198 research outputs found
Signals for Vector Leptoquarks in Hadronic Collisions
We analyze systematically the signatures of vector leptoquarks in hadronic
collisions. We examine their single and pair productions, as well as their
effects on the production of lepton pairs. Our results indicate that a machine
like the CERN Large Hadron Collider (LHC) will be able to unravel the existence
of vector leptoquarks with masses up to the range of -- TeV.Comment: 15 pages and 5 figures (available upon request or through anonymous
ftp), revtex3, IFUSP-P 108
Using to Probe Top Quark Couplings
Possible anomalous couplings of the top-quark to on-shell photons and gluons
are constrained by the recent results of the CLEO Collaboration on both
inclusive and exclusive radiative decays. We find that the process \bsg\
can lead to reasonable bounds on both the anomalous electric and magnetic
dipole moments of the top-quark, while essentially no limits are obtained on
the corresponding chromoelectric and chromomagnetic moments, which enter the
expression for the decay rate only through operator mixing.Comment: 10 pages plus 6 figures (available by request), LaTex,
ANL-HEP-PR-93-3
Histological renal osteodystrophy, and 25 hydroxycholecalciferol and aluminum levels in patients on continuous ambulatory peritoneal dialysis
Renal osteodystrophy, which influences the quality of life and contributes to the morbidity of patients with endstage renal failure [1], has been reported to deteriorate in patients treated with continuous ambulatory peritoneal dialysis (CAPD) [2]. However, better control of serum calcium and phosphate in these patients [3] has provided preliminary data that show improvement in histological grading of osteitis fibrosa (OF) in our patients treated with CAPD [41.Another form of bone disease, the osteomalacic dialysis osteodystrophy (OM), which may be associated with dialysis encephalopathy, is thought in some instances to be due to aluminum toxicity [5] from untreated or softened water used in hemodialysis in areas where the aluminum content of water supplies is high [6]. In patients undergoing CAPD any exposure to aluminum is likely to stem from the use of aluminum-containing phosphate binders (ACPB) since the process of preparation of peritoneal dialysis fluid reduces most of the trace metals.In our unit, since the inception of the CAPD program in January 1979, 72 patients have been treated by this method in the first 2 years. In this report we present data on the improvement of histological renal osteodystrophy in CAPD patients and relate this to serum concentrations of calcium, phosphate, 25 hydroxycholecalciferol [25-(0H)CC] and immunoreactive parathormone (PTH). In addition, sequential serum aluminum concentrations are reported. These levels have been related to concentrations of aluminum in the peritoneal dialysis (PD) fluid and to the use of ACPB. One patient with aluminum toxicity prior to starting CAPD was studied to evaluate the chelating effect of disferrioxamine (DFO) on aluminum and its subsequent removal in the PD fluid
Signal and Backgrounds for Leptoquarks at the LHC
We study the potentiality of the CERN Large Hadron Collider (LHC) to unravel
the existence of first generation scalar leptoquarks.
Working with the most general invariant leptoquark
interactions, we analyze in detail the signals and backgrounds that lead to a
final state containing a pair and jets. Our results indicate that a
machine like the LHC will be able to discover leptoquarks with masses up to
2--3 TeV depending on their couplings.Comment: 37 pages, revtex, uses epsfig.sty (included), 15 figures (included
Status of the superworld: from theory to experiment
Review to appear in Progress in Particle and Nuclear Physics. Contents:
{1}Introduction}{1} {2}High precision LEP data and convergence of couplings:
physics is not Euclidean geometry}{2} {3}Interconnections between the measured
quantities due to Unification}{7} {4}The origin of and why it should
be abandoned: masses and spectra are needed}{13} {5}The new step forward:
Supergravity}{21} {6}The SU(5) Supergravity Model}{22} {7}SU(5)xU(1)
Supergravity}{32} {8}Detailed calculations for the Tevatron}{47} {9}Detailed
calculations for LEP}{48} {10}Detailed calculations for HERA}{53} {11}Detailed
calculations for Underground Labs and Underwater facilities}{55} {12}Detailed
calculations for indirect experimental detection}{65} {13}The problem of mass
and }{73} {14}Conclusions}{77}Comment: 90 pages, 41 figures (not included), latex. Send requests for hard
copies to "[email protected]". CERN-TH.7136/94, CTP-TAMU-80/9
Scalar Dark Matter From Theory Space
The scalar dark matter candidate in a prototypical theory space little Higgs
model is investigated. We review all details of the model pertinent to dark
matter. We perform a thermal relic density calculation including couplings to
the gauge and Higgs sectors of the model. We find two regions of parameter
space that give acceptable dark matter abundances. The first region has a dark
matter candidate with a mass of order 100 GeV, the second region has a heavy
candidate with a mass greater than about 500 GeV$. The dark matter candidate in
either region is an admixture of an SU(2) triplet and an SU(2) singlet, thereby
constituting a WIMP (weakly interacting massive particle).Comment: 18 pages, 2 figures, version to appear in PR
Signal and Backgrounds for Leptoquarks at the LHC II: Vector Leptoquarks
We perform a detailed analyses of the CERN Large Hadron Collider (LHC)
capability to discover first generation vector leptoquarks through their pair
production. We study the leptoquark signals and backgrounds that give rise to
final states containing a pair e+e- and jets. Our results show that the LHC
will be able to discover vector leptoquarks with masses up to 1.3-2.1 TeV
depending on their couplings to fermions and gluons.Comment: 18 pages, 3 figures, REVTe
Precision Electroweak Tests of the Minimal and Flipped SU(5) Supergravity Models
We explore the one-loop electroweak radiative corrections in the minimal
and the no-scale flipped supergravity models via explicit
calculation of vacuum polarization contributions to the
parameters. Experimentally, are obtained from a global fit
to the LEP observables, and measurements. We include -dependent
effects which have been neglected in most previous ``model-independent"
analyses of this type. These effects induce a large systematic negative shift
on for light chargino masses (m_{\chi^\pm_1}\lsim70\GeV).
In agreement with previous general arguments, we find that for increasingly
large sparticle masses, the heavy sector of both models rapidly decouples, \ie,
the values for quickly asymptote to the Standard Model
values with a {\it light} Higgs (m_{H_{SM}}\sim100\GeV). Specifically, at
present the CL upper limit on the top-quark mass is m_t\lsim175\GeV in
the no-scale flipped supergravity model. These bounds can be
strengthened for increasing chargino masses in the 50-100\GeV interval. In
particular, for m_t\gsim160\GeV, the Tevatron may be able to probe through
gluino() and squark() production up to m_{\tilde g}\approx
m_{\tilde q}\approx250\GeV, exploring at least half of the parameter space in
this model.Comment: 15 pages,(6 ps figures available upon request), TeX(harvmac),
CTP-TAMU-19/93, ACT-07/9
Signal and Backgrounds for the Single Production of Scalar and Vector Leptoquarks at the LHC
We perform a detailed analysis of the potentiality of the CERN Large Hadron
Collider to study the single production of leptoquarks via
leptoquark , with generated by the splitting of photons
radiated by the protons. Working with the most general
invariant effective lagrangian for scalar and vector leptoquarks, we analyze in
detail the leptoquark signals and backgrounds that lead to a final state
containing an and a hard jet with approximately balanced transverse
momenta. Our results indicate that the LHC will be able to discover leptoquarks
with masses up to 2--3 TeV, depending on their type, for Yukawa couplings of
the order of the electromagnetic one.Comment: Revtex, 23 pages, 11 postscript files. Uses axodraw.sty (included)
and epsfig.sty. Typos corrected. To be published in Phys. Rev.
Effects of the littlest Higgs model with T-parity on Higgs boson production at high energy colliders
The Higgs boson production processes , , and
are very important for studying Higgs boson
properties and further testing new physics beyond the standard model() in
the high energy linear
collider(). We estimate the contributions of the littlest
Higgs model with T-parity( model) to these processes and find that the
model can generate significantly corrections to the production cross
sections of these processes.
We expect the possible signals of the model can be detected via these
processes in the future experiments.Comment: 9 pages, 2 figures, references adde
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