Phenomenological Lagrangians

Electric dipole moments of light nuclei from chiral effective field theory

“…Each interaction with the correct symmetry transformation properties has a strength determined by details of the QCD dynamics. Until they are known, they are estimated using naive dimensional analysis (NDA) [16,51,13]. For example, the pion mass term originates from explicit chiral-symmetry breaking by the average quark mass, so m 2 π = O(mM QCD ).…”

“…For simplicity, we count ε ∼ 1/3 as O(1) and α em /4π as O(m 3 π /M 3 QCD ), since numerically α em /4π ∼ εm 3 π /(2πF π ) 3 . It is convenient to organize the infinity of effective interactions in the Lagrangian using an integer "chiral index" ∆ and the number f of fermion fields [16,18]:…”

“…In the power counting of χPT [16], one considers typical momenta Q ∼ m π ∼ F π ≪ M QCD ∼ m N ∼ 2πF π and assigns…”

Octet Baryon Quark Flavor Distribution Functions

“…One of the most successful nonperturbative approach is the chiral constituent quark model (χCQM) [11]. The underlying idea is that the set of internal Goldstone bosons (GBs) couple directly to the valence quarks in the interior of hadron, but not at so small distances that perturbative QCD is applicable.…”

Lowest-lying spin-1/2 and spin-3/2 baryon magnetic moments in chiral perturbation theory

“…Chiral symmetry and its breaking pattern, in combination with the concept of effective field theory first systematically put forward by Weinberg [2] , has led to a low-energy effective theory of QCD-Chiral Perturbation Theory (ChPT) [3][4][5][6][7][8][9][10] . It has long been realized that ChPT may be employed to study SU (3) breaking effects on the MMs of the baryon octet.…”