2,119 research outputs found
The Lightest Higgs Boson Mass in the Minimal Supersymmetric Standard Model
We compute the upper bound on the mass of the lightest Higgs boson in the
Minimal Supersymmetric Standard Model in a model-independent way, including
leading (one-loop) and next-to-leading order (two-loop) radiative corrections.
We find that (contrary to some recent claims) the two-loop corrections are
negative with respect to the one-loop result and relatively small (\simlt
3\%). After defining physical (pole) top quark mass , by including QCD
self-energies, and physical Higgs mass , by including the electroweak
self-energies , we obtain the upper limit on
as a function of supersymmetric parameters. We include as supersymmetric
parameters the scale of supersymmetry breaking , the value of
and the mixing between stops (which is responsible
for the threshold correction on the Higgs quartic coupling). Our results do not
depend on further details of the supersymmetric model. In particular, for
TeV, maximal threshold effect and any value of
, we find GeV for GeV. In the particular
scenario where the top is in its infrared fixed point we find GeV
for GeV.Comment: 24 pages + 15 figures in one compressed uuencoded tarred postscript
file (The figures can be obtained by e-mail from [email protected]; also,
the whole postscript file of the text including the figures can be obtained
by ANONYMOUS FTP from ROCA.CSIC.ES (161.111.20.20) at the directory HEP the
file being HIGGS.PS: just type GET HEP/HIGGS.PS), Latex, CERN-TH.7334/9
Split extended supersymmetry from intersecting branes
We study string realizations of split extended supersymmetry, recently
proposed in hep-ph/0507192. Supersymmetry is broken by small ()
deformations of intersection angles of -branes giving tree-level masses of
order , where is the string scale, to localized
scalars. We show through an explicit one-loop string amplitude computation that
gauginos acquire hierarchically smaller Dirac masses . We also evaluate the one-loop Higgsino mass, , and show that,
in the absence of tree-level contributions, it behaves as . Finally we discuss an alternative suppression of scales using
large extra dimensions. The latter is illustrated, for the case where the gauge
bosons appear in N=4 representations, by an explicit string model with Standard
Model gauge group, three generations of quarks and leptons and gauge coupling
unification.Comment: 32 pages, 3 figure
Infinite impulse response modal filtering in visible adaptive optics
Diffraction limited resolution adaptive optics (AO) correction in visible
wavelengths requires a high performance control. In this paper we investigate
infinite impulse response filters that optimize the wavefront correction: we
tested these algorithms through full numerical simulations of a
single-conjugate AO system comprising an adaptive secondary mirror with 1127
actuators and a pyramid wavefront sensor (WFS). The actual practicability of
the algorithms depends on both robustness and knowledge of the real system:
errors in the system model may even worsen the performance. In particular we
checked the robustness of the algorithms in different conditions, proving that
the proposed method can reject both disturbance and calibration errors
The Higgs as a Portal to Plasmon-like Unparticle Excitations
A renormalizable coupling between the Higgs and a scalar unparticle operator
O_U of non-integer dimension d_U<2 triggers, after electroweak symmetry
breaking, an infrared divergent vacuum expectation value for O_U. Such IR
divergence should be tamed before any phenomenological implications of the
Higgs-unparticle interplay can be drawn. In this paper we present a novel
mechanism to cure that IR divergence through (scale-invariant) unparticle
self-interactions, which has properties qualitatively different from the
mechanism considered previously. Besides finding a mass gap in the unparticle
continuum we also find an unparticle pole reminiscent of a plasmon resonance.
Such unparticle features could be explored experimentally through their mixing
with the Higgs boson.Comment: 12 LaTeX pages, 2 figure
- …