67 research outputs found
B ->PV Decays in the QCD Improved Factorization Approach
Motivated by recent CELO measurements and the progress of the theory of B
decays, we investigate decay modes in
the framework of QCD improved factorization. We find that all the measured
branching ratios are well accommodated in the reasonable parameter space and
predictions for the other decay modes are well below the experimental upper
limits. We also have calculated CP asymmetries in these decay modes.Comment: 24 pages, LaTex-2e, typos correcte
The dependence of the hard diffractive photoproduction of vector meson or photon and the range of pQCD validity
We consider two coupled problems.
We study the dependence on photon virtuality for the semihard
quasi--elastic photoproduction of neutral vector mesons on a quark, gluon or
real photon (at
GeV)). To this end we calculate the corresponding amplitudes (in an
analytical form) in the lowest nontrivial approximation of perturbative QCD. It
is shown that the amplitude for the production of light meson varies very
rapidly with the photon virtuality near .
We estimate the bound of the pQCD validity region for such processes. For the
real incident photon the obtained bound for the meson production is very
high. This bound decreases fast with the increase of , and we expect that
the virtual photoproduction at HERA gives opportunity to test the pQCD results.
The signature of this region is discussed. For the hard Compton effect the pQCD
should work good at not too high , and this effect seems measurable
at HERA.Comment: ReVTeX, 36 pages, 5 Postscript figures, uses epsf.st
Excitonic Funneling in Extended Dendrimers with Non-Linear and Random Potentials
The mean first passage time (MFPT) for photoexcitations diffusion in a
funneling potential of artificial tree-like light-harvesting antennae
(phenylacetylene dendrimers with generation-dependent segment lengths) is
computed. Effects of the non-linearity of the realistic funneling potential and
slow random solvent fluctuations considerably slow down the center-bound
diffusion beyond a temperature-dependent optimal size. Diffusion on a
disordered Cayley tree with a linear potential is investigated analytically. At
low temperatures we predict a phase in which the MFPT is dominated by a few
paths.Comment: 4 pages, 4 figures, To be published in Phys. Rev. Let
Proceedings of the third French-Ukrainian workshop on the instrumentation developments for HEP
The reports collected in these proceedings have been presented in the third
French-Ukrainian workshop on the instrumentation developments for high-energy
physics held at LAL, Orsay on October 15-16. The workshop was conducted in the
scope of the IDEATE International Associated Laboratory (LIA). Joint
developments between French and Ukrainian laboratories and universities as well
as new proposals have been discussed. The main topics of the papers presented
in the Proceedings are developments for accelerator and beam monitoring,
detector developments, joint developments for large-scale high-energy and
astroparticle physics projects, medical applications.Comment: 3rd French-Ukrainian workshop on the instrumentation developments for
High Energy Physics, October 15-16, 2015, LAL, Orsay, France, 94 page
Search for double beta decay processes in 106Cd with the help of 106CdWO4 crystal scintillator
A search for the double beta processes in 106Cd was carried out at the Gran
Sasso National Laboratories of the INFN (Italy) with the help of a 106CdWO4
crystal scintillator (215 g) enriched in 106Cd up to 66%. After 6590 h of data
taking, new improved half-life limits on the double beta processes in 106Cd
were established at the level of 10^{19}-10^{21} yr; in particular,
T_{1/2}(2\nu \epsilon \beta^+) > 2.1 10^{20} yr, T_{1/2}(2\nu 2\beta^+) > 4.3
10^{20} yr, and T_{1/2}(0\nu 2\epsilon) > 1.0 10^{21} yr. The resonant
neutrinoless double electron captures to the 2718 keV, 2741 keV and 2748 keV
excited states of 106Pd are restricted to T_{1/2}(0\nu 2K) > 4.3 10^{20} yr,
T_{1/2}(0\nu KL1) > 9.5 10^{20} yr and T_{1/2}(0\nu KL3) > 4.3 10^{20} yr,
respectively (all limits at 90% C.L.). A possible resonant enhancement of the
0\nu 2\epsilon processes is estimated in the framework of the QRPA approach.
The radioactive contamination of the 106CdWO4 crystal scintillator is reported.Comment: Minor changes of half-life limits after improving the data analysis;
version accepted for publication on Phys. Rev.
Purification of molybdenum oxide, growth and characterization of medium size zinc molybdate crystals for the LUMINEU program
The LUMINEU program aims at performing a pilot experiment on neutrinoless
double beta decay of 100Mo using radiopure ZnMoO4 crystals operated as
scintillating bolometers. Growth of high quality radiopure crystals is a
complex task, since there are no commercially available molybdenum compounds
with the required levels of purity and radioactive contamination. This paper
discusses approaches to purify molybdenum and synthesize compound for high
quality radiopure ZnMoO4 crystal growth. A combination of a double sublimation
(with addition of zinc molybdate) with subsequent recrystallization in aqueous
solutions (using zinc molybdate as a collector) was used. Zinc molybdate
crystals up to 1.5 kg were grown by the low-thermal-gradient Czochralski
technique, their optical, luminescent, diamagnetic, thermal and bolometric
properties were tested.Comment: Contribution to Proc. of Int. Workshop on Radiopure Scintillators
RPSCINT 2013, 17-20 September 2013, Kyiv, Ukraine; to be published in EPJ Web
of Conferences; expected to be online in January 2014; 6 pages, 6 figures,
and 3 table
Качество жизни больных хронической обструктивной болезнью легких в России: результаты многоцентрового популяционного исследования «ИКАР-ХОБЛ»
The objective of the “IKAR-COPD” study was to evaluate quality of life in COPD patients with different treatment regimens. This multi-center population-based study was performed in 10 regions of Russia, 702 COPD patients aged 40 to 85 yrs were included in this study: 18.5 % with COPD stage I, 20.7 % with COPD stage II, 40.9 % with COPD stage III and 19.9 % with COPD stage IV (according to the GOLD 2003 criteria). The official Russian versions of the MOS SF-36 questionnaire and the St. George’s Respiratory Questionnaire (SGRQ) were used as generic and disease-specific health-related measures of quality of life. COPD significantly impaired the patients’ quality of life, mostly their physical activity. The quality of life depended on severity of COPD, a patient’s age, duration of the disease and smoking history.Целью исследования «ИКАР-ХОБЛ» было изучение влияния хронической обструктивной болезни легких (ХОБЛ) и тактики ее лечения на качество жизни (КЖ) больных. Многоцентровое популяционное исследование проведено в 10 регионах РФ. В него были включено 702 пациента с ХОБЛ в возрасте от 40 до 85 лет: 18,5 % пациентов — с I стадией, 20,7 % – со II стадией, 40,9 % – с III стадией и 19,9 % – с IV стадией ХОБЛ (по критериям GOLD, 2003). Исследование КЖ проводилось с использованием общего «Краткого вопросника оценки статуса здоровья» (официального русскоязычного аналога вопросника MOS SF-36), и русскоязычной версии «Респираторного вопросника госпиталя Святого Георгия» – St. George’s Respiratory Questionnaire (SGRQ). Выявлено, что ХОБЛ оказывает выраженное негативное воздействие на КЖ пациентов, в первую очередь на их физический статус. Выраженность отклонений определяется степенью тяжести ХОБЛ, возрастом пациентов, длительностью заболевания, индексом курения
Ethanol reforming in non-equilibrium plasma of glow discharge
The results of a detailed kinetic study of the main plasma chemical processes
in non-equilibrium ethanol/argon plasma are presented. It is shown that at the
beginning of the discharge the molecular hydrogen is mainly generated in the
reaction of ethanol H-abstraction. Later hydrogen is formed from active H,
CH2OH and CH3CHOH and formaldehyde. Comparison with experimental data has shown
that the used kinetic mechanism predicts well the concentrations of main
species at the reactor outlet.Comment: 16 pages, 8 figure
Development of Mo-containing scintillating bolometers for a high-sensitivity neutrinoless double-beta decay search
We report recent achievements in the development of scintillating bolometers to search for neutrinoless double-beta decay of Mo. The presented results have been obtained in the framework of the LUMINEU, LUCIFER and EDELWEISS collaborations, and are now part of the R\&D activities towards CUPID (CUORE Update with Particle IDentification), a proposed next-generation double-beta decay experiment based on the CUORE experience. We have developed a technology for the production of large mass (1 kg), high optical quality, radiopure zinc and lithium molybdate crystal scintillators (ZnMoO and LiMoO, respectively) from deeply purified natural and Mo-enriched molybdenum. The procedure is applied for a routine production of enriched crystals. Furthermore, the technology of a single detector module consisting of a large-volume (~cm) ZnMoO and LiMoO scintillating bolometer has been established, demonstrating performance and radiopurity that are close to satisfy the demands of CUPID. In particular, the FWHM energy resolution of the detectors at 2615 keV --- near the -value of the double-beta transition of Mo (3034~keV) --- is 4--10~keV. The achieved rejection of -induced dominant background above 2.6~MeV is at the level of more than 99.9\%. The bulk activity of Th (Th) and Ra in the crystals is below 10 Bq/kg. Both crystallization and detector technologies favor LiMoO, which was selected as a main element for the realization of a CUPID demonstrator (CUPID-0/Mo) with 7 kg of Mo
- …