3,404 research outputs found
The Bose-Einstein distribution functions and the multiparticle production at high energies
The evolution properties of propagating particles produced at high energies
in a randomly distributed environment are studied. The finite size of the phase
space of the multiparticle production region as well as the chaoticity can be
derived.Comment: 18 pages, LaTeX, no figures, no table
Like Sign Dilepton Signature for R-Parity Violating SUSY Search at the Tevatron Collider
The like sign dileptons provide the most promising signature for
superparticle search in a large category of -parity violating SUSY models.
We estimate the like sign dilepton signals at the Tevatron collider, predicted
by these models, over a wide region of the MSSM parameter space. One expects an
unambiguous signal upto a gluino mass of GeV ( GeV) with
the present (proposed) accumulated luminosity of .Comment: 12 page LaTeX file; 5 figures available upon request from the autho
Lepton flavor conserving Z -> l^+ l^-$ decays in the general two Higgs doublet model
We calculate the new physics effects to the branching ratios of the lepton
flavor conserving decays Z -> l^+ l^- in the framework of the general two Higgs
Doublet model. We predict the upper limits for the couplings
|\bar{\xi}^{D}_{N,\mu\tau}| and |\bar{\xi}^{D}_{N,\tau\tau}| as 3\times 10^2
GeV and 1\times 10^2 GeV, respectively.Comment: 9 pages, 3 figure
Bounds on Vector Leptoquarks
We derive bounds on vector leptoquarks coupling to the first generation,
using data from low energy experiments as well as from high energy
accelerators. Similarly to the case of scalar leptoquarks, we find that the
strongest indirect bounds arise from atomic parity violation and universality
in leptonic pi decays. These bounds are considerably stronger than the first
direct bounds of HERA, restricting vector leptoquarks that couple with
electromagnetic strength to right-handed quarks to lie above 430 GeV or 460
GeV, and leptoquarks that couple with electromagnetic strength to left-handed
quarks to lie above 1.3 TeV, 1.2 TeV and 1.5 TeV for the SU(2)_W singlet,
doublet and triplet respectively.Comment: 14 Pages (LaTeX), including 1 uufiled postscript figure.
WIS-93/119/Dec-P
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
A Comprehensive Study of Leptoquark Bounds
We make a comprehensive study of indirect bounds on scalar leptoquarks that
couple chirally and diagonally to the first generation by examining available
data from low energy experiments as well as from high energy e+ e- and p pbar
accelerators. The strongest bounds turn out to arise from low energy data: For
leptoquarks that couple to right--handed quarks, the most stringent bound comes
from atomic parity violation. For leptoquarks that couple to left--handed
quarks, there are two mass regions: At low masses the bounds arise from atomic
parity violation or from universality in leptonic pi decays. At masses above a
few hundred GeV's, the dominant bounds come from the FCNC processes that are
unavoidable in these leptoquarks: The FCNC bound of the up sector, that arises
from D-Dbar mixing, combines with the FCNC bounds from the down sector, that
arise from rare K decays and K-Kbar mixing, to a bound on the flavour
CONSERVING coupling to the first generation.
The bounds restrict leptoquarks that couple with electromagnetic strength to
lie above 600 GeV or 630 GeV for leptoquarks that couple to RH quarks, and
above 1040 GeV, 440 GeV, and 750 GeV for the SU(2)_W scalar, doublet and
triplet leptoquarks that couple to LH quarks. These bounds are considerably
stronger than the first results from the direct searches at HERA. Our bounds
also already exclude large regions in the parameter space that could be
examined by various methods proposed for indirect leptoquark searches.Comment: 23 Pages (LaTeX), including 3 uufiled postscript figures.
WIS--93/90/Sept--PH. To appear in PRD. Changes: updated numbers ---> stronger
bound
Transverse Tau Polarization in Decays of the Top and Bottom Quarks in the Weinberg Model of CP Non-conservation
We show that the transverse polarization asymmetry of the -lepton in
the decay is extremely sensitive to CP violating
phases arising from the charged Higgs exchange in the Weinberg model of CP
non-conservation. Qualitatively, the polarization asymmetries are enhanced over
rate or energy asymmetries by a factor of . Thus for optimal values of the parameters the method requires top pairs to be observable rather than needed for rate or energy
asymmetries. We also examine polarization in b decays via and find that it can also be very effective in constraining the CP
violation parameters of the extended Higgs sector.Comment: 11,1 figure, SLAC-PUB-608
Four-jet angular distributions and color charge measurements: leading order versus next-to-leading order
We present the next-to-leading order perturbative QCD prediction to the
four-jet angular distributions used by experimental collaborations at LEP for
measuring the QCD color charge factors. We compare our results to ALEPH data
corrected to parton level. We perform a leading order ``measurement'' of the
QCD color factor ratios by fitting the leading order perturbative predictions
to the next-to-leading order result. Our result shows that in an experimental
analysis for measuring the color charge factors the use of the O()
QCD predictions instead of the O() results may shift the center of
the fit by a relative factor of 1+2\as in the direction.Comment: 14 pages, 10 tables, 5 figures, revtex, eps style
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
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
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