45 research outputs found
Today and Future Neutrino Experiments at Krasnoyarsk Nuclear Reactor
The results of undergoing experiments and new experiment propositions at
Krasnoyarsk underground nuclear reactor are presentedComment: 4 page
Soft and virtual corrections to pp -> H + X at NNLO
The contributions of virtual corrections and soft gluon emission to the
inclusive Higgs production cross section pp -> H + X are computed at
next-to-next-to-leading order in the heavy top quark limit. We show that this
part of the total cross section is well behaved in the sense of perturbative
convergence, with the NNLO corrections amounting to an enhancement of the NLO
cross section by \sim 5% for LHC and 10-20% for the Tevatron. We compare our
results with an existing estimate of the full NNLO effects and argue that an
analytic evaluation of the hard scattering contributions is needed.Comment: 16 pages, 7 figures, 16 ps files embedded with epsf. Minor
modifications: references and note added, results unchange
Voronoi-Delaunay analysis of normal modes in a simple model glass
We combine a conventional harmonic analysis of vibrations in a one-atomic
model glass of soft spheres with a Voronoi-Delaunay geometrical analysis of the
structure. ``Structure potentials'' (tetragonality, sphericity or perfectness)
are introduced to describe the shape of the local atomic configurations
(Delaunay simplices) as function of the atomic coordinates. Apart from the
highest and lowest frequencies the amplitude weighted ``structure potential''
varies only little with frequency. The movement of atoms in soft modes causes
transitions between different ``perfect'' realizations of local structure. As
for the potential energy a dynamic matrix can be defined for the ``structure
potential''. Its expectation value with respect to the vibrational modes
increases nearly linearly with frequency and shows a clear indication of the
boson peak. The structure eigenvectors of this dynamical matrix are strongly
correlated to the vibrational ones. Four subgroups of modes can be
distinguished
Quantum Radiation from a 5-Dimensional Rotating Black Hole
We study a massless scalar field propagating in the background of a
five-dimensional rotating black hole. We showed that in the Myers-Perry metric
describing such a black hole the massless field equation allows the separation
of variables. The obtained angular equation is a generalization of the equation
for spheroidal functions. The radial equation is similar to the radial
Teukolsky equation for the 4-dimensional Kerr metric. We use these results to
quantize the massless scalar field in the space-time of the 5-dimensional
rotating black hole and to derive expressions for energy and angular momentum
fluxes from such a black hole.Comment: references added, accepted for publication in Physical Review
New precise determination of the \tau lepton mass at KEDR detector
The status of the experiment on the precise lepton mass measurement
running at the VEPP-4M collider with the KEDR detector is reported. The mass
value is evaluated from the cross section behaviour around the
production threshold. The preliminary result based on 6.7 pb of data is
MeV. Using 0.8 pb of data
collected at the peak the preliminary result is also obtained:
eV.Comment: 6 pages, 8 figures; The 9th International Workshop on Tau-Lepton
Physics, Tau0
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
Black Holes at the LHC
In these two lectures, we will address the topic of the creation of small
black holes during particle collisions in a ground-based accelerator, such as
LHC, in the context of a higher-dimensional theory. We will cover the main
assumptions, criteria and estimates for their creation, and we will discuss
their properties after their formation. The most important observable effect
associated with their creation is likely to be the emission of Hawking
radiation during their evaporation process. After presenting the mathematical
formalism for its study, we will review the current results for the emission of
particles both on the brane and in the bulk. We will finish with a discussion
of the methodology that will be used to study these spectra, and the observable
signatures that will help us identify the black-hole events.Comment: 37 pages, 14 figures, lectures presented in the 4th Aegean Summer
School on Black Holes, 17-22 September 2007, Lesvos, Greece, typos corrected,
comments and references adde
Современные концепции процессов физиологического и репаративного остеогенеза
Studies conducted in the recent years by biologists strongly suggest that physiological and reparative osteogenesis, as well as of the functional, adaptive, and post-traumatic reconstruction of bone tissues are based on common and stereotypical molecular and cellular mechanisms. Our experimental studies have shown that all stages of the bone microstructure morphogenesis are synchronously and continuously associated with focal and stereotypical angiogenesis (capillarogenesis). A powerful factor in the implementation of reparative osteogenesis is the osteoinductive interaction of the ends of the damaged bone segments, which positively shows itself even in cases of large diastasis between the fragments (provided that the fragments are steadily fixed). After any kind of stable osteosynthesis, by ensuring the stability of the bone fragments for the entire period of consolidation, an endosteal cortical bone regeneration by direct osteogenesis (i.e. without fibro-cartilaginous tissue) is observed in the minimum amount at the shortest time period. Periosteal bone formation in this case is actually a reserve source of bone formation, which becomes effective during insufficiently stable conditions. The instability of the bone damage area particularly that of the metal implants results in the most severe destructive consequences. Исследования последних лет, выполненные биологами, убедительно свидетельствуют, что в основе физиологического и репаративного остеогенеза, а также функционально-адаптивной и посттравматической перестройки костной ткани лежат единые и стереотипные молекулярно-клеточные механизмы. Собственные экспериментальные исследования авторов показали: все этапы морфогенеза костных микроструктур синхронно обеспечиваются и непрерывно сопровождаются очаговым и стереотипным ангиогенезом (капиллярогенезом). Мощным фактором реализации репаративного остеогенеза выступает остеоиндуцирующее взаимодействие концов поврежденного костного сегмента, которое положительно проявляется даже в случаях значительных диастазов между отломками (но стабильно фиксированных). При обеспечении стабильности зоны костного повреждения на весь период консолидации после любого вида стабильного остеосинтеза формируется эндостально-кортикальный костный регенерат за счет прямого остеогенеза (то есть без фиброзно-хрящевой ткани) минимального объема и в кратчайшие сроки. Периостальный остеогенез при этом фактически становится резервным источником костеобразования, который проявляется в недостаточно стабильных условиях. Нестабильность зоны костного повреждения и особенно металлического имплантата чревата самыми тяжелыми деструктивными последствиями.
ТКАНЕВАЯ И КЛЕТОЧНАЯ РЕАКЦИЯ СИНОВИАЛЬНОЙ СРЕДЫ НА ВНУТРИСУСТАВНОЕ ВВЕДЕНИЕ ПОЛИМЕРНОГО ВИСКОПРОТЕЗА «НОЛТРЕКС» В УСЛОВИЯХ ЭКСПЕРИМЕНТА
Reaction of synovial membrane and cartilage on 1 ml of polymer gel «NOLTREX» injected into the cavity of jumping joint of 20 rabbits was investigated. Biological inertness and safety of noltrex injected into the joint cavity was established. Изучена реакция синовиальной оболочки и хряща 20 кроликов на введение 1 мл полимерного геля «Нолтрекс» в полость скакательного сустава. Сделан вывод о биологической инертности и безопасности нолтрекса при его введении в полость сустава