3,396 research outputs found
Local and Effective Temperatures of Quantum Driven Systems
We introduce thermometers to define the local temperature of an electronic
system driven out-of-equilibrium by local AC fields. We also define the
effective temperature in terms of a local fluctuation-dissipation-relation. We
show that within the weak driving regime these two temperatures coincide. We
also discuss the behavior of the local temperature along the sample. We show
that it exhibits spatial fluctuations following an oscillatory pattern. For
weak driving, regions of the sample become heated, while others become cooled
as a consequence of the driving
Multi-rate demodulator architecture
A unique digital multi-rate demodulator (MRD) architecture is presented for onboard satellite communications processing. The multi-rate feature enables the same demodulator hardware to process either one wideband channel (WBC), or process up to thirty-two independent narrowband channels (NBC) that are time division multiplexed (TDM). The MRD can process many quadrature modulation format such as offset quadrature phase shift keying (OQPSK). Possible applications include voice and data transmission for commercial or military users
Relation Between Local Temperature Gradients and the Direction of Heat Flow in Quantum Driven Systems
We introduce thermometers to define the local temperature of an electronic
system driven out-of-equilibrium by local ac fields. We discuss the behavior of
the local temperature along the sample, showing that it exhibits spatial
fluctuations following an oscillatory pattern. We show explicitly that the
local temperature is the correct indicator for heat flow.Comment: 3 pages, 2 figure
Observation of a Broad L=1 State in at CLEO
Using 4.7 fb^-1 of data taken at CESR at energies at and near the Upsilon(4S)
we have studied the decay B- -> D{*+}pi-pi- (and its conjugate). We observe a
new, broad charmed meson state, which we interpret as D_J(j=1/2), in its decay
to D{*+}pi-. Our preliminary results indicate the mass and width of this L=1
state to be m = (2461 +41/-3} +/-10 +/-32) MeV and Gamma = (290 +101/-79 +/-26
+/-36) MeV, with the third uncertainty associated with the parameterization of
the relative strong phases. In addition we have measured several new branching
fractions of charged B mesons. All quoted results are preliminary.Comment: 7 pages postscript, also available through
http://w4.lns.cornell.edu/public/CLN
Long distance contribution to , - a searching ground mode for new physics
The decay has been sugested as a test for minimal
supersymmetric standard model and for supersymmetric models with R-parity
violating couplings, in view of its extreme smallnesss in the standard model.
We calculate two long distance contributions to this decay, that associated
with and intermediate states and that induced by virtual ,
mesons. The branching ratio due to these contributions is ,
which is somewhat smaller than the standard model short distance result,
leaving this decay free for the search of new physics.Comment: 13 pages, 2 figures, revised versio
Predictions for the unitarity triangle angles in a new parametrization
A new approach to the parametrization of the CKM matrix, , is considered
in which is written as a linear combination of the unit matrix and a
non-diagonal matrix which causes intergenerational-mixing, that is
. Such a depends on 3 real parameters
including the parameter . It is interesting that a value of
is required to fit the available data on the CKM-matrix
including CP-violation. Predictions of this fit for the angles ,
and for the unitarity triangle corresponding to
, are given. For
=, we obtain , and
. These values are just about in agreement, within errors,
with the present data. It is very interesting that the unitarity triangle is
expected to be approximately a right-angled, isosceles triangle. Our prediction
is in excellent agreement with the value reported by the Belle collaboration at the Lepton-Photon 2001 meeting.Comment: 11 pages, latex, no figure
CP, T and CPT Violations in the K^0 - bar{K^0} System -- Present Status --
Possible violation of CP, T and CPT symmetries in the K^0 - bar{K^0} system
is studied in a way as phenomenological and comprehensive as possible. For this
purpose, we first introduce parameters which represent violation of these
symmetries in mixing parameters and decay amplitudes in a convenient and
well-defined way and, treating these parameters as small, derive formulas which
relate them to the experimentally measured quantities. We then perform
numerical analyses to derive constraints to these symmetry-violating
parameters, with the latest data reported by KTeV Collaboration, NA48
Collaboration and CPLEAR Collaboration, along with those compiled by Particle
Data Group, used as inputs. The result obtained by CPLEAR Collaboration from an
unconstrained fit to a time-dependent leptonic asymmetry, aided by the
Bell-Steinberger relation, enables us to determine or constrain most of the
parameters separately. It is shown among the other things that (1) CP and T
symmetries are violated definitively at least at the level of 10^{-4} in 2 pi
decays, (2) CP and T symmetries are violated at least at the level of 10^{-3}
in the K^0 - bar{K^0} mixing, and (3) CPT symmetry is at present tested to the
level of 10^{-5} at the utmost.Comment: 20 page
Review of Recent Searches for Rare and Forbidden Dilepton Decays of Charmed Mesons
I briefly review the results of recent searches for flavor-changing neutral
current and lepton-flavor and lepton-number violating decays of D+, Ds, and D0
mesons (and their antiparticles) into modes containing muons and electrons. The
primary focus is the results from Fermilab charm hadroproduction experiment
E791. E791 examined 24 pi,l,l and K,l,l decay modes of D+ and Ds and l+l- decay
modes of D0. Limits presented by E791 for 22 rare and forbidden dilepton decays
of D mesons were more stringent than those obtained from previous searches, or
else were the first reported.Comment: 8 pages, 1 figure, uses psfig.sty and RevTeX, submitted to Modern
Physics Letters A, based on a Fermilab "Joint Theoretical and Experimental"
tal
Primordial Nucleosynthesis: Accurate Predictions
A new accurate evaluation of primordial light nuclei abundances is presented.
The proton to neutron conversion rates have been corrected to take into account
radiative effects, finite nucleon mass, thermal and plasma corrections. The
theoretical uncertainty on 4He is so reduced to the order of 0.1%.Comment: 4 pages, Talk given at the International Workshop on Particles in
Astrophysics and Cosmology: From Theory to Observation, Valencia 199
Perturbative QCD Correction to the Light-Cone Sum Rule for the and Couplings
The and couplings have previously been derived from a QCD
light-cone sum rule in leading order. Here, we describe the calculation of the
correction to the twist 2 term of this sum rule. The result is
used for a first next-to-leading order analysis. We obtain and , where the error indicates the remaining
theoretical uncertainty.Comment: 11 pages, 1 figure, Latex, epsfi
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