Determination of ππ scattering lengths from measurement of [formula omitted] atom lifetime

B Adeva,A Rodriguez Fernandez,M Kobayashi,A Dudarev,M Benayoun,A Kulikov,A Penzo,M Zhabitsky,A Lanaro,J.L Fungueiriño Pazos,M Chiba,C Santamarina,J Gerndt,D Drijard,A Gorin,T Vrba,V Olchevskii,T Trojek,V Yazkov,O Vázquez Doce,G Caragheorgheopol,P Kokkas,T Ponta,L Tauscher,Z Berka,A Romero Vidal,Z Hons,P Levi Sandri,M Pentia,Y Yoshimura,L Kruglova,J.M Perreau,L Afanasyev,S Constantinescu,S Vlachos,C Schuetz,A Riazantsev,A Sidorov,M Iliescu,I Manuilov,P Zrelov,M Hansroul,M.J Tobar,P Doskarova,V Lucherini,P Gianotti,A Lamberto,C Willmott,S Costantini,D Goldin,J Saborido,A Pazos,M Gugiu,C Ciocarlan,A Benelli,V Brekhovskikh,J Schacher,S Trusov,M Nikitin,C Guaraldo,R Lednický ,V.g Lapshin ,O O Voskresenskaya ,O.e Gorchakov ,V M Ronjin ,C Curceanu ,V.v Karpukhin ,R Hošek ,Kenji Okada ,V.i Komarov ,F Takéutchi ,K Kuroda ,P Chliapnikov ,A.v Kuptsov ,L.l Nemenov ,J Klusoň ,Ph Leruste ,J L Narjoux ,V.v Kruglov ,G F Rappazzo ,A.v Tarasov ,T Núñez Pardo ,A López Agüera ,Victor A Utkin ,F Gómez ,J Molina Rodriguez ,M Pló ,M Ferro‐Luzzi ,V.i Rykalin ,Diego Dreossi ,J C Marin ,J Smolík ,T Mäki ,Mercedes Gallas Torreira ,T Čechák

doi:10.1016/j.physletb.2011.08.074

Abstract

The DIRAC experiment at CERN has achieved a sizeable production of π + π − atoms and has significantly improved the precision on its lifetime determination. From a sample of 21 227 atomic pairs, a 4% measurement of the S-wave ππ scattering length difference | a 0 − a 2 | = ( 0.2533 − 0.0078 + 0.0080 | stat | syst − 0.0073 + 0.0078 ) M π + − 1 has been attained, providing an important test of Chiral Perturbation Theory.

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