Radiative corrections to neutral pion-pair production

We calculate the one-photon loop radiative corrections to the neutral pion-pair photoproduction process $\pi^-\gamma \to \pi^-\pi^0\pi^0$. At leading order this reaction is governed by the chiral pion-pion interaction. Since the chiral $\pi^+\pi^-\to\pi^0\pi^0$ contact-vertex depends only on the final-state invariant-mass it factors out of all photon-loop diagrams. We give analytical expressions for the multiplicative correction factor $R\sim \alpha/2\pi$ arising from eight classes of contributing one-photon loop diagrams. An electromagnetic counterterm has to be included in order to cancel the ultraviolet divergences generated by the photon-loops. Infrared finiteness of the virtual radiative corrections is achieved (in the standard way) by including soft photon radiation below an energy cut-off $\lambda$. The radiative corrections to the total cross section vary between $+2\%$ and $-2\%$ for center-of-mass energies from threshold up to $7m_\pi$. The finite part of the electromagnetic counterterm gives an additional constant contribution of about $1\%$, however with a large uncertainty.Comment: 10 pages, 6 figures, submitted to Eur. Phys. J.

Available drugs during of military state: social-economic strategies of functioning reimbursumen’t system

The Russian aggresion against Ukraine became a new reality in the XXI century and definitely shook the whole World. New realities are forcing all spheres of science and practice to work harder and develop, that is why philosophers of law are tended to call war “the driving force of progress”. Our modern life in the condition of war proves, that the technical and scientific progress as it is, is created and developed on thousands and millions of destroyed human lives. But, in order to make a warring society to move successfully forward, save as many innocent lives as possible and meet basic needs of a particularly vulnerable polutation, it is not only army, which is supposed to work for 100%, but also “home front workers” has to try harder. The current war has dimished an understanding of difference between quintiles of population, especially, if we are taking into account differences between beneficiaries of the Affordable Medicines Program (AM). At the beginning of the War, all beneficiaries of the AM, despite of level of their well-being had to suffer equally because of the short-term period of medicines’ shortage due to destroyed infrastructure of cities and regions. They were afraid that those highly necessary medicines would not return to the pharmacies neither in the sphere of the AM, nor even for normal sale. Because of the aforementioned force-majeure, most of people were not even assured that their basic needs will be met, especially were worried those ones, who have been active users of the AM for a long period of time. However, despite of the aforementioned destruction of the insfrastrucutre, the commons fears and dangers of war, the AM has not stopped working. On the contrary, it has become even more successful and progressive. The need to react quickly to the circumstances that took place, forced to achieve long-term plans of the AM creators in a very short time. Thus, the pilot program has finally fit into the general outline of the life support and health care system of Ukraine and became perhaps the most progressive in the whole Europe. But, nevertheless, the progress is definitely not standing still, the situation remains critical, the humanitarian catastrophe is becoming more and more real today, and, thus, the AM opens new promising ways of development for the coming month and years. In fact, our study was devoted to the analysis of the changes that took place since February 24, 2022, as well as promising directions for the development of AM, which are mostly dictated by the newly created humaniatrian crises in the current article.Новою реалією ХХІ століття стала загарбницька війна Росії проти України, яка без сумніву сколихнула цілий світ. Нові реалії життя змушують всі сфери науки і практики працювати у посиленому режимі та розвиватись, саме тому філософи права називають війну “рушійною силою прогресу”. Сучасне життя доводить, що технічний і науковий прогрес, як виявилось, створюється і розвивається на тисячах і мільйонах зруйнованих людських життів. Але, задля того, щоб суспільство країни, що воює, змогло рухатись далі, змогло врятувати якумога більше безвинних життів та забезпечувати базові потреби особливо вразливого контингенту населення, не тільки армія, але й “герої тилу”, тобто медики і вся система охорони здоров’я мають працювати на 100%, як це власне і відбувається зараз. Війна знизила важливість понять “квінтилі населення”, особливо якщо йдеться про прямих бенефіціарів програми “Доступні ліки”, адже серед них всі, незалежно від особистого та фінансового благополуччя, були піддані необхідності страждати від першострокової нестачі ліків, які забезпечувались програмою; були підвергнуті страху, що ці ліки не повернуться не тільки в рамках програми Доступні ліки (ДЛ), але і в принципі будуть недоступні через знищену інфраструктуру багатьох міст, а отже здійснився такий force majeure, при якому жодна людина не могла бути впевнена у власному забезпеченні навіть базових потреб, і особливо ті, хто протягом тривалого часу вже був активним користувачем ДЛ. Тим не менш, не дивлячись на вищезгадану зруйновану інфраструктуру, загальні страх і небезпеку, які приносить із собою війна, програма ДЛ не припинила свою роботу, навпаки, стала навіть більш прогресивною і успішною. Необхідність стрімко реагувати на обставини, які мали місце з погляду на війну, змусили досягнути довготривалі плани творців ДЛ за дуже короткий термін. Таким чином, пілотна програма остаточно вписалась в загальну канву системи життєзабезпечення та охорони здоров’я України і стали чи не найбільш прогресивною в цілій Європі. Але, тим не менш, прогрес безумовно не стоїть на місці, ситуація залишається критичною, гуманітарна катастрофа стає все більш реальною на сьогоднішній день, а отже ДЛ відкриває нові перспективні шляхи розвитку на найближчі місяці і роки. Власне аналізові змін, які мали місце, починаючи від 24-го лютого 2022 року, а також перспективним напрямкам розвитку ДЛ, які здебільшого продиктовані новоствореними гуманітраними кризами населення нашої країни, які мали місце через війну, і було присвячено наше дослідження, результати якого будуть освітлені у нинішній статті

Diagrammatic routes to nonlocal correlations beyond dynamical mean field theory

Strong electronic correlations pose one of the biggest challenges to solid state theory. We review recently developed methods that address this problem by starting with the local, eminently important correlations of dynamical mean field theory (DMFT). On top of this, non-local correlations on all length scales are generated through Feynman diagrams, with a local two-particle vertex instead of the bare Coulomb interaction as a building block. With these diagrammatic extensions of DMFT long-range charge-, magnetic-, and superconducting fluctuations as well as (quantum) criticality can be addressed in strongly correlated electron systems. We provide an overview of the successes and results achieved---hitherto mainly for model Hamiltonians---and outline future prospects for realistic material calculations.Comment: 60 pages, 42 figures, replaced by the version to be published in Rev. Mod. Phys. 201

Optical echo in photonic crystals

The dynamics of photonic wavepacket in the effective oscillator potential is studied. The oscillator potential is constructed on a base of one dimensional photonic crystal with a period of unit cell adiabatically varied in space. The structure has a locally equidistant discrete spectrum. This leads to an echo effect, i.e. the periodical reconstruction of the packet shape. The effect can be observed in a nonlinear response of the system. Numerical estimations for porous-silicon based structures are presented for femtosecond Ti:Sapphire laser pump.Comment: 4 page

Positive parity pentaquark towers in large Nc QCD

We construct the complete set of positive parity pentaquarks, which correspond in the quark model to {\bar s} q^{Nc+1} states with one unit of orbital angular momentum L=1. In the large Nc limit they fall into the K=1/2 and K=3/2 irreps (towers) of the contracted SU(4)c symmetry. We derive predictions for the mass spectrum and the axial couplings of these states at leading order in 1/Nc. The strong decay width of the lowest-lying positive parity exotic state is of order O(1/Nc), such that this state is narrow in the large Nc limit. Replacing the antiquark with a heavy antiquark {\bar Q} q^{Nc+1}, the two towers become degenerate, split only by O(1/mQ) hyperfine interactions. We obtain predictions for the strong decay widths of heavy pentaquarks to ordinary baryons and heavy H(*)_{\bar Q} mesons at leading order in 1/Nc and 1/mQ.Comment: 21 pages, 2 figures, 5 table

Phenomenological study of light (anti)nuclei, (anti)hypertriton and di-Lambda production at RHIC

We present the production of light (anti)nuclei, (anti)hypertriton and di-Lambda based on coalescence model in central Au+Au collisions at $\sqrt{s_{NN}}=200GeV$. The invariant yields of \He(\Hebar), \hypert(\hypertbar), \Hee(\Heebar) obtained is found to be consistent with the STAR measurements. The $p_{T}$ integrated yields for di-Lambda $dN_{\Lambda\Lambda}/dy \sim 2.23\times10^{-5}$, and is not strongly dependent on the parameter employed for coalescence process. Relative particle ratios of light anti(nuclei) and (anti)hypertriton are explored, and agree with experimental data and thermal model predictions quite well. An exponential reducion behavior is presented for the differential invariant yields with increased baryon number. The production rate reduces by a factor of 1692 (1285) for each additional antinucleon (nucleon) added to antinuclei (nuclei), and the production rate of \Libar is predicted to be $10^{-16}$ which is consistent with STAR result.Comment: 4 pages, 3 figures parallel talk delivered by L. Xue at the 14th national conference on nuclear structure, April 12nd - 16th, 2012, Huzhou, Chin

Generation and Structure of Solitary Rossby Vortices in Rotating Fluids

The formation of zonal flows and vortices in the generalized Charney-Hasegawa-Mima equation is studied. We focus on the regime when the size of structures is comparable to or larger than the deformation (Rossby) radius. Numerical simulations show the formation of anticyclonic vortices in unstable shear flows and ring-like vortices with quiescent cores and vorticity concentrated in a ring. Physical mechanisms that lead to these phenomena and their relevance to turbulence in planetary atmospheres are discussed.Comment: 3 pages in REVTeX, 5 postscript figures separately, submitted to Phys. Rev.

Synthesis of Single Phase Hg-1223 High Tc Superconducting Films With Multistep Electrolytic Process

We report the multistep electrolytic process for the synthesis of high Tc single phase HgBa2Ca2Cu3O8+ (Hg-1223) superconducting films. The process includes : i) deposition of BaCaCu precursor alloy, ii) oxidation of BaCaCu films, iii) electrolytic intercalation of Hg in precursor BaCaCuO films and iv) electrochemical oxidation and annealing of Hg-intercalated BaCaCuO films to convert into Hg1Ba2Ca2Cu3O8+ (Hg-1223). Films were characterized by thermo-gravimetric analysis (TGA) and differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrolytic intercalation of Hg in BaCaCuO precursor is proved to be a novel alternative to high temperature-high pressure mercuration process. The films are single phase Hg-1223 with Tc = 121.5 K and Jc = 4.3 x 104 A/cm2.Comment: 17 Pages, 10 Figures. Submitted to Superconductor Science and Technolog

Индуктивность прямоугольных контуров

The influence of two rectangular contours with their various configurations is considered. The formulas for calculation of mutual induction are received and based on them the dependences of the coefficient of mutual induction of the distance between the contours with various shapes are built. The connection of the coefficients of mutual induction for a variety contours is installed.Рассмотрено взаимное влияние двух прямоугольных контуров при их различных конфигурациях. Получены формулы для расчета взаимоиндукции и на их основе построены зависимости коэффициента взаимной индукции от расстояния между различными по форме контурами. Установлена связь коэффициентов взаимной индукции для различных вариантов контуров