2008/01/31 by Aneesh V. Manohar, A. V. Manohar, Vicent Mateu +1 · 8 citations
Physics and Astronomy · #Black Holes and Theoretical Physics #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ph
paper · pdf · doi:10.1103/physrevd.77.094019
published as Phys.Rev.D77:094019,2008 · 12 pages, 8 figures. Two references added, a few minor changes. Published version
openalex publication_date 2008/05/22 · arxiv created 2008/05/26 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
Axiomatic principles such as analyticity, unitarity, and crossing symmetry constrain the second derivative of the \ensuremathπ\ensuremathπ scattering amplitudes in some channels to be positive in a region of the Mandelstam plane. Since this region lies in the domain of validity of chiral perturbation theory, we can use these positivity conditions to bound linear combinations of l1 and l2. We compare our predictions with those derived previously in the literature using similar methods. We compute the one-loop \ensuremathπ\ensuremathπ scattering amplitude in the linear sigma model (LSM) using the MS scheme, a result hitherto absent in the literature. The LSM values for l1 and l2 violate the bounds for small values of m_\ensuremathσ/m_\ensuremathπ. We show how this can occur, while still being consistent with the axiomatic principles.