2,690 research outputs found
Two-color interference stabilization of atoms
The effect of interference stabilization is shown to exist in a system of two
atomic levels coupled by a strong two-color laser field, the two frequencies of
which are close to a two-photon Raman-type resonance between the chosen levels,
with open channels of one-photon ionization from both of them. We suggest an
experiment, in which a rather significant (up to 90%) suppression of ionization
can take place and which demonstrates explicitly the interference origin of
stabilization. Specific calculations are made for H and He atoms and optimal
parameters of a two-color field are found. The physics of the effect and its
relation with such well-known phenomena as LICS and population trapping in a
three-level system are discussed.Comment: the paper includes 1 TeX file and 16 picture
Measurement of decay rate and parameters at KEDR
Using the inclusive photon spectrum based on a data sample collected at the
peak with the KEDR detector at the VEPP-4M collider, we
measured the rate of the radiative decay as well
as mass and width. Taking into account an asymmetric photon
lineshape we obtained keV, MeV/, MeV.Comment: 6 pages, 3 figure
Measurement of J/psi to eta_c gamma at KEDR
We present a study of the inclusive photon spectra from 5.9 million J/psi
decays collected with the KEDR detector at the VEPP-4M e+e- collider. We
measure the branching fraction of radiative decay J/psi to eta_c gamma, eta_c
width and mass. Our preliminary results are: M(eta_c) = 2979.4+-1.5+-1.9 MeV,
G(eta_c) = 27.8+-5.1+-3.3 MeV, B(J/psi to eta_c gamma) = (2.34+-0.15+-0.40)%.Comment: To be published in Proceedings of the PhiPsi09, Oct. 13-16, 2009,
Beijing, Chin
Measurement of B(J/psi->eta_c gamma) at KEDR
We present a study of the inclusive photon spectrum from 6.3 million J/psi
decays collected with the KEDR detector at the VEPP-4M e+e- collider. We
measure the branching fraction of the radiative decay J/psi -> eta_c gamma,
eta_c width and mass. Taking into account an asymmetric photon line shape we
obtain: M(eta_c) = (2978.1 +- 1.4 +- 2.0) MeV/c^2, Gamma(eta_c) = (43.5 +- 5.4
+- 15.8) MeV, B(J/psi->eta_c gamma) = (2.59 +- 0.16 +- 0.31)%$.Comment: 6 pages, 1 figure. To be published in the proceedings of the 4th
International Workshop on Charm Physics (Charm2010), October 21-24, 2010,
IHEP, Beijin
Short-Wave Excitations in Non-Local Gross-Pitaevskii Model
It is shown, that a non-local form of the Gross-Pitaevskii equation allows to
describe not only the long-wave excitations, but also the short-wave ones in
the systems with Bose-condensate. At given parameter values, the excitation
spectrum mimics the Landau spectrum of quasi-particle excitations in superfluid
Helium with roton minimum. The excitation wavelength, at which the roton
minimum exists, is close to the inter-particle interaction range. It is shown,
that the existence domain of the spectrum with a roton minimum is reduced, if
one accounts for an inter-particle attraction.Comment: 5 pages, 5 figures, UJP style; presented at Bogolyubov Kyiv
Conference "Modern Problems of Theoretical and Mathematical Physics",
September 15-18, 200
Familial adenomatosis of the colon: current state of the problem
The urgency of the problem of familial adenomatosis of the colon (FAC) is caused both by the severity of the disease with the inevitable development of cancer without timely treatment, and the involvement of the patient's blood relatives in this problem. Due to the rare incidence of this disease, many issues require discussion. Aim. To determine the possibility of timely treatment of FAC patients maintaining a satisfactory quality of life. Materials and methods. The data on 5 FAC patients and 12 their blood relatives were studied. Clinical, endoscopic and genetic characteristics of the disease and treatment were analyzed. Results. demonstrated that family history, genetic and endoscopic examinations allow diagnosis of FAC. Colectomy with rectal resection and the creation of a small intestine reservoir with reservoir-rectal anastomosis provide a sufficient quality of life for patients. Examination of the patient's blood relatives reveals new patients requiring additional examination and treatment. Conclusion. The problem of FAC is multidisciplinary and involves therapists, gastroenterologists, pediatricians, geneticists, endoscopists, radiologists, surgeons and oncologists. Only a timely diagnosis can help the patient to undergo radical treatment before the development of colon cancer
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