4,753 research outputs found
Reparametrization Invariance Constraints on Inclusive Decay Spectra and Masses
Reparametrization invariance relations are determined for the inclusive decay
spectra of heavy hadrons. They connect the leading order result to the lambda_1
term, and the lambda_2 and rho_2 terms, and imply that the lambda_1 and rho_2
terms in the total rate occur in the combinations 1+lambda_1/(2m_Q^2) and
lambda_2-rho_2/m_Q. The relations are satisfied by the known results for the
hadronic decay tensors for B -> X e nu, B -> X gamma and B -> X e+ e- decays.
An interesting field-theory result, the connection between currents in full and
effective theories and the change in currents under field redefinitions, is
discussed. The hadron masses are given to order (Lambda_QCD)^3/m_Q^2 including
radiative corrections, and provide an example illustrating the relation between
renormalization and reparametrization invariance and mu-independence of 1/m_Q^3
corrections to physical quantities.Comment: 8 page
-Frequent hypercyclicity in spaces of operators
We provide conditions for a linear map of the form to be
-frequently hypercyclic on algebras of operators on separable Banach spaces.
In particular, if is a bounded operator satisfying the -Frequent
Hypercyclicity Criterion, then the map = is shown to be
-frequently hypercyclic on the space of all compact
operators and the real topological vector space of all
self-adjoint operators on a separable Hilbert space . Further we provide a
condition for to be -frequently hypercyclic on the Schatten von
Neumann classes . We also characterize frequent hypercyclicity of
on the trace-class of the Hardy space, where the
symbol denotes the multiplication operator associated to .Comment: The previous version has been changed considerably with many
corrections rectifie
Renormalization Group Scaling of the 1/m^2 HQET Lagrangian
The operator mixing matrix for the dimension six operators in the heavy quark
effective theory Lagrangian is computed at one loop. The results are shown to
be consistent with constraints from the equations of motion, and from
reparametrization invariance.Comment: 8 pages, revte
The Nucleon-Nucleon Potential in the 1/N_c Expansion
The nucleon-nucleon potential is analysed using the 1/N_c expansion of QCD.
The NN potential is shown to have an expansion in 1/N_c^2, and the strengths of
the leading order central, spin-orbit, tensor, and quadratic spin-orbit forces
(including isospin dependence) are determined. Comparison with a successful
phenomenological potential (Nijmegen) shows that the large-N_c analysis
explains many of the qualitative features observed in the nucleon-nucleon
interaction. The 1/N_c expansion implies an effective Wigner supermultiplet
symmetry for light nuclei. Results for baryons containing strange quarks are
presented in an appendix.Comment: 17 pages, 3 figures, TeX, macros harvmac and eps
Deep inelastic scattering as x -> 1 using soft-collinear effective theory
Soft-collinear effective theory (SCET) is used to sum Sudakov
double-logarithms in the x ->1 endpoint region for the deep inelastic
scattering structure function. The calculations are done in both the target
rest frame and the Breit frame. The separation of scales in the effective
theory implies that the anomalous dimension of the SCET current is linear in ln
mu, and the anomalous dimension for the Nth moment of the structure function is
linear in ln N, to all orders in perturbation theory. The SCET formulation is
shown to be free of Landau pole singularities. Some important differences
between the deep inelastic structure function and the shape function in B decay
are discussed.Comment: 19 pages, minor typos fixed, and a comment added on the longitudinal
structure functio
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