2,174 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-
Probing the indefinite CP nature of the Higgs Boson through decay distributions in the process
The recently discovered scalar resonance at the LHC is now almost confirmed
to be a Higgs Boson, whose CP properties are yet to be established. At the ILC
with and without polarized beams, it may be possible to probe these properties
at high precision. In this work, we study the possibility of probing departures
from the pure CP-even case, by using the decay distributions in the process
, with mainly decaying into a
pair. We have compared the case of a minimal extension of the SM case (Model I)
with an additional pseudoscalar degree of freedom, with a more realistic case
namely the CP-violating Two-Higgs Doublet Model (Model II) that permits a more
general description of the couplings. We have considered the ILC with
\,GeV and integrated luminosity of . Our
main findings are that even in the case of small departures from the CP-even
case, the decay distributions are sensitive to the presence of a CP-odd
component in Model II, while it is difficult to probe these departures in Model
I unless the pseudoscalar component is very large. Noting that the proposed
degrees of beam polarization increases the statistics, the process demonstrates
the effective role of beam polarization in studies beyond the Standard Model.
Further, our study shows that an indefinite CP Higgs would be a sensitive
laboratory to physics beyond the SM.Comment: 14 pages using revtex, 10 figures, corresponds to version accepted
for publication in Phys. Rev. D.; compared to v1, discussion extended, figure
added, table added, section reorganize
Invisible decays of the lightest Higgs boson in supersymmetric models
We consider supersymmetric models in which the lightest Higgs scalar can
decay invisibly consistent with the constraints on the ~GeV state
discovered at the CERN LHC. We consider the invisible decay in the minimal
supersymmetric standard model~(MSSM), as well its extension containing an
additional chiral singlet superfield, the so-called next-to-minimal or
nonminimal supersymmetric standard model~(NMSSM).We consider the case of MSSM
with both universal as well as nonuniversal gaugino masses at the grand unified
scale, and find that only an grand unified model with unnaturally large
representation can give rise to sufficiently light neutralinos which can
possibly lead to the invisible decay . Following this, we consider the case of NMSSM in detail, where also
we find that it is not possible to have the invisible decay of the lightest
Higgs scalar with universal gaugino masses at the grand unified scale. We
delineate the regions of the NMSSM parameter space where it is possible to have
the lightest Higgs boson to have a mass of about GeV, and then
concentrate on the region where this Higgs can decay into light neutralinos,
with the soft gaugino masses and as two independent parameters,
unconstrained by grand unification. We also consider, simultaneously, the other
important invisible Higgs decay channel in the NMSSM, namely the decay into the
lightest CP odd scalars, , which is studied in detail. With
the invisible Higgs branching ratio being constrained by the present LHC
results, we find that ~GeV and ~GeV is disfavored in
NMSSM for fixed values of the other input parameters. The dependence of our
results on the parameters of NMSSM is discussed in detail.Comment: 20 pages, 14 figures, to appear in Physical Review
Strings with extended non-Abelian gauge interaction
The new generalization of the gauge interaction for the bosonic strings is
found. We consider some quasiequivariant maps from the space of metrics on the
worldsheet to the space of -tuples of one- and two-dimensional loops. The
two-dimensional case is based on the cylinders interacted with a path space
connection. The special 2-gauge string model is formulated using two
1-connections, non-Abelian background symmetric tensor field and non-Abelian
2-form. The branched non-Abelian space-time is the result of our construction.Comment: 11 page
Realization of Resistorless Lossless Positive and Negative Grounded Inductor Simulators Using Single ZC-CCCITA
This paper is in continuation with the very recent work of Prasad et al. [14], wherein new realizations of grounded and floating positive inductor simulator using current differencing transconductance amplifier (CDTA) are reported. The focus of the paper is to provide alternate realizations of lossless, both positive and negative inductor simulators (PIS and NIS) in grounded form using z-copy current-controlled current inverting transconductance amplifier (ZC-CCCITA), which can be considered as a derivative of CDTA, wherein the current differencing unit (CDU) is reduced to a current-controlled current inverting unit. We demonstrate that only a single ZC-CCCITA and one grounded capacitor are sufficient to realize grounded lossless PIS or NIS. The proposed circuits are resistorless whose parameters can be controlled through the bias currents. The workability of the proposed PIS is validated by SPICE simulations on three RLC prototypes
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