5,789 research outputs found
Higher triplet state of fullerene C70 revealed by electron spin relaxation
Spin-lattice relaxation timesT1 of photoexcited triplets 3C70 in glassy
decalin were obtained from electron spin echo inversion recovery dependences.
In the range 30–100 K, the temperature dependence of T1 was fitted by the
Arrhenius law with an activation energy of 172 cm−1. This indicates that the
dominant relaxation process of 3C70 is described by an Orbach-Aminov mechanism
involving the higher triplet state t2 which lies 172 cm−1 above the lowest
triplet state t1. Chemical modification of C70fullerene not only decreases the
intrinsic triplet lifetime by about ten times but also increases T1 by several
orders of magnitude. The reason for this is the presence of a low-lying
excited triplet state in 3C70 and its absence in triplet C70 derivatives. The
presence of the higher triplet state in C70 is in good agreement with the
previous results from phosphorescence spectroscopy
Real-Time Data Processing in the Muon System of the D0 Detector
This paper presents a real-time application of the 16-bit fixed point Digital
Signal Processors (DSPs), in the Muon System of the D0 detector located at the
Fermilab Tevatron, presently the world's highest-energy hadron collider. As
part of the Upgrade for a run beginning in the year 2000, the system is
required to process data at an input event rate of 10 KHz without incurring
significant deadtime in readout. The ADSP21csp01 processor has high I/O
bandwidth, single cycle instruction execution and fast task switching support
to provide efficient multisignal processing. The processor's internal memory
consists of 4K words of Program Memory and 4K words of Data Memory. In addition
there is an external memory of 32K words for general event buffering and 16K
words of Dual Port Memory for input data queuing. This DSP fulfills the
requirement of the Muon subdetector systems for data readout. All error
handling, buffering, formatting and transferring of the data to the various
trigger levels of the data acquisition system is done in software. The
algorithms developed for the system complete these tasks in about 20
microseconds per event.Comment: 4 pages, Presented and published at the 11th IEEE NPSS Real Time
Conference, held at Santa Fe, New Mexico, USA, from June 14-18, 199
Finite Temperature QCD with Two Flavors of Non-perturbatively Improved Wilson Fermions
We study QCD with two flavors of non-perturbatively improved Wilson fermions
at finite temperature on the lattice. We determine the transition
temperature at lattice spacings as small as fm, and study string
breaking below the finite temperature transition. We find that the static
potential can be fitted by a two-state ansatz, including a string state and a
two-meson state. We investigate the role of Abelian monopoles at finite
temperature.Comment: 29 pages, 22 figures, Late
Measurement of the decay form factors in the OKA experiment
A precise measurement of the vector and axial-vector form factors difference
in the decay is presented.
About 95K events of are selected in
the OKA experiment. The result is .
Both errors are smaller than in the previous measurements.Comment: 9 pages, 8 figure
- …