Observation of the decay 𝐵⎯⎯⎯⎯0𝑠→𝜒𝑐2𝐾+𝐾− in the ϕ mass region
The 𝐵0𝑠⎯⎯⎯⎯⎯⎯⎯→𝜒𝑐2𝐾+𝐾−Bs0¯→χc2K+K− decay mode is observed and its branching fraction relative to the corresponding 𝜒𝑐1χc1decay mode, in a ±15MeV/𝑐2±15MeV/c2 window around the 𝜙ϕ mass, is found to be (𝐵0𝑠⎯⎯⎯⎯⎯⎯⎯→𝜒𝑐2𝐾+𝐾−)(𝐵0𝑠⎯⎯⎯⎯⎯⎯⎯→𝜒𝑐1𝐾+𝐾−)=(17.1±3.1±0.4±0.9)%,B(Bs0¯→χc2K+K−)B(Bs0¯→χc1K+K−)=(17.1±3.1±0.4±0.9)%, where the first uncertainty is statistical, the second systematic and the third due to the knowledge of the branching fractions of radiative 𝜒𝑐χc decays. The decay mode 𝐵0𝑠⎯⎯⎯⎯⎯⎯⎯→𝜒𝑐1𝐾+𝐾−Bs0¯→χc1K+K− allows the 𝐵0𝑠Bs0 mass to be measured as 𝑚(𝐵0𝑠)=5366.83±0.25±0.27MeV/𝑐2,m(Bs0)=5366.83±0.25±0.27MeV/c2,where the first uncertainty is statistical and the second systematic. A combination of this result with other LHCb determinations of the 𝐵0𝑠Bs0 mass is made.
Differences in the behaviour of matter and antimatter have been observed in K and B meson decays, but not yet in any baryon decay. Such differences are associated with the non-invariance of fundamental interactions under the combined charge-conjugation and parity transformations, known as CP violation. Here, using data from the LHCb experiment at the Large Hadron Collider, we search for CP-violating asymmetries in the decay angle distributions of Λb0 baryons decaying to pπ−π+π− and pπ−K+K− final states. These four-body hadronic decays are a promising place to search for sources of CP violation both within and beyond the standard model of particle physics. We find evidence for CPviolation in Λb0 to pπ−π+π− decays with a statistical significance corresponding to 3.3 standard deviations including systematic uncertainties. This represents the first evidence for CP violation in the baryon sector.
A measurement of the time-integrated CP asymmetry in the Cabibbo-suppressed decay D0→K−K+ is performed using pp collision data, corresponding to an integrated luminosity of 3fb−1, collected with the LHCb detector at centre-of-mass energies of 7 and 8 TeV. The flavour of the charm meson at production is determined from the charge of the pion in ⁎D⁎+→D0π+ and ⁎D⁎−→D‾0π− decays. The time-integrated CP asymmetry ACP(K−K+) is obtained assuming negligible CP violation in charm mixing and in Cabibbo-favoured D0→K−π+, D+→K−π+π+ and D+→K‾0π+ decays used as calibration channels. It is found to beACP(K−K+)=(0.14±0.15(stat)±0.10(syst))%.
A combination of this result with previous LHCb measurements yieldsACP(K−K+)=(0.04±0.12(stat)±0.10(syst))%,ACP(π−π+)=(0.07±0.14(stat)±0.11(syst))%.
These are the most precise measurements from a single experiment. The result for ACP(K−K+) is the most precise determination of a time-integrated CP asymmetry in the charm sector to date, and neither measurement shows evidence of CP asymmetry.
The production of ϒ(nS) mesons (n = 1, 2, 3) in pPb and Pbp collisions at a centre-of-mass energy per nucleon pair 𝑠NN‾‾‾‾√=8.16sNN=8.16 TeV is measured by the LHCb experiment, using a data sample corresponding to an integrated luminosity of 31.8 nb−1−1. The ϒ(nS) mesons are reconstructed through their decays into two opposite-sign muons. The measurements comprise the differential production cross-sections of the ϒ(1S) and ϒ(2S) states, their forward-to-backward ratios and nuclear modification factors. The measurements are performed as a function of the transverse momentum p𝑇T and rapidity in the nucleon-nucleon centre-of-mass frame y∗∗ of the ϒ(nS) states, in the kinematic range p𝑇T < 25 GeV/c and 1.5 < y∗∗ < 4.0 (−5.0 < y∗∗ < −2.5) for pPb (Pbp) collisions. In addition, production cross-sections for ϒ(3S) are measured integrated over phase space and the production ratios between all three ϒ(nS) states are determined. Suppression for bottomonium in proton-lead collisions is observed, which is particularly visible in the ratios. The results are compared to theoretical models.
A model for organizing cargo transportation between two node stations connected by a railway line which contains a certain number of intermediate stations is considered. The movement of cargo is in one direction. Such a situation may occur, for example, if one of the node stations is located in a region which produce raw material for manufacturing industry located in another region, and there is another node station. The organization of freight traﬃc is performed by means of a number of technologies. These technologies determine the rules for taking on cargo at the initial node station, the rules of interaction between neighboring stations, as well as the rule of distribution of cargo to the ﬁnal node stations. The process of cargo transportation is followed by the set rule of control. For such a model, one must determine possible modes of cargo transportation and describe their properties. This model is described by a ﬁnite-dimensional system of diﬀerential equations with nonlocal linear restrictions. The class of the solution satisfying nonlocal linear restrictions is extremely narrow. It results in the need for the “correct” extension of solutions of a system of diﬀerential equations to a class of quasi-solutions having the distinctive feature of gaps in a countable number of points. It was possible numerically using the Runge–Kutta method of the fourth order to build these quasi-solutions and determine their rate of growth. Let us note that in the technical plan the main complexity consisted in obtaining quasi-solutions satisfying the nonlocal linear restrictions. Furthermore, we investigated the dependence of quasi-solutions and, in particular, sizes of gaps (jumps) of solutions on a number of parameters of the model characterizing a rule of control, technologies for transportation of cargo and intensity of giving of cargo on a node station.
Event logs collected by modern information and technical systems usually contain enough data for automated process models discovery. A variety of algorithms was developed for process models discovery, conformance checking, log to model alignment, comparison of process models, etc., nevertheless a quick analysis of ad-hoc selected parts of a journal still have not get a full-fledged implementation. This paper describes an ROLAP-based method of multidimensional event logs storage for process mining. The result of the analysis of the journal is visualized as directed graph representing the union of all possible event sequences, ranked by their occurrence probability. Our implementation allows the analyst to discover process models for sublogs defined by ad-hoc selection of criteria and value of occurrence probability
The dynamics of a two-component Davydov-Scott (DS) soliton with a small mismatch of the initial location or velocity of the high-frequency (HF) component was investigated within the framework of the Zakharov-type system of two coupled equations for the HF and low-frequency (LF) fields. In this system, the HF field is described by the linear Schrödinger equation with the potential generated by the LF component varying in time and space. The LF component in this system is described by the Korteweg-de Vries equation with a term of quadratic influence of the HF field on the LF field. The frequency of the DS soliton`s component oscillation was found analytically using the balance equation. The perturbed DS soliton was shown to be stable. The analytical results were confirmed by numerical simulations.