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Determination of the pole position of the lightest hybrid meson candidate



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Rodas Bilbao, Arkaitz and Pilloni, A. and Albaladejo, M. and Fernández Ramírez, C. and Jackura, A. and Mathieu, V. and Mikhasenko, M. and Nys, J. and Pauk, V. and Ketzer, B. and Szczepaniak, A. P. (2019) Determination of the pole position of the lightest hybrid meson candidate. Physical review letters, 122 (4). ISSN 0031-9007

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Official URL: http://dx.doi.org/10.1103/PhysRevLett.122.042002


Mapping states with explicit gluonic degrees of freedom in the light sector is a challenge, and has led to controversies in the past. In particular, the experiments have reported two different hybrid candidates with spin-exotic signature, pi¬_1(1400) and pi_1 (1600), which couple separately to eta pi and eta'pi. This picture is not compatible with recent Lattice QCD estimates for hybrid states, nor with most phenomenological models. We consider the recent partial wave analysis of the eta^(')pi system by the COMPASS Collaboration. We fit the extracted intensities and phases with a coupled-channel amplitude that enforces the unitarity and analyticity of the S matrix. We provide a robust extraction of a single exotic pi_1 resonant pole, with mass and width 1564 +/- 24 +/- 86 and 492 +/- 54 +/- 102 MeV, which couples to both eta^(')pi channels. We find no evidence for a second exotic state. We also provide the resonance parameters of the a_2 (1320) and a_2^' (1700).

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©2019 American Physical Society
We would like to thank the COMPASS Collaboration for useful comments. A. P. thanks the Mainz Institute for Theoretical Physics (MITP) for its kind hospitality while this work was being completed. This work was supported by the U.S. Department of Energy under Grants No. DE-AC05-06OR23177 and No. DE-FG02-87ER40365, U.S. National Science Foundation under Grant No. PHY-1415459, Ministerio de Ciencia, Innovacion y Universidades (Spain) Grants No. FPA2016-75654-C2-2-P and No. FPA2016-77313-P, Universidad Complutense de Madrid predoctoral scholarship program, Research Foundation-Flanders (FWO), PAPIIT-DGAPA (UNAM, Mexico) under Grants No. IA101717 and No. IA101819, CONACYT (Mexico) under Grant No. 251817, the German Bundesministerium fur Bildung und Forschung (BMBF), and Deutsche Forschungsgemeinschaft (DFG) through the Collaborative Research Center [The Low-Energy Frontier of the Standard Model (SFB 1044)] and the Cluster of Excellence [Precision Physics, Fundamental Interactions and Structure of Matter (PRISMA)].

Uncontrolled Keywords:Eta-pi; Model; Pomeron; Exotics; Pi(-)p; System; States; Rest; Wave
Subjects:Sciences > Physics > Physics-Mathematical models
Sciences > Physics > Mathematical physics
ID Code:51776
Deposited On:12 Mar 2019 16:16
Last Modified:13 Mar 2019 11:59

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