652 research outputs found
Phase Diagram of Gross-Neveu Model at Finite Temperature, Density and Constant Curvature
We discuss a phase structure of chiral symmetry breaking in the Gross-Neveu
model at finite temperature, density and constant curvature. The effective
potential is evaluated in the leading order of the -expansion and in a
weak curvature approximation. The third order critical line is found on the
critical surface in the parameter space of temperature, chemical potential and
constant curvature.Comment: 11 pages, Latex. 3 figures (eps files
Search for lepton flavor violation via the intense high-energy muon beam
A deep inerastic scattering process \mutau is discussed to study lepton
flavor violation between muons and tau leptons. In supersymmetric models, the
Higgs boson mediated diagrams could be important for this reaction. We find
that at a muon energy () higher than 50 GeV, the predicted cross
section significantly increases due to the contribution from sea -quarks.
The number of produced tau leptons can be at = 300
GeV from muons, whereas events are given at
GeV.Comment: Contribution to the 6th International Workshop on Neutrino Factories
& Superbeams(NuFact04), Jul. 26-Aug. 1, 2004, Osaka Univerisity, Osaka,
Japan, talk given by S.K., to appear in the Proceedings, 3 pages, 4 figure
Yukawa Matrix for the Neutrino and Lepton Flavour Violation
We estimate the magnitude of Lepton Flavour Violation (LFV) from the phase of
the neutrino Yukawa matrix. In the minimal supersymmetric standard model with
right-handed neutrinos, the LFV processes l_i \to l_j \gamma can appear through
the slepton mixing, which comes from the renormalization group effect on the
right-handed neutrino Yukawa interaction between the Grand Unified Theory scale
and the heavy right-handed neutrino mass scale. Two types of phases exist in
the neutrino Yukawa matrix. One is the Majorana phase, which can change the
magnitude of the LFV branching ratios by a few factor. The other phases relate
for the size of the Yukawa hierarchy and its phase effect can change the LFV
branching ratios by several orders of magnitude.Comment: Talk given by K. Tsumura at NuFact04, Osaka, Japan, July 26 - August
1,2004 - 3 pages, 2 figure
Determining the Chirality of Yukawa Couplings via Single Charged Higgs Boson Production in Polarized Photon Collision
When the charged Higgs boson is too heavy to be produced in pairs, the
predominant production mechanism at Linear Colliders is via the single charged
Higgs boson production processes, such as and . We show that
the yield of a heavy charged Higgs boson at a collider is
typically one or two orders of magnitude larger than that at an
collider. Furthermore, a polarized collider can determine the
chirality of the Yukawa couplings of fermions with charged Higgs boson via
single charged Higgs boson production, and thus discriminate models of new
physics.Comment: Version accepted by Physical Review Letters (references added, minor
rewording, RevTex4
Some aspects of radiative corrections and non-decoupling effects of heavy Higgs bosons in two Higgs Doublet Model
The possibility of having relatively large non-decoupling effects of the
heavy Higgs particles within the two-Higgs doublet extension of the electroweak
standard model is briefly discussed and demonstrated on an example of the
one-loop amplitude of the process e^+e^- -> W^+W^-Comment: 6 pages, 3 figures; to appear in the proceedings of the AM2003
conferenc
Bi-maximal mixing at GUT, the low energy data and the leptogenesis
In the framework of the minimum supersymmetric model with right-handed
neutrinos, we consider the Bi-maximal mixing which is realized at the GUT scale
and discuss a question that this model can reproduce the low energy phenomena
and the leptogenesis.Comment: Talk given by E. Takasugi at NuFact04, Osaka, Japan, July 26 - August
1,2004 - 3 pages, 4 figure
Enhancement of Loop Induced Vertex in Two Higgs-doublet Model
The non-decoupling effects of heavy Higgs bosons as well as fermions on the
loop-induced vertex are discussed in the general two Higgs
doublet model. The decay width of the process is calculated
at one-loop level and the possibility of its enhancement is explored both
analytically and numerically. We find that the novel enhancement of the decay
width can be realized by the Higgs non-decoupling effects with large
mass-splitting between the charged Higgs boson and the CP-odd one. This is due
to the large breakdown of the custodial invariance in the Higgs
sector. The branching ratio can amount to for GeV within the constraint from the present experimental data. Hence this
mode may be detectable at LHC or future linear colliders.Comment: 31+1 pages, Latex with 8 eps-file
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