304 research outputs found
Empirical central limit theorems for ergodic automorphisms of the torus
Let T be an ergodic automorphism of the d-dimensional torus T^d, and f be a
continuous function from T^d to R^l. On the probability space T^d equipped with
the Lebesgue-Haar measure, we prove the weak convergence of the sequential
empirical process of the sequence (f o T^i)_{i \geq 1} under some mild
conditions on the modulus of continuity of f. The proofs are based on new limit
theorems and new inequalities for non-adapted sequences, and on new estimates
of the conditional expectations of f with respect to a natural filtration.Comment: 32 page
Standard Model Baryogenesis
Simply on CP arguments, we argue against a Standard Model explanation of
baryogenesis via the charge transport mechanism. A CP-asymmetry is found in the
reflection coefficients of quarks hitting the electroweak phase boundary
created during a first order phase transition. The problem is analyzed both in
an academic zero temperature case and in the realistic finite temperature one.
At finite temperature, a crucial role is played by the damping rate of
quasi-quarks in a hot plasma, which induces loss of spatial coherence and
suppresses reflection on the boundary even at tree-level. The resulting baryon
asymmetry is many orders of magnitude below what observation requires. We
comment as well on related works.Comment: 10 pages, CERN-TH. 7368/94, LPTHE Orsay-94/71, HD-THEP-94-2
Uraltsev Sum Rule in Bakamjian-Thomas Quark Models
We show that the sum rule recently proved by Uraltsev in the heavy quark
limit of QCD holds in relativistic quark models \`a la Bakamjian and Thomas,
that were already shown to satisfy Isgur-Wise scaling and Bjorken sum rule.
This new sum rule provides a {\it rationale} for the lower bound of the slope
of the elastic IW function obtained within the BT
formalism some years ago. Uraltsev sum rule suggests an inequality
. This difference is interpreted in the BT
formalism as due to the Wigner rotation of the light quark spin, independently
of a possible LS force. In BT models, the sum rule convergence is very fast,
the state giving the essential contribution in most of the
phenomenological potential models. We underline that there is a serious
problem, in the heavy quark limit of QCD, between theory and experiment for the
decays , independently of any model
calculation.Comment: 16 pages, Late
On the IR behaviour of the Landau-gauge ghost propagator
We examine analytically the ghost propagator Dyson-Schwinger Equation (DSE)
in the deep IR regime and prove that a finite ghost dressing function at
vanishing momentum is an alternative solution (solution II) to the usually
assumed divergent one (solution I). We furthermore find that the Slavnov-Taylor
identities discriminate between these two classes of solutions and strongly
support the solution II. The latter turns out to be also preferred by lattice
simulations within numerical uncertainties.Comment: 15 pages, Axodraw neede
Gluon propagator, triple gluon vertex and the QCD coupling constant
We study the UV-scaling of the flavorless gluon propagator in the Landau
gauge in an energy window up to 9 GeV. Dominant hypercubic lattice artifacts
are eliminated. A large set of renormalization schemes is used to test
asymptotic scaling. We compare with our results obtained directly from the
triple gluon vertex. We end-up with \Lambda_{\bar{\rm{MS}}} = 318(12)(5) MeV
and 292(5)(15) MeV respectively for these two methods, compatible which each
other but significantly above the Schrodinger method estimate.Comment: 3 pages, LaTeX with two figures; presented at LATTICE9
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