scholarly journals Mixed QCD-EW corrections for Higgs leptonic decay via HW+W− vertex

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Chichuan Ma ◽  
Yuxuan Wang ◽  
Xiaofeng Xu ◽  
Li Lin Yang ◽  
Bin Zhou
Keyword(s):  
Differential Equations ◽  
Production Process ◽  
Canonical Basis ◽  
Intersection Theory ◽  
Leptonic Decay ◽  
Decay Rates ◽  
Decay Process ◽  
Higgs Production ◽  
Multiple Polylogarithms ◽  
Analytic Expressions

Abstract We consider the two-loop corrections to the HW+W− vertex at order ααs. We construct a canonical basis for the two-loop integrals using the Baikov representation and the intersection theory. By solving the ϵ-form differential equations, we obtain fully analytic expressions for the master integrals in terms of multiple polylogarithms, which allow fast and accurate numeric evaluation for arbitrary configurations of external momenta. We apply our analytic results to the decay process H → νeeW, and study both the integrated and differential decay rates. Our results can also be applied to the Higgs production process via W boson fusion.

scholarly journals The diagrammatic coaction beyond one loop

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
Samuel Abreu ◽  
Ruth Britto ◽  
Claude Duhr ◽  
Einan Gardi ◽  
James Matthew
Keyword(s):  
Differential Equations ◽  
Hypergeometric Functions ◽  
Differential Forms ◽  
Feynman Graph ◽  
Loop Order ◽  
Feynman Integrals ◽  
Mathematical Properties ◽  
Multiple Polylogarithms ◽  
Complete Set ◽  
General Tool

Abstract The diagrammatic coaction maps any given Feynman graph into pairs of graphs and cut graphs such that, conjecturally, when these graphs are replaced by the corresponding Feynman integrals one obtains a coaction on the respective functions. The coaction on the functions is constructed by pairing a basis of differential forms, corresponding to master integrals, with a basis of integration contours, corresponding to independent cut integrals. At one loop, a general diagrammatic coaction was established using dimensional regularisation, which may be realised in terms of a global coaction on hypergeometric functions, or equivalently, order by order in the ϵ expansion, via a local coaction on multiple polylogarithms. The present paper takes the first steps in generalising the diagrammatic coaction beyond one loop. We first establish general properties that govern the diagrammatic coaction at any loop order. We then focus on examples of two-loop topologies for which all integrals expand into polylogarithms. In each case we determine bases of master integrals and cuts in terms of hypergeometric functions, and then use the global coaction to establish the diagrammatic coaction of all master integrals in the topology. The diagrammatic coaction encodes the complete set of discontinuities of Feynman integrals, as well as the differential equations they satisfy, providing a general tool to understand their physical and mathematical properties.

scholarly journals Electromagnetic corrections to the leptonic decay rates of charged pseudoscalar mesons: lattice results

2016 ◽  
Author(s):  
Silvano Simula ◽  
Vittorio Lubicz ◽  
Guido Martinelli ◽  
Christopher Sachrajda ◽  
Francesco Sanfilippo ◽  
...  
Keyword(s):  
Leptonic Decay ◽  
Decay Rates ◽  
Pseudoscalar Mesons

scholarly journals Light-meson leptonic decay rates in lattice QCD+QED

2019 ◽  
Vol 100 (3) ◽  
Author(s):  
M. Di Carlo ◽  
G. Martinelli ◽  
D. Giusti ◽  
V. Lubicz ◽  
C. T. Sachrajda ◽  
...  
Keyword(s):  
Lattice Qcd ◽  
Leptonic Decay ◽  
Decay Rates ◽  
Light Meson

Luminescence Emission Mediated by Surface Plasmon in the Semiconductor Quantum Dots

NANO ◽  
2015 ◽  
Vol 10 (01) ◽  
pp. 1550009 ◽  
Author(s):  
Huibing Mao ◽  
Ling Du ◽  
Ye Chen ◽  
Bo Li ◽  
Rong Huang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Surface Plasmon ◽  
Resonance Energy ◽  
Blue Shift ◽  
Energy Difference ◽  
Decay Rates ◽  
Decay Process ◽  
Fast Decay ◽  
Surface Plasmon Coupling ◽  
Coupling Rate

The luminescence of the hybrid CdSe / ZnS QDs– Ag nanocrystals has a weak blue shift in comparison with the luminescence of the pure quantum dots (QDs). The luminescence of the CdSe / ZnS QDs only has a single exponential decay process, and the decay rates are almost same for different emission wavelengths. The luminescence of the hybrid CdSe / ZnS QDs– Ag nanocrystals structure has two decay processes: The first is a fast decay process, and then there is a slow decay process with nearly the same decay rate of the pure QDs. The fast decay process is due to the surface plasmon coupling and the coupling rate depends on the energy difference between the confined exciton in the QDs and the resonance energy of the Ag plasmon.

scholarly journals Analytic tadpole coefficients of one-loop integrals

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Bo Feng ◽  
Tingfei Li ◽  
Xiaodi Li
Keyword(s):  
Differential Equations ◽  
Recurrence Relations ◽  
Differential Operators ◽  
Tensor Structure ◽  
Loop Integral ◽  
Cut Method ◽  
Analytic Expressions

Abstract One remaining problem of unitarity cut method for one-loop integral reduction is that tadpole coefficients can not be straightforward obtained through this way. In this paper, we reconsider the problem by applying differential operators over an auxiliary vector R. Using differential operators, we establish the corresponding differential equations for tadpole coefficients at the first step. Then using the tensor structure of tadpole coefficients, we transform the differential equations to the recurrence relations for undetermined tensor coefficients. These recurrence relations can be solved easily by iteration and we can obtain analytic expressions of tadpole coefficients for arbitrary one-loop integrals.

Strangeness-Changing Leptonic Decay Rates for theΣ±Hyperons

1971 ◽  
Vol 4 (3) ◽  
pp. 631-635 ◽  
Author(s):  
J. Cole ◽  
J. Lee-Franzini ◽  
R. J. Loveless ◽  
C. Baltay ◽  
P. Franzini ◽  
...  
Keyword(s):  
Leptonic Decay ◽  
Decay Rates

Water Hammer Peak Pressures and Decay Rates of Transients in Smooth Lines With Turbulent Flow

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
David A. Hullender
Keyword(s):  
Transfer Function ◽  
Differential Equations ◽  
Turbulent Flow ◽  
Ordinary Differential Equations ◽  
Damping Ratio ◽  
Reynolds Numbers ◽  
Water Hammer ◽  
Decay Rates ◽  
Pressure Transients ◽  
Peak Pressures

Transient pressure peak values and decay rates associated with water hammer surges in fluid lines are investigated using an analytical method that has been formulated, in a previous publication, to simulate pressure transients in turbulent flow. The method agrees quite well with method of characteristics (MOC) simulations of unsteady friction models and has been verified with experimental data available for Reynolds numbers out to 15,800. The method is based on the formulation of ordinary differential equations from the frequency response of a pressure transfer function using an inverse frequency algorithm. The model is formulated by dividing the line into n-sections to distribute the turbulence resistance along the line at higher Reynolds numbers. In this paper, it will be demonstrated that convergence of the analytical solution is achieved with as few as 5–10 line sections for Reynolds numbers up to 200,000. The method not only provides for the use of conventional time domain solution algorithms for ordinary differential equations but also provides empirical equations for estimating peak surge pressures and transient decay rates as defined by eigenvalues. For typical sets of line and fluid properties, the trend of the damping ratio of the first or dominate mode of the pressure transients transfer function is found to be an approximate linear function of a dimensionless parameter that is a function of the Reynolds number. In addition, a reasonably accurate dimensionless trend formula for estimates of the normalized peak pressures is formulated and presented.

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