The soft and the hard pomerons in hadron elastic scattering at small t

We consider simple-pole descriptions of soft elastic scattering for pp, pbar p, pi+ p, pi- p, K+ p and K- p. We work at t and s small enough for rescatterings to be neglected, and allow for the presence of a hard pomeron. After building and discussing an exhaustive dataset, we show that simple poles provide an excellent description of the data in the region - 0.5 GeV^2 < t < -0.1 GeV^2, 6 GeV<sqrt(s)< 63 GeV. We show that new form factors have to be used, and get information on the trajectories of the soft and hard pomerons.Comment: 27 pages, 9 figures, LaTeX. A few typos fixed, and references correcte

On the rise of proton-proton cross-sections at high energies

The rise of the total, elastic and inelastic hadronic cross sections at high energies is investigated by means of an analytical parametrization, with the exponent of the leading logarithm contribution as a free fit parameter. Using derivative dispersion relations with one subtraction, two different fits to proton-proton and antiproton-proton total cross section and rho parameter data are developed, reproducing well the experimental information in the energy region 5 GeV - 7 TeV. The parametrization for the total cross sections is then extended to fit the elastic (integrated) cross section data in the same energy region, with satisfactory results. From these empirical results we extract the energy dependence of several physical quantities: inelastic cross section, ratios elastic/total, inelastic/total cross sections, ratio total-cross-section/elastic-slope, elastic slope and optical point. All data, fitted and predicted, are quite well described. We find a statistically consistent solution indicating: (1) an increase of the hadronic cross sections with the energy faster than the log-squared bound by Froissart and Martin; (2) asymptotic limits 1/3 and 2/3 for the ratios elastic/total and inelastic/total cross sections, respectively, a result in agreement with unitarity. These indications corroborate recent theoretical arguments by Ya. I. Azimov on the rise of the total cross section.Comment: 35 pages, 12 figures, discussions improved with further clarifications, references added and updated, one note added, results and conclusions unchanged. Version to be published in J. Phys. G: Nucl. Part. Phy

Rare B decays and Tevatron top-pair asymmetry

The recent Tevatron result on the top quark forward-backward asymmetry, which deviates from its standard model prediction by 3.4$\sigma$, has prompted many authors to build new models to account for this anomaly. Among the various proposals, we find that those mechanisms which produce $t\bar t$ via $t$- or $u$-channel can have a strong correlation to the rare B decays. We demonstrate this link by studying a model with a new charged gauge boson, $W'$. In terms of the current measurements on $B\to \pi K$ decays, we conclude that the branching ratio for $B^-\to \pi^- \bar K^0$ is affected most by the new effects. Furthermore, using the world average branching ratio for the exclusive B decays at $2\sigma$ level, we discuss the allowed values for the new parameters. Finally, we point out that the influence of the new physics effects on the direct CP asymmetry in B decays is insignificant.Comment: 15 page, 6 figures, typos corrected and references added, final version to appear journa

Гиперфиксации 11С-метионина в абсцедирующей гранулеме головного мозга: радиологическая семиотика, метаболическая характеристика и патоморфологические находки: клинический случай

An increased amino acid metabolism is characteristic for many brain malignancies. Combined positron emission and computed tomography (PET/CT) with radiolabeled amino acids is often used in recognizing the tumor nature of the structural brain lesion detected on MRI. On 11C-methionine PET/CT a hallmark of a brain tumor is an increased amino acid uptake, topographically coinciding with a structural lesion on MRI. However, high 11C-methionine uptake in the brain lesion is not tumor specific and could be seen in a number of non-tumor diseases. The paper presents three observations of a brain abscess, radiological and metabolic data of which in MRI and 11C-methionine PET/CT simulated a malignant cerebral tumor. The reasons for patients seeking nuclear medicine examination were seizures or focal neurological symptoms, as well as a suspicion of a cerebral tumor based on the contrast-enhanced MRI. Knowledge of the non-tumor disease characterized by high 11C-methionine uptake will help avoid misdiagnosis of a cerebral tumor.Ускоренный транспорт и метаболизм аминокислот характерен для разных типов опухолей головного мозга. Позитронная эмиссионная томография (ПЭТ), совмещенная с компьютерной томографией (ПЭТ/КТ), с радиотрейсерами класса аминокислот часто используется для уточнения природы церебрального поражения, обнаруженного при магнитно-резонансной томографии (МРТ). Базовым принципом диагностики опухоли головного мозга при помощи ПЭТ/КТ с 11С-метионином является гиперфиксации радиотрейсера, топографически совпадающая с участком структурного поражения. Однако высокий захват 11С-метионина не является уникальным признаком опухоли и встречается при ряде неопухолевых заболеваний. В данной работе представлены три наблюдения абсцесса мозга, лучевые проявления которых при МРТ и ПЭТ/КТ с 11С-метионином симулировали злокачественную церебральную опухоль. Причинами обращения пациентов за медицинской помощью послужили судорожные приступы или появление очаговой неврологической симптоматики, а также подозрение на церебральную опухоль по результатам МРТ с контрастированием. Представление о неопухолевых причинах гиперфиксации 11С-метионина и ПЭТ-семиотики этих поражений поможет избежать ошибочной диагностики церебральной опухоли

Two-pion Bose-Einstein correlations in central Pb-Pb collisions at sNN\sqrt{s_{\rm NN}} = 2.76 TeV

The first measurement of two-pion Bose-Einstein correlations in central Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV at the Large Hadron Collider is presented. We observe a growing trend with energy now not only for the longitudinal and the outward but also for the sideward pion source radius. The pion homogeneity volume and the decoupling time are significantly larger than those measured at RHIC.Comment: 17 pages, 5 captioned figures, 1 table, authors from page 12, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/388

A Cryogenic Silicon Interferometer for Gravitational-wave Detection

The detection of gravitational waves from compact binary mergers by LIGO has opened the era of gravitational wave astronomy, revealing a previously hidden side of the cosmos. To maximize the reach of the existing LIGO observatory facilities, we have designed a new instrument that will have 5 times the range of Advanced LIGO, or greater than 100 times the event rate. Observations with this new instrument will make possible dramatic steps toward understanding the physics of the nearby universe, as well as observing the universe out to cosmological distances by the detection of binary black hole coalescences. This article presents the instrument design and a quantitative analysis of the anticipated noise floor