Towards a complete next-to-logarithmic description of forward exclusive diffractive dijet electroproduction at HERA: real corrections

We studied the $ep\rightarrow ep+2jets$ diffractive cross section with ZEUS phase space. Neglecting the $t$-channel momentum in the Born and gluon dipole impact factors, we calculated the corresponding contributions to the cross section differential in $\beta=\frac{Q^{2}}{Q^{2}+M_{2jets}^{2}}$ and the angle $\phi$ between the leptonic and hadronic planes. The gluon dipole contribution was obtained in the exclusive $k_{t}$-algorithm with the exclusive cut $y_{cut}=0.15$ in the small $y_{cut}$ approximation. In the collinear approximation we canceled singularities between real and virtual contributions to the $q\bar{q}$ dipole configuration, keeping the exact $y_{cut}$ dependency. We used the Golec-Biernat - W\"usthoff (GBW) parametrization for the dipole matrix element and linearized the double dipole contributions. The results give roughly $\frac{1}{2}$ of the observed cross section for small $\beta$ and coincides with it for large $\beta.$Comment: 40 pages, 7 figure

Impact factor for high-energy two and three jets diffractive production

We present the calculation of the impact factor for the gamma(*) -> q qb g transition within Balitsky's high energy operator expansion. We also rederive the impact factor for the gamma(*) -> q qb transition within the same framework. These results provide the necessary building blocks for further phenomenological studies of inclusive diffractive deep inelastic scattering as well as for two and three jets diffractive production which go beyond approximations discussed in the litterature.Comment: 27 pages, 2 figure

Impact Factor for Exclusive Diffractive Dijet Production with NLO Accuracy

Relying on the shockwave approach, we present the main steps of the computation of the impact factor for the exclusive diffractive photo- or electro- production of a forward dijet with NLO accuracy. We provide details of the cancellation mechanisms for all the divergences which appear in the intermediate results.Comment: 4 pages, 1 figure; proceedings of "Diffraction 2016", International Workshop on Diffraction in High-Energy Physics, Acireale (Catania, Sicily), Sept. 2-8, 2016; to be published in the conference proceedings by AI

NLO exclusive diffractive processes with saturation

We present two NLO exclusive impact factors computed in the QCD shock wave approach. These are the very first steps towards precision studies of a wide range of high energy exclusive processes with saturation effects in $ep$, $eA$, $pp$ and $pA$ collisions.Comment: 8 pages, 2 figures, to appear in the proceedings of XXV International Workshop on Deep-Inelastic Scattering and Related Subject - DIS 2017, 3-7 April 2017, University of Birmingham, U

Paving the Way Towards Precision Physics in Saturation Studies Through Exclusive Diffractive Light Neutral Vector Meson Production

We perform the first next-to-leading order computation of the $\gamma^{(*)} \to V$ ($\rho, \phi, \omega$) impact factor in the QCD shockwave approach and in the most general kinematics. This paves the way to the very first quantitative study of high-energy nucleon and nucleus saturation beyond the leading order, in various processes to be measured in $ep$, $eA$, $pp$ and $pA$ collisions at existing and future colliders.Comment: 7 pages, 1 figur

The Period Changes of the Cepheid RT Aurigae

Observations of the light curve for the 3.7-day Cepheid RT Aur both before and since 1980 indicate that the variable is undergoing an overall period increase, amounting to +0.082 +-0.012 s/yr, rather than a period decrease, as implied by all observations prior to 1980. Superposed on the star's O-C variations is a sinusoidal trend that cannot be attributed to random fluctuations in pulsation period. Rather, it appears to arise from light travel time effects in a binary system. The derived orbital period for the system is P = 26,429 +-89 days (72.36 +-0.24 years). The inferred orbital parameters from the O-C residuals differ from those indicated by existing radial velocity data. The latter imply the most reasonable results, namely a1 sin i = 9.09 (+-1.81) x 10^8 km and a minimum secondary mass of M2 = 1.15 +-0.25 Msun. Continued monitoring of the brightness and radial velocity changes in the Cepheid are necessary to confirm the long-term trend and to provide data for a proper spectroscopic solution to the orbit.Comment: Accepted for publication in PASP (November 2007

Дискретно-континуальное упрочнение контактирующих элементов конструкций: концепция, математическое и численное моделирование

The paper proposes a variant of discrete and continual strengthening of contacting elements of machine-building structures. One of the parts is strengthened discretely, and its counterpart is strengthened continually. The resulting pair combines positive qualities of two different types of strengthening methods. Investigations on stressed-deformed state of the treated fragments provides a basis for conclusion about high efficiency of the proposed combined strengthening method. While applying the method mechanisms of negative feedback between the stages “loading – contact interaction – friction – wear” are involved unlike with conventional versions of strengthening technologies. In this way, positive integral effect results from an application of the developed strengthening technology. This effect is significantly higher than the sum of effects obtained owing to application of every strengthening technology. In this case a favorable distribution of contact pressures between contacting bodies has been ensured. This, in its turn, leads to a decrease in wear that prevents a sharp increase in loads acting between bodies. Thus stabilization of the investigated processes occur. The papers considers stress-strain state of a representative fragment of the investigated system in order to demonstrate positive effects arising from the contact of strengthened bodies. Results of the calculations indicate validity of forecast assumptions. Indeed, the strengthened zones can bear high loads. However, due to high tribo-mechanical properties of the material in the hardened zones, friction and wear in them are much lower than for a base material. Due to this, all positive components of the total effect are formed. This effect is supported by the fact that a counterpart is processed continually. In particular, metals from aluminum-type materials are coated with a thin layer of oxides by forming them in a strong electric field of a special medium. Formed solid phases of oxides serve as a structural basis for formation of surface layers. In combination with discretely strengthened surfaces of counterparts the formed pair acquires high strength, antifriction and anti-wear properties.Предложен вариант дискретно-континуального упрочнения контактирующих элементов машиностроительных конструкций. Одна из деталей упрочняется дискретно, а ответная – континуально. Получаемая пара сочетает положительные качества двух разнотипных методов упрочнения. Исследование напряженно-деформированного состояния обработанных фрагментов дает основание для вывода о высокой эффективности предложенного комбинированного метода упрочнения. При его использовании, в отличие от традиционных вариантов технологий упрочнения, задействуются механизмы отрицательной обратной связи между этапами «нагружение – контактное взаимодействие – трение – износ». В результате получается положительный интегральный эффект от применения разработанной технологии упрочнения. Данный эффект существенно превышает сумму эффектов от использования каждой из технологий упрочнения. При этом обеспечивается благоприятное распределение контактных давлений между контактирующими телами. Это, в свою очередь, приводит к уменьшению износа, что препятствует резкому возрастанию действующих между телами нагрузок. Таким образом происходит стабилизация исследуемых процессов. Для демонстрации положительных эффектов, возникающих при контакте упрочненных тел, рассмотрено напряженнодеформированное состояние представительного фрагмента исследуемой системы. Результаты расчетов свидетельствуют о справедливости прогнозных предположений. Действительно, упрочненные зоны воспринимают большие нагрузки. Однако в силу высоких трибомеханических свойств материала в упрочненных зонах трение и износ в них намного ниже, чем у основного материала. За счет этого формируются все положительные компоненты суммарного эффекта. Данный эффект подкрепляется тем, что ответная деталь обработана континуально. В частности, металлы из материалов типа алюминия покрываются тонким слоем оксидов путем их образования в сильном электрическом поле в специальной среде. Образуемые твердые фазы оксидов служат структурной основой формирования поверхностных слоев. В сочетании с дискретно упрочненными поверхностями ответных деталей образуемая пара приобретает высокие прочностные, антифрикционные и противоизносные свойства