6 research outputs found
Associated production of neutral toppion with a pair of heavy quarks in collisions
We have studied a neutral toppion production process in the topcolor-assisted technicolor(TC2) model. We
find that the cross section of is much
larger than that of . On the other hand,
the cross section can be obviously enhanced with the increasing of c.m.energy.
With GeV, the cross section of production can
reach the level of a few fb. The results show that is the most ideal channel to detect
neutral toppion due to the clean SM background. With such sufficient signals
and clean background, neutral toppion could be detected at TESLA with high
c.m.energy.Comment: 11 pages, 5 figure
Using Scalars to Probe Theories of Low Scale Quantum Gravity
Arkani-Hamed, Dimopoulos and Dvali have recently suggested that gravity may
become strong at energies near 1 TeV which would remove the hierarchy problem.
Such a scenario can be tested at present and future colliders since the
exchange of towers of Kaluza-Klein gravitons leads to a set of new dimension-8
operators that can play important phenomenological roles. In this paper we
examine how the production of pairs of scalars at , and
hadron colliders can be used to further probe the effects of graviton tower
exchange. In particular we examine the tree-level production of pairs of
identical Higgs fields which occurs only at the loop level in both the Standard
Model and its extension to the Minimal Supersymmetric Standard Model. Cross
sections for such processes are found to be potentially large at the LHC and
the next generation of linear colliders. For the case the role
of polarization in improving sensitivity to graviton exchange is emphasized.Comment: 32 pages, 12 figures, latex, remarks added to tex
Measurements of the SUSY Higgs self-couplings and the reconstruction of the Higgs potential
We address the issue of the reconstruction of the scalar potential of a
two-Higgs doublet model having in mind that of the MSSM.
We first consider the general CP conserving dim-4 effective potential. To
fully reconstruct this potential, we show that even if all the Higgs masses and
their couplings to the standard model particles are measured one needs not only
to measure certain trilinear Higgs self-couplings but some of the quartic
couplings as well. We also advocate expressing the Higgs self couplings in the
mass basis. We show explicitly, that in the so-called decoupling limit, the
most easily accessible Higgs self-couplings are given in terms of the Higgs
mass while all other dependencies on the parameters of the general effective
potential are screened. This helps also easily explain how, in the
MSSM, the largest radiative corrections which affect these self couplings are
reabsorbed by using the corrected Higgs mass. We also extend our analysis to
higher order operators in the effective Higgs potential. While the above
screening properties do not hold, we argue that these effects must be small and
may not be measured considering the foreseen poor experimental precision in the
extraction of the SUSY Higgs self-couplings.Comment: 25 pages, 3 figure
Neutral Higgs boson pair production via collision in the minimal supersymmetric standard model at linear colliders
We investigate in detail the fusion production mechanisms of
two neutral Higgs bosons (, , and ) within
the framework of the mSUGRA-inspired minimal supersymmetric standard
model(MSSM) at an linear colliders, which provide a probe of the
trilinear Higgs self-couplings. We calculate the dependence of the production
rates on Higgs boson masses, the ratio of the vacuum expectation values and the CMS energy . We find that the cross section for the
production at LC can reach , while the cross section of
production is only under our parameters.Comment: Accepted by Phys. Rev.
Single Top Quark at Future Hadron Colliders. Complete Signal and Background Study
We perform a detail theoretical study including decays and jet fragmentation
of all the important modes of the single top quark production and all basic
background processes at the upgraded Tevatron and LHC colliders. Special
attention was paid to the complete tree level calculation of the QCD fake
background which was not considered in the previous studies. Analysis of the
various kinematical distributions for the signal and backgrounds allowed to
work out a set of cuts for an efficient background suppression and extraction
of the signal. It was shown that the signal to background ratio after optimized
cuts could reach about 0.4 at the Tevatron and 1 at the LHC. The remaining
after cuts rate of the signal at the LHC for the signature is
expected to be about 6.1 pb and will be enough to study the single top physics
even during the LHC operation at a low luminosity.Comment: 15 pages, LaTex, 7 figure
Polarized Single Top Quark Production in e\gamma Collision and Anomalous Wtb Couplings
We investigate the potential of collisions to probe anomalous
couplings via the polarized single top quark production process . We find 95% confidence level limits on the
anomalous coupling parameters and with an integrated
luminosity of and and 1.5 TeV energies. The
effects of top quark spin polarization on the anomalous couplings are
discussed. It is shown that polarization leads to a considerable improvement in
the sensitivity limits.Comment: published versio