9,760 research outputs found
Lower limit in semiclassical form for the number of bound states in a central potential
We identify a class of potentials for which the semiclassical estimate
of
the number of (S-wave) bound states provides a (rigorous) lower limit:
, where the double braces denote the integer part.
Higher partial waves can be included via the standard replacement of the
potential with the effective -wave potential
. An analogous upper
limit is also provided for a different class of potentials, which is however
quite severely restricted.Comment: 9 page
Upper limit on the critical strength of central potentials in relativistic quantum mechanics
In the context of relativistic quantum mechanics, where the Schr\"odinger
equation is replaced by the spinless Salpeter equation, we show how to
construct a large class of upper limits on the critical value,
, of the coupling constant, , of the central potential,
. This critical value is the value of for which a first
-wave bound state appears.Comment: 8 page
Lower bounds for the spinless Salpeter equation
We obtain lower bounds on the ground state energy, in one and three
dimensions, for the spinless Salpeter equation (Schr\"odinger equation with a
relativistic kinetic energy operator) applicable to potentials for which the
attractive parts are in for some ( or 3). An extension
to confining potentials, which are not in , is also presented.Comment: 11 pages, 2 figures. Contribution to a special issue of Journal of
Nonlinear Mathematical Physics in honour of Francesco Calogero on the
occasion of his seventieth birthda
Upper limit on the number of bound states of the spinless Salpeter equation
We obtain, using the Birman-Schwinger method, upper limits on the total
number of bound states and on the number of -wave bound states of the
semirelativistic spinless Salpeter equation. We also obtain a simple condition,
in the ultrarelativistic case (), for the existence of at least one
-wave bound states: , where is a known function of and
.Comment: 18 page
B decays to final states including D_s^{(*)} and D^*
The e^+e^- annihilation data recorded with the BABAR detector has been used
to study B decays to D_s^(*) and D^* mesons. The production fraction of
inclusive D_s^(*) and the corresponding momentum spectra have been determined.
Exclusive decays B^0 --> D^{*-}D_s^{(*)+} have been identified with a partial
reconstruction technique and their branching fractions have been measured. We
also report branching fraction measurements for the exclusive hadronic modes
B^0 --> D^{*-} pi^+ and B^0 --> D^{*-} rho^+.Comment: 5 pages, 4 postscript figures, contributed paper to DPF200
Scattering solutions of the spinless Salpeter equation
A method to compute the scattering solutions of a spinless Salpeter equation
(or a Schrodinger equation) with a central interaction is presented. This
method relies on the 3-dimensional Fourier grid Hamiltonian method used to
compute bound states. It requires only the evaluation of the potential at
equally spaced grid points and yields the radial part of the scattering
solution at the same grid points. It can be easily extended to the case of
coupled channel equations and to the case of non-local interactions.Comment: 7 page
A Measurement of the Ratio of the W + 1 Jet to Z + 1 Jet Cross Sections with ATLAS
The measurement of hadronic activity recoiling against W and Z vector bosons
provides an important test of perturbative QCD, as well as a method of
searching for new physics in a model independent fashion. We present a study of
the cross-section ratio for the production of W and Z gauge bosons in
association with exactly one jet Rjet = {\sigma}(W + 1jet)/{\sigma}(Z + 1jet),
in pp collisions at \surds = 7 TeV. The study is performed in the electron and
muon channels with data collected with the ATLAS detector at the LHC. The ratio
Rjet is studied as a function of the cumulative transverse momentum
distribution of the jet. This result can be compared to NLO pQCD calculations
and the prediction from LO matrix element + parton shower generators.Comment: 8 pages, 4 figures, conference proceedings for DPF 201
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