5,837 research outputs found
Survival before annihilation in Psi-prime decays
We extend the simple scenario for decays suggested a few years ago.
The pair in the does not annihilate directly into three
gluons but rather survives before annihilating. An interesting prediction is
that a large fraction of all decays could originate from the channel which we urge experimentalists to identify. Our model
solves the problem of the apparent hadronic excess in decays as well as
the puzzle since, in our view, the two-body decays of the are
naturally of electromagnetic origin. Further tests of this picture are
proposed, e.g. .Comment: 6 pages, no figur
Hadronic Phases and Isospin Amplitudes in and Decays
Hadronic phase in and channels are calculated a la
Regge. At the D mass one finds and in good agreement with the CLEO data while at the B
mass these angles are predicted to be, respectively, and .
With the hadronic phase taken into account, a quark
diagram decomposition of the isospin invariant amplitudes in
decays fits the data provided the exchange diagram contribution is about 1/3 of
the tree level one.Comment: 10pages,late
Characters of the W3 algebra
Traces of powers of the zero mode in the W3 Algebra have recently been found
to be of interest, for example in relation to Black Hole thermodynamics, and
arise as the terms in an expansion of the full characters of the algebra. We
calculate the first few such powers in two cases. Firstly, we find the traces
in the 3-state Potts model by using null vectors to derive modular differential
equations for the traces. Secondly, we calculate the exact results for Verma
module representations. We compare our two methods with each other and the
result of brute-force diagonalisation for low levels and find complete
agreement.Comment: v2: Numerous small changes, version to appear in JHEP, 22 pages. v3:
Typos corrected, matches published version, 22 page
Controlling the dynamics of a coupled atom-cavity system by pure dephasing : basics and potential applications in nanophotonics
The influence of pure dephasing on the dynamics of the coupling between a
two-level atom and a cavity mode is systematically addressed. We have derived
an effective atom-cavity coupling rate that is shown to be a key parameter in
the physics of the problem, allowing to generalize the known expression for the
Purcell factor to the case of broad emitters, and to define strategies to
optimize the performances of broad emitters-based single photon sources.
Moreover, pure dephasing is shown to be able to restore lasing in presence of
detuning, a further demonstration that decoherence can be seen as a fundamental
resource in solid-state cavity quantum electrodynamics, offering appealing
perspectives in the context of advanced nano-photonic devices.Comment: 10 pages, 7 figure
Final State Interaction Phases in Decay Amplitudes
A simple Regge pole model for scattering explains the large between isospin amplitudes which is observed at the D meson mass
(). It predicts
at the B mass. Implications for () decays and extensions of the
model to other two-body decay channels are briefly discussed.Comment: 8pages,late
Trace anomalies and the rule
Trace Anomaly Dominance in weak -decays successfully reproduces the
selection rule results, as observed in and .Comment: 10 pages, no figur
Pure emitter dephasing : a resource for advanced solid-state single photon sources
We have computed the spectrum emitted spontaneously by a quantum dot coupled
to an arbitrarily detuned single mode cavity, taking into account pure
dephasing processes. We show that if the emitter is incoherent, the cavity can
efficiently emit photons with its own spectral characteristics. This effect
opens unique opportunities for the development of devices exploiting both
cavity quantum electrodynamics effects and pure dephasing, such as wavelength
stabilized single photon sources robust against spectral diffusion.Comment: 5 pages, 3 figure
Electric field sensing with a scanning fiber-coupled quantum dot
We demonstrate the application of a fiber-coupled quantum-dot-in-a-tip as a
probe for scanning electric field microscopy. We map the out-of-plane component
of the electric field induced by a pair of electrodes by measurement of the
quantum-confined Stark effect induced on a quantum dot spectral line. Our
results are in agreement with finite element simulations of the experiment.
Furthermore, we present results from analytic calculations and simulations
which are relevant to any electric field sensor embedded in a dielectric tip.
In particular, we highlight the impact of the tip geometry on both the
resolution and sensitivity.Comment: 10 pages, 4 figure
Phases and Amplitudes in Inclusive and Decays
In inclusive decays of the (3097), electromagnetic and gluonic
annihilation amplitudes add incoherently, namely they are 90 out of
phase. We argue that this incoherence must persist in each exclusive decay
channel. For inclusive (3686) decays, we suggest the absence of a
significant direct annihilation amplitude into three gluons and propose a new
amplitude via QCD anomalies and the (3526) off shell. Phenomenological
implications for exclusive decay channels are pointed out.Comment: 10 page
Non-Arrhenius conduction due to the interface-trap-induced disorder in X-doped amorphous InXZnO thin-film transistors
Thin film transistors, with channels composed of In-X-Zn oxides, IXZO, with X
dopants: Ga, Sb, Be, Mg, Ag, Ca, Al, Ni, and Cu, were fabricated and their I-V
characteristics were taken at selected temperatures in the 77K<T<300K range.
The low field mobility, mu, and the interface defect density, Nst were
extracted from the characteristics for each of the studied IXZOs. At higher T
the mobility follows the Arrhenius law with an upward distortion, increasing as
T was lowered, gradually transforming into the exp [-(T0/T)1/4] variation. We
showed that mu(T, Nst) follows mu0exp[-Eaeff(T,Nst)/kT], with T-dependent
effective activation energy Eaeff(T, Nst) accounts for the data, revealing a
linear correlation between Eaeff and Nst at higher T. Temperature variation of
Eaeff(T, Nst) was evaluated using a model assuming a random distribution of
conduction mobility edge Ec values in the oxides, stemming from spatial
fluctuations induced by disorder in the interface traps distribution. For a
Gaussian distribution of Ec, the activation energy Eaeff(T, Nst) varies
linearly with 1/T, which accounts satisfactorily for the data obtained on all
the studied IXZOs. The model also shows that Eaeff(T, Nst) is a linear function
of Nst at a fixed T, which explains the exponential decrease of mu with NST
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