The use of helicity amplitudes in superconvergent sum rules

1967 ◽  
Vol 51 (4) ◽  
pp. 1021-1032 ◽  
Author(s):  
R. Odorico
Keyword(s):  
Sum Rules ◽  
Helicity Amplitudes

scholarly journals Sum rules for e+e− → W+W− helicity amplitudes from BRS invariance

1999 ◽  
Vol 541 (1-2) ◽  
pp. 50-86 ◽  
Author(s):  
S. Alam ◽  
K. Hagiwara ◽  
S. Kanemura ◽  
R. Szalapski ◽  
Y. Umeda
Keyword(s):  
Sum Rules ◽  
Helicity Amplitudes

scholarly journals Sum rules in the standard model effective field theory from helicity amplitudes

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Jiayin Gu ◽  
Lian-Tao Wang
Keyword(s):  
Field Theory ◽  
Standard Model ◽  
Effective Field Theory ◽  
Sum Rules ◽  
High Energy ◽  
Effective Field ◽  
Low Energy ◽  
Tree Level ◽  
The Standard Model ◽  
Helicity Amplitudes

Abstract The dispersion relation of an elastic 4-point amplitude in the forward direction leads to a sum rule that connects the low energy amplitude to the high energy observables. We perform a classification of these sum rules based on massless helicity amplitudes. With this classification, we are able to systematically write down the sum rules for the dimension-6 operators of the Standard Model Effective Field Theory (SMEFT), some of which are absent in previous literatures. These sum rules offer distinct insights on the relations between the operator coefficients in the EFT and the properties of the full theory that generates them. Their applicability goes beyond tree level, and in some cases can be used as a practical method of computing the one loop contributions to low energy observables. They also provide an interesting perspective for understanding the custodial symmetries of the SM Higgs and fermion sectors.

A Perturbation Theory for the Population of Atomic Energy Levels in Non-Lte Plasmas

1988 ◽  
Vol 102 ◽  
pp. 343-347
Author(s):  
M. Klapisch
Keyword(s):  
Perturbation Theory ◽  
Small Parameter ◽  
Classification Scheme ◽  
Sum Rules ◽  
Energy Levels ◽  
Natural Classification ◽  
Quantum Numbers ◽  
Formal Expansion ◽  
Atomic Energy Levels ◽  
As Effects

AbstractA formal expansion of the CRM in powers of a small parameter is presented. The terms of the expansion are products of matrices. Inverses are interpreted as effects of cascades.It will be shown that this allows for the separation of the different contributions to the populations, thus providing a natural classification scheme for processes involving atoms in plasmas. Sum rules can be formulated, allowing the population of the levels, in some simple cases, to be related in a transparent way to the quantum numbers.

KRAMERS--KRONIG RELATIONS AND SUM RULES.

1972 ◽  
Author(s):  
R Kubo ◽  
M Ichimura
Keyword(s):  
Sum Rules

scholarly journals Consistency of nucleon-transfer sum rules in well-deformed nuclei

2021 ◽  
Vol 103 (2) ◽  
Author(s):  
B. P. Kay ◽  
J. P. Schiffer ◽  
S. J. Freeman ◽  
T. L. Tang ◽  
B. D. Cropper ◽  
...  
Keyword(s):  
Sum Rules ◽  
Deformed Nuclei ◽  
Nucleon Transfer

scholarly journals |Vcb| and γ from B-mixing — Addendum to “Bs mixing observables and |Vtd/Vts| from sum rules”

2020 ◽  
Vol 2020 (3) ◽  
Author(s):  
Daniel King ◽  
Matthew Kirk ◽  
Alexander Lenz ◽  
Thomas Rauh
Keyword(s):  
Sum Rules ◽  
B Mixing
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