scholarly journals s -wave baryon nonleptonic decay amplitude in large−Nc chiral perturbation theory

2019 ◽  
Vol 99 (9) ◽  
Author(s):  
Rubén Flores-Mendieta
Keyword(s):  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Decay Amplitude ◽  
Nonleptonic Decay ◽  
S Wave ◽  
Chiral Perturbation

scholarly journals Equivalence Between Vector Meson Dominance and Unitarised Chiral Perturbation Theory

2015 ◽  
Vol 24 (4) ◽  
pp. 289
Author(s):  
Truong Nguyen Tran ◽  
Le Viet Dung
Keyword(s):  
Perturbation Theory ◽  
Vector Meson ◽  
Chiral Perturbation Theory ◽  
Vector Meson Dominance ◽  
S Wave ◽  
Chiral Perturbation ◽  
Scalar Form Factor ◽  
Scalar Form ◽  
Standard Vector ◽  
The One

It is explicitly shown that either the approximate solution of the integral equation for the inverse of the pion form facto,r or the result of the Pad\(\text{\'e}\) approximant method of resumming the one loop Chiral Perturbation Theory (CPTH) are equivalent to the standard vector meson dominance (VMD) models, using the vector meson coupling to two pseudoscalars given by the KSRF relation. Inconsistencies between the one loop CPTH and its unitarised version (or the VMD model) are pointed out. The situation is better for the CPTH calculation of the scalar form factor and the related S-wave $\pi \pi$ scattering. The branching ratios of \(\tau \to \pi^+ \pi^0 \nu \), \(\tau \to K \pi \nu \), \(\tau \to K^+ \eta \nu\) and $\tau \to K^+ \bar{K^0} \nu\) using only two inputs as the \(\rho\) and \(K^*\) masses, or the two corresponding rms radii, agree with the experimental data. Using the same number of parameters, the corresponding one loop CPTH calculation cannot explain the $\tau$ data.

THE $K_L^0\to \pi ^0 \gamma \gamma$ DECAY IN CHIRAL PERTURBATION THEORY BASED ON THE EXTENDED NAMBU-JONA-LASINIO MODEL

1992 ◽  
Vol 07 (21) ◽  
pp. 5115-5129 ◽  
Author(s):  
ANDREI N. IVANOV
Keyword(s):  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Chiral Limit ◽  
Decay Amplitude ◽  
Low Energy ◽  
Chiral Perturbation ◽  
Photon Exchange ◽  
Two Photon ◽  
Energy Approximation ◽  
Gamma Decay

The [Formula: see text] decay is analyzed within chiral perturbation theory based on the extended Nambu-Jona-Lasinio model, which is used as a low energy approximation of QCD. The two-photon spectrum of the [Formula: see text] decay and the value of the probability [Formula: see text] are obtained in good agreement with experimental data. It is shown that the CP-conserving two-photon exchange contribution to the [Formula: see text] decay mplitude is negligibly small compared to that of the CP-violating one-photon exchange. Also presented is the derivation of the low-energy theorem for the [Formula: see text] decay amplitude in the chiral limit.

scholarly journals S-wave scattering in chiral perturbation theory with resonances

2000 ◽  
Vol 587 (1-3) ◽  
pp. 331-362 ◽  
Author(s):  
Matthias Jamin ◽  
José Antonio Oller ◽  
Antonio Pich
Keyword(s):  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Wave Scattering ◽  
S Wave ◽  
Chiral Perturbation

scholarly journals Weak nonleptonic decay in chiral perturbation theory

1999 ◽  
Vol 451 (3-4) ◽  
pp. 267-274 ◽  
Author(s):  
David A. Egolf ◽  
Ilarion V. Melnikov ◽  
Roxanne P. Springer
Keyword(s):  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Nonleptonic Decay ◽  
Chiral Perturbation

scholarly journals Revisiting $\bar{K}N$ scattering and relevant baryon resonances

2014 ◽  
Vol 29 ◽  
pp. 1460242
Author(s):  
Zhi-Hui Guo ◽  
J. A. Oller
Keyword(s):  
Experimental Data ◽  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Wave Scattering ◽  
Threshold Behavior ◽  
S Wave ◽  
Chiral Perturbation ◽  
Baryon Spectroscopy ◽  
Baryon Resonances

We give an updated study on meson-baryon scattering within the framework of unitary chiral perturbation theory. We focus on S-wave scattering with strangeness -1 channel. After fixing the unknown couplings through fitting to experimental data, we then analyze the baryon spectroscopy and the sub-threshold behavior of the [Formula: see text] amplitude. We end with a summary and a brief outlook.

scholarly journals REMARK ON PION SCATTERING LENGTHS

2009 ◽  
Vol 24 (28) ◽  
pp. 2285-2289 ◽  
Author(s):  
DEIRDRE BLACK ◽  
AMIR H. FARIBORZ ◽  
RENATA JORA ◽  
NAE WOONG PARK ◽  
JOSEPH SCHECHTER ◽  
...  
Keyword(s):  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Scattering Length ◽  
Linear Sigma Model ◽  
Isotopic Spin ◽  
S Wave ◽  
Tree Amplitude ◽  
Chiral Perturbation ◽  
Pion Scattering ◽  
Scattering Lengths

First it is shown that the tree amplitude for pion–pion scattering in the minimal linear sigma model has an exact expression which is proportional to a geometric series in the quantity [Formula: see text], where mB is the sigma mass which appears in the Lagrangian and is the only a priori unknown parameter in the model. This induces an infinite series for every predicted scattering length in which each term corresponds to a given order in the chiral perturbation theory counting. It is noted that, perhaps surprisingly, the pattern, though not the exact values, of chiral perturbation theory predictions for both the isotopic spin 0 and isotopic spin 2 s-wave pion–pion scattering lengths to orders p2, p4 and p6 seems to agree with this induced pattern. The values of the p8 terms are also given for comparison with a possible future chiral perturbation theory calculation. Further aspects of this approach and future directions are briefly discussed.

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.

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.

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