Parton Distributions of the Virtual Photon

We propose a generic ansatz for the extension of parton distributions of the real photon to those of the virtual photon. Alternatives and approximations are studied that allow closed-form parametrizations.Comment: 1+10 pages, LaTeX2e, 2 eps figures included in file using filecontents environment

Measuring Stellar Radial Velocities with a Dispersed Fixed-Delay Interferometer

We demonstrate the ability to measure precise stellar barycentric radial velocities with the dispersed fixed-delay interferometer technique using the Exoplanet Tracker (ET), an instrument primarily designed for precision differential Doppler velocity measurements using this technique. Our barycentric radial velocities, derived from observations taken at the KPNO 2.1 meter telescope, differ from those of Nidever et al. by 0.047 km/s (rms) when simultaneous iodine calibration is used, and by 0.120 km/s (rms) without simultaneous iodine calibration. Our results effectively show that a Michelson interferometer coupled to a spectrograph allows precise measurements of barycentric radial velocities even at a modest spectral resolution of R ~ 5100. A multi-object version of the ET instrument capable of observing ~500 stars per night is being used at the Sloan 2.5 m telescope at Apache Point Observatory for the Multi-object APO Radial Velocity Exoplanet Large-area Survey (MARVELS), a wide-field radial velocity survey for extrasolar planets around TYCHO-2 stars in the magnitude range 7.6<V<12. In addition to precise differential velocities, this survey will also yield precise barycentric radial velocities for many thousands of stars using the data analysis techniques reported here. Such a large kinematic survey at high velocity precision will be useful in identifying the signature of accretion events in the Milky Way and understanding local stellar kinematics in addition to discovering exoplanets, brown dwarfs and spectroscopic binaries.Comment: 9 pages, 4 figures. Accepted for publication in Ap

Geometry of W-algebras from the affine Lie algebra point of view

To classify the classical field theories with W-symmetry one has to classify the symplectic leaves of the corresponding W-algebra, which are the intersection of the defining constraint and the coadjoint orbit of the affine Lie algebra if the W-algebra in question is obtained by reducing a WZNW model. The fields that survive the reduction will obey non-linear Poisson bracket (or commutator) relations in general. For example the Toda models are well-known theories which possess such a non-linear W-symmetry and many features of these models can only be understood if one investigates the reduction procedure. In this paper we analyze the SL(n,R) case from which the so-called W_n-algebras can be obtained. One advantage of the reduction viewpoint is that it gives a constructive way to classify the symplectic leaves of the W-algebra which we had done in the n=2 case which will correspond to the coadjoint orbits of the Virasoro algebra and for n=3 which case gives rise to the Zamolodchikov algebra. Our method in principle is capable of constructing explicit representatives on each leaf. Another attractive feature of this approach is the fact that the global nature of the W-transformations can be explicitly described. The reduction method also enables one to determine the ``classical highest weight (h. w.) states'' which are the stable minima of the energy on a W-leaf. These are important as only to those leaves can a highest weight representation space of the W-algebra be associated which contains a ``classical h. w. state''.Comment: 17 pages, LaTeX, revised 1. and 7. chapter

Density Correlation Functions in Calogero Sutherland Models

Using arguments from two dimensional Yang-Mills theory and the collective coordinate formulation of the Calogero-Sutherland model, we conjecture the dynamical density correlation function for coupling $l$ and $1/l$, where $l$ is an integer. We present overwhelming evidence that the conjecture is indeed correct.Comment: 12 pages phyzzx, CERN-TH/94.7243 One reference change

ЧТО МЫ ЗНАЕМ О БРИКС?

.БРИКС (англ. BRICS – сокращение от Brazil, Russia, India, China, South Africa) – группа из пяти стран: Бразилия, Россия, Индия, Китай,Южно-Африканская республика 1. Возникновение названия Сокращение БРИК (BRIC) было впервые предложено аналитиком Джимом О’Нилом в ноябре 2001 года в аналитической записке банка «Goldman Sachs» Building Better Global Economic (кирпичи для новой экономики). До 2011 года по отношению к организации использовалась аббревиатура БРИК. В связи с присоединением ЮАР к БРИК 18 февраля 2011 года, по заявлению индийского министра финансов с этого времени группа стала носить название BRICS. Последовательность букв в слове определяется не только благозвучием, но и тем, что само слово в английской транскрипции BRICS очень похоже на английское слово bricks – «кирпичи», таким образом, данный термин используется в качестве обозначения группы стран, за счёт роста которых во многом будет обеспечиваться будущий рост мировой экономики

Wannier functions for quasi-periodic finite-gap potentials

In this paper we consider Wannier functions of quasi-periodic g-gap ($g\geq 1$) potentials and investigate their main properties. In particular, we discuss the problem of averaging underlying the definition of Wannier functions for both periodic and quasi-periodic potentials and express Bloch functions and quasi-momenta in terms of hyperelliptic $\sigma$ functions. Using this approach we derive a power series expansion of the Wannier function for quasi-periodic potentials valid at $|x|\simeq 0$ and an asymptotic expansion valid at large distance. These functions are important for a number of applied problems

The ρ\rho Meson Light-Cone Distribution Amplitudes of Leading Twist Revisited

We give a complete re-analysis of the leading twist quark-antiquark light-cone distribution amplitudes of longitudinal and transverse $\rho$ mesons. We derive Wandzura-Wilczek type relations between different distributions and update the coefficients in their conformal expansion using QCD sum rules including next-to-leading order radiative corrections. We find that the distribution amplitudes of quarks inside longitudinally and transversely polarized $\rho$ mesons have a similar shape, which is in contradiction to previous analyses.Comment: 21 pages, latex2e, requires a4wide.sty and epsf.sty, 6 PS figures include

The First Extrasolar Planet Discovered with a New Generation High Throughput Doppler Instrument

We report the detection of the first extrasolar planet, ET-1 (HD 102195b), using the Exoplanet Tracker (ET), a new generation Doppler instrument. The planet orbits HD 102195, a young star with solar metallicity that may be part of the local association. The planet imparts radial velocity variability to the star with a semiamplitude of $63.4\pm2.0$ m s$^{-1}$ and a period of 4.11 days. The planetary minimum mass ($m \sin i$) is $0.488\pm0.015$ $M_J$.Comment: 42 pages, 11 figures and 5 tables, Accepted for publication in Ap

ИССЛЕДОВАНИЕ ФАЗОВОГО И ПРИМЕСНОГО СОСТАВА ЛЕНТ КАТОДНЫХ СПЛАВОВ Pd—Ba и Pt—Ba

We have  studied the  phase and  impurity composition of Pd—Ba  and  Pt—Ba cathode alloys obtained on an A 535.02TO arc melting plant using a technology developed by AO Shokin NPP Istok. The study  showed that  the  concentration of detrimental impurities (C; Zn; Cu; Al) in the specimens is within the allowed range. Pd—Ba tapes are rich in Ba but this does not compromise their quality. We have confirmed the earlier found domination of two−phase composition in Pd—Ba and Pt—Ba alloys where  one of the phase is an intermetallic compound (Pd5Ba, Pt5Ba) and the other  is a noble metal(the matrix). The intermetallide is distributed in the  platinum  metal  matrix quite inhomogeneously, this tangibly impairing the operation parameters of cathodes produced from these alloys. For the first time we have shown the high efficiency  of transmission electron microscopy for studying Pd—Ba and  Pt—Ba cathode alloys. We have  for the first time found the Pd2О phase in Pd—Ba. It may significantly reduce the secondary electron emission coefficient and the quality of devices based on this alloy. We have determined the Pd and Pd5Ba grain size in the Pd—Ba alloys and the Pt and Pt5Ba grain size in the Pt—Ba alloys. All the Pd and Pt5Ba grains contain high densities of randomly arranged dislocations, and Pt5Ba grains  contain internal  stresses. Recommendations have been given concerning the improvement of the current Pd—Ba and Pt—Ba cathode alloy tape  technology.Изучен примесный и фазовый состав лент катодных сплавов Pd—Ba и Pt— Ba, полученных на установке дуговой плавки А 535.02ТО  по технологии, разработанной в АО «НПП «Исток им.  Шокина». Установлено, что концентрация вредных примесей (C, Zn, Cu, Al) в исследованных образцах не превышает допустимой нормы. Ленты состава Pd—Ba содержат повышенную концентрацию Ba, однако  это не сказывается на их качестве.Подтверждена обнаруженная ранее превалирующая двухфазность сплавов Pd—Ba и Pt—Ba: одна из фаз — интерметаллическое соединение (Pd5Ba, Pt5Ba),  вторая — благородный металл (матрица). При этом интерметаллид очень неравномерно распределен в матрице металла платиновой группы, что существенно понижает эксплуатационные  характеристики катодов на основе этих сплавов. Впервые показана высокая эффективность просвечивающей электронной микроскопии для исследования катодных сплавов Pd—Ba и Pt—Ba.В сплаве Pd—Ba впервые обнаружена фаза Pd2О. Это может приводить к существенному понижению коэффициента вторичной электронной эмиссии и падению эксплуатационных характеристик приборов на базе этого сплава. Определен размер зерен Pd и Pd5Ba в сплавах Pd—Ba, и зерен Pt и Pt5Ba в сплавах Pt—Ba. Обнаружено, что во всех зернах Pd и Pt5Ba наблюдается высокая плотность хаотически расположенных дислокаций, внутри зерен Pt5Ba имеются напряжения.Приведены рекомендации по совершенствованию существующей технологии получения лент катодных сплавов Pd—Ba и Pt—Ba