173 research outputs found
Prospects of Measuring General Higgs Couplings at e^+e^- Linear Colliders
We examine how accurately the general HZV couplings, with V=Z,gamma, may be
determined by studying e^+e^- --> Hff-bar processes at future e^+e^- linear
colliders. By using the optimal-observable method, which makes use of all
available experimental information, we find out which combinations of the
various HZV coupling terms may be constrained most efficiently with high
luminosity. We also assess the benefits of measuring the tau-lepton helicities,
identifying the bottom-hadron charges, polarizing the electron beam and running
at two different collider energies. The HZZ couplings are generally found to be
well constrained, even without these options, while the HZ-gamma couplings are
not. The constraints on the latter may be significantly improved by beam
polarization.Comment: 28 pages (LaTeX), 5 figures (axodraw and eps
High Resolution Hybrid Pixel Sensors for the e+e- TESLA Linear Collider Vertex Tracker
In order to fully exploit the physics potential of a future high energy e+e-
linear collider, a Vertex Tracker, providing high resolution track
reconstruction, is required. Hybrid Silicon pixel sensors are an attractive
option, for the sensor technology, due to their read-out speed and radiation
hardness, favoured in the high rate environment of the TESLA e+e- linear
collider design but have been so far limited by the achievable single point
space resolution. In this paper, a conceptual design of the TESLA Vertex
Tracker, based on a novel layout of hybrid pixel sensors with interleaved cells
to improve their spatial resolution, is presented.Comment: 12 pages, 5 figures, to appear in the Proceedings of the Vertex99
Workshop, Texel (The Netherlands), June 199
A No-Lose Theorem for Higgs Searches at a Future Linear Collider
Assuming perturbativity up to a high energy scale GeV, we
demonstrate that a future linear collider operating at
500 GeV with 500 fb per year (such as the recently
proposed TESLA facility) will detect a Higgs boson signal regardless of the
complexity of the Higgs sector and of how the Higgs bosons decay.Comment: 4 pages, LaTe
BPS Monopole Equation in Omega-background
We study deformed supersymmetries in N=2 super Yang-Mills theory in the
Omega-backgrounds characterized by two complex parameters . When one of the -parameters vanishes, the theory has
extended supersymmetries. We compute the central charge of the algebra and
obtain the deformed BPS monopole equation. We examine supersymmetries preserved
by the equation.Comment: 14 pages, typos corrected, published version in JHE
Evaluation of measurement accuracies of the Higgs boson branching fractions in the International Linear Collider
Precise measurement of Higgs boson couplings is an important task for
International Linear Collider (ILC) experiments and will facilitate the
understanding of the particle mass generation mechanism.
In this study, the measurement accuracies of the Higgs boson branching
fractions to the and quarks and gluons, , were evaluated with the full International Large
Detector model (\texttt{ILD\_00}) for the Higgs mass of 120 GeV at the
center-of-mass (CM) energies of 250 and 350 GeV using neutrino, hadronic and
leptonic channels and assuming an integrated luminosity of ,
and an electron (positron) beam polarization of -80% (+30%).
We obtained the following measurement accuracies of the Higgs cross section
times branching fraction () for decay
of the Higgs into , , and ; as 1.0%, 6.9%, and 8.5% at
a CM energy of 250 GeV and 1.0%, 6.2%, and 7.3% at 350 GeV, respectively.
After the measurement accuracy of the cross section ()
was corrected using the results of studies at 250 GeV and their extrapolation
to 350 GeV, the derived measurement accuracies of the branching fractions
() to , , and gg were 2.7%, 7.3%, and 8.9% at
a CM energy of 250 GeV and 3.6%, 7.2%, and 8.1% at 350 GeV, respectively.Comment: 15 pages, 6 figure
Theoretical Higgs Mass Bounds in the Standard Model and Supersymmetric Extensions
These lectures provide a very basic introduction to different theoretical
limits on the mass of Higgs scalars. Particular attention is devoted to the
pure Standard Model and its Minimal Supersymmetric extension (MSSM). [Lectures
presented at the XXIV ITEP Winter School, Snegiri (Russia), February 96]Comment: 37 pages, TeX, 15 postscript figures include
Probing Noncommutative Space-Time in the Laboratory Frame
The phenomenological investigation of noncommutative space-time in the
laboratory frame are presented. We formulate the apparent time variation of
noncommutativity parameter in the laboratory frame due to the
earth's rotation. Furthermore, in the noncommutative QED, we discuss how to
probe the electric-like component
by the
process at future linear collider.
We may determine the magnitude and the direction of
by detailed study of the apparent time
variation of total cross section.
In case of us observing no signal, the upper limit on the magnitude of
can be determined independently of its
direction.Comment: 12 pages, 7 figures, typos are corrected, one graph have been added
in figure
TeV Scale Implications of Non Commutative Space time in Laboratory Frame with Polarized Beams
We analyze , and processes within the
Seiberg-Witten expanded noncommutative scenario using polarized beams. With
unpolarized beams the leading order effects of non commutativity starts from
second order in non commutative(NC) parameter i.e. , while with
polarized beams these corrections appear at first order () in cross
section. The corrections in Compton case can probe the magnetic
component() while in Pair production and Pair annihilation
probe the electric component() of NC parameter. We include the
effects of earth rotation in our analysis. This study is done by investigating
the effects of non commutativity on different time averaged cross section
observables. The results which also depends on the position of the collider,
can provide clear and distinct signatures of the model testable at the
International Linear Collider(ILC).Comment: 22 pages, 19 figures, new comments and references added, few typos
corrected, Published in JHE
Neutral Higgs sector of the next-to-minimal supersymmetric standard model with explicit CP violation
The neutral Higgs sector of the next-to-minimal supersymmetric standard model
(NMSSM) with explicit CP violation is investigated at the 1-loop level, using
the effective potential method; not only the loops involving the third
generation of quarks and scalar quarks, but also the loops involving boson,
charged Higgs boson, and chargino are taken into account. It is found that for
some parameter values of the NMSSM the contributions from the boson,
charged Higgs boson, and chargino loops may modify the masses of the neutral
Higgs bosons and the mixings among them significantly, depending on the CP
phase. In collisions, the prospects for discovering neutral Higgs
bosons are investigated within the context of the NMSSM with explicit CP
violation when the dominant component of the lightest neutral Higgs boson is
the Higgs singlet field of the NMSSM.Comment: Latex, 23 pages, 6 figure
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