First Measurement of Chiral Dynamics in \pi^- \gamma -> \pi^- \pi^- \pi^+
High Energy Physics - Experiment
2015-06-03 v2
Abstract
The COMPASS collaboration at CERN has investigated the \pi^- \gamma -> \pi^- \pi^- \pi^+ reaction at center-of-momentum energy below five pion masses, sqrt(s) < 5 m(\pi), embedded in the Primakoff reaction of 190 GeV pions impinging on a lead target. Exchange of quasi-real photons is selected by isolating the sharp Coulomb peak observed at smallest momentum transfers, t' < 0.001 (GeV/c)^2. Using partial-wave analysis techniques, the scattering intensity of Coulomb production described in terms of chiral dynamics and its dependence on the 3\pi-invariant mass m(3\pi) = sqrt(s) were extracted. The absolute cross section was determined in seven bins of with an overall precision of 20%. At leading order, the result is found to be in good agreement with the prediction of chiral perturbation theory over the whole energy range investigated.
Keywords
Cite
@article{arxiv.1111.5954,
title = {First Measurement of Chiral Dynamics in \pi^- \gamma -> \pi^- \pi^- \pi^+},
author = {M. G. Alekseev and V. Yu. Alexakhin and Yu. Alexandrov and G. D. Alexeev and A. Amoroso and A. Austregesilo and B. Badelek and F. Balestra and J. Barth and G. Baum and Y. Bedfer and J. Bernhard and R. Bertini and M. Bettinelli and K. Bicker and R. Birsa and J. Bisplinghoff and P. Bordalo and F. Bradamante and A. Bravar and A. Bressan and E. Burtin and D. Chaberny and M. Chiosso and S. U. Chung and A. Cicuttin and M. L. Crespo and S. Dalla Torre and S. Das and S. S. Dasgupta and O. Yu. Denisov and L. Dhara and S. V. Donskov and N. Doshita and V. Duic and W. Dünnweber and M. Dziewiecki and A. Efremov and P. D. Eversheim and W. Eyrich and M. Faessler and A. Ferrero and A. Filin and M. Finger and M. Finger and H. Fischer and C. Franco and N. du Fresne von Hohenesche and J. M. Friedrich and R. Garfagnini and F. Gautheron and O. P. Gavrichtchouk and R. Gazda and S. Gerassimov and R. Geyer and M. Giorgi and I. Gnesi and B. Gobbo and S. Goertz and S. Grabm\" uller and A. Grasso and B. Grube and R. Gushterski and A. Guskov and F. Haas and D. von Harrach and T. Hasegawa and F. H. Heinsius and F. Herrmann and C. Hess and F. Hinterberger and N. Horikawa and Ch. Höppner and N. d'Hose and S. Huber and S. Ishimoto and O. Ivanov and Yu. Ivanshin and T. Iwata and R. Jahn and P. Jasinski and G. Jegou and R. Joosten and E. Kabuss and D. Kang and B. Ketzer and G. V. Khaustov and Yu. A. Khokhlov and Yu. Kisselev and F. Klein and K. Klimaszewski and S. Koblitz and J. H. Koivuniemi and V. N. Kolosov and K. Kondo and K. Königsmann and I. Konorov and V. F. Konstantinov and A. Korzenev and A. M. Kotzinian and O. Kouznetsov and M. Krämer and Z. V. Kroumchtein and F. Kunne and K. Kurek and L. Lauser and A. A. Lednev and A. Lehmann and S. Levorato and J. Lichtenstadt and A. Maggiora and A. Magnon and N. Makke and G. K. Mallot and A. Mann and C. Marchand and A. Martin and J. Marzec and F. Massmann and T. Matsuda and W. Meyer and T. Michigami and Yu. V. Mikhailov and M. A. Moinester and A. Morreale and A. Mutter and A. Nagaytsev and T. Nagel and F. Nerling and S. Neubert and D. Neyret and V. I. Nikolaenko and W. -D. Nowak and A. S. Nunes and A. G. Olshevsky and M. Ostrick and A. Padee and R. Panknin and D. Panzieri and B. Parsamyan and S. Paul and E. Perevalova and G. Pesaro and D. V. Peshekhonov and G. Piragino and S. Platchkov and J. Pochodzalla and J. Polak and V. A. Polyakov and G. Pontecorvo and J. Pretz and C. Quintans and J. -F. Rajotte and S. Ramos and V. Rapatsky and G. Reicherz and A. Richter and E. Rocco and E. Rondio and D. I. Ryabchikov and V. D. Samoylenko and A. Sandacz and H. Santos and M. G. Sapozhnikov and S. Sarkar and I. A. Savin and G. Sbrizzai and P. Schiavon and C. Schill and T. Schlüter and L. Schmitt and S. Schopferer and W. Schröder and O. Yu. Shevchenko and H. -W. Siebert and L. Silva and L. Sinha and A. N. Sissakian and M. Slunecka and G. I. Smirnov and S. Sosio and F. Sozzi and A. Srnka and M. Stolarski and M. Sulc and R. Sulej and P. Sznajder and S. Takekawa and S. Tessaro and F. Tessarotto and A. Teufel and L. G. Tkatchev and S. Uhl and I. Uman and M. Vandenbroucke and M. Virius and N. V. Vlassov and R. Windmolders and W. Wiślicki and H. Wollny and K. Zaremba and M. Zavertyaev and E. Zemlyanichkina and M. Ziembicki and N. Zhuravlev and A. Zvyagin},
journal= {arXiv preprint arXiv:1111.5954},
year = {2015}
}
Comments
10 pages, 5 figures