607 research outputs found
Hadronic three-body decays of light vector mesons
The decays of light vector mesons into three pseudoscalar mesons are
calculated to leading order in the recently proposed counting scheme that is
based on the hadrogenesis conjecture. Fully differential as well as integrated
decay widths are presented. Since the required parameters have been fixed by
other processes, the considered three-body decays are predictions of the
presented approach. The decay width of the omega meson into three pions agrees
very well with experiment. The partial decay widths of the K^* into its three
K-pi-pi channels are predicted.Comment: 7 page
Properties of the vector meson nonet at large N_c beyond the chiral limit
Masses and especially coupling constants of the vector meson nonet are
determined in the large-N_c limit, but beyond the chiral limit taking into
account terms up to quadratic order in the Goldstone boson masses. With two
input parameters five coupling constants for hadronic and dilepton decays are
determined which agree very well with the experimental results. The obtained
parameters are also used to calculate the pion and kaon decay constant in the
large-N_c limit. A consistent picture is only obtained, if the correct
assignment of the N_c-dependence of the electromagnetic charges of the quarks
is taken into account.Comment: 12 pages, strongly rewritten, more focussed on the central issu
Information on the structure of the a1 from tau decay
The decay is analysed using different methods to
account for the resonance structure, which is usually ascribed to the a1. One
scenario is based on the recently developed techniques to generate axial-vector
resonances dynamically, whereas in a second calculation the a1 is introduced as
an explicit resonance. We investigate the influence of different assumptions on
the result. In the molecule scenario the spectral function is described
surprisingly well by adjusting only one free parameter. This result can be
systematically improved by adding higher order corrections to the iterated
Weinberg-Tomozawa interaction. Treating the a1 as an explicit resonance on the
other hand leads to peculiar properties
Quantum control of the motional states of trapped ions through fast switching of trapping potentials
We propose a new scheme for supplying voltages to the electrodes of
microfabricated ion traps, enabling access to a regime in which changes to the
trapping potential are made on timescales much shorter than the period of the
secular oscillation frequencies of the trapped ions. This opens up
possibilities for speeding up the transport of ions in segmented ion traps and
also provides access to control of multiple ions in a string faster than the
Coulomb interaction between them. We perform a theoretical study of ion
transport using these methods in a surface-electrode trap, characterizing the
precision required for a number of important control parameters. We also
consider the possibilities and limitations for generating motional state
squeezing using these techniques, which could be used as a basis for
investigations of Gaussian-state entanglement.Comment: Accepted by New Journal of Physic
Evaluating chiral symmetry restoration through the use of sum rules
We pursue the idea of assessing chiral restoration via in-medium
modifications of hadronic spectral functions of chiral partners. The usefulness
of sum rules in this endeavor is illustrated, focusing on the vector and
axial-vector channels. We first present an update on constructing quantitative
results for pertinent vacuum spectral functions. These spectral functions serve
as a basis upon which the in-medium spectral functions can be constructed. A
striking feature of our analysis of the vacuum spectral functions is the need
to include excited resonances, dictated by satisfying the Weinberg-type sum
rules. This includes excited states in both the vector and axial-vector
channels. Preliminary results for the finite temperature vector spectral
function are presented. Based on a rho spectral function tested in dilepton
data which develops a shoulder at low energies, we find that the rho' peak
flattens off. The flattening may be a sign of chiral restoration, though a
study of the finite temperature axial-vector spectral function remains to be
carried out.Comment: 9 pages, conference proceedings from Resonance Workshop at UT Austin,
March 5-7 201
Ultrafast process in bacterial antennas studied by nonlinear polarization spectroscopy (frequence domain)
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