460 research outputs found
Probing Intermediate Mass Higgs Interactions at the CERN Large Hadron Collider
We analyze the potentiality of the CERN Large Hadron Collider to probe the
Higgs boson couplings to the electroweak gauge bosons. We parametrize the
possible deviations of these couplings due to new physics in a model
independent way, using the most general dimension--six effective lagrangian
where the SU(2)_L x U(1)_Y is realized linearly. For intermediate Higgs masses,
the decay channel into two photons is the most important one for Higgs searches
at the LHC. We study the effects of these new interactions on the Higgs
production mechanism and its subsequent decay into two photons. We show that
the LHC will be sensitive to new physics scales beyond the present limits
extracted from the LEP and Tevatron physics.Comment: 13 pages, 1 figure included using epsfig, RevTe
Bounds on Higgs and Gauge--Boson Interactions from LEP2 Data
We derive bounds on Higgs and gauge--boson anomalous interactions using the
LEP2 data on the production of three photons and photon pairs in association
with hadrons. In the framework of effective
Lagrangians, we examine all dimension--six operators that lead to anomalous
Higgs interactions involving and . The search for Higgs boson
decaying to pairs allow us to obtain constrains on these
anomalous couplings that are comparable with the ones originating from the
analyses of collisions at the Tevatron. Our results also show that
if the coefficients of all ``blind'' operators are assumed to have same
magnitude, the indirect constraints on the anomalous couplings obtained from
this analyses, for Higgs masses 140 GeV, are more restrictive
than the ones coming from the production.Comment: 14 pages Latex file using RevTeX, 3 figures as .eps file
Testing Anomalous Higgs Couplings in Triple Photon Production at the Tevatron Collider
We derive bounds on Higgs and gauge--boson anomalous interactions using the
CDF data for the process . We use a
linearly realized invariant effective Lagrangian to
describe the bosonic sector of the Standard Model, keeping the fermionic
couplings unchanged. All dimension--six operators that lead to anomalous Higgs
interactions involving and are considered. We also show the
sensitivity that can be achieved for these couplings at Fermilab Tevatron
upgrades.Comment: 13 pages, RevTeX, 2 figures included using epsfi
Quartic Anomalous Couplings in Colliders
We study the production of gauge boson pairs at the next generation of linear
colliders operating in the mode. The processes (, , or and or )
can give valuable information on possible deviations of the quartic vector
boson couplings from the Standard Model predictions. We establish the range of
the new couplings that can be explored in these colliders based on a
effect in the total cross section. We also present several kinematical
distributions of the final state particles that could manifest the underlying
new dynamics. Our results show that an collider can extend
considerably the bounds on anomalous interactions coming from oblique radiative
corrections and from direct searches in colliders.Comment: 21 pages and 7 figures appended as a postscript file (uuencoded),
MAD/PH/764, IFT-P.031/93, IFUSP-P 1047 (uses REVTeX3
Excited Fermion Contribution to Z Physics at One Loop
We investigate the effects induced by excited leptons at the one-loop level
in the observables measured on the peak at LEP. Using a general effective
Lagrangian approach to describe the couplings of the excited leptons, we
compute their contributions to both oblique parameters and partial widths.
Our results show that the new effects are comparable to the present
experimental sensitivity, but they do not lead to a significant improvement on
the available constraints on the couplings and masses of these states.Comment: 25 pages 6 figure
Searching for an Invisibly Decaying Higgs Boson in E^+E^-, E-Gamma, and Gamma-Gamma Collisions
Higgs bosons can have a substantial ``invisible'' branching ratio in many
extensions of the Standard Model, such as models where the Higgs bosons decay
predominantly into light or massless weakly interacting Goldstone bosons. In
this work, we examine the production mechanisms and backgrounds for invisibly
decaying Higgs bosons at the Next Linear Collider operating in the
modes , , and . We demonstrate that such machine
is much more efficient to survey for invisibly decaying Higgs bosons than the
Large Hadron Collider at CERN.Comment: (LaTex file, 9 figures in postcript available upon request.
MAD/PH/81
Search for the standard model Higgs boson decaying to a pair in events with no charged leptons and large missing transverse energy using the full CDF data set
We report on a search for the standard model Higgs boson produced in
association with a vector boson in the full data set of proton-antiproton
collisions at TeV recorded by the CDF II detector at the
Tevatron, corresponding to an integrated luminosity of 9.45 fb. We
consider events having no identified charged lepton, a transverse energy
imbalance, and two or three jets, of which at least one is consistent with
originating from the decay of a quark. We place 95% credibility level upper
limits on the production cross section times standard model branching fraction
for several mass hypotheses between 90 and . For a Higgs
boson mass of , the observed (expected) limit is 6.7
(3.6) times the standard model prediction.Comment: Accepted by Phys. Rev. Let
Search for the standard model Higgs boson decaying to a bb pair in events with one charged lepton and large missing transverse energy using the full CDF data set
We present a search for the standard model Higgs boson produced in
association with a W boson in sqrt(s) = 1.96 TeV p-pbar collision data
collected with the CDF II detector at the Tevatron corresponding to an
integrated luminosity of 9.45 fb-1. In events consistent with the decay of the
Higgs boson to a bottom-quark pair and the W boson to an electron or muon and a
neutrino, we set 95% credibility level upper limits on the WH production cross
section times the H->bb branching ratio as a function of Higgs boson mass. At a
Higgs boson mass of 125 GeV/c2 we observe (expect) a limit of 4.9 (2.8) times
the standard model value.Comment: Submitted to Phys. Rev. Lett (v2 contains clarifications suggested by
PRL
Search for the standard model Higgs boson decaying to a bb pair in events with two oppositely-charged leptons using the full CDF data set
We present a search for the standard model Higgs boson produced in
association with a Z boson in data collected with the CDF II detector at the
Tevatron, corresponding to an integrated luminosity of 9.45/fb. In events
consistent with the decay of the Higgs boson to a bottom-quark pair and the Z
boson to electron or muon pairs, we set 95% credibility level upper limits on
the ZH production cross section times the H -> bb branching ratio as a function
of Higgs boson mass. At a Higgs boson mass of 125 GeV/c^2 we observe (expect) a
limit of 7.1 (3.9) times the standard model value.Comment: To be submitted to Phys. Rev. Let
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