scholarly journals SPIN POLARIZABILITY OF THE NUCLEON IN THE EFFECTIVE FIELD THEORY OF HEAVY BARYON

2006 ◽  
Vol 21 (19n20) ◽  
pp. 3947-3966
Author(s):  
K. B. VIJAYA KUMAR ◽  
YONG-LIANG MA ◽  
YUE-LIANG WU
Keyword(s):  
Field Theory ◽  
Perturbation Theory ◽  
Effective Field Theory ◽  
Chiral Perturbation Theory ◽  
Heavy Baryon ◽  
Effective Field ◽  
Leading Order ◽  
Chiral Perturbation ◽  
Spin Polarizability ◽  
Large Correction

We have constructed a heavy baryon effective field theory with photon as an external field in accordance with the symmetry requirements similar to the heavy quark effective field theory. By treating the heavy baryon and antibaryon equally on the same footing in the effective field theory, we have calculated the spin polarizabilities γi, i = 1,…,4 of the nucleon at third order and at fourth-order of the spin-dependent Compton scattering. At leading order (LO), our results agree with the corresponding results of the heavy baryon chiral perturbation theory, at the next-to-leading order (NLO) the results show a large correction to the ones in the heavy baryon chiral perturbation theory due to baryon–antibaryon coupling terms. The low-energy theorem is satisfied both at LO and at NLO. The contributions arising from the heavy baryon–antibaryon vertex were found to be significant and the results of the polarizabilities obtained from our theory is much closer to the experimental data.

scholarly journals Chiral Perturbation Theory at NNNLO

Symmetry ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1262
Author(s):  
Nils Hermansson-Truedsson
Keyword(s):  
Field Theory ◽  
Perturbation Theory ◽  
Effective Field Theory ◽  
Chiral Perturbation Theory ◽  
Pion Mass ◽  
Effective Field ◽  
Leading Order ◽  
Chiral Perturbation ◽  
Effective Lagrangian ◽  
Low Energies

Chiral perturbation theory is a much successful effective field theory of quantum chromodynamics at low energies. The effective Lagrangian is constructed systematically order by order in powers of the momentum p2, and until now the leading order (LO), next-to leading order (NLO), next-to-next-to leading order (NNLO) and next-to-next-to-next-to leading order (NNNLO) have been studied. In the following review we consider the construction of the Lagrangian and in particular focus on the NNNLO case. We in addition review and discuss the pion mass and decay constant at the same order, which are fundamental quantities to study for chiral perturbation theory. Due to the large number of terms in the Lagrangian and hence low energy constants arising at NNNLO, some remarks are made about the predictivity of this effective field theory.

πNN SYSTEM AT LOW ENERGY

2011 ◽  
Vol 26 (03n04) ◽  
pp. 586-588 ◽  
Author(s):  
VADIM BARU
Keyword(s):  
Field Theory ◽  
Perturbation Theory ◽  
Effective Field Theory ◽  
Chiral Perturbation Theory ◽  
High Accuracy ◽  
Effective Field ◽  
Low Energy ◽  
Chiral Perturbation ◽  
Recent Developments

With the advent of chiral perturbation theory, the low-energy effective field theory of QCD, high accuracy calculations for hadronic reactions have become possible. We review the recent developments in the reaction NN → NNπ in chiral EFT.

scholarly journals NEW PREDICTIONS OF GENERALIZED SPIN POLARIZABILITIES IN HEAVY BARYON CHIRAL PERTURBATION THEORY

2006 ◽  
Vol 21 (10) ◽  
pp. 2027-2148 ◽  
Author(s):  
CHUNG-WEN KAO
Keyword(s):  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Spin Structure ◽  
Sum Rules ◽  
Heavy Baryon ◽  
Virtual Compton Scattering ◽  
Leading Order ◽  
Chiral Perturbation ◽  
Theoretical Understanding ◽  
Existing Data

We review the recent progress of the theoretical understanding of the spin structure of the nucleon based on Heavy Baryon Chiral Perturbation Theory (HBChPT). At low Q2 the spin structure of the nucleon is encoded into the generalized spin polarizabilities (spin GP's) extracted from the virtual Compton scattering (VCS) amplitudes. The spin GP's of the nucleon have been calculated up to next-to-leading order in HBChPT. Furthermore, the forward spin generalized polarizabilities, which are related to the nucleon polarized structure functions g1 and g2 through the sum rules based on dispersion relations, also have been calculated in HBChPT up to next-to-leading order. As a summary, the physics content of the existing data is discussed and some perspectives for future theoretical and experimental activities in this field are also presented.

scholarly journals Recent results of the pion-nucleon scattering and the widths of the delta and Roper resonances in BChPT

2019 ◽  
Vol 199 ◽  
pp. 01005
Author(s):  
J. Gegelia
Keyword(s):  
Field Theory ◽  
Perturbation Theory ◽  
Effective Field Theory ◽  
Degrees Of Freedom ◽  
Effective Field ◽  
Chiral Perturbation ◽  
Nucleon Scattering ◽  
Delta Resonances ◽  
Pion Nucleon ◽  
Dynamical Degrees

Recent calculations of the pion-nucleon scattering in covariant baryon chiral perturbation theory with explicit delta resonances are presented. Two-loop results of the widths of the Δ and Roper resonances are discussed in the framework of an effective field theory with nucleons, pions and the Roper and delta resonances as dynamical degrees of freedom.

scholarly journals THE ROLE OF THE Δ(1232)-RESONANCE IN COVARIANT BARYON CHIRAL PERTURBATION THEORY

2014 ◽  
Vol 26 ◽  
pp. 1460088
Author(s):  
J. M. ALARCÓN
Keyword(s):  
Field Theory ◽  
Perturbation Theory ◽  
Effective Field Theory ◽  
Effective Field ◽  
Scattering Data ◽  
Theory Approach ◽  
Chiral Perturbation ◽  
Chiral Effective Field Theory ◽  
Dynamical Degree

We stress, on theoretical and phenomenological grounds, the importance of the Δ(1232)-resonance in a chiral effective field theory approach to the study of πN scattering. We show how its inclusion as a dynamical degree of freedom allow us to obtain reliably valuable information from πN scattering data.

scholarly journals On the three-particle analog of the Lellouch-Lüscher formula

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Fabian Müller ◽  
Akaki Rusetsky
Keyword(s):  
Field Theory ◽  
Finite Volume ◽  
Effective Field Theory ◽  
Effective Field ◽  
Infinite Volume ◽  
Leading Order ◽  
Particle Decay ◽  
Particle Decays

Abstract Using non-relativistic effective field theory, we derive a three-particle analog of the Lellouch-Lüscher formula at the leading order. This formula relates the three-particle decay amplitudes in a finite volume with their infinite-volume counterparts and, hence, can be used to study the three-particle decays on the lattice. The generalization of the approach to higher orders is 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.

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