3,041 research outputs found

    NNLO QCD Corrections to γ+ηc(ηb)\gamma + \eta_c(\eta_b) Exclusive Production in Electron-Positron Collision

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    Based on the NRQCD factorization formalism, we calculate the next-to-next-to-leading order QCD corrections to the heavy quarkonium ηc(ηb)\eta_c (\eta_b) production associated with a photon at electron-positron colliders. By matching the amplitudes calculated in full QCD theory to a series of operators in NRQCD, the short-distance coefficients up to NNLO QCD radiative corrections are determined. It turns out that the full set of master integrals that we obtained could be analytically expressed in terms of Goncharov Polylogarithms, Chen's iterated integrals, and elliptic functions, which mostly do not exist in the literature and could be employed in the analyses of other physical processes. In phenomenology, numerical calculations of NNLO K-factors and cross sections of e+eγ+ηc(ηb)e^+e^-\rightarrow \gamma + \eta_c(\eta_b) processes in BESIII and B-factory experiments are performed, which may stand as a test of the NRQCD higher order calculation while confronting to the data.Comment: 12 pages, 5 firue

    Product Pricing Based on Activity-Based Costing

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    Activity-based costing could provide relatively accurate cost information and better serve the enterprise’s product pricing decision. Through the analysis of cost behavior on activities, it divides product costs into unit level, batch level, product-sustaining level and facility level activity costs, which can avoid the overlapping between the costs caused by dividing the costs into variable cost, activity cost and fixed cost. On this base, product pricing model is established based on the information of activity based costing. Case study shows that different pricing methods get different prices, which will provide different product-mix pricing decisions for enterprises. Keywords: Activity-based costing, Pricing decisions, Cost behavio

    Diquark mass differences from unquenched lattice QCD

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    We calculate diquark correlation functions in the Landau gauge on the lattice using overlap valence quarks and 2+1-flavor domain wall fermion configurations. Quark masses are extracted from the scalar part of quark propagators in the Landau gauge. Scalar diquark quark mass difference and axial vector scalar diquark mass difference are obtained for diquarks composed of two light quarks and of a strange and a light quark. Light sea quark mass dependence of the results is examined. Two lattice spacings are used to check the discretization effects. The coarse and fine lattices are of sizes 243×6424^3\times64 and 323×6432^3\times64 with inverse spacings 1/a=1.75(4) GeV1/a=1.75(4) {\rm~GeV} and 2.33(5) GeV2.33(5) {\rm~GeV}, respectively.Comment: 9 figure

    Exact solution of the Bose Hubbard model with unidirectional hopping

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    A one-dimensional Bose Hubbard model with unidirectional hopping is shown to be exactly solvable. Applying the algebraic Bethe ansatz method, we prove the integrability of the model and derive the Bethe ansatz equations. The exact eigenvalue spectrum can be obtained by solving these equations. The distribution of Bethe roots reveals the presence of a superfluid-Mott insulator transition at the ground state, and the critical point is determined. By adjusting the boundary parameter, we demonstrate the existence of non-Hermitian skin effect even in the presence of interaction, but it is completely suppressed for the Mott insulator state in the thermodynamical limit. Our result represents a new class of exactly solvable non-Hermitian many-body systems, which have no Hermitian correspondence and can be used as a benchmark for various numerical techniques developed for non-Hermitian many-body systems.Comment: 6+8 pages, 2+6 figure

    Intravitreous injection of Lucentis combined with argon laser photocoagulation for treatment of retinal macroaneurysm

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    AIM: To evaluate the clinical efficacy of intravitreous injection of Lucentis combined with argon laser photocoagulation on retinal macroaneurysm.<p>METHODS: A retrospective observation about intravitreous injection of Lucentis combined with argon laser photocoagulation was performed on 9 patients(9 eyes)with retinal macroaneurysms with macular edema between January 2011 and July 2013. Through the collection of clinical data in patients best-corrected visual acuity, change of the retinal macroaneurysm, optical coherence tomography and fluoresce in fundus angiography before therapy and 1 mouth,3 mouths after therapy, comparative analysis the changes in best-corrected visual acuity and central macular retinal thickness(CMT)between before and after treatment.<p>RESULTS: Followed for more than 3 months, all patients' best-corrected visual acuity were improved obviously, the difference was significant(<i>P</i><0.05); The patients' macular edema was obviously absorbed and the average CMT was significantly lower, the difference was significant(<i>P</i><0.05). In fundus fluorescein angiography, the neoplasia body was atrophied inordinately after 3 months of treatment.<p>CONCLUSION:Intravitreous injection of Lucentis combined with argon laser photocoagulation is effective and security to improving visual acuity of retinal macroaneurysms with macular edema

    Use of Structural Equation Modelling and Neural Network to Analyse Shared Parking Choice Behaviour

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    The shared parking mode represents a feasible solution to the persistent problem of parking scarcity in urban areas. This paper aims to examine the shared parking choice behaviours using a combination of structural equation modelling (SEM) and neural network, taking into account both the parking location characteristics and the travellers’ characteristics. Data were collected from a commercial district in Nanjing, China, through an online questionnaire survey covering 11 factors affecting shared parking choice. The method involved two steps: firstly, SEM was applied to examine the influence of these factors on shared parking choice. Following this, the seven factors with the strongest correlation to shared parking choice were used to train a neural network model for shared parking prediction. This SEM-informed model was found to outperform a neural network model trained on all eleven factors across precision, recall, accuracy, F1 and AUC metrics. The research concluded that the selected factors significantly influence shared parking choice, reinforcing the hypothesis regarding the importance of parking location and traveller characteristics. These findings provide valuable insights to support the effective implementation and promotion of shared parking
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