scholarly journals Lorentz- and CPT -violating standard model extension in chiral perturbation theory

2019 ◽  
Vol 100 (7) ◽  
Author(s):  
Brett Altschul ◽  
Matthias R. Schindler
Keyword(s):  
Perturbation Theory ◽  
Standard Model ◽  
Chiral Perturbation Theory ◽  
Standard Model Extension ◽  
Chiral Perturbation ◽  
Model Extension

scholarly journals New series representations for the two-loop massive sunset diagram

2020 ◽  
Vol 80 (7) ◽  
Author(s):  
B. Ananthanarayan ◽  
Samuel Friot ◽  
Shayan Ghosh
Keyword(s):  
Perturbation Theory ◽  
Standard Model ◽  
Analytic Continuation ◽  
Chiral Perturbation Theory ◽  
Convergent Series ◽  
Regions Of Interest ◽  
External Momentum ◽  
Chiral Perturbation ◽  
Physical Problems ◽  
Series Representations

Abstract We derive new convergent series representations for the two-loop sunset diagram with three different propagator masses $$m_1,\, m_2$$m1,m2 and $$m_3$$m3 and external momentum p by techniques of analytic continuation on a well-known triple series that corresponds to the Lauricella $$F_C^{(3)}$$FC(3) function. The convergence regions of the new series contain regions of interest to physical problems. These include some ranges of masses and squared external momentum values which make them useful from Chiral Perturbation Theory to some regions of the parameter space of the Minimal Supersymmetric Standard Model. The analytic continuation results presented for the Lauricella series could be used in other settings as well.

scholarly journals CP VIOLATION IN KAON DECAYS

1998 ◽  
Vol 13 (01) ◽  
pp. 1-93 ◽  
Author(s):  
GIANCARLO D'AMBROSIO ◽  
GINO ISIDORI
Keyword(s):  
Perturbation Theory ◽  
Cp Violation ◽  
Standard Model ◽  
Chiral Perturbation Theory ◽  
Chiral Perturbation ◽  
Kaon Decays ◽  
The Standard Model ◽  
Model Predictions ◽  
Effective Hamiltonians

We review the Standard Model predictions of CP violation in kaon decays. We present an elementary introduction to Chiral Perturbation Theory, four-quark effective Hamiltonians and the relation among them. Particular attention is devoted to K→3π, K→ 2πγ and [Formula: see text] decays.

scholarly journals The axion-baryon coupling in SU(3) heavy baryon chiral perturbation theory

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Thomas Vonk ◽  
Feng-Kun Guo ◽  
Ulf-G. Meißner
Keyword(s):  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Heavy Baryon ◽  
Power Counting ◽  
Flavor Symmetry ◽  
Chiral Perturbation ◽  
Third Order ◽  
Stellar Objects ◽  
The Past ◽  
Dense Nuclear Matter

Abstract In the past, the axion-nucleon coupling has been calculated in the framework of SU(2) heavy baryon chiral perturbation theory up to third order in the chiral power counting. Here, we extend these earlier studies to the case of heavy baryon chiral perturbation theory with SU(3) flavor symmetry and derive the axion coupling to the full SU(3) baryon octet, showing that the axion also significantly couples to hyperons. As studies on dense nuclear matter suggest the possible existence of hyperons in stellar objects such as neutron stars, our results should have phenomenological implications related to the so-called axion window.

scholarly journals Challenges for a QCD axion at the 10 MeV scale

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Jia Liu ◽  
Navin McGinnis ◽  
Carlos E. M. Wagner ◽  
Xiao-Ping Wang
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Structure Constant ◽  
Fine Structure Constant ◽  
Multiple Sources ◽  
Standard Model Extension ◽  
Mixing Angles ◽  
Quark Masses ◽  
Model Extension ◽  
The One

Abstract We report on an interesting realization of the QCD axion, with mass in the range $$ \mathcal{O} $$ O (10) MeV. It has previously been shown that although this scenario is stringently constrained from multiple sources, the model remains viable for a range of parameters that leads to an explanation of the Atomki experiment anomaly. In this article we study in more detail the additional constraints proceeding from recent low energy experiments and study the compatibility of the allowed parameter space with the one leading to consistency of the most recent measurements of the electron anomalous magnetic moment and the fine structure constant. We further provide an ultraviolet completion of this axion variant and show the conditions under which it may lead to the observed quark masses and CKM mixing angles, and remain consistent with experimental constraints on the extended scalar sector appearing in this Standard Model extension. In particular, the decay of the Standard Model-like Higgs boson into two light axions may be relevant and leads to a novel Higgs boson signature that may be searched for at the LHC in the near future.

Light front Hamiltonian for boson form of QED (1 + 1) in Pauli–Villars regularization

2019 ◽  
Vol 34 (21) ◽  
pp. 1950113
Author(s):  
V. A. Franke ◽  
M. Yu. Malyshev ◽  
S. A. Paston ◽  
E. V. Prokhvatilov ◽  
M. I. Vyazovsky
Keyword(s):  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Chiral Condensate ◽  
Light Front ◽  
Coupling Constants ◽  
Hamiltonian Approach ◽  
Chiral Perturbation ◽  
Dimensional Models ◽  
Villars Regularization ◽  
Ultraviolet Regularization

Light front (LF) Hamiltonian for QED in [Formula: see text] dimensions is constructed using the boson form of this model with additional Pauli–Villars-type ultraviolet regularization. Perturbation theory, generated by this LF Hamiltonian, is proved to be equivalent to usual covariant chiral perturbation theory. The obtained LF Hamiltonian depends explicitly on chiral condensate parameters which enter in a form of some renormalization of coupling constants. The obtained results can be useful when one attempts to apply LF Hamiltonian approach for [Formula: see text]-dimensional models like QCD.

scholarly journals K0 → π0γγ decays in chiral perturbation theory

1987 ◽  
Vol 189 (3) ◽  
pp. 363-368 ◽  
Author(s):  
Gerhard Ecker ◽  
Antonio Pich ◽  
Eduardo De Rafael
Keyword(s):  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Chiral Perturbation
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