71 research outputs found

    Development of methods for determining the coordinates of firing positions of roving mortars by a network of counter-battery radars

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    The mathematical formulation of the problem of determining the coordinates of targets in the network of counter-battery radars is formulated. It has been established that the problem of estimating the coordinates of targets in the network of counter-battery radars for an excessive number of estimates of primary coordinates should be considered as a statistical problem. The method for determining the coordinates of the firing positions of roving mortars has been improved, in which, in contrast to the known ones, the coordinates of targets on the flight trajectory are coordinated with space and time and the information is processed by a network of counter-battery radars. The developed simulation mathematical model for determining the coordinates of the firing positions of roving mortars by a network of counter-battery radars. Simulation modeling of the method for determining the coordinates of the firing positions of roving mortars by a network of counter-battery radars has been carried out. It has been established that the use of a network of radars makes it possible to increase the accuracy of determining the coordinates of the firing means on average from 23 % to 71 %, depending on the number of counter-battery radars in the network. It has also been found that the appropriate number of counter-battery warfare radars in the network is three or four. A further increase in the number of counter-battery warfare radars in the network does not lead to a significant increase in the accuracy of determining the coordinates of artillery and mortar firing positions. In carrying out further research, it is necessary to develop a method for the spatial separation of elements of a group of targets and interfering objects by a network of counter-battery warfare radar

    Production of heavy flavours at HERA

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    Development of methods for determining the coordinates of firing positions of roving mortars by a network of counter-battery radars

    No full text
    The mathematical formulation of the problem of determining the coordinates of targets in the network of counter-battery radars is formulated. It has been established that the problem of estimating the coordinates of targets in the network of counter-battery radars for an excessive number of estimates of primary coordinates should be considered as a statistical problem. The method for determining the coordinates of the firing positions of roving mortars has been improved, in which, in contrast to the known ones, the coordinates of targets on the flight trajectory are coordinated with space and time and the information is processed by a network of counter-battery radars. The developed simulation mathematical model for determining the coordinates of the firing positions of roving mortars by a network of counter-battery radars. Simulation modeling of the method for determining the coordinates of the firing positions of roving mortars by a network of counter-battery radars has been carried out. It has been established that the use of a network of radars makes it possible to increase the accuracy of determining the coordinates of the firing means on average from 23 % to 71 %, depending on the number of counter-battery radars in the network. It has also been found that the appropriate number of counter-battery warfare radars in the network is three or four. A further increase in the number of counter-battery warfare radars in the network does not lead to a significant increase in the accuracy of determining the coordinates of artillery and mortar firing positions. In carrying out further research, it is necessary to develop a method for the spatial separation of elements of a group of targets and interfering objects by a network of counter-battery warfare radars</jats:p

    Development of Methods for Determining the Coordinates of Firing Positions of Roving Mortars by A Network of Counter-battery Radars

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    The mathematical formulation of the problem of determining the coordinates of targets in the network of counter-battery radars is formulated. It has been established that the problem of estimating the coordinates of targets in the network of counter-battery radars for an excessive number of estimates of primary coordinates should be considered as a statistical problem. The method for determining the coordinates of the firing positions of roving mortars has been improved, in which, in contrast to the known ones, the coordinates of targets on the flight trajectory are coordinated with space and time and the information is processed by a network of counter-battery radars. The developed simulation mathematical model for determining the coordinates of the firing positions of roving mortars by a network of counter-battery radars. Simulation modeling of the method for determining the coordinates of the firing positions of roving mortars by a network of counter-battery radars has been carried out. It has been established that the use of a network of radars makes it possible to increase the accuracy of determining the coordinates of the firing means on average from 23&nbsp;% to 71&nbsp;%, depending on the number of counter-battery radars in the network. It has also been found that the appropriate number of counter-battery warfare radars in the network is three or four. A further increase in the number of counter-battery warfare radars in the network does not lead to a significant increase in the accuracy of determining the coordinates of artillery and mortar firing positions. In carrying out further research, it is necessary to develop a method for the spatial separation of elements of a group of targets and interfering objects by a network of counter-battery warfare radar

    Azimuthal correlations in photoproduction and deep inelastic epep scattering at HERA

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    Collective behaviour of final-state hadrons, and multiparton interactions are studied in high-multiplicity ep scattering at a centre-of-mass energy (s)\sqrt(s) = 318 GeV with the ZEUS detector at HERA. Two- and four-particle azimuthal correlations, as well as multiplicity, transverse momentum, and pseudorapidity distributions for charged particle multiplicities Nch_{ch} ≥ 20 are measured. The dependence of two-particle correlations on the virtuality of the exchanged photon shows a clear transition from photoproduction to neutral current deep inelastic scattering. For the multiplicities studied, neither the measurements in photoproduction processes nor those in neutral current deep inelastic scattering indicate significant collective behaviour of the kind observed in high-multiplicity hadronic collisions at RHIC and the LHC. Comparisons of PYTHIA predictions with the measurements in photoproduction strongly indicate the presence of multiparton interactions from hadronic fluctuations of the exchanged photon

    Measurement of the branching fractions of Bˉ→D(∗)K−K(S)(∗)0\bar{B}\to D^{(*)} K^- K^{(*)0}_{(S)} and Bˉ→D(∗)Ds−\bar{B}\to D^{(*)}D_s^{-} decays at Belle II

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    International audienceWe present measurements of the branching fractions of eight B‾0→D(∗)+K−K(S)(∗)0\overline B{}^0\to D^{(*)+} K^- K^{(*)0}_{(S)}, B−→D(∗)0K−K(S)(∗)0B^{-}\to D^{(*)0} K^- K^{(*)0}_{(S)} decay channels. The results are based on data from SuperKEKB electron-positron collisions at the Υ(4S)\Upsilon(4S) resonance collected with the Belle II detector, corresponding to an integrated luminosity of 362 fb−1362~\text{fb}^{-1}. The event yields are extracted from fits to the distributions of the difference between expected and observed BB meson energy, and are efficiency-corrected as a function of m(K−K(S)(∗)0)m(K^-K^{(*)0}_{(S)}) and m(D(∗)K(S)(∗)0)m(D^{(*)}K^{(*)0}_{(S)}) in order to avoid dependence on the decay model. These results include the first observation of B‾0→D+K−KS0\overline B{}^0\to D^+K^-K_S^0, B−→D∗0K−KS0B^-\to D^{*0}K^-K_S^0, and B‾0→D∗+K−KS0\overline B{}^0\to D^{*+}K^-K_S^0 decays and a significant improvement in the precision of the other channels compared to previous measurements. The helicity-angle distributions and the invariant mass distributions of the K−K(S)(∗)0K^- K^{(*)0}_{(S)} systems are compatible with quasi-two-body decays via a resonant transition with spin-parity JP=1−J^P=1^- for the K−KS0K^-K_S^0 systems and JP=1+J^P= 1^+ for the K−K∗0K^-K^{*0} systems. We also present measurements of the branching fractions of four B‾0→D(∗)+Ds−\overline B{}^0\to D^{(*)+} D_s^-, B−→D(∗)0Ds−B^{-}\to D^{(*)0} D_s^- decay channels with a precision compatible to the current world averages

    Measurement of the branching fractions of B‾ \overline{B} → D(∗)^{(*)}K−K(S)(∗)0^{−} {K}_{(S)}^{\left(\ast \right)0} and B‾ \overline{B} → D(∗)Ds−^{(*)} {D}_s^{-} decays at Belle II

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    We present measurements of the branching fractions of eight B‾0 {\overline{B}}^0 → D(∗)+^{(*)+}K−K(S)(∗)0^{−} {K}_{(S)}^{\left(\ast \right)0} , B−^{−} → D(∗)0^{(*)0}K−K(S)(∗)0^{−} {K}_{(S)}^{\left(\ast \right)0} decay channels. The results are based on data from SuperKEKB electron-positron collisions at the Υ(4S) resonance collected with the Belle II detector, corresponding to an integrated luminosity of 362 fb−1^{−1}. The event yields are extracted from fits to the distributions of the difference between expected and observed B meson energy, and are efficiency-corrected as a function of m(K−K(S)(∗)0^{−} {K}_{(S)}^{\left(\ast \right)0} ) and m(D(∗)K(S)(∗)0^{(*)} {K}_{(S)}^{\left(\ast \right)0} ) in order to avoid dependence on the decay model. These results include the first observation of B‾0 {\overline{B}}^0 → D+^{+}K−KS0^{−} {K}_S^0 , B−^{−} → D*0^{0}K−KS0^{−} {K}_S^0 , and B‾0 {\overline{B}}^0 → D*+^{+}K−KS0^{−} {K}_S^0 decays and a significant improvement in the precision of the other channels compared to previous measurements. The helicity-angle distributions and the invariant mass distributions of the K−K(S)(∗)0^{−} {K}_{(S)}^{\left(\ast \right)0} systems are compatible with quasi-two-body decays via a resonant transition with spin-parity JP^{P} = 1−^{−} for the K−KS0^{−} {K}_S^0 systems and JP^{P} = 1+^{+} for the K−^{−}K*0^{0} systems. We also present measurements of the branching fractions of four B‾0 {\overline{B}}^0 → D(∗)+Ds−^{(*)+} {D}_s^{-} , B−^{−} → D(∗)0Ds−^{(*)0} {D}_s^{-} decay channels with a precision compatible to the current world averages.[graphic not available: see fulltext

    Test of light-lepton universality in Ï„\tau decays with the Belle II experiment

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    We present a measurement of the ratio Rμ=B(τ−→μ−νˉμντ)/B(τ−→e−νˉeντ)R_\mu = \mathcal{B}(\tau^-\to \mu^-\bar\nu_\mu\nu_\tau) / \mathcal{B}(\tau^-\to e^-\bar\nu_e\nu_\tau) of branching fractions B\mathcal{B} of the τ\tau lepton decaying to muons or electrons using data collected with the Belle II detector at the SuperKEKB e+e−e^+e^- collider. The sample has an integrated luminosity of 362 fb−1^{-1} at a centre-of-mass energy of 10.58 GeV. Using an optimised event selection, a binned maximum likelihood fit is performed using the momentum spectra of the electron and muon candidates. The result, Rμ=0.9675±0.0007±0.0036R_\mu = 0.9675 \pm 0.0007 \pm 0.0036, where the first uncertainty is statistical and the second is systematic, is the most precise to date. It provides a stringent test of the light-lepton universality, translating to a ratio of the couplings of the muon and electron to the WW boson in τ\tau decays of 0.9974±0.00190.9974 \pm 0.0019, in agreement with the standard model expectation of unity

    Test of light-lepton universality in Ï„\tau decays with the Belle II experiment

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    International audienceWe present a measurement of the ratio Rμ=B(τ−→μ−νˉμντ)/B(τ−→e−νˉeντ)R_\mu = \mathcal{B}(\tau^-\to \mu^-\bar\nu_\mu\nu_\tau) / \mathcal{B}(\tau^-\to e^-\bar\nu_e\nu_\tau) of branching fractions B\mathcal{B} of the τ\tau lepton decaying to muons or electrons using data collected with the Belle II detector at the SuperKEKB e+e−e^+e^- collider. The sample has an integrated luminosity of 362 fb−1^{-1} at a centre-of-mass energy of 10.58 GeV. Using an optimised event selection, a binned maximum likelihood fit is performed using the momentum spectra of the electron and muon candidates. The result, Rμ=0.9675±0.0007±0.0036R_\mu = 0.9675 \pm 0.0007 \pm 0.0036, where the first uncertainty is statistical and the second is systematic, is the most precise to date. It provides a stringent test of the light-lepton universality, translating to a ratio of the couplings of the muon and electron to the WW boson in τ\tau decays of 0.9974±0.00190.9974 \pm 0.0019, in agreement with the standard model expectation of unity
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