γ
p
→
K
+
Λ
differential cross sections and recoil polarisation data from threshold for extremely forward angles are presented. The measurements were performed at the BGOOD experiment at ELSA, ...utilising the high angular and momentum resolution forward spectrometer for charged particle identification. The high statistics and forward angle acceptance enables the extraction of the cross section as the minimum momentum transfer to the recoiling hyperon is approached.
Modern street crime has been increasingly affecting the formation of the criminogenic situation in Russia. The main goal of this paper is exploring the possible application of modern digital ...technologies in the evaluation and prevention of public crime. The methods presented in this empirical research are: monitoring, statistical methods, modeling and questioning, content analysis, research result processing. As a result of the analysis of the received data, generalized quantitative and qualitative indicators of modern street crime were presented: prevalence of mercenary and violent crimes (61,4%) in the current criminal situation in the city streets (structure of street crime); the percentage of street crime in relation to all crime done in public places is 45,0% with the rising tendency of serious crime and latency; places where street crime takes place are empty, open city spaces composing about 12% of all the streets of the city; the prevailing “work schedule” of a street criminal is determined by the time of the year (fallwinter); day of the week (Friday, weekends and holidays) and time of day (evening-night); the increase in mobile phone theft from people passing in the streets; a characteristic way of street theft and robbery is their suddenness and unpredictability. The article supports the conclusion that the current system of street crime prevention methods and its practice doesn`t provide salvation from street criminals and thus requires further improvement with the consideration of the rising possibilities of the internet-space, specifically, usage of digital applications and devices.
K+Λ(1405) photoproduction has been studied at the BGOOD experiment via the all neutral decay, Λ(1405)→Σ0π0. The unique BGOOD experimental setup allows both the cross section and Λ(1405) invariant ...mass distribution (line shape) to be measured over a broad K+ polar angle range, extending to extreme forward K+ angles unattainable at previous experiments.
Evidence is provided for the role of a triangle singularity driven by the N⁎(2030) resonance, which appears to contribute significantly to K+Λ(1405) photoproduction. This is observed in the integrated cross section which was determined with unprecedented energy resolution and supported by the angular distributions. The measured line shape is also in agreement with the previous results of CLAS and ANKE, and is consistent with two poles derived in χPT based models.
The coherent reaction, γd→π0π0d was studied with the BGOOD experiment at ELSA from threshold to a centre-of-mass energy of 2850MeV. A full kinematic reconstruction was made, with final state ...deuterons identified in the forward spectrometer and π0 decays in the central BGO Rugby Ball. The strength of the differential cross section exceeds what can be described by models of coherent photoproduction and instead supports the three isoscalar dibaryon candidates reported by the ELPH collaboration at 2.38, 2.47 and 2.63GeV/c2. A low mass enhancement in the π0π0 invariant mass is also observed at the d⁎(2380) centre-of-mass energy which is consistent with the ABC effect. At higher centre-of-mass energies, a narrow peak in the π0d invariant mass at 2114MeV/c2 with a width of 20MeV/c2 supports a sequential two-dibaryon decay mechanism.
The possibility of short-term and long-term forecasting of water levels, including those associated with dangerous hydrological phenomena on the Marmarik River, using various probabilistic ...approaches, including regression dependencies, an integrated moving average autoregression model, and multilayer perceptron models, is considered. To evaluate the effectiveness of prognostic methods, the statistical parameters of a random process are calculated, while recommendations are given using the classical criteria for the effectiveness of issued forecasts. For long-term forecasting, the expediency of using the integrated moving average autoregression model was assessed, while it is noted that these models in the classical representation are not applicable due to time gaps, and therefore it is recommended to focus on the mathematical expectation of a random process. For short-term forecasting one or two steps ahead, the method of training artificial neural networks was used. The analysis carried out in the work revealed that in the case of short-term forecasting of water levels for one period in advance (12 h), it is most expedient to focus on the value of the water level attributable to the date of issue of the forecast, the standard error of such a forecast is 5 cm. For a 24-h water level forecast forward, it is expedient to develop neural network forecasting models, taking into account the development of the situation on Gomraget-Meghradzor. A further increase in the quality of the outputs is possible when using data for a longer observation period and a whole year. At the same time, as an alternative to neural network forecasting models, physical and mathematical (hydraulic) models of the formation of water levels can be used.
The γp→K+Σ0 differential cross section at extremely forward angles was measured at the BGOOD experiment. A three-quarter drop in strength over a narrow range in energy and a strong dependence on the ...polar angle of the K+ in the centre-of-mass of the reaction is observed at a centre-of-mass energy of 1900 MeV. Residing close to multiple open and hidden strangeness thresholds, the structure appears consistent with meson-baryon threshold effects which may contribute to the reaction mechanism.
The BGOOD experimental setup at ELSA Alef, S.; Bauer, P.; Bayadilov, D. ...
The European physical journal. A, Hadrons and nuclei,
04/2020, Letnik:
56, Številka:
4
Journal Article
Recenzirano
Odprti dostop
The BGOOD experiment at the ELSA facility in Bonn has been commissioned within the framework of an international collaboration. The experiment pursues a systematic investigation of non-strange and ...strange meson photoproduction, in particular
t
-channel processes at low momentum transfer. The setup uniquely combines a central almost
4
π
acceptance BGO crystal calorimeter with a large aperture forward magnetic spectrometer providing excellent detection of both neutral and charged particles, complementary to other setups such as Crystal Barrel, Crystal Ball, LEPS and CLAS.
The photoproduction of η′-mesons off different nuclei has been measured with the CBELSA/TAPS detector system for incident photon energies between 1500–2200 MeV. The transparency ratio has been ...deduced and compared to theoretical calculations describing the propagation of η′-mesons in nuclei. The comparison indicates a width of the η′-meson of the order of Γ=15–25 MeV at ρ=ρ0 for an average momentum pη′=1050 MeV/c, at which the η′-meson is produced in the nuclear rest frame. The inelastic η′N cross section is estimated to be 3–10 mb. Parameterizing the photoproduction cross section of η′-mesons by σ(A)=σ0Aα, a value of α=0.84±0.03 has been deduced.
Different interpretations of narrow structures at
W
~ 1.68 and 1.72 GeV observed in several reactions are discussed. It is questionable whether interference phenomena could explain the whole complex ...of experimental findings. More probable hypotheses would be the existence of one or two narrow resonances
N
(1685) and
N
(1726) and/or the sub-threshold virtual
K
Σ and ω
p
production (cusps).
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