131 research outputs found
Anomalous Capacitive Sheath with Deep Radio Frequency Electric Field Penetration
A novel nonlinear effect of anomalously deep penetration of an external radio
frequency electric field into a plasma is discribed. A self-consistent kinetic
treatment reveals a transition region between the sheath and the plasma.
Because of the electron velocity modulation in the sheath, bunches in the
energetic electron density are formed in the transition region adjusted to the
sheath. The width of the region is of order , where V_{T} is the
electron thermal velocity, and is frequency of the electric field. The
presence of the electric field in the transition region results in a cooling of
the energetic electrons and an additional heating of the cold electrons in
comparison with the case when the transition region is neglected.Comment: 14,4 figure
Gold-plated Mode of CP-Violation in Decays of B_c Meson from QCD Sum Rules
The model-independent method based on the triangle ideology is implemented to
extract the CKM-matrix angle gamma in the decays of doubly heavy long-lived
meson B_c. We analyze a color structure of diagrams and conditions to
reconstruct two reference-triangles by tagging the flavor and CP eigenstates of
D^0 meson in the fixed exclusive channels. The characteristic branching ratios
are evaluated in the framework of QCD sum rules.Comment: 11 pages, RevTeX4 file, 4 eps-figure
Effect of Electron Energy Distribution Function on Power Deposition and Plasma Density in an Inductively Coupled Discharge at Very Low Pressures
A self-consistent 1-D model was developed to study the effect of the electron
energy distribution function (EEDF) on power deposition and plasma density
profiles in a planar inductively coupled plasma (ICP) in the non-local regime
(pressure < 10 mTorr). The model consisted of three modules: (1) an electron
energy distribution function (EEDF) module to compute the non-Maxwellian EEDF,
(2) a non-local electron kinetics module to predict the non-local electron
conductivity, RF current, electric field and power deposition profiles in the
non-uniform plasma, and (3) a heavy species transport module to solve for the
ion density and velocity profiles as well as the metastable density. Results
using the non-Maxwellian EEDF model were compared with predictions using a
Maxwellian EEDF, under otherwise identical conditions. The RF electric field,
current, and power deposition profiles were different, especially at 1mTorr,
for which the electron effective mean free path was larger than the skin depth.
The plasma density predicted by the Maxwellian EEDF was up to 93% larger for
the conditions examined. Thus, the non-Maxwellian EEDF must be accounted for in
modeling ICPs at very low pressures.Comment: 19 pages submitted to Plasma Sources Sci. Techno
ĐŃĐ”ĐœĐșĐž ĐŸĐżĐ”ŃĐ°ŃĐŸŃĐ° ĐĐŸŃĐŽĐŸĐ±Ń - ЀДŃĐœĐ°ĐœĐŽĐ”ŃĐ° ĐČ ĐżŃĐŸŃŃŃĐ°ĐœŃŃĐČĐ°Ń ĐĐ°ŃŃĐžĐœĐșĐ”ĐČĐžŃĐ°
In the A. Cordoba and P. Fernandez research of the divergence of greedy algorithms in Lebesgue spaces some maximum operator P*(x) played the key role. This article reviews the assessment P*(x) in Marcinkiewicz spaces.Đ ŃĐ°Đ±ĐŸŃĐ°Ń
Đ. ĐĐŸŃĐŽĐŸĐ±Ń Đž Đ. ЀДŃĐœĐ°ĐœĐŽĐ”ŃĐ° ĐŸ ŃĐ°ŃŃ
ĐŸĐŽĐžĐŒĐŸŃŃĐž Đ¶Đ°ĐŽĐœŃŃ
Đ°Đ»ĐłĐŸŃĐžŃĐŒĐŸĐČ ĐČ ĐżŃĐŸŃŃŃĐ°ĐœŃŃĐČĐ°Ń
ĐДбДга ĐșĐ»ŃŃĐ”ĐČŃŃ ŃĐŸĐ»Ń ĐžĐłŃĐ°Đ» ĐœĐ”ĐșĐŸŃĐŸŃŃĐč ĐŒĐ°ĐșŃĐžĐŒĐ°Đ»ŃĐœŃĐč ĐŸĐżĐ”ŃĐ°ŃĐŸŃ Pn**(x). Đ ĐœĐ°ŃŃĐŸŃŃĐ”Đč ŃŃĐ°ŃŃĐ” ŃĐ°ŃŃĐŒĐŸŃŃĐ”ĐœŃ ĐŸŃĐ”ĐœĐșĐž P*(x) ĐČ ĐżŃĐŸŃŃŃĐ°ĐœŃŃĐČĐ°Ń
ĐĐ°ŃŃĐžĐœĐșĐ”ĐČĐžŃĐ°
Landau damping and anomalous skin effect in low-pressure gas discharges: Self-consistent treatment of collisionless heating
In low-pressure discharges, where the electron mean free path is larger or comparable with the discharge length, the electron dynamics is essentially nonlocal. Moreover, the electron energy distribution function (EEDF) deviates considerably from a Maxwellian. Therefore, an accurate kinetic description of the low-pressure discharges requires knowledge of the nonlocal conductivity operator and calculation of the non-Maxwellian EEDF. The previous treatments made use of simplifying assumptions: a uniform density profile and a Maxwellian EEDF. In the present study a self-consistent system of equations for the kinetic description of nonlocal, nonuniform, nearly collisionless plasmas of low-pressure discharges is reported. It consists of the nonlocal conductivity operator and the averaged kinetic equation for calculation of the non-Maxwellian EEDF. This system was applied to the calculation of collisionless heating in capacitively and inductively coupled plasmas. In particular, the importance of accounting for the nonuniform plasma density profile for computing the current density profile and the EEDF is demonstrated. The enhancement of collisionless heating due to the bounce resonance between the electron motion in the potential well and the external radio-frequency electric field is investigated. It is shown that a nonlinear and self-consistent treatment is necessary for the correct description of collisionless heating
Mass spectra of doubly heavy Omega_QQ' baryons
We evaluate the masses of baryons composed of two heavy quarks and a strange
quark with account for spin-dependent splittings in the framework of potential
model with the KKO potential motivated by QCD with a three-loop beta-function
for the effective charge consistent with both the perturbative limit at short
distances and linear confinement term at long distances between the quarks. The
factorization of dynamics is supposed and explored in the nonrelativistic
Schroedinger equation for the motion in the system of two heavy quarks
constituting the doubly heavy diquark and the strange quark interaction with
the diquark. The limits of approach, its justification and uncertainties are
discussed. Excited quasistable states are classified by the quantum numbers of
heavy diquark composed by the heavy quarks of the same flavor.Comment: 14 pages, revtex4-file, 3 eps-figures, 5 tables, typos correcte
Heavy quarkonium: progress, puzzles, and opportunities
A golden age for heavy quarkonium physics dawned a decade ago, initiated by
the confluence of exciting advances in quantum chromodynamics (QCD) and an
explosion of related experimental activity. The early years of this period were
chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in
2004, which presented a comprehensive review of the status of the field at that
time and provided specific recommendations for further progress. However, the
broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles
could only be partially anticipated. Since the release of the YR, the BESII
program concluded only to give birth to BESIII; the -factories and CLEO-c
flourished; quarkonium production and polarization measurements at HERA and the
Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the
deconfinement regime. All these experiments leave legacies of quality,
precision, and unsolved mysteries for quarkonium physics, and therefore beg for
continuing investigations. The plethora of newly-found quarkonium-like states
unleashed a flood of theoretical investigations into new forms of matter such
as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the
spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b},
and b\bar{c} bound states have been shown to validate some theoretical
approaches to QCD and highlight lack of quantitative success for others. The
intriguing details of quarkonium suppression in heavy-ion collisions that have
emerged from RHIC have elevated the importance of separating hot- and
cold-nuclear-matter effects in quark-gluon plasma studies. This review
systematically addresses all these matters and concludes by prioritizing
directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K.
Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D.
Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A.
Petrov, P. Robbe, A. Vair
Estimates of the Cordoba - Fernandez operator in Marcinkiewicz spaces
In the A. Cordoba and P. Fernandez research of the divergence of greedy algorithms in Lebesgue spaces some maximum operator P*(x) played the key role. This article reviews the assessment P*(x) in Marcinkiewicz spaces
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