8,566 research outputs found
Technicolor contribution to lepton + photon + missing energy events at the Tevatron
Events with one lepton, one photon and missing energy are the subject of
recent searches at the Fermilab Tevatron. We compute possible contributions to
these type of events from the process p pbar --> photon l nu_l nu_tau
nubar_tau, where l=e,mu in the context of a Low Scale Technicolor Model. We
find that with somewhat tighter cuts than the ones used in the CDF search, it
could be possible to either confirm or exclude this model in a small region of
its parameter space.Comment: 4 pages, 3 figures. Improved text and figures, including comments and
new reference
Constraints on a scalar-pseudoscalar Higgs mixing at future e+e- colliders: an update
We perform an update of our previous analysis on the constraints on possible
deviations of Hbb coupling from its Standard Model value, arising from a
scalar-pseudoscalar mixing. In this paper we include a complete simulation of
the process e+ e- -> b bbar e+ e- and combine it with our previous results to
obtain tighter bounds on the deviations of the parameters describing this
coupling that could be measured at the Next Linear Collider.Comment: 3 pages, 2 figures, to be submitted to Phys. Rev.
Depletion potential in hard-sphere mixtures: theory and applications
We present a versatile density functional approach (DFT) for calculating the
depletion potential in general fluid mixtures. In contrast to brute force DFT,
our approach requires only the equilibrium density profile of the small
particles {\em before} the big (test) particle is inserted. For a big particle
near a planar wall or a cylinder or another fixed big particle the relevant
density profiles are functions of a single variable, which avoids the numerical
complications inherent in brute force DFT. We implement our approach for
additive hard-sphere mixtures. By investigating the depletion potential for
high size asymmetries we assess the regime of validity of the well-known
Derjaguin approximation for hard-sphere mixtures and argue that this fails. We
provide an accurate parametrization of the depletion potential in hard-sphere
fluids which should be useful for effective Hamiltonian studies of phase
behavior and colloid structure
Lattice density-functional theory of surface melting: the effect of a square-gradient correction
I use the method of classical density-functional theory in the
weighted-density approximation of Tarazona to investigate the phase diagram and
the interface structure of a two-dimensional lattice-gas model with three
phases -- vapour, liquid, and triangular solid. While a straightforward
mean-field treatment of the interparticle attraction is unable to give a stable
liquid phase, the correct phase diagram is obtained when including a suitably
chosen square-gradient term in the system grand potential. Taken this theory
for granted, I further examine the structure of the solid-vapour interface as
the triple point is approached from low temperature. Surprisingly, a novel
phase (rather than the liquid) is found to grow at the interface, exhibiting an
unusually long modulation along the interface normal. The conventional
surface-melting behaviour is recovered only by artificially restricting the
symmetries being available to the density field.Comment: 16 pages, 6 figure
A new signature for color octet pseudoscalars at the LHC
Color octet (pseudo)scalars, if they exist, will be copiously produced at the
CERN Large Hadron Collider (LHC). However, their detection can become a very
challenging task. In particular, if their decay into a pair of top quarks is
kinematically forbidden, the main decay channel would be into two jets, with a
very large background. In this Brief Report we explore the possibility of using
anomaly-induced decays of the color octet pseudoscalars into gauge bosons to
find them at the LHC.Comment: 4 pages, 2 figures. New references adde
Three Jet Events and New Strong Couplings at LEP and NLC
We study the effects of new dimension--6 operators, resulting from a general
invariant effective Lagrangian, on
three jet production at LEP and at the Next Linear Collider. Contributions to
the total event rate and to some event shape variables are analysed in order to
establish bounds on these operators.Comment: 5 pages, LaTeX, 1 Figur
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