The inclusive top quark pair ([Formula: see text]) production cross-section [Formula: see text] has been measured in proton-proton collisions at [Formula: see text] and [Formula: see text] with the ATLAS experiment at the LHC, using [Formula: see text] events with an opposite-charge [Formula: see text] pair in the final state. The measurement was performed with the 2011 7 TeV dataset corresponding to an integrated luminosity of 4.6 [Formula: see text] and the 2012 8 TeV dataset of 20.3 [Formula: see text]. The numbers of events with exactly one and exactly two [Formula: see text]-tagged jets were counted and used to simultaneously determine [Formula: see text] and the efficiency to reconstruct and [Formula: see text]-tag a jet from a top quark decay, thereby minimising the associated systematic uncertainties. The cross-section was measured to be: [Formula: see text]where the four uncertainties arise from data statistics, experimental and theoretical systematic effects, knowledge of the integrated luminosity and of the LHC beam energy. The results are consistent with recent theoretical QCD calculations at next-to-next-to-leading order. Fiducial measurements corresponding to the experimental acceptance of the leptons are also reported, together with the ratio of cross-sections measured at the two centre-of-mass energies. The inclusive cross-section results were used to determine the top quark pole mass via the dependence of the theoretically predicted cross-section on [Formula: see text] giving a result of [Formula: see text][Formula: see text] GeV. By looking for an excess of [Formula: see text] production with respect to the QCD prediction, the results were also used to place limits on the pair-production of supersymmetric top squarks [Formula: see text] with masses close to the top quark mass, decaying via [Formula: see text] to predominantly right-handed top quarks and a light neutralino [Formula: see text], the lightest supersymmetric particle. Top squarks with masses between the top quark mass and 177 GeV are excluded at the 95 % confidence level.
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http://dx.doi.org/10.1140/epjc/s10052-014-3109-7 | DOI Listing |
Sci Rep
January 2025
Computational Physics Key Laboratory of Sichuan Province, Yibin University, Yibin, China.
The potential energy curves, dipole moments and transition dipole moments of the 14 Λ-S states and 30 Ω states of TlBr cation were performed using the multi-reference configuration interaction method. The Davidson correction and spin-orbit coupling effects were also considered. The spectroscopic properties and transition properties of TlBr cation were reported at the first time.
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January 2025
Laboratory for Artificial Intelligence, Institute for Computational Science and Artificial Intelligence, Van Lang University, Ho Chi Minh City, Vietnam.
Compliant mechanism has some advantages and has been widely applied in many accurate positioning systems. However, modeling the compliant mechanism behavior has suffered from many challenges, such as unstable results, and the limitation of training data set. In the field of compliant mechanism modeling, there has been no research interested in applying meta-heuristics optimization algorithms to optimize the weights and biases of the neural network globally.
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January 2025
College of Intelligent Systems Science and Engineering, Hubei Minzu University, Enshi, 445000, China.
This paper addresses the low level of intelligence in tea processing equipment in Enshi Prefecture by designing an intelligent withering control system based on the STMicroelectronics 32-bit Microcontroller (STM32). This control system can achieve real-time monitoring of the withering environment and automate the control of heating and ventilation dehumidification modules. By integrating IoT technology, relevant users can view the tea production process via mobile devices, enabling intelligent and remote production operations.
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January 2025
Department of Physics, The American University in Cairo, New Cairo, 11835, Egypt.
Inverse design with topology optimization considers a promising methodology for discovering new optimized photonic structure that enables to break the limitations of the forward or the traditional design especially for the meta-structure. This work presents a high efficiency mid infra-red imaging photonics element along mid infra-red wavelengths band starts from 2 to 5 µm based on silicon nitride optimized material structures. The first two designs are broadband focusing and reflective meta-lens under very high numerical aperture condition (NA = 0.
View Article and Find Full Text PDFPLoS One
January 2025
Centre National de la Recherche Scientifique, Institut des Sciences du Mouvement, Aix-Marseille Univ, Marseille, France.
Little is known about the influence of fatigue in repeated overground sprinting on force-velocity properties in children and adolescents, while this ability to repeat sprints is important for future progress in rugby union. Sprint time decline is commonly used to assess fatigability. However, it does not provide data on biomechanical aspects of sprint performance such as maximal power, force, and velocity production.
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