139 research outputs found
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
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
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
Higgs Boson Physics in the -channel at Colliders
Techniques and strategies for discovering and measuring the properties of
Higgs bosons via -channel production at a collider, and the
associated requirements for the machine and detector, are discussed in detail.
The unique feature of -channel production is that, with good energy
resolution, the mass, total width and partial widths of a Higgs boson can be
directly measured with remarkable accuracy in most cases. For the expected
machine parameters and luminosity the Standard Model (SM) Higgs boson \hsm,
with mass \lsim 2\mw, the light \hl of the minimal supersymmetric Standard
Model (MSSM), and the heavier MSSM Higgs bosons (the CP-odd \ha and the
CP-even \hh) can all be studied in the -channel, with the heavier states
accessible up to the maximal over a large fraction of the MSSM
parameter space. In addition, it may be possible to discover the \ha and
\hh by running the collider at full energy and observing excess events in the
bremsstrahlung tail at lower energy. The integrated luminosity, beam resolution
and machine/detector features required to distinguish between the \hsm and
\hl are delineated.Comment: 87 pages, uuencoded tex file and postscript figure files submitted,
full postscript file, including embedded figures, is available via anonymous
ftp at ftp://ucdhep.ucdavis.edu/gunion/higgs_mupmum.p
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
Neutrino-electron scattering in noncommutative space
Neutral particles can couple with the gauge field in the adjoint
representation at the tree level if the space-time coordinates are
noncommutative (NC). Considering neutrino-photon coupling in the NC QED
framework, we obtain the differential cross section of neutrino-electron
scattering. Similar to the magnetic moment effect, one of the NC terms is
proportional to , where is the electron recoil energy.
Therefore, this scattering provides a chance to achieve a stringent bound on
the NC scale in low energy by improving the sensitivity to the smaller electron
recoil energy.Comment: 12 pages, 2 figure
HIGGS PHENOMENOLOGY OF THE SUPERSYMMETRIC MODEL WITH A GAUGE SINGLET
We discuss the Higgs sector of the supersymmetric standard model extended by
a gauge singlet for the range of parameters, which is compatible with universal
soft supersymmetry breaking terms at the GUT scale. We present results for the
masses, couplings and decay properties of the lightest Higgs bosons, in
particular with regard to Higgs boson searches at LEP. The prospects differ
significantly from the ones within the MSSM.Comment: 12 pages (Plain Tex), 7 fig
Possibility of spontaneous CP violation in the nonminimal supersymmetric standard model with two neutral Higgs singlets
A supersymmetric standard model with two Higgs doublets and two Higgs
singlets is investigated if it can accommodate the possibility of spontaneous
CP violation. Assuming the degeneracy of the scalar quark masses of the third
generation, we find that spontaneous CP violation in the Higgs sector is viable
in our model. In the case of spontaneous CP violation, the masses of the
lightest two neutral Higgs bosons are estimated to be 80 and 125 GeV for some
parameter values in our model, which, are consistent with LEP2 data.Comment: 18 pages, 3figure
TESLA Technical Design Report Part III: Physics at an e+e- Linear Collider
The TESLA Technical Design Report Part III: Physics at an e+e- Linear
ColliderComment: 192 pages, 131 figures. Some figures have reduced quality. Full
quality figures can be obtained from http://tesla.desy.de/tdr. Editors -
R.-D. Heuer, D.J. Miller, F. Richard, P.M. Zerwa
- …