447 research outputs found
Two-loop calculations for the propagators of gluonic currents. Erratum
This is an erratum to the paper published in Nucl. Phys. B198(1982)508.Comment: 3 pages, Late
Signals of Supersymmetric Lepton Flavor Violation at the LHC
In a generic supersymmetric extension of the Standard Model, there will be
lepton flavor violation at a neutral gaugino vertex due to misalignment between
the lepton Yukawa couplings and the slepton soft masses. Sleptons produced at
the LHC through the cascade decays of squarks and gluinos can give a sizable
number of events with 4 leptons. This channel could give a clean signature of
supersymmetric lepton flavor violation under conditions which are identified.Comment: 21 page
The masses of vector supermultiplet and of the Higgs supertriplet in supersymmetric SU(5) model
The masses of vector supermultiplet and of the Higgs supertriplet in standard
supersymmetric SU(5) model are calculated. Taking into account uncertainties
related with the initial coupling constants and threshold corrections we find
that in supersymmetric SU(5) model the scale of the supersymmetry breaking
could be up to 50 Tev. We find that in the extensions of the standard SU(5)
supersymmetric model it is possible to increase the supersymmetry breaking
scale up to Gev. In standard supersymmetric SU(5) model it is
possible to increase the GUT scale up to Gev provided that
the masses of chiral superoctets and supertriplets are . We also propose SU(5) supersymmetric model with 6 light superdoublets and
superoctet with a mass Gev.Comment: 11 pages, latex, no figure
Tau neutrino magnetic moments from the Super-Kamiokande and e-scattering data
Combined results on oscillations and -scattering from the Super-Kamiokande and LAMPF experiments, respectively,
limit the Dirac diagonal magnetic moment to . For the scheme with 3 Majorana neutrinos the LAMPF
results allow the limitation of effective magnetic moment to
. The moments in the scheme with
additional Majorana light sterile neutrinos as well as experiments on
stimulated radiative neutrino conversion are also discussed.Comment: 12 pages, To appear in Phys. Lett.
On search for a new light gauge boson from decays in neutrino experiments
It is shown that a new light gauge boson which might be produced in the
decays of pseudoscalar mesons could be effectively
searched for in neutrino experiments via the Primakoff effect, in the process
of conversion in the external Coulomb field of a
nucleus. An estimate of the conversion rate for the NOMAD
neutrino detector at CERN is given.Comment: 9 pages, 2 figures, LaTex. Submitted to Phys. Lett.
Renormalizable 1/N_f Expansion for Field Theories in Extra Dimensions
We demonstrate how one can construct renormalizable perturbative expansion in
formally nonrenormalizable higher dimensional field theories. It is based on
-expansion and results in a logarithmically divergent perturbation
theory in arbitrary high space-time dimension. First, we consider a simple
example of -component scalar filed theory and then extend this approach to
Abelian and non-Abelian gauge theories with fermions. In the latter case,
due to self-interaction of non-Abelian fields the proposed recipe requires some
modification which, however, does not change the main results. The resulting
effective coupling is dimensionless and is running in accordance with the usual
RG equations. The corresponding beta function is calculated in the leading
order and is nonpolynomial in effective coupling. It exhibits either UV
asymptotically free or IR free behaviour depending on the dimension of
space-time. The original dimensionful coupling plays a role of a mass and is
also logarithmically renormalized. We analyze also the analytical properties of
a resulting theory and demonstrate that in general it acquires several ghost
states with negative and/or complex masses. In the former case, the ghost state
can be removed by a proper choice of the coupling. As for the states with
complex conjugated masses, their contribution to physical amplitudes cancels so
that the theory appears to be unitary.Comment: 32 pages, 20 figure
Four-dimensional lattice chiral gauge theories with anomalous fermion content
In continuum field theory, it has been discussed that chiral gauge theories
with Weyl fermions in anomalous gauge representations (anomalous gauge
theories) can consistently be quantized, provided that some of gauge bosons are
permitted to acquire mass. Such theories in four dimensions are inevitablly
non-renormalizable and must be regarded as a low-energy effective theory with a
finite ultraviolet (UV) cutoff. In this paper, we present a lattice framework
which enables one to study such theories in a non-perturbative level. By
introducing bare mass terms of gauge bosons that impose ``smoothness'' on the
link field, we explicitly construct a consistent fermion integration measure in
a lattice formulation based on the Ginsparg-Wilson (GW) relation. This
framework may be used to determine in a non-perturbative level an upper bound
on the UV cutoff in low-energy effective theories with anomalous fermion
content. By further introducing the St\"uckelberg or Wess-Zumino (WZ) scalar
field, this framework provides also a lattice definition of a non-linear sigma
model with the Wess-Zumino-Witten (WZW) term.Comment: 18 pages, the final version to appear in JHE
Probing Left-handed Slepton Flavor Mixing at Future Lepton Colliders
It has been argued in the literature that the search for the slepton
oscillation phenomenon can be a powerful probe of intergenerational mixing
between sleptons, once sleptons are found at future colliders. In this article
we estimate possible reach of future lepton colliders in probing left-handed
slepton flavor mixing, especially mixing between the first and third
generations, on which constraints imposed by other processes like are very weak. collider is suitable for this purpose, since it
can produce, if kinematically allowed, sleptons of the first generation via
t-channel, in addition to s-channel. Utilizing e^+e^- \to \tau e + 4jets + \E
signal at linear collider with integrated luminosity L=50 fb^{-1}(500
fb^{-1}) it may be possible to reach mixing angle and mass difference GeV for sneutrinos in the first and third generations at the
statistical significance of 5 \sigma.Comment: 27 pages, 6 figures. A new section added. Conclusion unchanged. To
appear in Phys. Rev.
SUSY model with R-parity violation, longlived charged slepton and quasistable matter
We construct SUSY electroweak models
with superweak R-parity. The scale of R-parity violation in one of the models
is determined by the Majorana mass of neutrino and it is very small that leads
to the existence of longlived () lightest superparticle.
If lightest superparticle is righthanded charged slepton that can be realized
within gaugino dominated scenario then the phenomenology of such model differs
in a drastic way from the standard SUSY phenomenology, in particular, longlived
charged sleptons can form bound states with ordinary matter - quasistable
supermatter (SUSY analogs of mu-atoms and muonium). We discuss possible
manifestations of the existence of such longlived charged particle at LEP2,
TEVATRON and LHC. We also construct model with Majorana mass and superweak R-parity violation.Comment: 12 pages, Latex, no figure
Standard Model Higgs boson mass from inflation: two loop analysis
We extend the analysis of \cite{Bezrukov:2008ej} of the Standard Model Higgs
inflation accounting for two-loop radiative corrections to the effective
potential. As was expected, higher loop effects result in some modification of
the interval for allowed Higgs masses m_min<m_H<m_max, which somewhat exceeds
the region in which the Standard Model can be considered as a viable effective
field theory all the way up to the Planck scale. The dependence of the index
n_s of scalar perturbations on the Higgs mass is computed in two different
renormalization procedures, associated with the Einstein (I) and Jordan (II)
frames. In the procedure I the predictions of the spectral index of scalar
fluctuations and of the tensor-to-scalar ratio practically do not depend on the
Higgs mass within the admitted region and are equal to n_s=0.97 and r=0.0034
respectively. In the procedure II the index n_s acquires the visible dependence
on the Higgs mass and and goes out of the admitted interval at m_H below m_min.
We compare our findings with the results of \cite{DeSimone:2008ei}.Comment: 24 paged, 9 figures. Journal version (typos fixed, expanded
discussions
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