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arXiv · 1707.02848

New analysis of $\eta\pi$ tensor resonances measured at the COMPASS experiment

A. Jackura·C. Fernandez-Ramirez·M. Mikhasenko·A. Pilloni·V. Mathieu·J. Nys·V. Pauk·A. P. Szczepaniak·G. Fox·M. Aghasyan·R. Akhunzyanov·M. G. Alexeev·G. D. Alexeev·A. Amoroso·V. Andrieux·N. V. Anfimov·V. Anosov·A. Antoshkin·K. Augsten·W. Augustyniak·A. Austregesilo·C. D. R. Azevedo·B. Badelek·F. Balestra·M. Ball·J. Barth·R. Beck·Y. Bedfer·J. Bernhard·K. Bicker·E. R. Bielert·R. Birsa·M. Bodlak·P. Bordalo·F. Bradamante·A. Bressan·M. Buechele·V. E. Burtsev·W. -C. Chang·C. Chatterjee·M. Chiosso·I. Choi·A. G. Chumakov·S. -U. Chung·A. Cicuttin·M. L. Crespo·S. Dalla Torre·S. S. Dasgupta·S. Dasgupta·O. Yu. Denisov·L. Dhara·S. V. Donskov·N. Doshita·Ch. Dreisbach·W. Duennweber·R. R. Dusaev·M. Dziewiecki·A. Efremov·P. D. Eversheim·M. Faessler·A. Ferrero·M. Finger·M. Finger jr.·H. Fischer·C. Franco·N. du Fresne von Hohenesche·J. M. Friedrich·V. Frolov·E. Fuchey·F. Gautheron·O. P. Gavrichtchouk·S. Gerassimov·J. Giarra·F. Giordano·I. Gnesi·M. Gorzellik·A. Grasso·M. Grosse Perdekamp·B. Grube·T. Grussenmeyer·A. Guskov·D. Hahne·G. Hamar·D. von Harrach·F. H. Heinsius·R. Heitz·F. Herrmann·N. Horikawa·N. d'Hose·C. -Y. Hsieh·S. Huber·S. Ishimoto·A. Ivanov·Yu. Ivanshin·T. Iwata·V. Jary·R. Joosten·P. Joerg·E. Kabuss·A. Kerbizi
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Abstract

We present a new amplitude analysis of the $\eta\pi$ $D$-wave in $\pi^- p\to \eta\pi^- p$ measured by COMPASS. Employing an analytical model based on the principles of the relativistic $S$-matrix, we find two resonances that can be identified with the $a_2(1320)$ and the excited $a_2^\prime(1700)$, and perform a comprehensive analysis of their pole positions. For the mass and width of the $a_2$ we find $M=(1307 \pm 1 \pm 6)$~MeV and $\Gamma=(112 \pm 1 \pm 8)$~MeV, and for the excited state $a_2^\prime$ we obtain $M=(1720 \pm 10 \pm 60)$~MeV and $\Gamma=(280\pm 10 \pm 70)$~MeV, respectively.

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A. Jackura, C. Fernandez-Ramirez, M. Mikhasenko, A. Pilloni, V. Mathieu, J. Nys, V. Pauk, A. P. Szczepaniak, G. Fox, M. Aghasyan, R. Akhunzyanov, M. G. Alexeev, G. D. Alexeev, A. Amoroso, V. Andrieux, N. V. Anfimov, V. Anosov, A. Antoshkin, K. Augsten, W. Augustyniak, A. Austregesilo, C. D. R. Azevedo, B. Badelek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E. R. Bielert, R. Birsa, M. Bodlak, P. Bordalo, F. Bradamante, A. Bressan, M. Buechele, V. E. Burtsev, W. -C. Chang, C. Chatterjee, M. Chiosso, I. Choi, A. G. Chumakov, S. -U. Chung, A. Cicuttin, M. L. Crespo, S. Dalla Torre, S. S. Dasgupta, S. Dasgupta, O. Yu. Denisov, L. Dhara, S. V. Donskov, N. Doshita, Ch. Dreisbach, W. Duennweber, R. R. Dusaev, M. Dziewiecki, A. Efremov, P. D. Eversheim, M. Faessler, A. Ferrero, M. Finger, M. Finger jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J. M. Friedrich, V. Frolov, E. Fuchey, F. Gautheron, O. P. Gavrichtchouk, S. Gerassimov, J. Giarra, F. Giordano, I. Gnesi, M. Gorzellik, A. Grasso, M. Grosse Perdekamp, B. Grube, T. Grussenmeyer, A. Guskov, D. Hahne, G. Hamar, D. von Harrach, F. H. Heinsius, R. Heitz, F. Herrmann, N. Horikawa, N. d'Hose, C. -Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, V. Jary, R. Joosten, P. Joerg, E. Kabuss, A. Kerbizi. 2017-07-10. New analysis of $\eta\pi$ tensor resonances measured at the COMPASS experiment. https://doi.org/10.1016/j.physletb.2018.01.017

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