Chiral perturbation theory for nonzero chiral imbalance
| Autor: | Domenec Espriu, A. Gómez Nicola, Andrea Vioque-Rodríguez |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Quark
Nuclear and High Energy Physics Física-Modelos matemáticos Chiral perturbation theory High Energy Physics::Lattice FOS: Physical sciences Discrete Symmetries Lattice QCD 01 natural sciences Theoretical physics High Energy Physics - Phenomenology (hep-ph) Pion Vacuum energy Lattice (order) 0103 physical sciences Perturbation (Quantum dynamics) Física matemática lcsh:Nuclear and particle physics. Atomic energy. Radioactivity Chirality 010306 general physics Pertorbació (Dinàmica quàntica) Physics 010308 nuclear & particles physics Observable Parity (physics) High Energy Physics - Phenomenology Quiralitat Phase Diagram of QCD Chiral Lagrangians lcsh:QC770-798 |
| Zdroj: | Journal of High Energy Physics Journal of High Energy Physics, Vol 2020, Iss 6, Pp 1-40 (2020) E-Prints Complutense. Archivo Institucional de la UCM instname E-Prints Complutense: Archivo Institucional de la UCM Universidad Complutense de Madrid |
| Popis: | We construct the most general low-energy effective lagrangian including local parity violating terms parametrized by an axial chemical potential or chiral imbalance $\mu_5$, up to ${\cal O}(p^4)$ order in the chiral expansion for two light flavours. For that purpose, we work within the Chiral Perturbation Theory framework where only pseudo-NGB fields are included, following the external source method. The $\cal{O}(p^2)$ lagrangian is only modified by constant terms, while the $\cal{O}(p^4)$ one includes new terms proportional to $\mu_5^2$ and new low-energy constants (LEC), which are renormalized and related to particular observables. In particular, we analyze the corrections to the pion dispersion relation and observables related to the vacuum energy density, namely the light quark condensate, the chiral and topological susceptibilities and the chiral charge density, providing numerical determinations of the new LEC when possible. In particular, we explore the dependence of the chiral restoration temperature $T_c$ with $\mu_5$. An increasing $T_c(\mu_5)$ is consistent with our fits to lattice data of the ChPT-based expressions. Although lattice uncertainties are still large and translate into the new LEC determination, a consistent physical description of those observables emerges from our present work, providing a theoretically robust model-independent framework for further study of physical systems where parity-breaking effects may be relevant, such as heavy-ion collisions. Comment: 28 pages, 9 figures. Version accepted in JHEP. References, comments, section 5F and Figs.8,9 added |
| Databáze: | OpenAIRE |
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