% IMPORTANT: The following is UTF-8 encoded. This means that in the presence % of non-ASCII characters, it will not work with BibTeX 0.99 or older. % Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or % “biber”. @ARTICLE{Adlarson:127615, author = {Adlarson, P. and Adolph, C. and Augustyniak, W. and Bardan, W. and Bashkanov, M. and Bednarski, T. and Bergmann, F. S. and Berłowski, M. and Bhatt, H. and Brinkmann, K.-T. and Büscher, M. and Calén, H. and Clement, H. and Coderre, D. and Czerwiński, E. and Doroshkevich, E. and Engels, R. and Erven, W. and Eyrich, W. and Fedorets, P. and Föhl, K. and Fransson, K. and Goldenbaum, F. and Goslawski, P. and Grigoryev, K. and Gullström, C.-O. and Hanhart, C. and Heijkenskjöld, L. and Heimlich, J. and Hejny, V. and Hinterberger, F. and Hodana, M. and Höistad, B. and Jacewicz, M. and Jany, A. and Jany, B. R. and Jarczyk, L. and Johansson, T. and Kamys, B. and Kemmerling, G. and Khakimova, O. and Khoukaz, A. and Kistryn, S. and Klaja, J. and Kleines, H. and Kłos, B. and Kren, F. and Krzemień, W. and Kulessa, P. and Kupść, A. and Lalwani, K. and Leupold, S. and Lorentz, B. and Magiera, A. and Maier, R. and Mariański, B. and Marciniewski, P. and Meißner, U.-G. and Mikirtychiants, M. and Morsch, H.-P. and Moskal, P. and Nandi, B. K. and Niedźwiecki, S. and Ohm, H. and Passfeld, A. and Pauly, C. and Perez del Rio, E. and Petri, T. and Petukhov, Y. and Piskunov, N. and Pluciński, P. and Podkopał, P. and Povtoreyko, A. and Prasuhn, D. and Pricking, A. and Pysz, K. and Pyszniak, A. and Rausmann, T. and Redmer, C. F. and Ritman, J. and Roy, A. and Rudy, Z. and Sawant, S. and Schadmand, S. and Schmidt, A. and Sefzick, T. and Serdyuk, V. and Shah, N. and Siemaszko, M. and Siudak, R. and Skorodko, T. and Skurzok, M. and Smyrski, J. and Sopov, V. and Stassen, R. and Stepaniak, J. and Sterzenbach, G. and Stockhorst, H. and Stollenwerk, F. and Ströher, H. and Szczurek, A. and Täschner, A. and Terschlüsen, C. and Tolba, T. and Trzciński, A. and Varma, R. and Vlasov, P. and Wagner, G. J. and Węglorz, W. and Winnemöller, A. and Wirzba, A. and Wolke, M. and Wrońska, A. and Wüstner, P. and Wurm, P. and Yuan, X. and Yurev, L. and Zabierowski, J. and Zheng, C. and Zieliński, M. J. and Zipper, W. and Złomańczuk, J. and Żuprański, P.}, title = {{E}xclusive measurement of the η→ $\pi^+ \pi^-$ γ decay}, journal = {Physics letters / B}, volume = {707}, number = {2}, address = {Amsterdam}, publisher = {North-Holland Publ.}, reportid = {FZJ-2012-00573}, pages = {243 - 249}, year = {2012}, abstract = {An exclusive measurement of the decay eta --> pi+ pi- gamma has been performed at the WASA facility at COSY. The eta mesons were produced in the fusion reaction pd --> 3He X at a proton beam momentum of 1.7 GeV/c. Efficiency corrected differential distributions have been extracted based on $13340\pm140$ events after background subtraction. The measured pion angular distribution is consistent with a relative p-wave of the two-pion system, whereas the measured photon energy spectrum was found at variance with the simplest gauge invariant matrix element of eta --> pi+ pi- gamma. A parameterization of the data can be achieved by the additional inclusion of the empirical pion vector form factor multiplied by a first-order polynomial in the squared invariant mass of the pi+ pi- system.}, keywords = {eta: radiative decay (INSPIRE) / pi: angular distribution (INSPIRE) / photon: energy spectrum (INSPIRE) / form factor: vector (INSPIRE) / invariance: gauge (INSPIRE) / beam: momentum (INSPIRE) / p deuteron: fusion (INSPIRE) / Juelich COSY PS (INSPIRE) / mass spectrum: (pi+ pi- photon) (INSPIRE) / eta: hadroproduction (INSPIRE) / experimental results (INSPIRE) / eta --> pi+ pi- photon (INSPIRE) / p deuteron --> helium eta (INSPIRE) / 1.7 GeV/c (INSPIRE)}, cin = {IAS-4 / IKP-3 / IKP-TH / IKP-2 / IKP-TA / IKP-1}, ddc = {530}, cid = {I:(DE-Juel1)IAS-4-20090406 / I:(DE-Juel1)IKP-3-20111104 / I:(DE-Juel1)VDB223 / I:(DE-Juel1)IKP-2-20111104 / I:(DE-Juel1)IKP-TA-20111104 / I:(DE-Juel1)IKP-1-20111104}, pnm = {531 - Hadron Structure and Dynamics (HSD) (POF2-531)}, pid = {G:(DE-HGF)POF2-531}, experiment = {EXP:(DE-Juel1)WASA-at-COSY-20170712}, typ = {PUB:(DE-HGF)16}, UT = {WOS:000300134400002}, eprint = {1107.5277}, howpublished = {arXiv:1107.5277}, archivePrefix = {arXiv}, SLACcitation = {$\%\%CITATION$ = $arXiv:1107.5277;\%\%$}, doi = {10.1016/j.physletb.2011.12.027}, url = {https://juser.fz-juelich.de/record/127615}, }