37,641 research outputs found
New Physics and novel Higgs signals
We review some of the results of our recent work dealing with the novel type
of Higgs signals that arise when one considers extensions of the standard
model.
We discuss first possible deviations on the Higgs couplings due to heavy
particles, in the context of the MSSM and with large extra-dimensions. Then, we
present several models where it is possible to induce flavor violating Higgs
couplings, and probe them at future hadron colliders through the LFV Higgs
decay h-> tau mu or with rare top decays.Comment: Talk given at the X Mexican School of Particles and Fields, Playa del
Carmen, Mexico, 200
Disc atmospheres and winds in X-ray binaries
We review the current status of studies of disc atmospheres and winds in low
mass X-ray binaries. We discuss the possible wind launching mechanisms and
compare the predictions of the models with the existent observations. We
conclude that a combination of thermal and radiative pressure (the latter being
relevant at high luminosities) can explain the current observations of
atmospheres and winds in both neutron star and black hole binaries. Moreover,
these winds and atmospheres could contribute significantly to the broad iron
emission line observed in these systems.Comment: Accepted for publication in Acta Polytechnica. Invited review talk at
the Vulcano Workshop 2012: "Frontier Objects in Astrophysics and Particle
Physics
History state formalism for Dirac's theory
We propose a history state formalism for a Dirac particle. By introducing a
reference quantum clock system it is first shown that Dirac's equation can be
derived by enforcing a timeless Wheeler-DeWitt-like equation for a global
state. The Hilbert space of the whole system constitutes a unitary
representation of the Lorentz group with respect to a properly defined
invariant product, and the proper normalization of global states directly
ensures standard Dirac's norm. Moreover, by introducing a second quantum clock,
the previous invariant product emerges naturally from a generalized continuity
equation. The invariant parameter associated with this second clock
labels history states for different particles, yielding an observable evolution
in the case of an hypothetical superposition of different masses. Analytical
expressions for both space-time density and electron-time entanglement are
provided for two particular families of electron's states, the former including
Pryce localized particles.Comment: 9 pages, 2 figures, final versio
Nonhyperbolic step skew-products: Ergodic approximation
We study transitive step skew-product maps modeled over a complete shift of
, , symbols whose fiber maps are defined on the circle and have
intermingled contracting and expanding regions. These dynamics are genuinely
nonhyperbolic and exhibit simultaneously ergodic measures with positive,
negative, and zero exponents.
We introduce a set of axioms for the fiber maps and study the dynamics of the
resulting skew-product. These axioms turn out to capture the key mechanisms of
the dynamics of nonhyperbolic robustly transitive maps with compact central
leaves.
Focusing on the nonhyperbolic ergodic measures (with zero fiber exponent) of
these systems, we prove that such measures are approximated in the weak
topology and in entropy by hyperbolic ones. We also prove that they are in the
intersection of the convex hulls of the measures with positive fiber exponent
and with negative fiber exponent. Our methods also allow us to perturb
hyperbolic measures. We can perturb a measure with negative exponent directly
to a measure with positive exponent (and vice-versa), however we lose some
amount of entropy in this process. The loss of entropy is determined by the
difference between the Lyapunov exponents of the measures.Comment: 43 pages, 5 figure
- …