scholarly journals Revisiting the spectrum of baryonium in heavy baryon chiral perturbation theory

2013 ◽  
Vol 88 (11) ◽  
Author(s):  
Yue-De Chen ◽  
Cong-Feng Qiao ◽  
Peng-Nian Shen ◽  
Zhuo-Quan Zeng
Keyword(s):  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Heavy Baryon ◽  
Chiral Perturbation

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.

Convergence issues in baryon chiral perturbation theory for the reaction π + N → 2π + N

2007 ◽  
Vol 85 (6) ◽  
pp. 663-669
Author(s):  
N Mobed ◽  
J Zhang ◽  
D Singh
Keyword(s):  
Experimental Data ◽  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Essential Role ◽  
Heavy Baryon ◽  
Transverse Polarization ◽  
Proton Target ◽  
Chiral Perturbation ◽  
Target Asymmetry ◽  
Chiral Order

We study the reaction π + N → 2π + N within the framework of heavy-baryon chiral perturbation theory of chiral order three. We find that contributions from amplitudes of chiral order three are large and play an essential role in reproducing the experimental data. In addition, we evaluate a polarization observable (target asymmetry) for the transverse polarization of the proton target and find that the asymmetry is generally small for the reaction under consideration. PACS Nos.: 25.80.Hp, 13.75.Gx, 11.30.Rd, 11.10.Ef

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