LanHEP - a package for the automatic generation of Feynman rules in field theory. Version 3.0

The LanHEP program version 3.0 for Feynman rules generation from the Lagrangian is described. It reads the Lagrangian written in a compact form, close to the one used in publications. It means that Lagrangian terms can be written with summation over indices of broken symmetries and using special symbols for complicated expressions, such as covariant derivative and strength tensor for gauge fields. Supersymmetric theories can be described using the superpotential formalism and the 2-component fermion notation. The output is Feynman rules in terms of physical fields and independent parameters in the form of CompHEP model files, which allows one to start calculations of processes in the new physical model. Alternatively, Feynman rules can be generated in FeynArts format or as LaTeX table. One-loop counterterms can be generated in FeynArts format.Comment: 39 pages, the program is available at http://theory.sinp.msu.ru/~semenov/lanhep.htm

RHEOLOGY OF CONFINED POLYMER MELTS UNDER SHEAR-FLOW - WEAK ADSORPTION LIMIT:Weak Adsorption Limit

The dynamics of a confined polymer melt between weakly adsorbing surfaces is considered theoretically. The finite chain extensibility is taken into account explicitly, and the tangential stress and the first and the second normal-stress differences are calculated as functions of shear rate gamma. For small shear velocities (u <u**) the surface slip is large, and the apparent viscosity, eta(app), is proportional to the layer thickness h and is independent of the shear rate. For very high shear rates, the surface slip is small and the tangential stress increases with velocity to the power 1/3. Alternatively, the apparent viscosity eta decreases as a function of gamma with a characteristic -2/3 power law

The dual parametrization for gluon GPDs

We consider the application of the dual parametrization for the case of gluon GPDs in the nucleon. This provides opportunities for the more flexible modeling unpolarized gluon GPDs in a nucleon which in particular contain the invaluable information on the fraction of nucleon spin carried by gluons. We perform the generalization of Abel transform tomography approach for the case of gluons. We also discuss the skewness effect in the framework of the dual parametrization. We strongly suggest to employ the fitting strategies based on the dual parametrization to extract the information on GPDs from the experimental data.Comment: 37 pages, 2 figure

Oil pollution in the southeastern Baltic Sea by satellite remote sensing data in 2004-2015

The results of satellite monitoring of oil pollution in the Southeastern Baltic Sea in 2004-2015 are discussed in the paper. Interannual and seasonal variability of oil pollution is investigated. A steady decrease in total oil pollution was observed from 2004 to 2011. After a sharp increase of oil pollution in 2012, oil pollution level has established at 0.39 PI Index. Maximum of oil spills is observed in the spring and summer, which is probably due to favorable weather conditions for the detection of oil spills on radar images. According to the analysis of the shapes of the detected oil spills, it was concluded that the main polluters of the sea surface are vessels. No oil spills originated from the oil platform D-6 was detected in 2004-2015. Results of numerical experiments with the Seatrack Web oil spill model show that in the case of potential discharge of oil from the D-6 platform, oil will not reach the Curonian Spit beaches during 48 h after an accident

Gap symmetry and charge density excitations in high-Tc superconductors with extended saddle points in electron spectrum

It is shown that the strong anisotropy of the one-particle electron spectrum, due to the presence of extended saddle-point features (ESPF) close to the Fermi level in the hole-type cuprates YBCO and BSCCO, leads to the occurrence of a low-frequency peak in the spectral function of the charge density fluctuations due to the presence of acoustic plasmon branch in the collective electron spectrum. The retarded anisotropic electron-plasmon interaction leads to the suppression of the static screened Coulomb repulsion for small transferred momenta and, consequently, to the effective attraction between electrons in the dx²-y²-wave channel of the Cooper pairing of current carriers. Breaking of C₄v symmetry in YBCO crystals leads to a possibility of a change of dx²-y²-wave symmetry of the gap to a mixed s − d gap symmetry for singlet Cooper pairs or to a p-wave gap symmetry for triplet pairs.Показано, що сильна анізотропія одночасткового електронного спектру веде, завдяки наявності подовжених сідлових особливостей біля рівня Фермі у купратах YBCO та BSCCO, до появи низькочастотного піку у спектральній функції флуктуацій зарядової густини, що є наслідком присутності гілки акустичних плазмонів у колективному електронному спектрі. Електрон-плазмонна взаємодія веде до значного зменшення статичного кулонівського відштовхування в області малих переданих імпульсів та, як наслідок, до ефективного притягнення між електронами у dx²-y²-хвильовому каналі куперівського спарювання носіїв струму. Порушення C₄v симетрії у кристалах YBCO призводить до можливості заміни dx²-y²-хвильової симетрії надпровідної щілини на змішану s − d симертрію для сінглетних куперівських пар або на p -хвильову симетрію щілини для триплетних пар

Oil pollution of the southeastern Baltic Sea by satellite remote sensing data and in-situ measurements

Results of operational satellite monitoring of oil pollution of the sea surface together with in-situ measurements of the oil products concentration in the water column for the first time allowed to establish relation between the surface pollution originated from ships, and the general characteristics of spatial and temporal distribution of oil products in the water column in the Southeastern Baltic Sea. Areas with heightened concentrations of oil products in the surface and bottom layers were determined for the study area. The main directions of the contamination propagation are agreed with the main direction of annual mean transport of substances in the Gdansk Basin

Confinement and soliton solutions in the SL(3) Toda model coupled to matter fields

We consider an integrable conformally invariant two dimensional model associated to the affine Kac-Moody algebra SL(3). It possesses four scalar fields and six Dirac spinors. The theory does not possesses a local Lagrangian since the spinor equations of motion present interaction terms which are bilinear in the spinors. There exists a submodel presenting an equivalence between a U(1) vector current and a topological current, which leads to a confinement of the spinors inside the solitons. We calculate the one-soliton and two-soliton solutions using a procedure which is a hybrid of the dressing and Hirota methods. The soliton masses and time delays due to the soliton interactions are also calculated. We give a computer program to calculate the soliton solutions.Comment: plain LaTeX, 37 page

First study of radiation hardness of lead tungstate crystals at low temperatures

The electromagnetic calorimeter of PANDA at the FAIR facility will rely on an operation of lead tungstate (PWO) scintillation crystals at temperatures near -25 deg.C to provide sufficient resolution for photons in the energy range from 8 GeV down to 10 MeV. Radiation hardness of PWO crystals was studied at the IHEP (Protvino) irradiation facility in the temperature range from room temperature down to -25 deg.C. These studies have indicated a significantly different behaviour in the time evolution of the damaging processes well below room temperature. Different signal loss levels at the same dose rate, but at different temperatures were observed. The effect of a deep suppression of the crystal recovery process at temperatures below 0 deg.C has been seen.Comment: 10 pages 7 figure

Сравнение двухэнергетических денситометров различных моделей

Background. Dual-energy X-ray absorptiometry (DXA) is an effective method for bone mineral density (BMD) and subcutaneous fat percentage estimation. The constant development of new densitometry techniques, the demographic change and the higher potential of artificial intelligence in healthcare enhance requirements for the high-quality measurements in DXA. This study aimed to develop a quality control method for DXA scanners and compare four DXA systems with different X-ray geometries and manufacturers when simulating fat-water environments. Methods. We evaluated the accuracy (relative error (%) and precision (CV%)) of the bone mineral density (BMD) measurements, performed by the four DXA scanners: 2 with narrow-angle fan beam (64- and 16-channel detectors (DXA-1, DXA-2)); 1 with wide-angle fan beam (DXA-3); 1 with pencil beam (DXA-4). We used a PHK (PHantom Kalium) designed to imitate spine. The PHK contained four vertebras filled with a K2HPO4 solution in various concentrations (50-200 mg/ml). The PHK also included paraffin patches (thickness 40 mm) to simulate the fat layer. Results. DXA-1 and DXA-2 demonstrated the best CV% ranged from 0.56% to 1.05%. The least % was observed when scanning PHK with fat layer on DXA-1 and DXA-2 (1.74% and 0.85%) and DXA-4 (1.47%). DXA-3 produced significantly lower BMD (= -14.56%, p = 0.000). After removing the fat layer, we observed reduction (p = 0.000) of BMD for DXA- 1 and DXA-2 (= -5.11% and -6.12% respectively) and weak deviation (p = 0.80) for DXA-4 (0.87%). For DXA-3, removal of the fat layer also resulted in a significant reduction in BMD ( = -16.44%, p = 0.000). The subcutaneous fat modeling showed that all these DXA systems automatically determine the percentage of fat in the scanned area with weak underestimation: for DXA-1, DXA-2 and DXA-4 the % were -5,9%, -6,3% and -2,3% respectively. CV% were 0.15%; 0.39%; 1.6%, respectively. Conclusions. We proved a significant underestimation of the BMD measurements across the entire range of simulated parameters for the DXA scanners when the model did not include the subcutaneous fat layer. All models demonstrated high accuracy in measuring the fat layer, with the exception of the DXA-3 model, which was not assessed in these studies.Актуальность. Двухэнергетическая рентгеновская абсорбциометрия (ДРА) это эффективный метод оценки минеральной плотности костной ткани (МПК) и подкожно-жировой клетчатки (ПЖК). Постоянное развитие новых методов денситометрии, старение населения и высокий потенциал применения технологий искусственного интеллекта в здравоохранении усиливают потребности в получении высококачественных измерений МПК в ДРА. Цель исследования разработать средства и методы контроля ДРА сканеров и провести сравнение четырех денситометров разной геометрии и фирм-производителей при моделировании различного водно-жирового окружения. Материал и методы. В ходе работы проведена оценка точности (относительной погрешности (%) и воспроизводимости (CV%)) измерений МПК четырех рентгеновских денситометров: два с узковеерным пучком рентгеновского излучения с 64- и 16 рядами детекторов (DXA-1, DXA-2), один с широковеерным пучком (DXA-3); один с пучком карандашного типа (DXA-4). Для сравнения использовался фантом PHK (PHantom Kalium), моделирующий МПК поясничной области: четыре модели позвонков от нормы до остеопороза, содержащие гидрофосфат калия в различной концентрации 50200 мг/мл. PHK также включал парафиновые накладки (толщиной 40 мм), имитирующие ПЖК. Результаты. DXA-1 и DXA-2 имеют наилучшую CV%, определенную в диапазоне от 0,56% до 1,05%. Наименьшая % отмечена при сканировании PHK с ПЖК для DXA-1 и DXA-2 (1,74% и 0,85%) и DXA-4 (1,47%). При исключении ПЖК наблюдаются снижение МПК для DXA-1 и DXA-2 ( = -5,11% и -6,12% соответственно) и небольшое отклонение (p = 0,80) для DXA-4 ( = 0,87%). DXA-3 демонстрирует существенно заниженные данные измеренной МПК ( = -14,56%; p = 0,000) при сканировании PHK с ПЖК. Однако исключение ПЖК также приводит к значительному (p = 0,000) снижению МПК ( = -16,44%; p = 0,000). При анализе точности определения жирового слоя для DXA-1, DXA-2, DXA-4 отмечалась незначительная недооценка заданных показателей на -5,9%, -6,3% и -2,3% соответственно. При этом CV результатов составила 0,15%; 0,39%; 1,6%. Заключение. Результаты исследования подтвердили значительную недооценку МПК для всего диапазона возможных значений при сканировании PHK без ПЖК. Модели продемонстрировали высокую точность измерения жирового слоя за исключением DXA-3 сканера, для которого этот параметр в исследовании не оценивался

Correlation of Beam Electron and LED Signal Losses under Irradiation and Long-term Recovery of Lead Tungstate Crystals

Radiation damage in lead tungstate crystals reduces their transparency. The calibration that relates the amount of light detected in such crystals to incident energy of photons or electrons is of paramount importance to maintaining the energy resolution the detection system. We report on tests of lead tungstate crystals, read out by photomultiplier tubes, exposed to irradiation by monoenergetic electron or pion beams. The beam electrons themselves were used to measure the scintillation light output, and a blue light emitting diode (LED) was used to track variations of crystals transparency. We report on the correlation of the LED measurement with radiation damage by the beams and also show that it can accurately monitor the crystals recovery from such damage.Comment: 9 pages, 6 figures, LaTeX2