2,962 research outputs found
Communication system features dual mode range acquisition plus time delay measurement
Communication system combines range acquisition system and time measurement system for tracking high velocity aircraft and spacecraft. The range acquisition system uses a pseudonoise code to determine range and the time measurement system reduces uncontrolled phase variations in the demodulated signal
The Anomalous Magnetic Moment of the Muon and Higgs-Mediated Flavor Changing Neutral Currents
In the two-Higgs doublet extension of the standard model, flavor-changing
neutral couplings arise naturally. In the lepton sector, the largest such
coupling is expected to be $\mu-\tau-\phi#. We consider the effects of this
coupling on the anomalous magnetic moment of the muon. The resulting bound on
the coupling, unlike previous bounds, is independent of the value of other
unknown couplings. It will be significantly improved by the upcoming E821
experiment at Brookhaven National Lab.Comment: 7 pages Latex, 2 figure
CP Nonconservation in
CP violation effects in are examined. CP-odd,
-odd and -even observables can both be used to extract information on
the real and imaginary parts of Feynman amplitudes. Two Higgs doublet model
with CP violating phase from neutral Higgs exchange is used to estimate
possible effects.Comment: 9 pages, 4 Figures, Late
Implications of a W^+W^- (ZZ) - Higgs - t c-bar$ Interaction for e^+e^- -> t c-bar \nu_e \nu_e-bar, t c-bar e^+ e^-, t c-bar Z and for t -> cW^+W^-, cZZ in a Two Higgs Doublet Model
The Standard Model with one extra Higgs doublet may give rise to enhanced
TREE-LEVEL flavor-changing-scalar coupling of a neutral Higgs to a pair of
top-charm quarks. This coupling may drive a large TREE-LEVEL effective
W^+W^-(ZZ) - Higgs - t c-bar interaction. As a result we find that the
reactions e^+e^- -> t c-bar \nu_e \nu_e-bar, t c-bar e^+ e^-, t c-bar Z and the
two rare top decays t -> cW^+W^-, t -> cZZ become very sensitive probes of such
an effective interaction. The most promising ones, e^+e^- -> t c-bar \nu_e
\nu_e-bar, t c-bar e^+ e^-, may yield several hundreds and up to thousands of
such events at the Next Linear Collider with a center of mass energy of
\sqrt{s}=0.5 - 2 TeV if the mass of the lightest neutral Higgs is a few hundred
GeV. The rare decays t -> cW^+W^- and t -> cZZ may be accessible at the LHC if
the mass of the lightest neutral Higgs lies in the narrow window 150 GeV < m_h
< 200 GeV.Comment: 18 pages, plain latex, 12 figures embadded in the text using epsfi
Desperately Seeking Non-Standard Phases via Direct CP Violation in Process
Attributing the recent CLEO discovery of to originate
(primarily) from the fragmentation of an off-shell gluon () via , , we emphasize that many such states () should
materialize. Indeed the hadronic fragments () of states are closely
related to those seen in . A particular
final state of considerable interest is . Signals from such states
in decays can be combined to provide a very sensitive search for CP
violating phase(s) from non-standard physics. The method should work even if
the contribution of these source(s) to the rates is rather small () to
the point that a comparison between theory and experiment may find it extremely
difficult to reveal the presence of such a new physics.Comment: 16 pages, 5 figure
Two body decays of the -quark: Applications to direct CP violation, searches for electro-weak penguins and new physics
A systematic experimental search for two-body hadronic decays of the b-quark
of the type b to quark + meson is proposed. These reactions have a well defined
experimental signature and they should be theoretically cleaner compared to
exclusive decays. Many modes have appreciable branching ratios and partial rate
asymmetries may also be quite large (about 8-50%) in several of them. In a few
cases electroweak penguins appear to be dominant and may be measurable. CP
violating triple correlation asymmetries provide a clean test of the Standard
Model.Comment: 12 pages 1 figure 1 tabl
Polarized Single Top Production at Leptonic Colliders from Broken R Parity Interactions Incorporating CP Violation
The contribution from the R parity violating interactions in the associated
production of a top quark with a charm antiquark is examined for high energy
leptonic colliders. We concentrate on the reactions associated with the
semileptonic top decay. A set of characteristic dynamical distributions for the
signal events is evaluated and the results contrasted against those from the
standard model W-boson pair production background. Next, we turn to a study of
a CP-odd observable, associated with the top spin, which leads to an asymmetry
in the energy distribution of the emitted charged leptons for the pair of
CP-conjugate final states, and . A
non vanishing asymmetry arises from a CP-odd phase, embedded in the R parity
violating coupling constants, through interference terms between the R parity
violating amplitudes at both the tree and loop levels.Comment: revtex file. 17 pages. 7 postscript figures. 1 table. The revised
version includes an estimate of experimental uncertainties. Submitted to
Phys. Rev.
CP Nonconservation in at the Tevatron
The reaction is found to be rather rich in exhibiting
several different types of CP asymmetries. The spin of the top quark plays an
important role. Asymmetries are related to form factors arising from radiative
corrections of the production vertex due to non-standard physics. As
illustrations, effects are studied in two Higgs Doublet Models and in
Supersymmetric Models; asymmetries up to a few percent may be possible.Comment: 14 pages, 3 figures. Note: replaced due to minor problems that
appeared on some postscript previewers. No change in conten
Determining the top-antitop and Couplings of a Neutral Higgs Boson of Arbitrary CP Nature at the NLC
The optimal procedure for extracting the coefficients of different components
of a cross section which takes the form of unknown coefficients times functions
of known kinematical form is developed. When applied to \epem\to t\anti
t+Higgs production at \rts=1\tev and integrated luminosity of 200\fbi, we
find that the t\anti t\toHiggs CP-even and CP-odd couplings and, to a lesser
extent, the Higgs (CP-even) coupling can be extracted with reasonable
errors, assuming the Higgs sector parameter choices yield a significant
production rate. Indeed, the composition of a mixed-CP Higgs eigenstate can be
determined with sufficient accuracy that a SM-like CP-even Higgs boson can be
distinguished from a purely CP-odd Higgs boson at a high level of statistical
significance, and vice versa.Comment: 8 pages, full postscript file also available via anonymous ftp at
ftp://ucdhep.ucdavis.edu/gunion/eetottbh.p
Lepton Flavor Violation in the Two Higgs Doublet Model type III
We consider the Two Higgs Doublet Model (2HDM) of type III which leads to
Flavour Changing Neutral Currents (FCNC) at tree level in the leptonic sector.
In the framework of this model we can have, in principle, two situations: the
case (a) when both doublets acquire a vacuum expectation value different from
zero and the case (b) when only one of them is not zero. In addition, we show
that we can make two types of rotations for the flavor mixing matrices which
generates four types of lagrangians, with the rotation of type I we recover the
case (b) from the case (a) in the limit , and with the
rotation of type II we obtain the case (b) from (a) in the limit Moreover, two of the four possible lagrangians correspond to the models
of types I and II plus Flavor Changing (FC) interactions. The analitical
expressions of the partial lepton number violating widths and are derived for the cases (a) and (b) and both
types of rotations.In all cases these widths go asymptotically to zero in
the decoupling limit for all Higgses. We present from our analysis upper bounds
for the flavour changing transition and we show that such bounds
are sensitive to the VEV structure and the type of rotation utilized.Comment: 7 pages RevTeX4, 4 figures postscript, new section added and some new
reference
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