Towards the NNLL precision in Bˉ→Xsγ\bar B \to X_s \gamma

The present NLL prediction for the decay rate of the rare inclusive process $\bar B \to X_s \gamma$ has a large uncertainty due to the charm mass renormalization scheme ambiguity. We estimate that this uncertainty will be reduced by a factor of 2 at the NNLL level. This is a strong motivation for the on-going NNLL calculation, which will thus significantly increase the sensitivity of the observable $\bar B \to X_s \gamma$ to possible new degrees of freedom beyond the SM. We also give a brief status report of the NNLL calculation.Comment: 5 pages, 2 figures, contribution to the proceedings of EPS-HEP 200

Reduction of Charm Quark Mass Scheme Dependence in Bˉ→Xsγ\bar B \to X_s \gamma at the NNLL Level

The uncertainty of the theoretical prediction of the $\bar B \to X_s \gamma$ branching ratio at NLL level is dominated by the charm mass renormalization scheme ambiguity. In this paper we calculate those NNLL terms which are related to the renormalization of $m_c$, in order to get an estimate of the corresponding uncertainty at the NNLL level. We find that these terms significantly reduce (by typically a factor of two) the error on ${BR}(\bar B \to X_s \gamma)$ induced by the definition of $m_c$. Taking into account the experimental accuracy of around 10% and the future prospects of the $B$ factories, we conclude that a NNLL calculation would increase the sensitivity of the observable $\bar B \to X_s \gamma$ to possible new degrees of freedom beyond the SM significantly.Comment: 13 pages including 3 figure

The totally asymmetric exclusion process with generalized update

We consider the totally asymmetric exclusion process in discrete time with generalized updating rules. We introduce a control parameter into the interaction between particles. Two particular values of the parameter correspond to known parallel and sequential updates. In the whole range of its values the interaction varies from repulsive to attractive. In the latter case the particle flow demonstrates an apparent jamming tendency not typical for the known updates. We solve the master equation for $N$ particles on the infinite lattice by the Bethe ansatz. The non-stationary solution for arbitrary initial conditions is obtained in a closed determinant form.Comment: 11 pages, 3 figure

Universal exit probabilities in the TASEP

We study the joint exit probabilities of particles in the totally asymmetric simple exclusion process (TASEP) from space-time sets of given form. We extend previous results on the space-time correlation functions of the TASEP, which correspond to exits from the sets bounded by straight vertical or horizontal lines. In particular, our approach allows us to remove ordering of time moments used in previous studies so that only a natural space-like ordering of particle coordinates remains. We consider sequences of general staircase-like boundaries going from the northeast to southwest in the space-time plane. The exit probabilities from the given sets are derived in the form of Fredholm determinant defined on the boundaries of the sets. In the scaling limit, the staircase-like boundaries are treated as approximations of continuous differentiable curves. The exit probabilities with respect to points of these curves belonging to arbitrary space-like path are shown to converge to the universal Airy$_2$ process.Comment: 46 pages, 7 figure

The use of combined hormonal contraception in the context of the COVID-19 pandemic

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV2) was declared the cause of a global pandemic in early 2020. Patients with COVID-19 are at high risk for thrombotic occlusions of the arteries and veins. There are many ways that explain the high risk of thrombosis in COVID-19, they are conditionally divided into two main categories: mechanisms in which the renin-angiotensinaldosterone system is involved and mechanisms that affect the regulation of the immune response. It is assumed that the uncomplicated course of the disease is characterized by endothelial dysfunction, but if the process progresses with a pronounced immune response, plasma coagulation factors may also be involved, which significantly increases the risks of thromboembolic complications. The use of combined hormonal contraception (CHC) in the current conditions raises a number of concerns. According to some researchers, disorders of the hemostasis system observed in patients with COVID-19 may worsen while taking CHC and increase the risk of thromboembolic complications, which is especially important in severe disease with prolonged immobilization. However, with the use of CHC, the increase in thrombotic risks is explained primarily by changes in the plasma component of the hemostasis sys tem. At first glance, the recommendations to stop hormone therapy with confirmed COVID-19 seem logical, but they are based only on the procoagulant activity of estrogens, and not on real evidence. In patients with COVID-19, the increase in coagulation is associ ated with massive damage to the vascular endothelium (the so-called «external» coagulation pathway) and the immune response, and not with a primary increase in the level of coagulation factors per se. At the same time, stopping the intake of estrogens deprives the patient of their important protective effect. Thus, it became necessary to develop clinical guidelines for the management of women using contraception in the context of the COVID-19 pandemic

NNLL QCD Contribution of the Electromagnetic Dipole Operator to Gamma(anti-B -> X(s) gamma)

We present an independent calculation of that part of the O(\alpha_s^2) contribution to the decay width \Gamma(\bar B -> X_s \gamma) which arises from the self-interference term of the electromagnetic dipole operator O_7. Using a different method, we find complete agreement with a previous calculation. This NNLL contribution is an important ingredient for the complete NNLL prediction of \Gamma(\bar B -> X_s \gamma) which will resolve the charm quark mass ambiguity appearing at NLL accuracy.Comment: 15 pages, uses axodraw.st

Multispecies virial expansions

We study the virial expansion of mixtures of countably many different types of particles. The main tool is the Lagrange–Good inversion formula, which has other applications such as counting coloured trees or studying probability generating functions in multi-type branching processes. We prove that the virial expansion converges absolutely in a domain of small densities. In addition, we establish that the virial coefficients can be expressed in terms of two-connected graphs

Робот-ассистированная трансплантация почки. Первый опыт

Kidney transplantation is the preferred renal replacement therapy for patients with end-stage renal disease. Traditional surgical approaches consisting of vascular and urinary outflow reconstruction during kidney transplant have been sufficiently studied and standardized. However, surgical techniques are still evolving. The objective of this clinical report is to focus the attention of kidney transplant surgeons and specialists on the currently trending robot-assisted kidney transplantation (RAKT) as a minimally invasive procedure for surgical treatment of patients with end-stage renal disease. In our first experience, good primary graft function was achieved. This shows that RAKT is a surgical option. With considerable number of surgeries and experience, RAKT outcomes would be improved significantly.Аллотрансплантация почки в настоящее время во всем мире является предпочтительным методом заместительной терапии у пациентов с терминальной стадией поражения почечной функции. Классические хирургические принципы сосудистой реконструкции и создания мочевого оттока при пересадке почки полностью изучены и стандартизированы. Несмотря на это, эволюция хирургической техники все же является непрерывным процессом. Целью данного клинического сообщения является акцентирование внимания хирургов-трансплантологов и специалистов, занятых в лечении реципиентов почек, на отражающем современные тенденции развития хирургии виде робот-ассистированной трансплантации почки (РАТП), как на щадящем методе оперативного лечения пациентов с терминальной стадией поражения почек. Результаты первого опыта в виде хорошей первичной функции трансплантата почки демонстрируют возможность использования РАТП как варианта хирургического вмешательства. Накопление же достаточного пула проведенных операций в значительной степени улучшит результаты использования такого метода лечения

Charged-Particle Multiplicity in Proton-Proton Collisions

This article summarizes and critically reviews measurements of charged-particle multiplicity distributions and pseudorapidity densities in p+p(pbar) collisions between sqrt(s) = 23.6 GeV and sqrt(s) = 1.8 TeV. Related theoretical concepts are briefly introduced. Moments of multiplicity distributions are presented as a function of sqrt(s). Feynman scaling, KNO scaling, as well as the description of multiplicity distributions with a single negative binomial distribution and with combinations of two or more negative binomial distributions are discussed. Moreover, similarities between the energy dependence of charged-particle multiplicities in p+p(pbar) and e+e- collisions are studied. Finally, various predictions for pseudorapidity densities, average multiplicities in full phase space, and multiplicity distributions of charged particles in p+p(pbar) collisions at the LHC energies of sqrt(s) = 7 TeV, 10 TeV, and 14 TeV are summarized and compared.Comment: Invited review for Journal of Physics G -- version 2: version after referee's comment

ϕ\phi Meson Production in In-In Collisions and the ϕ\phi Puzzle

The NA60 experiment measured dimuon production in In-In collisions at 158 AGeV. This paper presents a high statistics measurement of $\phi\to\mu\mu$ with the specific objective to provide insight on the $\phi$ puzzle, i.e. the difference in the inverse $T$ slopes and absolute yields measured by NA49 and NA50 in the kaon and lepton channel, respectively. Transverse momentum distributions were studied as a function of centrality. The slope parameter $T$ shows a rapid increase with centrality, followed by a saturation. Variations of $T$ with the fit range of the order of 15 MeV were observed, possibly as a consequence of radial flow. The $\phi$ meson yield normalized to the number of participants increases with centrality and is consistently higher than the yield measured by the NA49 experiment at any centrality.Comment: 4 Pages, 2 Figures. Proceedings of the 20$^{th}$ International Conference on Ultra-Relativistic Nucleus Nucleus Collision