1,307 research outputs found
Radiation-hard ASICs for optical data transmission in the ATLAS pixel detector
We have developed two radiation-hard ASICs for optical data transmission in
the ATLAS pixel detector at the LHC at CERN: a driver chip for a Vertical
Cavity Surface Emitting Laser (VCSEL) diode for 80 Mbit/s data transmission
from the detector, and a Bi-Phase Mark decoder chip to recover the control data
and 40 MHz clock received optically by a PIN diode. We have successfully
implemented both ASICs in 0.25 um CMOS technology using enclosed layout
transistors and guard rings for increased radiation hardness. We present
results from prototype circuits and from irradiation studies with 24 GeV
protons up to 57 Mrad (1.9 x 10e15 p/cm2).Comment: 8th Tropical Seminar on Innovative Particle and Radiation Detectors,
Siena, Italy (2002
Effects of manipulating hypothalamic triiodothyronine concentrations on seasonal body weight and torpor cycles in siberian hamsters
Peer reviewedPublisher PD
ATLAS Pixel Opto-Electronics
We have developed two radiation-hard ASICs for optical data transmission in
the ATLAS pixel detector at the LHC at CERN: a driver chip for a Vertical
Cavity Surface Emitting Laser (VCSEL) diode for 80 Mbit/s data transmission
from the detector, and a Bi-Phase Mark decoder chip to recover the control data
and 40 MHz clock received optically by a PIN diode. We have successfully
implemented both ASICs in 0.25 micron CMOS technology using enclosed layout
transistors and guard rings for increased radiation hardness. We present
results of the performance of these chips, including irradiation with 24 GeV
protons up to 61 Mrad (2.3 x 10e15 p/cm^2).Comment: 17 pages, 23 figures, submitted to NIM Added references. Added figure
15. Moved sec. IV to sec. I
Determination of the Michel Parameters and the tau Neutrino Helicity in tau Decay
Using the CLEO II detector at the storage ring CESR, we have
determined the Michel parameters , , and in decay as well as the tau neutrino helicity parameter
in decay. From a data sample of
tau pairs produced at , using events of
the topology and , and the determined sign of , the combined
result of the three samples is: , , , and
. The results are in agreement with
the Standard Model V-A interaction.Comment: 18 page postscript file, postscript file also available through
http://w4.lns.cornell.edu/public/CLN
Observation of a New Charmed Strange Meson
Using the CLEO-II detector, we have obtained evidence for a new meson
decaying to . Its mass is
{}~MeV/ and its width is ~MeV/. Although we do not
establish its spin and parity, the new meson is consistent with predictions for
an , , charmed strange state.Comment: 9 pages uuencoded compressed postscript (process with uudecode then
gunzip). hardcopies with figures can be obtained by sending mail to:
[email protected]
Precision Measurement of the Mass Difference
We have measured the vector-pseudoscalar mass splitting , significantly more precise than the previous
world average. We minimize the systematic errors by also measuring the
vector-pseudoscalar mass difference using the radiative
decay , obtaining
. This is
then combined with our previous high-precision measurement of
, which used the decay . We also
measure the mass difference MeV, using the
decay modes of the and mesons.Comment: 18 pages uuencoded compressed postscript (process with uudecode then
gunzip). hardcopies with figures can be obtained by sending mail to:
[email protected]
Study of the q^2-Dependence of B --> pi ell nu and B --> rho(omega)ell nu Decay and Extraction of |V_ub|
We report on determinations of |Vub| resulting from studies of the branching
fraction and q^2 distributions in exclusive semileptonic B decays that proceed
via the b->u transition. Our data set consists of the 9.7x10^6 BBbar meson
pairs collected at the Y(4S) resonance with the CLEO II detector. We measure
B(B0 -> pi- l+ nu) = (1.33 +- 0.18 +- 0.11 +- 0.01 +- 0.07)x10^{-4} and B(B0 ->
rho- l+ nu) = (2.17 +- 0.34 +0.47/-0.54 +- 0.41 +- 0.01)x10^{-4}, where the
errors are statistical, experimental systematic, systematic due to residual
form-factor uncertainties in the signal, and systematic due to residual
form-factor uncertainties in the cross-feed modes, respectively. We also find
B(B+ -> eta l+ nu) = (0.84 +- 0.31 +- 0.16 +- 0.09)x10^{-4}, consistent with
what is expected from the B -> pi l nu mode and quark model symmetries. We
extract |Vub| using Light-Cone Sum Rules (LCSR) for 0<= q^2<16 GeV^2 and
Lattice QCD (LQCD) for 16 GeV^2 <= q^2 < q^2_max. Combining both intervals
yields |Vub| = (3.24 +- 0.22 +- 0.13 +0.55/-0.39 +- 0.09)x10^{-3}$ for pi l nu,
and |Vub| = (3.00 +- 0.21 +0.29/-0.35 +0.49/-0.38 +-0.28)x10^{-3} for rho l nu,
where the errors are statistical, experimental systematic, theoretical, and
signal form-factor shape, respectively. Our combined value from both decay
modes is |Vub| = (3.17 +- 0.17 +0.16/-0.17 +0.53/-0.39 +-0.03)x10^{-3}.Comment: 45 pages postscript, also available through
http://w4.lns.cornell.edu/public/CLNS, submitted to PR
Semileptonic Branching Fraction of Charged and Neutral B Mesons
An examination of leptons in events tagged by reconstructed
decays yields semileptonic branching fractions of for charged and for neutral mesons.
This is the first measurement for charged . Assuming equality of the charged
and neutral semileptonic widths, the ratio is
equivalent to the ratio of lifetimes. A postscript version is available through
World-Wide-Web in http://w4.lns.cornell.edu/public/CLNS/1994Comment: 9 pages (in REVTEX format) Preprint CLNS94-1286, CLEO 94-1
Two-Body B Meson Decays to and -- Observation of {'}K$
In a sample of 6.6 million produced B mesons we have observed decays B ->
eta' K, with branching fractions BR(B+ -> eta' K+ = 6.5 +1.5 -1.4 +- 0.9) x
and BR(B0 -> eta' K0 = 4.7 +2.7 -2.0 +- 0.9) x . We have
searched with comparable sensitivity for 17 related decays to final states
containing an eta or eta' meson accompanied by a single particle or low-lying
resonance. Our upper limits for these constrain theoretical interpretations of
the B -> eta' K signal.Comment: 12 page postscript file, postscript file also available through
http://w4.lns.cornell.edu/public/CLN
Branching Fractions of tau Leptons to Three Charged Hadrons
From electron-positron collision data collected with the CLEO detector
operating at CESR near \sqrt{s}=10.6 GeV, improved measurements of the
branching fractions for tau decays into three explicitly identified hadrons and
a neutrino are presented as {\cal
B}(\tau^-\to\pi^-\pi^+\pi^-\nu_\tau)=(9.13\pm0.05\pm0.46)%, {\cal B}(\tau^-\to
K^-\pi^+\pi^-\nu_\tau)=(3.84\pm0.14\pm0.38)\times10^{-3}, {\cal B}(\tau^-\to
K^-K^+\pi^-\nu_\tau)=(1.55\pm0.06\pm0.09)\times10^{-3}, and {\cal B}(\tau^-\to
K^-K^+K^-\nu_\tau)<3.7\times10^{-5} at 90% C.L., where the uncertainties are
statistical and systematic, respectively.Comment: 10 pages postscript, also available through
http://w4.lns.cornell.edu/public/CLNS, to appear in Phys. Rev. Let
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