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 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.

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 Perturbative QCD at High Temperature

1997 ◽  
Vol 12 (08) ◽  
pp. 1431-1464 ◽  
Author(s):  
Agustin Nieto
Keyword(s):  
Field Theory ◽  
Free Energy ◽  
Perturbation Theory ◽  
High Temperature ◽  
Perturbative Qcd ◽  
Effective Field Theory ◽  
Quark Gluon Plasma ◽  
Gluon Plasma ◽  
Effective Field ◽  
Recent Developments

Recent developments of perturbation theory at finite temperature based on effective field theory methods are reviewed. These methods allow the contributions from the different scales to be separated and the perturbative series to be reorganized. The construction of the effective field theory is shown in detail for ϕ4 theory and QCD. It is applied to the evaluation of the free energy of QCD at order g5 and the calculation of the g6 term is outlined. Implications for the application of perturbative QCD to the quark–gluon plasma are also discussed.

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 Constraints on the charged currents in general neutrino interactions with sterile neutrinos

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Tong Li ◽  
Xiao-Dong Ma ◽  
Michael A. Schmidt
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Neutral Current ◽  
New Physics ◽  
Effective Field ◽  
Lepton Number ◽  
Low Energy ◽  
Electroweak Scale ◽  
Sterile Neutrinos ◽  
Neutrino Interactions

Abstract In this work we investigate the implication of low-energy precision measurements on the quark-lepton charged currents in general neutrino interactions with sterile neutrinos in effective field theories. The physics in low-energy measurements is described by the low-energy effective field theory extended with sterile neutrinos (LNEFT) defined below the electroweak scale. We also take into account renormalization group running and match the LNEFT onto the Standard Model (SM) effective field theory with sterile neutrinos (SMNEFT) to constrain new physics (NP) above the electroweak scale. The most sensitive low-energy probes are from leptonic decays of pseudoscalar mesons and hadronic tau lepton decays in terms of precise decay branching fractions, the lepton flavor universality and the Cabibbo-Kobayashi-Maskawa (CKM) unitarity. We also consider other constraints including nuclear beta decay. The constraints on charged current operators are generally stronger than the ones for quark-neutrino neutral current operators. We find that the most stringent bounds on the NP scale of lepton-number-conserving and lepton- number-violating operators in SMNEFT are 74 (110) TeV and 9.8 (13) TeV, respectively, for the operators with down (strange) quark.

Effective field theory for low-energy QCD

2014 ◽  
pp. 200-236
Author(s):  
John F. Donoghue ◽  
Eugene Golowich ◽  
Barry R. Holstein
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Effective Field ◽  
Low Energy
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