The nucleon anapole form factor in chiral perturbation theory to sub-leading order

Abstract We report on the calculation of the CP-violating form factor F3 and the corresponding electric dipole moment for charmed baryons in the spin-1/2 sector generated by the QCD θ-term. We work in the framework of covariant baryon chiral perturbation theory within the extended-on-mass-shell renormalization scheme up to next-to-leading order in the chiral expansion.

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Chiral perturbation theory and nucleon–pion-state contaminations in lattice QCD

International Journal of Modern Physics A ◽

10.1142/s0217751x17300113 ◽

2017 ◽

Vol 32 (15) ◽

pp. 1730011 ◽

Cited By ~ 12

Author(s):

Oliver Bär

Keyword(s):

Perturbation Theory ◽

Chiral Perturbation Theory ◽

Distribution Functions ◽

Leading Order ◽

Chiral Perturbation ◽

Parton Distribution Functions ◽

Physical Point ◽

Source Sink ◽

The Impact ◽

Quark Momentum

Multiparticle states with additional pions are expected to be a non-negligible source of excited-state contamination in lattice simulations at the physical point. It is shown that baryon chiral perturbation theory can be employed to calculate the contamination due to two-particle nucleon–pion-states in various nucleon observables. Leading order results are presented for the nucleon axial, tensor and scalar charge and three Mellin moments of parton distribution functions (quark momentum fraction, helicity and transversity moment). Taking into account phenomenological results for the charges and moments the impact of the nucleon–pion-states on lattice estimates for these observables can be estimated. The nucleon–pion-state contribution results in an overestimation of all charges and moments obtained with the plateau method. The overestimation is at the 5–10% level for source-sink separations of about 2 fm. The source-sink separations accessible in contemporary lattice simulations are found to be too small for chiral perturbation theory to be directly applicable.

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Two-flavor chiral perturbation theory at nonzero isospin: pion condensation at zero temperature

The European Physical Journal C ◽

10.1140/epjc/s10052-019-7381-4 ◽

2019 ◽

Vol 79 (10) ◽

Cited By ~ 12

Author(s):

Prabal Adhikari ◽

Jens O. Andersen ◽

Patrick Kneschke

Keyword(s):

Perturbation Theory ◽

Equation Of State ◽

Condensed Phase ◽

Chiral Perturbation Theory ◽

Chemical Potential ◽

Tree Level ◽

Zero Temperature ◽

Leading Order ◽

Chiral Perturbation ◽

Pion Condensation

Abstract In this paper, we calculate the equation of state of two-flavor finite isospin chiral perturbation theory at next-to-leading order in the pion-condensed phase at zero temperature. We show that the transition from the vacuum phase to a Bose-condensed phase is of second order. While the tree-level result has been known for some time, surprisingly quantum effects have not yet been incorporated into the equation of state. We find that the corrections to the quantities we compute, namely the isospin density, pressure, and equation of state, increase with increasing isospin chemical potential. We compare our results to recent lattice simulations of 2 + 1 flavor QCD with physical quark masses. The agreement with the lattice results is generally good and improves somewhat as we go from leading order to next-to-leading order in $$\chi $$χPT.

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Quark and pion condensates at finite isospin density in chiral perturbation theory

The European Physical Journal C ◽

10.1140/epjc/s10052-020-08574-8 ◽

2020 ◽

Vol 80 (11) ◽

Author(s):

Prabal Adhikari ◽

Jens O. Andersen

Keyword(s):

Perturbation Theory ◽

Chiral Perturbation Theory ◽

Chemical Potential ◽

Chiral Condensate ◽

Zero Temperature ◽

Leading Order ◽

Chiral Perturbation ◽

Pion Condensate ◽

Independent Analysis ◽

Model Independent

AbstractIn this paper, we consider two-flavor QCD at zero temperature and finite isospin chemical potential $$\mu _I$$ μ I using a model-independent analysis within chiral perturbation theory at next-to-leading order. We calculate the effective potential, the chiral condensate and the pion condensate in the pion-condensed phase at both zero and nonzero pionic source. We compare our finite pionic source results for the chiral condensate and the pion condensate with recent (2+1)-flavor lattice QCD results. Agreement with lattice results generally improves as one goes from leading order to next-to-leading order.

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