Observation of η ′ → π + π − μ + μ Achasov, M. N.; Adlarson, P.; Ahmed, S. ...
Physical review. D,
04/2021, Letnik:
103, Številka:
7
Journal Article
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Using ( 1310.6 ± 7.0 ) × 106 J / ψ events acquired with the BESIII detector at the BEPCII storage rings, the decay η ′ → π+ π−μ+μ− is observed for the first time with a significance of 8 σ via the ...process J / ψ → γ η ′ . We measure the branching fraction of η ′ → π+ π−μ+μ− to be B ( η ′ → π+ π−μ+μ− ) = ( 1.97 ± 0.33 ( stat ) ± 0.19 ( syst ) ) × 10−5, where the first and second uncertainties are statistical and systematic, respectively.
The rare decay η ′ → π+ π− e+ e− is studied using a sample of 1.3 × 109 J / ψ events collected with the BESIII detector at BEPCII in 2009 and 2012. The branching fraction is measured with improved ...precision to be ( 2.42 ± 0.0 5stat ± 0.0 8syst) × 10−3. Due to the inclusion of new data, this result supersedes the last BESIII result on this branching fraction. In addition, the C P -violating asymmetry in the angle between the decay planes of the π+π− -pair and the e+e− -pair is investigated. A measurable value would indicate physics beyond the standard model; the result is ACP = ( 2.9 ± 3. 7stat ± 1. 1syst) % , which is consistent with the standard model expectation of no C P -violation. The precision is comparable to the asymmetry measurement in the K0L → π+π− e+e− decay where the observed (14 ± 2) % effect is driven by a standard model mechanism.
We report a study of the e+e– → D+D–π+π– process using e+e– collision data samples with an integrated luminosity of 2.5 fb–1 at center-of-mass energies from 4.36 to 4.60GeV, collected with the BESIII ...detector at the BEPCII storage ring. The D1(2420)+ is observed in the D+π+π– mass spectrum. The mass and width of the D1(2420)+ are measured to be (2427.2 ± 1.0stat. ± 1.2syst.)MeV/c2 and (23.2 ± 2.3stat. ± 2.3syst.)MeV, respectively. The first errors are statistical and the second ones are systematic. In addition, the Born cross sections of the e+e– → D1(2420)+ D– + c.c. → D+D–π+π– and e+e– → ψ(3770)π+π– → D+D–π+π– processes are measured as a function of the center-of-mass energy.
We report the first observation of a_{0}^{0}(980)-f_{0}(980) mixing in the decays of J/ψ→ϕf_{0}(980)→ϕa_{0}^{0}(980)→ϕηπ^{0} and χ_{c1}→a_{0}^{0}(980)π^{0}→f_{0}(980)π^{0}→π^{+}π^{-}π^{0}, using data ...samples of 1.31×10^{9} J/ψ events and 4.48×10^{8} ψ(3686) events accumulated with the BESIII detector. The signals of f_{0}(980)→a_{0}^{0}(980) and a_{0}^{0}(980)→f_{0}(980) mixing are observed at levels of statistical significance of 7.4σ and 5.5σ, respectively. The corresponding branching fractions and mixing intensities are measured and the constraint regions on the coupling constants, g_{a_{0}K^{+}K^{-}} and g_{f_{0}K^{+}K^{-}}, are estimated. The results improve the understanding of the nature of a_{0}^{0}(980) and f_{0}(980).
Abstract Angiogenesis and blood-brain-barrier (BBB) damage have been proposed to contribute to epileptogenesis and/or ictogenesis in experimental and human epilepsy. We tested a hypothesis that after ...brain injury angiogenesis occurs in the most damaged hippocampal areas with the highest need of tissue repair, and associates with formation of epileptogenic neuronal networks. We induced status epilepticus (SE) with pilocarpine in adult rats, and investigated endothelial cell proliferation (BrdU and rat endothelial cell antigen-1 (RECA-1) double-labeling), vessel length (unbiased stereology), thrombocyte aggregation (thrombocyte immunostaining), neurodegeneration (Nissl staining), neurogenesis (doublecortin (DCX) immunohistochemistry), and mossy fiber sprouting (Timm staining) in the hippocampus at different time points post-SE. As functional measures we determined BBB leakage (quantified immunoglobulin G (IgG) immunostaining), and hippocampal blood volume (CBV) and flow (CBF) in vivo (magnetic resonance imaging, MRI). The total length of hippocampal blood vessels was decreased by 17% at 2 d after status epilepticus (SE) induced by pilocarpine in adult rats ( P <0.05 as compared to controls) which was not accompanied by alterations in hippocampal blood volume (BV) and flow (BF). Number of proliferating endothelial cells peaked at 4 d post-SE and correlated with an increase in vessel length ( r =0.900, P <0.05). Vessels length had recovered to control level or even higher at 2 wk post-SE, angiogenesis being most prominent in the CA3 (128% as compared to that in controls, P <0.05), and was associated with increased BV (178% as compared to that in controls, P <0.05). Enlargement of vessel diameter in the hippocampal fissure was associated with thrombocyte aggregation in distal capillaries. BBB was most leaky during the first 4 d post-SE and increased IgG extravasation was observed for 60 d. Our data show that magnitude of endothelial cell proliferation is not associated with severity of acute post-SE neurodegeneration or formation of abnormal neuronal network. This encourages identification of molecular targets that initiate and maintain specific aspects of tissue reorganization, including preservation and proliferation of endothelial cells to reduce the risk of epileptogenesis and enhance recovery after brain injury.
This paper presents a decision support system for identifying customer typology using cluster analysis to segment relevant customers. The approach is demonstrated using data from a company selling ...nutritional supplements, consisting of approximately 130,000 records from six Central European countries. The analysis results in distinct groups of customers, which are proposed for more effective management of customer relationships. The findings have implications for retailers, helping them focus on the most profitable customer segments to increase sales and profits and build lasting relationships. Furthermore, cluster analysis proves to be an appropriate statistical method for classification and provides valuable insights into patterns and trends in the analysed data. Overall, this paper contributes to development and comparison of methods for customer segmentation and demonstrates their potential for improving economic efficiency and building long-term customer relationships.
Despite considerable work to encourage women to enter the profession, engineering continues to be heavily male dominated. Research shows that women in engineering experience unequal treatment ...starting from their entry into the occupation. My research will discuss the experiences of gender inequality for women working in engineering fields by looking at the empirical literature examining the hiring process, chilly climates, hostile work environments, pay and promotion inequalities, and the challenges women engineers face due to competing identities and motherhood. I will show that the oppression and inequality of women reflects and perpetuates a culture that favors male-dominance and exclusionary practices within the engineering profession.
Headway variability has a negative impact on the public transport passengers’ perception of service quality. However, most of the existing methods aimed at improving the headway regularity operate in ...real time and require precise vehicle location data, making it difficult to implement them in practice. On the other hand, planning-level methods can be used to increase the resilience of public passenger transport (PPT) to the accumulation of headway disturbances. As this is typically done from the operator’s perspective, the passengers’ perspective tends to be overlooked, motivating the current work. In this article, an optimisation procedure for evaluating the viability of diametrical line splitting in terms of passenger travel time and headway regularity is proposed. The aim is to increase the robustness/resistance of the PPT system to the propagation of headway disturbances without reducing the service quality. The developed optimisation procedure was validated by applying it to real data pertaining to an urban PPT line. The results show that there is a positive correlation between the transport demand and the effects of the optimisation procedure, whereby an increase in the primary headway disturbance increases the sensitivity of the optimisation procedure to the transport demand.
Bus passenger transport is very important for sustainable urban mobility, and due to the characteristics of the street network, it is usually realized in the conditions of mixed traffic flow. ...Disturbances and sudden changes of traffic flow parameters occurring in the street network in a mixed traffic flow affect the disruptions in schedule and travel time of all vehicles in the traffic flow, including public transport (PT) vehicles. In order to keep to the planned schedule in the peak hours of PT lines carried out in the conditions of mixed traffic flow, the operators introduce new vehicles or reduce the vehicles’ dwell time at terminuses, which is often impossible to do. The use of a larger number of public transport vehicles increases the fuel consumption, pollutants’ emission, and the operating costs. In this paper, a network optimization model was developed for defining the influence of the change of traffic flow parameters in a mixed traffic flow on travel time of PT vehicles. The model takes into consideration uncertain time unevenness of the change of traffic flow parameters, which enables determining the optimization of travel time and defining the necessary number of public transport vehicles for the purpose of keeping to the planned schedule. In order to develop the transport model, counting and analysis of the characteristics of traffic flow at 61 intersections on the city territory were carried out. The model was tested on bus line number 4 of PT in Novi Sad. The model showed that it is possible to achieve certain savings regarding the number of vehicles with the unchanged headway, that is, the unchanged level of service which is offered to the users. With the application of the model in real traffic conditions, significant savings, as well as operating and external costs’ reduction, can be achieved, which contributes to the sustainability of public bus transport in urban environments.
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