14 research outputs found
Quartic Anomalous Couplings in Colliders
We study the constraints on the vertices ,
, and that can be obtained from
triple-gauge-boson production at the next generation of linear
colliders operating in the mode. We analyze the processes
(, or ) and show that these reactions
increase the potential of machines to search for anomalous
four-gauge-boson interactions.Comment: 15 pages, Latex file using ReVteX, 4 uufiled figures include
Probing Anomalous Quartic Couplings in e-gamma and gamma-gamma Colliders
We analyze the potential of the e+e- Linear Colliders, operating in the
e-gamma and gamma-gamma modes, to probe anomalous quartic vector--boson
interactions through the multiple production of W's and Z's. We examine all
chiral operators of order p^4 that lead to new
four--gauge--boson interactions but do not alter trilinear vertices. We show
that the e-gamma and gamma-gamma modes are able not only to establish the
existence of a strongly interacting symmetry breaking sector but also to probe
for anomalous quartic couplings of the order of 10^{-2} at 90% CL. Moreover,
the information gathered in the e-gamma mode can be used to reduced the
ambiguities of the e+e- mode.Comment: Revtex, 18 pages, 6 figure
Triple Electroweak Gauge-Boson Production at Fermilab Tevatron Energies
We calculate the three gauge-boson production in the Standard Model at
Fermilab Tevatron energies. At TeV in collisions, the
cross sections for the triple gauge-boson production are typically of order 10
femtobarns (fb). For the pure leptonic final states from the gauge-boson decays
and with some minimal cuts on final state photons, the cross sections for and
processes are of order a few fb, resulting in a few dozen clean leptonic events
for an integrated luminosity of 10 fb. The pure leptonic modes from
other gauge-boson channels give significantly smaller rate. Especially, the
trilepton modes from and
yield a cross section of order 0.1 fb if there is no significant Higgs boson
contribution. For a Higgs boson with , the triple
massive-gauge-boson production rate could be enhanced by a factor of .Comment: RevTeX 3.0; 14 pages plus 7 figures; ps files available via anonymous
ftp at ftp://ucdhep.ucdavis.edu/han/vvv/vvv.ps,fig*_vvv.p
Intermediate and heavy Higgs boson physics at a 0.5-TeV e+ e- collider
We explore the potential of a future e^+ e^- collider in the 0.5 TeV
center-of-mass energy range to detect intermediate or heavy Higgs bosons in the
Standard Model. We first briefly assess the production cross sections and
update the decay branching fractions for a Higgs boson of intermediate mass,
with M_Z < m_H < 2M_W. We then study in detail the possibility of detecting a
heavy Higgs boson, with m_H > 2M_W, through the production of pairs of weak
bosons. We quantitatively analyze the sensitivity of the process e^+ e^- --> nu
nubar W^+ W^- (ZZ) to the presence of a heavy Higgs-boson resonance in the
Standard Model. We compare this signal to various backgrounds and to the
smaller signal from e^+ e^- --> ZH --> mu^+ mu^- W^+ W^- (ZZ), assuming the
weak-boson pairs to be detected and measured in their dominant hadronic decay
modes W^+ W^- (ZZ) --> 4jets. A related Higgs-boson signal in 6-jet final
states is also estimated. We show how the main backgrounds from e^+ e^- W^+ W^-
(ZZ), e nu WZ, and t tbar production can be reduced by suitable acceptance
cuts. Bremsstrahlung and typical beamstrahlung corrections are calculated.
These corrections reduce Higgs-boson production by scattering mechanisms but
increase production by annihilation mechanisms; they also smear out some
dynamical features such as Jacobian peaks in p_T(H). With all these corrections
included, we conclude that it should be possible to detect a heavy Higgs-boson
signal in the nu nubar W^+ W^-(ZZ) channels up to mass m_H=350 GeV.Comment: 49 pages, 15 figures (not included
Additional file 1 of Local studies provide a global perspective of the impacts of climate change on Indigenous Peoples and local communities
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