Search

The cross section is measured in the center-of-mass energy range from 1.07 to 2.00 GeV in the decay channel , . The data set with an integrated luminosity of 242 pb accumulated in the experiment with the SND detector at the VEPP-2000 collider is analyzed. [ABSTRACT FROM AUTHOR]

The contributions of the axial-vector and vector resonance states to D → P(V)l&νmacr;[sub l] decays are investigated on the basis of phenomenological chiral Lagrangians. It is shown that inclusion of such intermediate states improves agreement with experimental data. [ABSTRACT FROM AUTHOR]

The authors as part of the HWW team of the ATLAS experiment at the LHC have studied events with two opposite-sign muons and two electrons in the search for the Standard Model Higgs boson H and a heavy resonance R in the channel of decay into two W-bosons. The analysis was carried out using the complete statistics of proton–proton collision events for 2015–2018 exposure for the c.m.s. energy of protons = 13 TeV. The application of a deep neural network made it possible to significantly improve our earlier results for separation of the H-boson signal in the vector-boson-fusion production mechanism. Various theoretical models were used to calculate the new expected upper limits for the production of R resonance with a spin 0, 1, or 2 in addition to those obtained earlier in a toy NWA model for a heavy Higgs boson. [ABSTRACT FROM AUTHOR]

In an experiment with the SND detector at the VEPP-2000 collider, the cross sections for the processes and were measured at collision energies of GeV in the center-of-mass frame. The results agree with the results of earlier measurements in the BABAR experiment and have a commensurate precision. [ABSTRACT FROM AUTHOR]

The cross section for the process e+e− → ηK+K− wasmeasured at c.m. energies in the range between 1.56 and 2.00 GeV in an experiment with the SND detector at the VEPP-2000 e+e− collider. The invariant-mass distribution of kaon pairs is consistent with the hypothesis that the transition through the ηφ intermediate state makes a dominant contribution to the transition in question. [ABSTRACT FROM AUTHOR]

Prospects for discovering heavy graviton resonances in decays to an electron-positron pair and for identifying the nature of these resonances in the ATLAS experiment at the Large Hadron Collider (LHC) are investigated. Gravitons in the Randall-Sundrum model, which features extra spatial dimensions, are considered by way of example. A comparative analysis of effects of new different-spin heavy resonances, scalar [supersymmetric neutrino (sneutrino)], vector (new gauge Z′ boson), and tensor (graviton) ones, is performed in order to identify the graviton spin. An identification of gravitons is performed by using the integrated center-edge asymmetry. For LHC, the graviton discovery (identification) reach is found to be 2.1 TeV (1.2 TeV) and 3.9 TeV (2.9 TeV) at a confidence level of 5 δ (95%) for the graviton coupling constants of k/ $$ \bar M $$Pl = 0.01 and 0.1, respectively. This analysis is the most general, since, for the first time, it takes into account the possible existence of scalar resonances, which affects substantially quantitative estimates of the identification reach. [ABSTRACT FROM AUTHOR]

The dielectron widths of Y( nS)( n = 1, ..., 7) and vector decay constants are calculated using the relativistic string Hamiltonian with a universal interaction. For Y( nS) ( n = 1, 2, 3) the dielectron widths and their ratios are obtained in full agreement with the latest CLEO data. For Y(10580) and Y(11020) a good agreement with experiment is reached only if the 4 S-3 D mixing (with a mixing angle θ = 27°± 4°) and 6 S-5 D mixing (with θ = 40°±5°) are taken into account. The possibility to observe higher “mixed D-wave” resonances, $$ \tilde \Upsilon $$( n3 D1) with n = 3, 4, 5 is discussed. In particular, $$ \tilde \Upsilon $$(≈11120), originating from the pure 53 D1 state, can acquire a rather large dielectron width, ∼130 eV, so that this resonance may become manifest in the e+ e− experiments. On the contrary, the widths of pure D-wave states are very small, Γ ee( n3 D1)≤ 2 eV. [ABSTRACT FROM AUTHOR]

The dielectron widths of ψ(4040), ψ(4160), and ψ(4415), and their ratios are shown to be in good agreement with experiment, if in all cases the S-D mixing with a large mixing angle θ ≅ 34° is taken. Arguments are presented why continuum states give small contributions to the wave functions at the origin. We find that the Y (4360) resonance, considered as a pure 3 3 D1 state, would have very small dielectron width, Γ ee( Y (4360)) = 0.060 keV. On the contrary, for large mixing between the 4 3 S1 and 3 3 D1 states with the mixing angle θ = 34.8°, Γ ee( ψ(4415)) = 0.57 keV coincides with the experimental number, while a second physical resonance, probably Y (4360), has also a rather large Γ ee( Y (∼4400)) = 0.61 keV. For the higher Y (4660) resonance, considered as a pure 5 3 S1 state, we predict the dielectron width Γ ee( Y (4660)) = 0.70 keV, but it becomes significantly smaller, namely 0.31 keV, if the mixing angle between the 5 3 S1 and 4 3 D1 states has the characteristic value θ = 34°. The mass and dielectron width of the 6 3 S1 charmonium state are calculated. [ABSTRACT FROM AUTHOR]

It is argued that the realization of gauge invariance condition as a consequent of cancellation between the ϕ → γf 0 → γπ 0 π 0 resonance contribution and the ϕ → γπ 0 π 0 background one, suggested by A.V. Anisovich et al., Yad. Fiz. 68, 1614 (2005), is misleading. [ABSTRACT FROM AUTHOR]