350 research outputs found
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
One-loop corrections to the Drell-Yan process in SANC (I). The charged current case
Radiative corrections to the charged current Drell-Yan processes are
revisited. Complete one-loop electroweak corrections are calculated within the
automatic SANC system. Electroweak scheme dependence and the choice of the
factorization scale are discussed. Comparisons with earlier calculations are
presented.Comment: extended version submitted to EPJ
Weak Isospin Violations in Charged and Neutral Higgs Couplings from SUSY Loop Corrections
Supersymmetric QCD and supersymmetric electroweak loop corrections to the
violations of weak isospin to Yukawa couplings are investigated. Specifically
it involves an analysis of the supersymmetric loop corrections to the Higgs
couplings to the third generation quarks and leptons. Here we analyze the SUSY
loop corrections to the charged Higgs couplings which are then compared with
the supersymmetric loop corrections to the neutral Higgs couplings previously
computed. It is found that the weak isospin violations can be quite
significant, i.e, as much as 40-50% or more of the total loop correction to the
Yukawa coupling. The effects of CP phases are also studied and it is found that
these effects can either enhance or suppress the weak isospin violations. We
also investigate the weak isospin violation effects on the branching ratio
and show that the effects
are sensitive to CP phases. Thus an accurate measurement of this branching
ratio along with the branching ratio of the neutral Higgs boson decays can
provide a measure of weak isospin violation along with providing a clue to the
presence of supersymmetry.Comment: 20 pages, 9 figure
Medium-modified DGLAP evolution of fragmentation functions from large to small x
The unified description of fragmentation function evolution from large to
small x which was developed for the vacuum in previous publications is now
generalized to the medium, and is studied for the case in which the complete
contribution from the largest class of soft gluon logarithms, the double
logarithms, are accounted for and with the fixed order part calculated to
leading order. In this approach it proves possible to choose the remaining
degrees of freedom related to the medium such that the distribution of produced
hadrons is suppressed at large momenta while the production of soft
radiation-induced charged hadrons at small momenta is enhanced, in agreement
with experiment. Just as for the vacuum, our approach does not require further
assumptions concerning fragmentation and is more complete than previous
computations of evolution in the medium
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
T-Violation in Decay And Supersymmetry
Measurement of the transverse muon polarization in the decay will be attempted for the first time at the
ongoing KEK E246 experiment and also at a proposed BNL experiment. We provide a
general analysis of how is sensitive to the physical
-violating phases in new physics induced four-Fermi interactions, and then
we calculate the dominant contributions to from squark family
mixings in generic supersymmetric models. Estimates of the upper bounds on
are also given. It is found that a supersymmetry-induced
right-handed quark current from boson exchange gives an upper limit on
as large as a few per cent, whereas with
charged-Higgs-exchange induced pseudoscalar interaction, is no
larger than a few tenths of a per cent. Possible correlations between the muon
polarization measurements in and decays are discussed, and distinctive patterns of
this correlation from squark family-mixings and from the three-Higgs-doublet
model are noted.Comment: Revtex, 29 pages including 4 epsf figure
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