Development of the self-modulation instability of a relativistic proton bunch in plasma

Self-modulation is a beam-plasma instability that is useful to drive large-amplitude wakefields with bunches much longer than the plasma skin depth. We present experimental results showing that, when increasing the ratio between the initial transverse size of the bunch and the plasma skin depth, the instability occurs later along the bunch, or not at all, over a fixed plasma length, because the amplitude of the initial wakefields decreases. We show cases for which self-modulation does not develop and we introduce a simple model discussing the conditions for which it would not occur after any plasma length. Changing bunch size and plasma electron density also changes the growth rate of the instability. We discuss the impact of these results on the design of a particle accelerator based on the self-modulation instability seeded by a relativistic ionization front, such as the future upgrade of the AWAKE experiment

Влияние применения биологических препаратов на формирование качественных показателей зерна яровой пшеницы

Relevance. For a more complete realization of the biological potential inherent in the culture and directly in each variety, in the agrotechnology used, separate elements are used that contribute to more effective plant development. This should include the use of biological preparations that are not only able to stimulate and regulate the growth and development of plants, but are also safe for the environment. In this regard, the research results presented in this paper are relevant and timely.Materials and methods. In our study, we studied the effect of pre-sowing treatment of spring wheat seeds and its (processing) aftereffect on grain quality indicators and seed sowing properties. The early-ripening variety of spring soft wheat Iren was taken as an object of research. The subject of the study is biological preparations, their effect and aftereffect during pre–sowing seed treatment on the formation of grain and the quality of the seed material of the crop.Results. Studies have revealed differences in the intensity of the effect of presowing seed treatment with biological preparations and the aftereffect of treatment on the quality indicators of spring wheat grain. The aftereffect of the drugs increased the protein content in the grain. The maximum protein content in the experiment was obtained in variant 2 (the preparation was obtained by the method of VAG based on pine needles (HS 22)) – 17.0%.The gluten content in the grain in variants of experiments 2 and 3 was formed above 32%, which corresponds to the 1st class. The maximum gluten content in the grain was obtained in variant 2 (HS 22) – 41.8% in experiment 3 (aftereffect). The vitreous content of the grain in all variants of experiments 2 and 3 is higher than 60%, which makes it possible to classify the grain to the 1st class. A higher level of grain nature was obtained on variants with the aftereffect of drugs. Grain on the variants of experiment 3: control, 3 (LP 4), 8 (Cytohumate), 9 (Lignohumate) with grain in kind above 750 g should be attributed to the 1st class.Актуальность. Для более полной реализации биологического потенциала, заложенного в культуре и непосредственно в каждом сорте, в используемой агротехнологии применяют отдельные элементы, способствующие более эффективному развитию растений. Сюда следует отнести использование биологических препаратов, которые не только способны стимулировать и регулировать рост и развитие растений, но и безопасны для окружающей среды. В связи с этим, представленные в данной работе результаты исследований актуальны и своевременны.Материалы и методы. В своём исследовании мы изучали влияние предпосевной обработки семян яровой пшеницы и её (обработки) последействие на показатели качества зерна. В качестве объекта исследований взят раннеспелый сорт яровой мягкой пшеницы Ирень. Предмет исследования – биологические препараты, их действие и последействие при предпосевной обработки семян на формирование качества зерна.Результаты. Исследования выявили различия в интенсивности влияния предпосевной обработки семян биологическими препаратами и последействие обработки на показатели качества зерна яровой пшеницы. Последействие препаратов усилило показатель содержания белка в зерне. Максимальное содержание белка в опыте получено в варианте 2 (препарат, получен методом ВАГ на основе хвои сосны (ХС 22)) – 17,0%.Содержание клейковины в зерне в вариантах опытов сформировалось выше 32%, что соответствует 1 классу. Максимальное содержание клейковины в зерне получено в варианте 2 (ХС 22) – 41,8% в опыте 2 (последействие). Стекловидность зерна во всех вариантах опытов 1 и 2 выше 60%, что позволяет отнести зерно к 1 классу. Более высокий уровень натуры зерна получен в вариантах с последействием препаратов. Зерно, полученное в вариантах опыта 2: контроль, 3 (ЛП 4), 8 (Цитогумат), 9 (Лигногумат) с натурой зерна выше 750 г следует отнести к 1 классу. Анализ результатов исследования показал, что последействие предпосевной обработки семян биологическими препаратами оказывает более действенное положительное влияние на качество зерна яровой пшеницы

Impact of hydrocarbon drilling mud on mud motor elastomers at different temperatures

The paper describes the experimental research of hydrocarbon drilling mud impact on engineering parameters of mud motor elastomer samples. It is believed to be urgent due to an increase in using mud motors in oil and gas well construction now, and the issue of intense exploitation is currently topical. The test results of elastomer IRP- 1226 dependent on the temperature are shown in the paper. It is proved that the hydrocarbon drilling muds have a significant impact on wearing of mud motors elastomers under the condition of a temperature increase

«Язык – это путь цивилизации и культуры»

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A concept of the transition radiation detector for a hadron separation in a forward direction of the LHC experiments

Studying of hadron production in forward direction at the LHC energy has a great interest both for understanding of the fundamental QCD processes and also in applied areas such as the description of ultra-high energy cosmic particle interactions. The energies of secondary hadrons in such studies almost reach the maximum energy available at the LHC of ∼6 TeV, which corresponds to a Lorentz γ-factor up to 104 and above. The only effective technique able to identify particles in this range is based on the transition radiation detectors (TRD). Prototypes of such kind of detector were built and tested at the CERN SPS accelerator. Some experimental results obtained in these tests are briefly presented here and compared with Monte Carlo (MC) simulations. MC model demonstrates a good agreement with the experiment. On this basis a concept of a full-scale TRD optimized for the hadron identification in the TeV energy region is proposed. Different particle identification techniques were considered and examined. The expected detector performance to reconstruct secondary hadrons produced in forward direction at the LHC is presented

Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

This paper presents measurements of the $W^+ \rightarrow \mu^+\nu$ and $W^- \rightarrow \mu^-\nu$ cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

Measurements of fiducial and differential cross sections for Higgs boson production in the diphoton decay channel at s√=8 TeV with ATLAS

Measurements of fiducial and differential cross sections are presented for Higgs boson production in proton-proton collisions at a centre-of-mass energy of s√=8 TeV. The analysis is performed in the H → γγ decay channel using 20.3 fb−1 of data recorded by the ATLAS experiment at the CERN Large Hadron Collider. The signal is extracted using a fit to the diphoton invariant mass spectrum assuming that the width of the resonance is much smaller than the experimental resolution. The signal yields are corrected for the effects of detector inefficiency and resolution. The pp → H → γγ fiducial cross section is measured to be 43.2 ±9.4(stat.) − 2.9 + 3.2 (syst.) ±1.2(lumi)fb for a Higgs boson of mass 125.4GeV decaying to two isolated photons that have transverse momentum greater than 35% and 25% of the diphoton invariant mass and each with absolute pseudorapidity less than 2.37. Four additional fiducial cross sections and two cross-section limits are presented in phase space regions that test the theoretical modelling of different Higgs boson production mechanisms, or are sensitive to physics beyond the Standard Model. Differential cross sections are also presented, as a function of variables related to the diphoton kinematics and the jet activity produced in the Higgs boson events. The observed spectra are statistically limited but broadly in line with the theoretical expectations

Measurement of the production of a W boson in association with a charm quark in pp collisions at √s = 7 TeV with the ATLAS detector

The production of a W boson in association with a single charm quark is studied using 4.6 fb−1 of pp collision data at s√ = 7 TeV collected with the ATLAS detector at the Large Hadron Collider. In events in which a W boson decays to an electron or muon, the charm quark is tagged either by its semileptonic decay to a muon or by the presence of a charmed meson. The integrated and differential cross sections as a function of the pseudorapidity of the lepton from the W-boson decay are measured. Results are compared to the predictions of next-to-leading-order QCD calculations obtained from various parton distribution function parameterisations. The ratio of the strange-to-down sea-quark distributions is determined to be 0.96+0.26−0.30 at Q 2 = 1.9 GeV2, which supports the hypothesis of an SU(3)-symmetric composition of the light-quark sea. Additionally, the cross-section ratio σ(W + +c¯¯)/σ(W − + c) is compared to the predictions obtained using parton distribution function parameterisations with different assumptions about the s−s¯¯¯ quark asymmetry