Near Threshold Enhancement of p pbar System and p pbar Elastic Scattering

The observed enhancement of $p\bar p$-production near the threshold in radiative decays of $J/\psi$ and $e^+e^-$-annihilations can be explained with final state interactions among the produced $N\bar N$ system, where the enhancement is essentially determined by $N\bar N$ elastic scattering amplitudes. We propose to use an effective theory for interactions in a $N\bar N$ system near its threshold. The effective theory is similar to the well-known one for interactions in a $NN$ system but with distinctions. It is interesting to note that in the effective theory some corrections to scattering amplitudes at tree-level can systematically be summed into a simple form. These corrections are from rescattering processes. With these corrected amplitudes we are able to describe the enhancement near the threshold in radiative decays of $J/\psi$ and $e^+e^-$-annihilations, and the $p\bar p$ elastic scattering near the threshold.Comment: Discussions and References added, Fig.2 redrawn. Published version in Phys. Lett.

Medium-chain triglyceride supplementation may increase working memory in older adults: A pilot study

Poster presentatio

Возможность прогнозирования клеточного типа увеальных меланом без использования инвазивных методов диагностики

Резюме. С помощью дискриминантного анализа установлена возможность определения клеточного типа меланомы увеального тракта в процессе проведения комбинированного (фотокоагуляция + брахитерапия) лечения. Разработана высокозначимая (l = 0,08; р = 0,002) дискриминантная модель, включающая ряд клинических (степень пигментации, пол, скорость роста меланомы) и иммунологических (количество Т- и В-лимфоцитов, процент Т-хелперов и др.) показателей. Особое место в модели занимают признаки, в наибольшей степени отражающие биологические особенности увеальных меланом различного клеточного состава, а именно — скорость изменения размера опухоли в процессе лечения и изменение показателей клеточного иммунитета. Ключевые слова: увеальная меланома, клеточный тип, клинико-морфологические, иммунологические показатели, дискриминантный анализ.Summary. Application of the discriminant analysis shows that it is possible to define the cell type of melanoma of uveal tract of the eye in the process of combined (photocoagulation + brachytherapy) treatment. A highly reliable (l= 0,08; р = 0,002) discriminant model was elaborated, involving a number of both clinical (pigmentation level, gender, melanoma growth rate) and immunological (number of T and B lymphocytes, T helper rate, etc.) indicators. In this model, especially important are those traits that most pronouncedly reflect the biological peculiarities of uveal melanomas of various cellular compositions, namely — the pace of tumor size growth in the process of treatment and changes in cell immunity indicators. Key Words: uveal melanoma, cell type, clinical and morphological, immunological indicators, discriminant analysis

Observation of Parity Violation in the Omega-minus -> Lambda + K-minus Decay

The alpha decay parameter in the process Omega-minus -> Lambda + K-minus has been measured from a sample of 4.50 million unpolarized Omega-minus decays recorded by the HyperCP (E871) experiment at Fermilab and found to be [1.78 +/- 0.19(stat) +/- 0.16(syst)]{\times}10^{-2}. This is the first unambiguous evidence for a nonzero alpha decay parameter, and hence parity violation, in the Omega-minus -> Lambda + K-minus decay.Comment: 10 pages, 7 figure

Lattice Study of the Massive Schwinger Model with a θ\theta term under L\"uscher's "Admissibility" condition

We present a numerical study of the massive two-flavor QED in two dimensions with the gauge action proposed by L\"uscher, which allows only ``admissible'' gauge fields. We find that the admissibility condition does not allow any topology changes by the local updation in Hybrid Monte Carlo algorithm so that the configurations in each topological sector can be generated separately. By developing a new method to sum over different topological sectors, we investigate $\theta$ vacuum effects. Combining with domain-wall fermion action, we obtain the fermion mass dependence and $\theta$ dependence of the meson masses, which are consistent with the analytic results by mass perturbation in the continuum theory.Comment: 3 pages, Lattice2003(chiral

HyperCP: A high-rate spectrometer for the study of charged hyperon and kaon decays

The HyperCP experiment (Fermilab E871) was designed to search for rare phenomena in the decays of charged strange particles, in particular CP violation in $\Xi$ and $\Lambda$ hyperon decays with a sensitivity of $10^{-4}$. Intense charged secondary beams were produced by 800 GeV/c protons and momentum-selected by a magnetic channel. Decay products were detected in a large-acceptance, high-rate magnetic spectrometer using multiwire proportional chambers, trigger hodoscopes, a hadronic calorimeter, and a muon-detection system. Nearly identical acceptances and efficiencies for hyperons and antihyperons decaying within an evacuated volume were achieved by reversing the polarities of the channel and spectrometer magnets. A high-rate data-acquisition system enabled 231 billion events to be recorded in twelve months of data-taking.Comment: 107 pages, 45 Postscript figures, 14 tables, Elsevier LaTeX, submitted to Nucl. Instrum. Meth.

Thermal kaons production in the relativistic heavy ions collision

We study the thermal production of kaons in hot and dense symmetric and asymmetric hypernuclear matter in the context of the modified quark-meson coupling model. All the baryon species and kaons are treated as MIT bags that interact with each other via the scalar mesons $\sigma,\sigma^*$ and the vector mesons $\omega,\phi$ as well as the isovector meson $\rho$. Furthermore, in our calculations, we use realistic sets of hyperon-hyperon (or $YY$) interactions based on several versions of Nijmegen core potential models. We consider a system of strange hadronic matter and kaons but with zero total net strangeness of the system and conserved small negative fraction of the isospin-charge. We find strange baryons as well as kaons are produced abundantly when the temperature increases and approaches the critical temperature for the phase transition to the quark-gluon plasma. Our results show that the kaons are produced only thermally in the symmetric and asymmetric hypernuclear matter and there is no signature for the onset of kaon condensation in the relativistic heavy ions collision. The kaons appear in the system only by thermal production. However, when the system cools down strange hadrons could survive.Comment: 40 pages, 21 figure

Prescription Opioid Use Among Hispanics/Latinos With Arthritis Symptoms: Results From the Hispanic Community Health Study/Study of Latinos

Introduction: To determine the prevalence of prescription opioid (PO) use among Hispanics/Latinos with arthritis symptoms and to characterize how demographic and cultural factors are associated with PO use. Method: Cross-sectional analysis of baseline visit data during 2008 to 2011 from the Hispanic Community Health Study/Study of Latinos, a population-based cohort study of 16,415 Hispanics/Latinos living in Chicago, Illinois, Miami, Florida, Bronx, New York, and San Diego, California. Included participants self-reported painful inflammation or swelling in one or more joints. Multivariate models controlling for physical and mental health scores were constructed to assess how demographic and cultural factors were associated with PO use. Results: A total of 9.3% were using POs at the time of the baseline visit. In multivariate models, persons of Cuban background (adjusted odds ratio [AOR] = 0.42, 95% confidence interval [CI; 0.21, 0.81]) and of Dominican background (AOR = 0.38, 95% CI [0.18, 0.80]) were significantly less likely to use POs compared with a reference group of persons of Mexican background. Greater language acculturation was also negatively associated with PO use (AOR = 0.68, 95% CI [0.53, 0.87]). Conclusion: POs were used relatively uncommonly, and use showed marked variation between Hispanic/Latino groups. Future study should determine mechanisms for why greater use of English among Hispanics/Latinos might influence PO use

Negative Kaons in Dense Baryonic Matter

Kaon polarization operator in dense baryonic matter of arbitrary isotopic composition is calculated including s- and p-wave kaon-baryon interactions. The regular part of the polarization operator is extracted from the realistic kaon-nucleon interaction based on the chiral and 1/N_c expansion. Contributions of the Lambda(1116), Sigma(1195), Sigma*(1385) resonances are taken explicitly into account in the pole and regular terms with inclusion of mean-field potentials. The baryon-baryon correlations are incorporated and fluctuation contributions are estimated. Results are applied for K- in neutron star matter. Within our model a second-order phase transition to the s-wave K- condensate state occurs at rho_c \gsim 4 \rho_0 once the baryon-baryon correlations are included. We show that the second-order phase transition to the p-wave $K^-$ condensate state may occur at densities $\rho_c \sim 3\div 5 \rho_0$ in dependence on the parameter choice. We demonstrate that a first-order phase transition to a proton-enriched (approximately isospin-symmetric) nucleon matter with a p-wave K- condensate can occur at smaller densities, \rho\lsim 2 \rho_0. The transition is accompanied by the suppression of hyperon concentrations.Comment: 41 pages, 24 figures, revtex4 styl