A new global fit of the Lir at next-to-next-to-leading order in Chiral Perturbation Theory

2011/03/31 by Johan Bijnens, Ilaria Jemos
Physics and Astronomy · #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ph

paper · pdf · doi:10.1016/j.nuclphysb.2011.09.013

41 pages, p^4 values of the l_i added, numerical values for f_+(0) in Kl3 added, a comparison with the LECS from Ecker et al., Phys. Lett. B692 (2010) 184 [arXiv:1004.3422 [hep-ph]] added

openalex publication_date 2011/09/25 · arxiv created 2011/10/03 · arxiv updated 2015/05/27 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31

Abstract

A new fit is done to obtain numerical values for the order p4 low-energy-constants Lir in Chiral Perturbation Theory. This includes both new data and new calculated observables. We take into account masses, decay constants, Kℓ4, ππ and πK scattering lengths and slopes and the slope of the pion scalar formfactor. We compare in detail where the changes w.r.t. the 10 years old “fit 10” come from. We discuss several scenarios for estimating the order p6 constants Cir and search for possible values of them that provide a good convergence for the ChPT series. We present two such sets. One big change is that the fits do not have the expected behaviour in the limit of large Nc as well as before.

Citations

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• Review of Particle Physics
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• KScattering in Three Flavour ChPT
• Chiral perturbation theory to one loop
• Two-point functions at two loops in three flavour chiral perturbation theory
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• Integrating out strange quarks in ChPT
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• Big Bang Nucleosynthesis (in "The Review of Particle Properties" 2004)
• Phenomenological Lagrangians