41 research outputs found
CP Violation in within the Minimal Supersymmetric Standard Model
The complete analysis of the CP violation in the process in frame of the Minimal Supersymmetric Model(MSSM) is presented. The
CP-odd observables for describing the CP violating effects in polarized and
unpolarized photon collisions, are calculated. We investigate the possible CP
violation sources induced by the complex soft breaking parameters and study the
CP violating effects contributed by gluino, neutralino and chargino sectors
appearing in the loop diagrams. We find that it is possible to observe the CP
violation effects in top quark pair production via polarized and unpolarized
photon fusions by using optimal observables and favorable parameters.Comment: 15 pages, LaTex, including 14 figures in eps file
SUSY QCD impact on top-pair production associated with a -boson at a photon-photon collider
The top-pair production in association with a -boson at a photon-photon
collider is an important process in probing the coupling between top-quarks and
vector boson and discovering the signature of possible new physics. We describe
the impact of the complete supersymmetric QCD(SQCD) next-to-leading order(NLO)
radiative corrections on this process at a polarized or unpolarized photon
collider, and make a comparison between the effects of the SQCD and the
standard model(SM) QCD. We investigate the dependence of the lowest-order(LO)
and QCD NLO corrected cross sections in both the SM and minimal supersymmetric
standard model(MSSM) on colliding energy in different polarized
photon collision modes. The LO, SM NLO and SQCD NLO corrected distributions of
the invariant mass of -pair and the transverse momenta of final
-boson are presented. Our numerical results show that the pure SQCD
effects in \ggttz process can be more significant in the polarized photon
collision mode than in other collision modes, and the relative SQCD radiative
correction in unpolarized photon collision mode varies from 32.09% to
when goes up from to .Comment: 22 pages and 13 figure
Probing flavor changing interactions in hadron collisions
The subprocess in the two-Higgs-doublet model with
flavor-changing scalar couplings is examined at the one loop level. With
perturbative QCD factorization theorem, the corresponding cross sections for
hadron-hadron collisions are computed numerically. The results are applicable
to the whole mass range of the weakly coupled Higgs bosons. In case we could
efficiently exclude the severe backgrounds of the
production signal, probing the flavor-changing top-charm-scalar vertex at
hadron colliders would be very promising and accessible experimentally.Comment: LaTex file, 14 pages, 8 EPS figure
Pair Production of the Lightest Chargino via Gluon-Gluon Collisions
The production of the lightest chargino pair from gluon-gluon fusion is
studied in the minimal supersymmetric model(MSSM) at proton-proton colliders.
We find that with the chosen parameters, the production rate of the subprocess
can be over 2.7 femto barn when the chargino is higgsino-like, and the
corresponding total cross section in proton-proton collider can reach 56 femto
barn at the LHC in the CP-conserving MSSM. It shows that this loop mediated
subprocess can be competitive with the standard Drell-Yan subprocess in
proton-proton colliders, especially at the LHC. Furthermore, our calculation
shows it would be possible to extract information about some CP-violating phase
parameters, if we collected enough chargino pair events.Comment: 39 pages, LaTex, 8 figure
R-parity violation effect on the top-quark pair production at linear colliders
We investigate in detail the effects of the R-parity lepton number violation
in the minimal supersymmetric standard model (MSSM) on the top-quark pair
production via both and collision modes at the linear
colliders. We find that with the present experimental constrained
parameters, the effect from interactions on the processes
and could be
significant and may reach -30% and several percent, respectively. Our results
show that the effects are sensitive to the c.m.s. energy and the
relevant parameters. However, they are not sensitive to squark and
slepton masses when (or ) and are almost independent on the Comment: Accepted by Phys.Rev.
The SUSY EW-like corrections to top pair production in photon-photon collisions
We studied the one-loop contributions of the gaugino-Higgsino-sector to the
process of top-pair production via fusion at NLC in frame of
the Minimal Supersymmetric Model(MSSM). We find that the corrections to and are found to
be significant and can approach to a few percent and one percent, respectively.
Furthermore, the dependences of the corrections on the supersymmetric
parameters are also investigated. The corrections are not sensitive to
(or ) when
(or ) and are weakly dependent on the with
(or ) being large enough. But they are sensitive to the c.m.s.
energy of the incoming photons.Comment: LaTex, 33 pages, 8 Eps figuer
One-loop quark and squark corrections to the lightest chargino pair production in photon-photon collisions
We present the detailed analytical and numerical investigations of the
one-loop radiative corrections of all quarks and squarks in the MSSM to the
lightest chargino pair production via fusion at the future NLC.
The numerical corrections show that the cross sections of the subprocess and
the parent process are typically enhanced by several percent. We studied also
the effects induced by the CP violating complex phases stemming from squark and
chargino mass matrices in the MSSM at one-loop level.Comment: 45 pages, LaTex, including 10 figures in eps file