Sum rules and pertubation theory

1967 ◽  
Vol 51 (4) ◽  
pp. 970-979 ◽  
Author(s):  
I. G. Halliday
Keyword(s):  
Sum Rules ◽  
Pertubation Theory

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

scholarly journals Unitarity in KK-graviton production, a case study in warped extra-dimensions

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
A. de Giorgi ◽  
S. Vogl
Keyword(s):  
Extra Dimensions ◽  
Sum Rules ◽  
Effective Theory ◽  
Higher Dimensional ◽  
Massive Spin ◽  
The Matrix ◽  
Dimensional Gravity ◽  
Warped Extra Dimensions ◽  
Kaluza Klein

Abstract The Kaluza-Klein (KK) decomposition of higher-dimensional gravity gives rise to a tower of KK-gravitons in the effective four-dimensional (4D) theory. Such massive spin-2 fields are known to be connected with unitarity issues and easily lead to a breakdown of the effective theory well below the naive scale of the interaction. However, the breakdown of the effective 4D theory is expected to be controlled by the parameters of the 5D theory. Working in a simplified Randall-Sundrum model we study the matrix elements for matter annihilations into massive gravitons. We find that truncating the KK-tower leads to an early breakdown of perturbative unitarity. However, by considering the full tower we obtain a set of sum rules for the couplings between the different KK-fields that restore unitarity up to the scale of the 5D theory. We prove analytically that these are fulfilled in the model under consideration and present numerical tests of their convergence. This work complements earlier studies that focused on graviton self-interactions and yields additional sum rules that are required if matter fields are incorporated into warped extra-dimensions.

scholarly journals X0,1(2900) and (D−K+) invariant mass from QCD Laplace sum rules at NLO

2021 ◽  
Vol 1007 ◽  
pp. 122113
Author(s):  
R. Albuquerque ◽  
S. Narison ◽  
D. Rabetiarivony ◽  
G. Randriamanatrika
Keyword(s):  
Invariant Mass ◽  
Sum Rules

scholarly journals QCD sum rules for parameters of the B -meson distribution amplitudes

2021 ◽  
Vol 104 (1) ◽  
Author(s):  
Muslem Rahimi ◽  
Marcel Wald
Keyword(s):  
B Meson ◽  
Sum Rules ◽  
Qcd Sum Rules

scholarly journals Light-cone sum rules for proton decay

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Ulrich Haisch ◽  
Amando Hala
Keyword(s):  
Lattice Qcd ◽  
Light Cone ◽  
Sum Rules ◽  
State Of The Art ◽  
Form Factors ◽  
Baryon Number ◽  
Proton Decay ◽  
Matrix Elements ◽  
Decay Channels ◽  
Systematic Uncertainties

Abstract We estimate the form factors that parametrise the hadronic matrix elements of proton-to-pion transitions with the help of light-cone sum rules. These form factors are relevant for semi-leptonic proton decay channels induced by baryon-number violating dimension-six operators, as typically studied in the context of grand unified theories. We calculate the form factors in a kinematical regime where the momentum transfer from the proton to the pion is space-like and extrapolate our final results to the regime that is relevant for proton decay. In this way, we obtain estimates for the form factors that show agreement with the state-of-the-art calculations in lattice QCD, if systematic uncertainties are taken into account. Our work is a first step towards calculating more involved proton decay channels where lattice QCD results are not available at present.

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