119,664 research outputs found
Extreme values for Benedicks-Carleson quadratic maps
We consider the quadratic family of maps given by with
, where is a Benedicks-Carleson parameter. For each of these
chaotic dynamical systems we study the extreme value distribution of the
stationary stochastic processes , given by , for
every integer , where each random variable is distributed
according to the unique absolutely continuous, invariant probability of .
Using techniques developed by Benedicks and Carleson, we show that the limiting
distribution of is the same as that which would
apply if the sequence was independent and identically
distributed. This result allows us to conclude that the asymptotic distribution
of is of Type III (Weibull).Comment: 18 page
Exploring RNA-targeted gene therapy approaches for hypertrophic cardiomyopathy
Relatório de projeto no âmbito do Programa de Bolsas Universidade de Lisboa/Fundação Amadeu Dias (2011/2012). Universidade de Lisboa. Faculdade de Medicin
Two-loop fermionic electroweak corrections to the Z-boson width and production rate
Improved predictions for the Z-boson decay width and the hadronic Z-peak
cross-section within the Standard Model are presented, based on a complete
calculation of electroweak two-loop corrections with closed fermion loops.
Compared to previous partial results, the predictions for the Z width and
hadronic cross-section shift by about 0.6 MeV and 0.004 nb, respectively.
Compact parametrization formulae are provided, which approximate the full
results to better than 4 ppm.Comment: 7 pages; v2: few typos fixed and minor corrections of numbers in
table
On minimal eigenvalues of Schrodinger operators on manifolds
We consider the problem of minimizing the eigenvalues of the Schr\"{o}dinger
operator H=-\Delta+\alpha F(\ka) () on a compact manifold
subject to the restriction that \ka has a given fixed average \ka_{0}.
In the one-dimensional case our results imply in particular that for
F(\ka)=\ka^{2} the constant potential fails to minimize the principal
eigenvalue for \alpha>\alpha_{c}=\mu_{1}/(4\ka_{0}^{2}), where is
the first nonzero eigenvalue of . This complements a result by Exner,
Harrell and Loss (math-ph/9901022), showing that the critical value where the
circle stops being a minimizer for a class of Schr\"{o}dinger operators
penalized by curvature is given by . Furthermore, we show that the
value of remains the infimum for all . Using
these results, we obtain a sharp lower bound for the principal eigenvalue for a
general potential.
In higher dimensions we prove a (weak) local version of these results for a
general class of potentials F(\ka), and then show that globally the infimum
for the first and also for higher eigenvalues is actually given by the
corresponding eigenvalues of the Laplace-Beltrami operator and is never
attained.Comment: 7 page
Distinguishing Majorana and Dirac Gluinos and Neutralinos
While gluinos and neutralinos are Majorana fermions in the MSSM, they can be
Dirac fermion fields in extended supersymmetry models. The difference between
the two cases manifests itself in production and decay processes at colliders.
In this contribution, results are presented for how the Majorana or Dirac
nature of gluinos and neutralinos can be extracted from di-lepton signals at
the LHC.Comment: 4 pages; to appear in the proceedings of the 17th International
Conference on Supersymmetry and the Unification of Fundamental Interactions
(SUSY09), Boston, USA, 5-10 Jun 200
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