2010/06/15 by Martin Vojik, Vojík, M., P. Lichard +6
Computer Science · Physics and Astronomy · #Algorithms and Data Compression #Computational Physics and Python Applications #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.1006.2919
openalex publication_date 2010/06/15 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
We show that the a1-rho-pi Lagrangian is a decisive element for obtaining a\ngood phenomenological description of the three-pion decays of the tau lepton.\nWe choose it in a two-component form with a flexible mixing parameter\nsin(theta). In addition to the dominant a1-> pho pi intermediate states, the\na1->pi sigma ones are included. When fitting the three-pion mass spectra,\nthree data sets are explored: (1) ALEPH 2005 pi-pi-pi+ data, (2) ALEPH 2005\npi-pi0pi0 data, and (3) previous two sets combined and supplemented with the\nARGUS 1993, OPAL 1997, and CLEO 2000 data. The corresponding confidence levels\nare (1) 28.3%, (2) 100%, and (3) 7.7%. After the inclusion of the a1(1640)\nresonance, the agreement of the model with data greatly improves and the\nconfidence level reaches 100% for each of the three data sets. From the fit to\nall five experiments [data set (3)] the following parameters of the a1(1260)\nare obtained ma1=(1233+/-18) MeV, Gammaa1=(431+/-20) MeV. The optimal\nvalue of the Lagrangian mixing parameter sin(theta)= 0.459+/-0.004 agrees with\nthe value obtained recently from the e+e- annihilation into four pions.\n