Observation of Top Quark Production in Proton-Nucleus Collisions

Peer reviewe

Observation of B-c(+) -> J/psi D-(*()) K-(*()) decays

A search for the decays $B_c^+ \to J/\psi D^{(*)0} K^+$ and $B_c^+ \to J/\psi D^{(*)+} K^{*0}$ is performed with data collected at the LHCb experiment corresponding to an integrated luminosity of 3 fb$^{-1}$. The decays $B_c^+ \to J/\psi D^0 K^+$ and $B_c^+ \to J/\psi D^{*0} K^+$ are observed for the first time, while first evidence is reported for the $B_c^+ \to J/\psi D^{*+} K^{*0}$ and $B_c^+ \to J/\psi D^+ K^{*0}$ decays. The branching fractions of these decays are determined relative to the $B_c^+ \to J/\psi \pi^+$ decay. The $B_c^+$ mass is measured, using the $J/\psi D^0 K^+$ final state, to be $6274.28 \pm 1.40 (stat) \pm 0.32 (syst)$ MeV/$c^2$. This is the most precise single measurement of the $B_c^+$ mass to date.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-055.htm

Study of the Process of Grain Pre-threshing by Working Bodies of a Combine Harvester Header

We improved the combined technological process of transportation and threshing of GSM and developed the device of preliminary grain threshing for a grain header of KZS 9-1 «Stavutich» harvester, which made it possible to separate 30–35 % of grain at the early phases of its transportation to TSS of a combine. We established that the coefficient of separation of grain from cones in a header with an intermediate thrashing drum, which contains four additional tooth-shaped bars of 30 mm in height, has the highest (0.32) value.We developed a calculation and experimental method for determining the amount (degree) of grain separation by a device of a header of a combine harvester. The method is based on the results of simulation of the combined process of transportation and threshing of grain caused by the interaction of a drum with grain and straw mass.We analyzed and proved the complex influence of structural parameters of the device and modes of implementation of the combined process of transportation and threshing of GSM at the level of separation of grain. And this make it possible to establish a theoretical dependence of the grain separation coefficient. The noted theoretical dependence provides the possibility to substantiate rational parameters and operating modes of the device of preliminary grain threshing of a combine harvester analytically.We determined dependences of the grain separation coefficient on the speed of a combine experimentally. The dependences take into account cancellations of mechanized technological operations caused by changes in kinematic operating modes of a combine, a number of stops and their height on a drum of a device of preliminary grain threshin

Thin­walled Structures: Analysis of the Stressed­strained State and Parameter Validation

The approach is developed to substantiate technical solutions for thin-walled machine building structures. It implies that the problem is considered in the space of generalized parameters. These parameters combine design and technological factors, as well as operating conditions. In addition, we introduce criterial and constraint dependences to a given space. In the generated uniform parametric space an approximated response surface is constructed, which stretches over a discrete set of solutions to analysis problems. For example, based on the results of examining the stresses-strained state, maximum stresses or displacements, mass or other controlled magnitudes are determined. They are unambiguously computed (a point in a common parametric space) for a specific set of variable generalized parameters. Having a cloud of such points, it is possible to construct an approximated response surface. Approximation constraints are also built on it. Next, by using the methods of nonlinear programming, we search on the set of permissible values for the minimum (or maximum) of quality function of the examined structure.Specifically, for the thin-walled structures, important parameters are the shape and dimensions in a plan, as well as thickness of individual elements. Using a number of structures as examples, authors of present work performed analysis of influence of these parameters on the strength of designed structures

Observation of B-c(+) -> J/psi D-(*()) K-(*()) decays

A search for the decays B-c(+) -> J/psi D-(*()0) Kappa(+) and B-c(+) -> J/psi D-(*K)+*(0) is performed with data collected at the LHCb experiment corresponding to an integrated luminosity of 3 fb(-1). The decays B-c(+) -> J/psi(DK+)-K-0 and B-c(+) -> J/psi D*K-0(+) are observed for the first time, while first evidence is reported for the B-c(broken vertical bar) -> J/psi D*K-broken vertical bar(*0) and B-c(broken vertical bar) -> J/psi(DK)-K-broken vertical bar*(0) decays. The branching fractions of these decays are determined relative to the B-c(+) -> J/psi pi(+) decay. The B-c(+) mass is measured, using the J/psi(DK+)-K-0 final state, to be 6274.28 +/- 1.40(stat) +/- 0.32(syst) MeV/c(2). This is the most precise single measurement of the B-c(+) mass to date

Observation of B+c→J/ψD(∗)K(∗) decays

See paper for full list of authors - All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-055.html - Submitted to Phys. Rev. DInternational audienceA search for the decays B+c→J/ψD(∗)0K+ and B+c→J/ψD(∗)+K∗0 is performed with data collected at the LHCb experiment corresponding to an integrated luminosity of 3 fb−1. The decays B+c→J/ψD0K+ and B+c→J/ψD∗0K+ are observed for the first time, while first evidence is reported for the B+c→J/ψD∗+K∗0 and B+c→J/ψD+K∗0 decays. The branching fractions of these decays are determined relative to the B+c→J/ψπ+ decay. The B+c mass is measured, using the J/ψD0K+ final state, to be 6274.28±1.40(stat)±0.32(syst) MeV/c2. This is the most precise single measurement of the B+c mass to date