold specific practices. Those with general medicinal applications can be useful as nutraceuticals, whereas those with specific claims can be screened further in order to identify pharmaceutical potentials. In addition to this the present work mentions the documentation of traditional ethno-myco-medicinal practices of several species for the first time ever
Bailouts in a common market: a strategic approach
Governments in the EU grant Rescue and Restructure Subsidies to bail out ailing firms. In an international asymmetric Cournot duopoly we study effects of such subsidies on market structure and welfare. We adopt a common market setting, where consumers from the two countries form one market. We show that the subsidy is positive also when it fails to prevent the exit. The reason is a strategic effect, which forces the more efficient firm to make additional cost-reducing effort. When the exit is prevented, allocative and productive efficiencies are lower and the only gaining player is the rescued firm
Singular Scaling Functions in Clustering Phenomena
We study clustering in a stochastic system of particles sliding down a
fluctuating surface in one and two dimensions. In steady state, the
density-density correlation function is a scaling function of separation and
system size.This scaling function is singular for small argument -- it exhibits
a cusp singularity for particles with mutual exclusion, and a divergence for
noninteracting particles. The steady state is characterized by giant
fluctuations which do not damp down in the thermodynamic limit. The
autocorrelation function is a singular scaling function of time and system
size. The scaling properties are surprisingly similar to those for particles
moving in a quenched disordered environment that results if the surface is
frozen.Comment: 8 pages, 3 figures, Invited talk delivered at Statphys 23, Genova,
July 200
Classical Integrable 2-dim Models Inspired by SUSY Quantum Mechanics
A class of integrable 2-dim classical systems with integrals of motion of
fourth order in momenta is obtained from the quantum analogues with the help of
deformed SUSY algebra. With similar technique a new class of potentials
connected with Lax method is found which provides the integrability of
corresponding 2-dim hamiltonian systems. In addition, some integrable 2-dim
systems with potentials expressed in elliptic functions are explored.Comment: 19 pages, LaTeX, final version to be published in J.Phys.
Condensation Transitions in Two Species Zero-Range Process
We study condensation transitions in the steady state of a zero-range process
with two species of particles. The steady state is exactly soluble -- it is
given by a factorised form provided the dynamics satisfy certain constraints --
and we exploit this to derive the phase diagram for a quite general choice of
dynamics. This phase diagram contains a variety of new mechanisms of condensate
formation, and a novel phase in which the condensate of one of the particle
species is sustained by a `weak' condensate of particles of the other species.
We also demonstrate how a single particle of one of the species (which plays
the role of a defect particle) can induce Bose-Einstein condensation above a
critical density of particles of the other species.Comment: 17 pages, 4 Postscript figure
Phase Separation in One-Dimensional Driven Diffusive Systems
A driven diffusive model of three types of particles that exhibits phase
separation on a ring is introduced. The dynamics is local and comprises nearest
neighbor exchanges that conserve each of the three species. For the case in
which the three densities are equal, it is shown that the model obeys detailed
balance. The Hamiltonian governing the steady state distribution in this case
is given and is found to have long range asymmetric interactions. The partition
sum and bounds on some correlation functions are calculated analytically
demonstrating phase separation.Comment: 4 Pages, Revtex, 2 Figures included, Submitted to Physical Review
Letter
All electromagnetic form factors
The electromagnetic form factors of spin-1/2 particles are known, but due to
historical reasons only half of them are found in many textbooks. Given the
importance of the general result, its model independence, its connection to
discrete symmetries and their violations we made an effort to derive and
present the general result based only on the knowledge of Dirac equation. We
discuss the phenomenology connected directly with the form factors, and spin
precession in external fields including time reversal violating terms. We apply
the formalism to spin-flip synchrotron radiation and suggest pedagogical
projects.Comment: Latex, 22 page
Spectral properties of a short-range impurity in a quantum dot
The spectral properties of the quantum mechanical system consisting of a
quantum dot with a short-range attractive impurity inside the dot are
investigated in the zero-range limit. The Green function of the system is
obtained in an explicit form. In the case of a spherically symmetric quantum
dot, the dependence of the spectrum on the impurity position and the strength
of the impurity potential is analyzed in detail. It is proven that the
confinement potential of the dot can be recovered from the spectroscopy data.
The consequences of the hidden symmetry breaking by the impurity are
considered. The effect of the positional disorder is studied.Comment: 30 pages, 6 figures, Late
- …