145 research outputs found
CP violating angular asymmetries of b and bbar quarks in e+e- -> t tbar
We obtain analytical formulae for the cross section and the angular
distributions of the b(bbar) quarks in the process e+e- -> t tbar, with t -> W+
b (tbar -> W- bbar) assuming CP violation in the \gamma t tbar and Z t tbar
vertices. We present CP violating asymmetries, which measure separately the
real and imaginary parts of the electroweak dipole moment form factors of the
top, d^{\gamma}(s) and d^{Z}(s). We give a numerical analysis of these
asymmetries within the Minimal Supersymmetric Standard Model with complex
parameters. They turn out to be of order <= 10^{-3}.Comment: 22 pages LaTeX with 3x3 figures included; some definitions for
polarization asymmetries and some notations are changed and some references
adde
Seesaw neutrinos with one right-handed singlet field and a second Higgs doublet
We study parameters of an extension of the Standard Model. The neutrino
sector is enlarged by one right-handed singlet field, allowing for the seesaw
mechanism type-I, and the Higgs sector contains one additional doublet, which
contributes to light neutrino masses through one-loop radiative corrections.
Employing an approximation for the effective light neutrino mass matrix we
express the masses of the light neutrinos analytically, allowing us to
parametrize the Yukawa couplings to neutrinos by the experimental measurements
on the neutrino sector and only two free parameters. We focus on a
CP-conserving Higgs potential for which we present the allowed ranges of the
input parameters and a statistical overview over the possible values of the
Yukawa couplings.Comment: 35 pages, 9 figures; v2: one figure and references added, some minor
changes to the tex
General Flavor Blind MSSM and CP Violation
We study the implications on flavor changing neutral current and CP violating
processes in the context of supersymmetric theories without a new flavor
structure (flavor blind supersymmetry). The low energy parameters are
determined by the running of the soft breaking terms from the grand unified
scale with SUSY phases consistent with the EDM constraints. We find that the CP
asymmetry in b --> s gamma can reach large values potentially measurable at B
factories, especially in the low BR(b --> s gamma) region. We perform a fit of
the unitarity triangle including all the relevant observables. In this case, no
sizeable deviations from the SM expectations are found. Finally we analyze the
SUSY contributions to the anomalous magnetic moment of the muon pointing out
its impact on the b --> s gamma CP asymmetry and on the SUSY spectrum including
chargino and stop masses.Comment: 40 pages, 8 figures, typos corrected, references adde
General Flavour Blind MSSM and CP Violation
We study FCNC and CP violating processes in the MSSM without a new flavour
structure (flavour blind MSSM). The low energy parameters are determined by the
running of the soft breaking terms from the GUT scale with SUSY phases
consistent with the EDM constraints. We find that the CP asymmetry in b -> s
gamma can reach large values potentially measurable at B factories, especially
in the low BR(b -> s gamma) region. We analyze the SUSY contributions to the
anomalous magnetic moment of the muon pointing out its impact on the b -> s
gamma CP asymmetry and on the SUSY spectrum.Comment: LaTex, 5 pages, 2 figures, Contribution to the International
Europhysics Conference on High Energy Physics (HEP 2001), Budapest, Hungary,
12-18 Jul 200
Parity and Time Reversal in J/Psi Decay
With the prospect of large numbers of decay events becoming
available in the near future, it is interesting to search for symmetry
violating effects as probes of new physics and tests of the standard model.
decay events could provide the first observation of weak effects in
otherwise strongly decaying particles. We calculate a T odd asymmetry in the
decay into photon plus lepton pair due to Z boson exchange. Extensions
to hadronic final states are also discussed.Comment: 9 pages, 3 eps figures revised to include additional relevant
reference
Triple product correlations in top squark decays
We propose several T-odd asymmetries in the decay chains of the top squarks
and and , for . We
calculate the asymmetries within the Minimal Supersymmetric Standard Model with
complex parameters , and . We give the analytic formulae for
the decay distributions. We present numerical results for the asymmetries and
estimate the event rates necessary to observe them. The largest T-odd asymmetry
can be as large as 40%.Comment: 26 pages, 5 figures; misprints corrected; reference adde
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