6,273 research outputs found
Hyperon weak radiative decays in chiral perturbation theory
We investigate the leading-order amplitudes for weak radiative decays of
hyperons in chiral perturbation theory. We consistently include contributions
from the next-to-leading order weak-interaction Lagrangian. It is shown that
due to these terms Hara's theorem is violated. The data for the decays of
charged hyperons can be easily accounted for. However, at this order in the
chiral expansion, the four amplitudes for the decays of neutral hyperons
satisfy relations which are in disagreement with the data. The asymmetry
parameters for all the decays can not be accounted for without higher-order
terms. We shortly comment on the effect of the 27-plet part of the weak
interaction.Comment: 8 pages of REVTeX and using macro-package "feynman.tex" (available at
http://xxx.lanl.gov/ftp/hep-ph/papers/macros) for the 2 figure
АСПЕКТЫ ПРИМЕНЕНИЯ ИНДОМЕТАЦИНА В МЕДИЦИНЕ И ФАРМАЦИИ
Indomethacin, a non-steroid anti-inflammatory drug (NSAID), has been used in different spheres of medicine since the 1960s. It is successfully administered as an anti-inflammatory and pain-relieving medication in rheumatoid and other diseases. According to recent research, indomethacin may become a promising drug enhancing endogenous remyelination in patients with multiple sclerosis. Also, indomethacin affects cell proliferation and invasion, thus it is used to manage pancreatic cancer in patients with hyperglycemia. In addition, indomethacin can inhibit protein synthesis in colorectal carcinoma and other types of cancer cells. The article reviews modern indomethacin medications and the different dosage forms on the Russian pharmaceutical market. Indomethacin poor water solubility is one of the reasons for decreasing its biopharmaceutical characteristics. According to the conducted research, a prospective way to improve indomethacin solubility and bioavailability is the Solid Dispersion (SD) method. SDs are bi- or multicomponent systems consisting of the drug and the carrier. They are a highly dispersed solid phase of the drug or molecular-dispersed solid solutions with a partial formation of a variable composition complex and a carrier. The article provides a brief overview on different aspects of obtaining, investigating, and applying indomethacin SDs with various polymers.Синтезированный в шестидесятых годах прошлого столетия типичный представитель класса нестероидных противовоспалительных средств индометацин нашел широкое применение в различных областях медицины. Сочетание противовоспалительного и обезболивающего действия обусловило успешное применение индометацина при ревматических заболеваниях. Новейшие исследования выявили, что препарат может стать перспективным средством и в терапии ряда иных патологий. В статье приведен краткий обзор ассортимента современных препаратов и различных лекарственных форм индометацина на отечественном фармацевтическом рынке. Одним из факторов, снижающих биофармацевтические характеристики препаратов индометацина, является его малая растворимость в воде. Согласно результатам анализа литературных данных, одной из перспективных технологий, способных успешно увеличить растворимость и биодоступность индометацина, является метод получения его твердых дисперсий. Твердые дисперсии ― это би- или многокомпонентные системы из лекарственного вещества и носителя, представляющие собой высокодиспергированную твердую фазу лекарственного вещества или молекулярно-дисперсные твердые или жидкие растворы с частичным образованием комплексов переменного состава с материалом носителя. Представлен краткий обзор работ, посвященных различным аспектам получения, исследования и применения твердых дисперсий индометацина с разными полимерами-носителями
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
Production and Decay of D_1(2420)^0 and D_2^*(2460)^0
We have investigated and final states and
observed the two established charmed mesons, the with mass
MeV/c and width MeV/c and
the with mass MeV/c and width
MeV/c. Properties of these final states, including
their decay angular distributions and spin-parity assignments, have been
studied. We identify these two mesons as the doublet predicted
by HQET. We also obtain constraints on {\footnotesize } as a function of the cosine of the relative phase of the two
amplitudes in the decay.Comment: 15 pages in REVTEX format. 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]
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]
First Observation of CP Violation in B0->D(*)CP h0 Decays by a Combined Time-Dependent Analysis of BaBar and Belle Data
We report a measurement of the time-dependent CP asymmetry of B0->D(*)CP h0
decays, where the light neutral hadron h0 is a pi0, eta or omega meson, and the
neutral D meson is reconstructed in the CP eigenstates K+ K-, K0S pi0 or K0S
omega. The measurement is performed combining the final data samples collected
at the Y(4S) resonance by the BaBar and Belle experiments at the
asymmetric-energy B factories PEP-II at SLAC and KEKB at KEK, respectively. The
data samples contain ( 471 +/- 3 ) x 10^6 BB pairs recorded by the BaBar
detector and ( 772 +/- 11 ) x 10^6, BB pairs recorded by the Belle detector. We
measure the CP asymmetry parameters -eta_f S = +0.66 +/- 0.10 (stat.) +/- 0.06
(syst.) and C = -0.02 +/- 0.07 (stat.) +/- 0.03 (syst.). These results
correspond to the first observation of CP violation in B0->D(*)CP h0 decays.
The hypothesis of no mixing-induced CP violation is excluded in these decays at
the level of 5.4 standard deviations.Comment: 9 pages, 2 figures, submitted to Physical Review Letter
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