1,342 research outputs found
Electroweak Gauge Theories and Alternative Theories at a Future Linear e+e- Collider
The measurement of Standard Model processes tests the validity of the model
at a given scale and is simultaneously sensitive to new physics through loop
effects or interference with the Standard Model amplitudes. A variety of
studies has been done to see what a linear collider in the energy range MZ <
sqrt{s} < 1 TeV can offer. The work that has been done within the ECFA/DESY
workshop on linear colliders is reviewed, especially what was not included in
the TESLA TDR.Comment: Invited talk presented at the Linear Collider Workshop, Amsterdam,
April 200
The physics goals of the TESLA project
As next generation e+e- linear collider the superconducting accelerator
project TESLA has been proposed. In this note the physics potential goals of
this project, which is highly complementary to LHC, are described.Comment: Invited talk presented at the ``Seventh Topical Seminar on The legacy
of LEP and SLC'', Siena, October 200
Experimental studies of Strong Electroweak Symmetry Breaking in gauge boson scattering and three gauge boson production
If no light Higgs boson exist, the interaction among the gauge bosons becomes
strong at high energies (~1TeV). The effects of strong electroweak symmetry
breaking (SEWSB) could manifest themselves as anomalous couplings before they
give rise to new physical states, thus measurement of all couplings and their
possible deviation from Standard Model (SM) values could give valuable
information for understanding the true nature of symmetry breaking sector. Here
we present a detailed study of the measurement of quartic gauge couplings in
weak boson scattering processes and a possibility for same measurement in
triple weak boson production. Expected limits on the parameters alpha_4
alpha_5,alpha_6, alpha_7 and alpha_10 in electroweak chiral Lagrangian are
given.Comment: talk presented at LCWS05, Stanford, USA, March 200
"Pair production of scalar top quarks in e+e- collisions at ILC."
We study the pair production of scalar top quarks in e+e- collisions with the
subsequent decay of the top squarks into b-quarks and charginos. We simulate
this process using PYTHIA6.4 for beam energies 2E_beam = 350, 400, 500, 800,
1000 GeV. Proposing a set of criteria we obtain a good separation of the signal
stop events from top quark pair production which is the main background. The
number of stop production events obtained with the proposed cuts for different
energies is calculated for an integrated luminosity of 1000 1/fb. We propose a
method to reconstruct the mass of the top squark, provided the mass of the
lightest neutralino is known, and estimate the error of the mass determination
for the case sqrt{s} = 500 GeV.Comment: 25 pages, 27 figures, ILC-NOTE-2008-042. v1 was presented by the 4-th
author and published in the Proceedings of the 15-th International Seminar on
High Energy Physics QUARKS-2008 (Institute for Nuclear Research of RAS,
Sergiev Posad, Russia, 23-29 May 2008), V1, p.227-246, ISBN
978-5-94274-123-5. v2 - another set of cuts was chosen. v3 - some typos
correcte
Measuring the Luminosity of a gamma gamma Collider with gamma gamma -> l+ l- gamma Events
The process gamma gamma -> l+ l- is highly suppressed when the total angular
momentum of the two colliding photons is zero so that it cannot be used for
luminosity determination. This configuration, however is needed for Higgs
production at a photon collider. It will be shown that the process gamma gamma
-> l+ l- gamma can be used in this case to measure the luminosity of a collider
with a precision that is good enough not to limit the error on the partial
decay width Gamma(H -> gamma gamma).Comment: Final version, accepted by journa
Measurement of Trilinear Gauge Couplings at a gamma-gamma and e-gamma Collider
The processes gamma gamma -> WW and e gamma -> nu W are sensitive to triple
gauge boson interactions. Both reactions have been simulated for hadronically
decaying W-bosons and the sensitivity to anomalous couplings has been
estimated.Comment: Talk presented at LCWS2002, August 2002, Jeju Island, Kore
The global electroweak fit at NNLO and prospects for the LHC and ILC
For a long time, global fits of the electroweak sector of the Standard Model
(SM) have been used to exploit measurements of electroweak precision
observables at lepton colliders (LEP, SLC), together with measurements at
hadron colliders (Tevatron, LHC), and accurate theoretical predictions at
multi-loop level, to constrain free parameters of the SM, such as the Higgs and
top masses. Today, all fundamental SM parameters entering these fits are
experimentally determined, including information on the Higgs couplings, and
the global fits are used as powerful tools to assess the validity of the theory
and to constrain scenarios for new physics. Future measurements at the Large
Hadron Collider (LHC) and the International Linear Collider (ILC) promise to
improve the experimental precision of key observables used in the fits. This
paper presents updated electroweak fit results using newest NNLO theoretical
predictions, and prospects for the LHC and ILC. The impact of experimental and
theoretical uncertainties is analysed in detail. We compare constraints from
the electroweak fit on the Higgs couplings with direct LHC measurements, and
examine present and future prospects of these constraints using a model with
modified couplings of the Higgs boson to fermions and bosons.Comment: 26 pages, 9 figure
- …