Phys.Lett. B606 (2005) 164-172 We investigate \tau\tau fusion to light h and heavy H and A Higgs bosons in
the Minimal Supersymmetric Standard Model (MSSM) at a photon collider as a
promising channel ...for measuring large values of tan(beta). For standard design
parameters of a photon collider an error \Delta tan(beta) \sim 1, uniformly for
tan(beta) \gsim 10, may be expected, improving on complementary measurements at
the LHC and e+e- linear colliders.
Comput.Phys.Commun.108:56-74,1998 We describe the Fortran code HDECAY which calculates the decay widths and the
branching ratios of the Standard Model Higgs boson, and of the neutral and
charged ...Higgs particles of the Minimal Supersymmetric extension of the Standard
Model. The program is self-contained (with all subroutines included), easy to
run, fast and calculates the decay widths and branching ratios according to the
current theoretical knowledge.
The occurrence of a significant amount of supersymmetric lepton flavour violation at laboratory energies, through \(\tilde\nu_\mu - \tilde\nu_\tau\) mixing, has become a realistic possibility in the ...wake of the super-Kamiokande atmospheric neutrino result. This effect can be observed in an e+e- linear collider with the distinct final state tau+mu+ jets+E_T. We show that the pair production of charginos can make an important contribution to this process and has to be taken into account in addition to that of sneutrinos or charged sleptons. Some case studies are presented with CM energies of 500 and 800 GeV and integrated luminosities of 50, 500 and 1000 fb-1.
Already in the simplest two-Higgs-doublet model with CP violation in the Higgs sector, the \(3\times3\) mixing matrix for the neutral Higgs bosons can substantially modify their couplings, thereby ...endangering the ``classical'' Higgs search strategies. However, there are sum rules relating Yukawa and Higgs-Z couplings which ensure that the ZZ, \(b\anti b\) and \(t\anti t\) couplings of a given neutral 2HDM Higgs boson cannot all be simultaneously suppressed. This result implies that any single Higgs boson will be detectable at an e^+e^- collider if the Z+Higgs, \(b\anti b+\)Higgs {\it and} \(t\anti t+\)Higgs production channels are all kinematically accessible {\it and} if the integrated luminosity is sufficient. We explore, as a function of Higgs mass, the luminosity required to guarantee Higgs boson detection, and find that for moderate \(\tan\beta\) values the needed luminosity is unlikely to be available for all possible mixing scenarios. The additional difficulties for the case when the two-doublet Higgs sector is extended by adding one more singlet are summarized. Implications of the sum rules for Higgs discovery at the Tevatron and LHC are briefly discussed.
Phys.Rev. D55 (1997) 5841-5844 Estimates for longitudinal spin asymmetries which single out new polarized
nucleon structure functions in deeply inelastic charged current interactions at
HERA energies ...are given, exploiting their interpretation in terms of polarized
quark distributions. These asymmetries turn out to be large and allow a
measurement of the new polarized structure functions $g_1^{W}$ and $g_5^{W}$,
which would add valuable tests and information on the spin content of quarks
inside a polarized proton. We also show that single spin asymmetries in neutral
current interactions are very small.
JHEP 0402 (2004) 035 We demonstrate how the interplay of a future e^+e^- LC at its first stage
with sqrt{s} sim 500 GeV and of the LHC could lead to a precise determination
of the fundamental SUSY ...parameters in the gaugino/higgsino sector without
assuming a specific supersymmetry breaking scheme. We demonstrate this for the
benchmark scenario SPS1a, taking into account realistic errors for the masses
and cross sections measured at the LC with polarised beams, including errors
coming from polarisation measurements, and mass measurements at the LHC. The
results clearly demonstrate the complementarity of the LHC and LC, and the
benefit from the joint analyses of their data.
For large masses, the two heavy neutral Higgs bosons are nearly degenerate in many 2--Higgs doublet models, and particularly in supersymmetric models. In such a scenario the mixing between the states ...can be very large if the theory is CP-noninvariant. We analyze the formalism describing this configuration, and we point to some interesting experimental consequences.
Z.Phys. C70 (1996) 435-448 We summarize the dominant decay modes of the neutral and charged Higgs bosons
in the Minimal Supersymmetric extension of the Standard Model. While two--body
decays are in ...general dominating, the branching ratios for three--body decays
of the heavy scalar, pseudoscalar and charged Higgs bosons can be large below
the thresholds if top quarks, $W/Z$ bosons or heavy scalar bosons are involved.
Analytical expressions have been derived for the partial decay widths and the
physical implications of these decay modes are discussed.
Phys.Lett. B479 (2000) 235-244 The chargino $\tilde{\chi}^\pm_{1,2}$ system can be reconstructed completely
in $e^+e^-$ collisions. By measuring the total cross sections and the
asymmetries with ...polarized beams in $e^+e^-\to\tilde{\chi}_i^+ \tilde{\chi}_j^-
i,j=1,2$, the chargino masses and the gaugino-higgsino mixing angles of these
states can be determined very accurately. If only the lightest charginos
$\tilde{\chi}_1^\pm$ are kinematically accessible, transverse beam polarization
is needed to determine the mixing angles unambiguously. From these observables
the fundamental SUSY parameters can be derived: the SU(2) gaugino mass $M_2$,
the modulus and the cosine of the CP-violating phase of the higgsino mass
parameter $\mu$, and $\tan\beta = v_2/v_1$, the ratio of the vacuum expectation
values of the two neutral Higgs doublet fields. The remaining two-fold
ambiguity of the phase can be resolved by measuring the normal polarization of
the charginos.
