1,647 research outputs found
Reconstruction of the Extended Gauge Structure from Observables at Future Colliders
The discovery of a new neutral gauge boson with a mass in the TeV region
would allow for determination of gauge couplings of the to ordinary quarks
and leptons in a model independent way. We show that these couplings in turn
would allow us to determine the nature of the extended gauge structure. As a
prime example we study the group. In this case two discrete constraints
on experimentally determined couplings have to be satisfied. If so, the
couplings would then uniquely determine the two parameters, and
, which fully specify the nature of the within . If the
is part of the gauge structure, then for TeV and
could be determined to around at the future colliders. The NLC
provides a unique determination of the two constraints as well as of and , though with slightly larger error bars than at the LHC. On
the other hand, since the LHC primarily determines three out of four normalized
couplings, it provides weaker constraints for the underlying gauge structure.Comment: 14 pages LaTeX using RevTeX and psfig.sty. TeX source and 3 PS
figures, tarred, compressed and uuencoded; also available via anonymous ftp
to ftp://dept.physics.upenn.edu/pub/Cvetic/UPR-636-T
Constraining differential renormalization in abelian gauge theories
We present a procedure of differential renormalization at the one loop level
which avoids introducing unnecessary renormalization constants and
automatically preserves abelian gauge invariance. The amplitudes are expressed
in terms of a basis of singular functions. The local terms appearing in the
renormalization of these functions are determined by requiring consistency with
the propagator equation. Previous results in abelian theories, with and without
supersymmetry, are discussed in this context.Comment: 13 pages, LaTeX. Some equations corrected and a reference added.
Complete ps paper also available at http://www-ftae.ugr.es/papiros.html or
ftp://ftae3.ugr.es/pub/rmt/ugft73.p
Looking for signals beyond the neutrino Standard Model
Any new neutrino physics at the TeV scale must include a suppression
mechanism to keep its contribution to light neutrino masses small enough. We
review some seesaw model examples with weakly broken lepton number, and comment
on the expected effects at large colliders and in neutrino oscillations.Comment: LaTeX 10 pages, 9 PS figures. Contribution to the Proceedings of the
XXXI International School of Theoretical Physics "Matter To The Deepest"
Ustron, Poland, September 5-11, 2007. Typos correcte
Comparison of the effect of locking vs standard screws on the mechanical properties of bone-plate constructs in a comminuted diaphyseal fracture model
The purpose of this study was to compare the mechanical properties of bone-plate constructs with locking compression plates (LCP) used either with standard screws or with locking screws on an experimental model of comminuted fracture
Quark mixings and flavor changing interactions with singlet quarks
Aspects of the quark mixings and flavor changing interactions are
investigated in electroweak models with singlet quarks. The effects on the
ordinary quark mixing are determined in terms of the quark masses and the
parameters describing the mixing between the ordinary quarks q and the singlet
quarks Q (q-Q mixing). Some salient features arise in the flavor changing
interactions through the q-Q mixing. The unitarity of the
Cabibbo-Kobayashi-Maskawa (CKM) matrix within the ordinary quark sector is
violated, and the flavor changing neutral currents (FCNC's) appear both in the
gauge and scalar couplings. The flavor changing interactions are calculated
appropriately in terms of the q-Q mixing parameters and the quark masses, which
really exhibit specific flavor structures. It is found that there are
reasonable ranges of the model parameters to reproduce the ordinary quark mass
hierarchy and the actual CKM structure even in the presence of q-Q mixing. Some
phenomenological effects of the singlet quarks are also discussed. In
particular, the scalar FCNC's may be more important in some cases, if the
singlet quarks as well as the extra scalar particles from the singlet Higgs
fields have masses 100 GeV -- 1 TeV.Comment: 32 pages, 7 figures, added reference
Model-Independent Searches for New Quarks at the LHC
New vector-like quarks can have sizable couplings to first generation quarks
without conflicting with current experimental constraints. The coupling with
valence quarks and unique kinematics make single production the optimal
discovery process. We perform a model-independent analysis of the discovery
reach at the Large Hadron Collider for new vector-like quarks considering
single production and subsequent decays via electroweak interactions. An early
LHC run with 7 TeV center of mass energy and 1 fb-1 of integrated luminosity
can probe heavy quark masses up to 1 TeV and can be competitive with the
Tevatron reach of 10 fb-1. The LHC with 14 TeV center of mass energy and 100
fb-1 of integrated luminosity can probe heavy quark masses up to 3.7 TeV for
order one couplings.Comment: 37 pages, 11 figures, 7 table
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