16 research outputs found
Double Chargino Production in scattering
We point out the production of the charginos and neutralinos in
electron-electron process in several supersymmetric models, in order to show
that the International Linear Collider can discover double charged charginos if
these particles really exist in nature.Comment: 9 pages, 9 figures, Talk given at CTP symposium on Supersymmetry at
LHC: Theoretical and Experimental Perspectives, The British University in
Egypt, Cairo, Egypt, 11-14 March 200
Fermion and Sfermion Effects in charged Higgs pair production
Top and bottom one loop corrections to are
considered at NLC energies and found to be significantly large and negative
over the full range of . Moreover, loop effects of moderately
heavy squarks and sleptons in the minimal supersymmetric extension of the
standard model, tend to cancel partly or fully these large corrections, thus
providing a useful indirect information about the supersymmetric sector. The
overall effect can still range between and , however lies
typically around in a wide range of the model parameters.Comment: latex, 16 pages and 9 figures (appended as a postscript file)
SLAC--PUB--6529, PM/94-1
The Other Natural Two Higgs Doublet Model
We characterize models where electroweak symmetry breaking is driven by two
light Higgs doublets arising as pseudo-Nambu-Goldstone bosons of new dynamics
above the weak scale. They represent the simplest natural two Higgs doublet
alternative to supersymmetry. We construct their low-energy effective
Lagrangian making only few specific assumptions about the strong sector. These
concern their global symmetries, their patterns of spontaneous breaking and the
sources of explicit breaking. In particular we assume that all the explicit
breaking is associated with the couplings of the strong sector to the Standard
Model fields, that is gauge and (proto)-Yukawa interactions. Under those
assumptions the scalar potential is determined at lowest order by very few free
parameters associated to the top sector. Another crucial property of our
scenarios is the presence of a discrete symmetry, in addition to custodial
SO(4), that controls the -parameter. That can either be simple CP or a
that distinguishes the two Higgs doublets. Among various possibilities we study
in detail models based on SO(6)/SO(4) SO(2), focussing on their
predictions for the structure of the scalar spectrum and the deviations of
their couplings from those of a generic renormalizable two Higgs doublet model.Comment: 54 page
Electroweak radiative corrections to the three channels of the process f_1 bar-f_1 ZA --> 0
We have calculated the electroweak radiative corrections at the O(alpha)
level to the three channels of the process f_1 bar-f_1 Z A --> 0 and
implemented them into the SANC system. Here A stands for the photon and f_1 for
a first generation fermion whose mass is neglected everywhere except in
arguments of logarithmic functions. The symbol --> 0 means that 4-momenta of
all the external particles flow inwards. We present the complete analytical
results for the covariant and helicity amplitudes for three cross channels: f_1
+ bar-f_1 --> Z + gamma, Z --> f_1 + bar-f_1 + gamma and f_1 + gamma --> f_1 +
Z. The one-loop scalar form factors of these channels are simply related by an
appropriate permutation of their arguments s,t,u. To check the correctness of
our results we first of all observe the independence of the scalar form factors
on the gauge parameters and the validity of the Ward identity, i.e. external
photon transversality, and, secondly, compare our numerical results with the
other independent calculations available to us.Comment: 19 pages, 6 figures, 10 table
Lepton masses in a supersymmetric 3-3-1 model
We consider the mass generation for both charginos and neutralinos in a 3-3-1
supersymmetric model. We show that R-parity breaking interactions leave the
electron and one of the neutrinos massless at the tree level. However the same
interactions induce masses for these particles at the 1-loop level. Unlike the
similar situation in the MSSM the masses of the neutralinos are related to the
masses of the charginos.Comment: RevTex, 11 pages incluing 2 .eps figures. Extended published versio
QCD corrections to scalar quark pair production in e+e- annihilation
We calculate the QCD radiative corrections to the production of
supersymmetric scalar partners of quarks in e+e- annihilation. We include both
the standard gluonic corrections and the genuine supersymmetric QCD corrections
due to quark--gluino loops, and allow for mixing between left-- and
right--handed scalar quarks which leads to the possibility that the two final
state particles have different masses. The corrections are found to be much
larger than the ones affecting the production of spin 1/2 particles.Comment: one typo corrected (2d paragraph of setion 5) and a better set of
figures has been included as an uuencoded compressed tar postscript fil
Weak radiative corrections at LEP
Weak radiative corrections in the Weinberg-Salam model are reviewed, in the perspective of new results at LEP. They should be identified with good precision. This would settle Weinberg-Salam model position among various possible extensions
Degenerate Higgs boson decays to γ γ and Zγ. in the type II Seesaw Model
International audienc