2,950 research outputs found
D_{sJ}(2860) as the first radial excitation of the D_{s0}^*(2317)
A coupled-channel model previously employed to describe the narrow
(2317) and broad (2400) charmed scalar mesons is generalized
so as to include all ground-state pseudoscalar-pseudoscalar and vector-vector
two-meson channels. All parameters are chosen fixed at published values, except
for the overall coupling constant, which is fine-tuned to reproduce the
(2317) mass. Thus, the radial excitations (2850) and
(2740) are predicted, both with a width of about 50 MeV. The former
state appears to correspond to the new (2860) resonance decaying to
announced by BABAR in the course of this work. Also the (2400)
resonance is roughly reproduced, though perhaps with a somewhat too low central
resonance peak.Comment: Plain LaTeX, 4 pages, 2 Postscript figures; v2: REVTeX, 4 pages,
introduction expanded, "Note added in proof" and references added, figures
with more detail and improved quality, version accepted for publication in
Physical Review Letter
Constituent and current quark masses at low chiral energies
Light constituent quark masses and the corresponding dynamical quark masses
are determined by data, the Quark-Level Linear Model, and infrared
QCD. This allows to define effective nonstrange and strange current quark
masses which reproduce the experimental pion and kaon masses very accurately,
by simple additivity. Moreover, the masses of the light scalar mesons
and can be obtained straightforwardly from the
constituent quark masses. In contrast, the usual nonstrange and strange current
quark masses employed by Chiral Perturbation Theory do not allow a simple
quantitative explanation of the pion and kaon masses.Comment: 5 pages, EPL style, accepted for publication in Europhys. Let
Light Higgs bosons from a strongly interacting Higgs sector
The mass and the decay width of a Higgs boson in the minimal standard model
are evaluated by a variational method in the limit of strong self-coupling
interaction. The non-perturbative technique provides an interpolation scheme
between strong-coupling regime and weak-coupling limit where the standard
perturbative results are recovered. In the strong-coupling limit the physical
mass and the decay width of the Higgs boson are found to be very small as a
consequence of mass renormalization. Thus it is argued that the eventual
detection of a light Higgs boson would not rule out the existence of a strongly
interacting Higgs sector.Comment: 2 figure
Photon-propagation model with random background field: Length scales and Cherenkov limits
We present improved experimental bounds on typical length scales of a
photon-propagation model with a frozen (time-independent) random background
field, which could result from anomalous effects of a static, multiply
connected spacetime foam.Comment: 6 pages with revtex4; v3: final versio
Energy efficiency of mmWave massive MIMO precoding with low-resolution DACs
With the congestion of the sub-6 GHz spectrum, the interest in massive
multiple-input multiple-output (MIMO) systems operating on millimeter wave
spectrum grows. In order to reduce the power consumption of such massive MIMO
systems, hybrid analog/digital transceivers and application of low-resolution
digital-to-analog/analog-to-digital converters have been recently proposed. In
this work, we investigate the energy efficiency of quantized hybrid
transmitters equipped with a fully/partially-connected phase-shifting network
composed of active/passive phase-shifters and compare it to that of quantized
digital precoders. We introduce a quantized single-user MIMO system model based
on an additive quantization noise approximation considering realistic power
consumption and loss models to evaluate the spectral and energy efficiencies of
the transmit precoding methods. Simulation results show that
partially-connected hybrid precoders can be more energy-efficient compared to
digital precoders, while fully-connected hybrid precoders exhibit poor energy
efficiency in general. Also, the topology of phase-shifting components offers
an energy-spectral efficiency trade-off: active phase-shifters provide higher
data rates, while passive phase-shifters maintain better energy efficiency.Comment: Published in IEEE Journal of Selected Topics in Signal Processin
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