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A high-statistics data sample of the [Formula omitted] decays is recorded by the OKA collaboration. A missing mass analysis is performed to search for a light invisible pseudoscalar axion-like particle (ALP) a in the decay [Formula omitted]. No signal is observed, and the upper limits for the branching ratio of the decay are calculated. The [Formula omitted] confidence level upper limit changes from [Formula omitted] to [Formula omitted] for the ALP mass from 0 to 200 MeV/ [Formula omitted], except for the region of [Formula omitted] mass, where the upper limit is [Formula omitted].

Measurements of multiplicity and transverse momentum fluctuations of charged particles were performed in inelastic p+p interactions at 20, 31, 40, 80, and 158  GeV / c beam momentum. Results for the scaled variance of the multiplicity distribution and for three strongly intensive measures of multiplicity and transverse momentum fluctuations Δ [ P T , N ] , Σ [ P T , N ] and Φ p T are presented. For the first time the results on fluctuations are fully corrected for experimental biases. The results on multiplicity and transverse momentum fluctuations significantly deviate from expectations for the independent particle production. They also depend on charges of selected hadrons. The string-resonance Monte Carlo models Epos and U r qmd do not describe the data. The scaled variance of multiplicity fluctuations is significantly higher in inelastic p+p interactions than in central Pb+Pb collisions measured by NA49 at the same energy per nucleon. This is in qualitative disagreement with the predictions of the Wounded Nucleon Model. Within the statistical framework the enhanced multiplicity fluctuations in inelastic p+p interactions can be interpreted as due to event-by-event fluctuations of the fireball energy and/or volume.

A high-statistics data sample of the K + decays is recorded by the OKA collaboration. A missing mass analysis is performed to search for a light invisible pseudoscalar axion-like particle (ALP) a in the decay K + → π + π 0 a . No signal is observed, and the upper limits for the branching ratio of the decay are calculated. The 90 % confidence level upper limit changes from 2.5 · 10 - 6 to 2 · 10 - 7 for the ALP mass from 0 to 200 MeV/ c 2 , except for the region of π 0 mass, where the upper limit is 4.4 · 10 - 6 .

The K + → π + π 0 π 0 γ decay is observed by the OKA collaboration. About 60 events of the decay observed with signal:noise ≈ 1 . The branching ratio obtained by normalization to K + → π + π 0 π 0 is measured to be ( 3.7 ± 0.9 ( s t a t ) ± 0.3 ( s y s t ) ) × 10 - 6 for E γ ∗ > 10 MeV . The branching ratio, γ energy spectrum and angular distribution are consistent with ChPT prediction.

Strong and superstrong magnetic storms on Earth are the greatest manifestation of solar activity. The distribution of the magnetic field in the inner magnetosphere changes, the fluxes of acting charged particles grow, and the structure of the field is altered, resulting in stronger ionospheric currents in auroral, subauroral, and middle latitudes. The ultimate effect of this process can be a change in the parameters of the ionosphere, accompanied by the excitation of geomagnetically induced current in such conductive systems as power lines, communication cables, and mains at both high and middle latitudes.

Measurements of multiplicity fluctuations of identified hadrons produced in inelastic p+p interactions at 31, 40, 80, and 158 Ge/c beam momentum are presented. Three different measures of multiplicity fluctuations are used: the scaled variance ω and strongly intensive measures Σ and Δ. These fluctuation measures involve second and first moments of joint multiplicity distributions. Data analysis is preformed using the Identity method which corrects for incomplete particle identification. Strongly intensive quantities are calculated in order to allow for a direct comparison to corresponding results on nucleus–nucleus collisions. The results for different hadron types are shown as a function of collision energy. A comparison with predictions of string-resonance Monte-Carlo models: Epos, Smash and Venus, is also presented.

A measurement of charged hadron pair correlations in two-dimensional$$\\Delta \\eta \\Delta \\phi $$Δ η Δ ϕ   space is presented. The analysis is based on total 30 million central Be + Be collisions observed in the NA61/SHINE detector at the CERN SPS for incident beam momenta of 19 A , 30 A , 40 A , 75 A , and 150 A  $$\\text {Ge} \\text {V}/c$$Ge / c . Measurements were carried out for unlike-sign and like-sign charge hadron pairs independently. The$$C(\\Delta \\eta ,\\Delta \\phi )$$C ( Δ η , Δ ϕ ) correlation functions were compared with results from a similar analysis on p + p interactions at similar beam momenta per nucleon. General trends of the back-to-back correlations are similar in central Be + Be collisions and p + p interactions, but are suppressed in magnitude due to the increased combinatorial background. Predictions from the Epos and UrQMD models are compared to the measurements. Evolution of an enhancement around$$(\\Delta \\eta ,\\Delta \\phi ) = (0,0)$$( Δ η , Δ ϕ ) = ( 0 , 0 ) with incident energy is observed in central Be + Be collisions. It is not predicted by both models and almost non-existing in proton–proton collisions at the same momentum per nucleon.

The measurement of$$K^{*}(892)^0$$K ∗ ( 892 ) 0 resonance production via its$$K^{+}\\pi ^{-}$$K + π - decay mode in inelastic p+p collisions at beam momentum 158 $$\\text{ Ge }\\text{ V }\\!/\\!c$$Ge V / c ($$\\sqrt{s_{NN}}=17.3$$s NN = 17.3  $$\\text{ Ge }\\text{ V }$$Ge V ) is presented. The data were recorded by the NA61/SHINE hadron spectrometer at the CERN Super Proton Synchrotron. The template method was used to extract the$$K^{*}(892)^0$$K ∗ ( 892 ) 0 signal and double-differential transverse momentum and rapidity spectra were obtained. The full phase-space mean multiplicity of$$K^{*}(892)^0$$K ∗ ( 892 ) 0 mesons was found to be$$(78.44 \\pm 0.38 \\mathrm {(stat)} \\pm 6.0 \\mathrm {(sys)) \\cdot 10^{-3}}$$( 78.44 ± 0.38 ( stat ) ± 6.0 ( sys ) ) · 10 - 3 . The NA61/SHINEresults are compared with the Epos1.99 and Hadron Resonance Gas models as well as with world data from p+p and nucleus–nucleus collisions.

Inhalation of air-dispersed sub-micrometre and nano-sized particles presents a risk factor for animal and human health. Here, we show that nasal aerodynamics plays a pivotal role in the protection of the subterranean mole vole Ellobius talpinus from an increased exposure to nano-aerosols. Quantitative simulation of particle flow has shown that their deposition on the total surface of the nasal cavity is higher in the mole vole than in a terrestrial rodent Mus musculus (mouse), but lower on the olfactory epithelium. In agreement with simulation results, we found a reduced accumulation of manganese in olfactory bulbs of mole voles in comparison with mice after the inhalation of nano-sized MnCl2 aerosols. We ruled out the possibility that this reduction is owing to a lower transportation from epithelium to brain in the mole vole as intranasal instillations of MnCl2 solution and hydrated nanoparticles of manganese oxide MnO · (H2O)x revealed similar uptake rates for both species. Together, we conclude that nasal geometry contributes to the protection of brain and lung from accumulation of air-dispersed particles in mole voles.