Photoproduction of the $f_1\left(1285\right)$ meson

Journal Article · Wed Jun 01 00:00:00 EDT 2016 · Physical Review C

DOI:https://doi.org/10.1103/PhysRevC.93.065202· OSTI ID:1256692

Dickson, Ryan ^[1]; Schumacher, Reinhard A. ^[1]; Adhikari, K. P.; Akbar, Z.; Amaryan, M. J.; Anefalos Pereira, S.; Badui, R. A.; Ball, J.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A.; Boiarinov, S.; Briscoe, W. J.; Burkert, V. D.; Cao, T.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G. ; Chetry, T.; Ciullo, G.; Colaneri, L.; Cole, P. L.; Compton, N.; Contalbrigo, M.; Cortes, O.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dugger, M.; Dupre, R.; El Alaoui, A.; El Fassi, L.; Eugenio, P.; Fanchini, E.; Fedotov, G.; Filippi, A.; Fleming, J. A.; Gevorgyan, N.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Gothe, R. W.; Griffioen, K. A.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Hattawy, M.; Holtrop, M.; Hicks, K.; Hughes, S. M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jiang, H.; Jo, H. S.; Joosten, S.; Keller, D.; Khachatryan, G.; Khandaker, M.; Kim, A.; Kim, W.; Klein, F. J.; Kubarovsky, V.; Kuleshov, S. V.; Lanza, L.; Lenisa, P.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Mattione, P.; McKinnon, B.; Meyer, C. A.; Mirazita, M.; Markov, N.; Mokeev, V.; Moriya, K.; Munevar, E.; Murdoch, G.; Nadel-Turonski, P.; Net, L. A.; Ni, A.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Phelps, W.; Pisano, S.; Pogorelko, O.; Price, J. W.; Prok, Y.; Puckett, A. J. R.; Raue, B. A.; Ripani, M.; Rizzo, A.; Rosner, G.; Roy, P.; Salgado, C.; Seder, E.; Sharabian, Y. G.; Skorodumina, Iu.; Smith, E. S.; Smith, G. D.; Sober, D.; Sokhan, D.; Sparveris, N.; Stepanyan, S.; Strakovsky, I. I.; Stankovic, I.; Strauch, S.; Sytnik, V.; Taiuti, M.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Weygand, D.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zonta, I.

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1. Carnegie Mellon Univ., Pittsburgh, PA (United States)

The $$f_1(1285)$$ meson with mass $$1281.0 \pm 0.8$$ MeV/$c^2$ and width $$18.4 \pm 1.4$$ MeV (FWHM) was measured for the first time in photoproduction from a proton target using CLAS at Jefferson Lab. Differential cross sections were obtained via the $$\eta\pi^{+}\pi^{-}$$, $$K^+\bar{K}^0\pi^-$$, and $$K^-K^0\pi^+$$ decay channels from threshold up to a center-of-mass energy of 2.8 GeV. The mass, width, and an amplitude analysis of the $$\eta\pi^{+}\pi^{-}$$ final-state Dalitz distribution are consistent with the axial-vector $J^P=1^+$ $$f_1(1285)$$ identity, rather than the pseudoscalar $0^-$ $$\eta(1295)$$. The production mechanism is more consistent with $$s$$-channel decay of a high-mass $N^*$ state, and not with $$t$$-channel meson exchange. Decays to $$\eta\pi\pi$$ go dominantly via the intermediate $$a_0^\pm(980)\pi^\mp$$ states, with the branching ratio $$\Gamma(a_0\pi \text{ (no} \bar{K} K\text{)}) / \Gamma(\eta\pi\pi \text{(all)}) = 0.74\pm0.09$$. The branching ratios $$\Gamma(K \bar{K} \pi)/\Gamma(\eta\pi\pi) = 0.216\pm0.033$$ and $$\Gamma(\gamma\rho^0)/\Gamma(\eta\pi\pi) = 0.047\pm0.018$$ were also obtained. The first is in agreement with previous data for the $$f_1(1285)$$, while the latter is lower than the world average.

• Research Organization: Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP)
• Contributing Organization: CLAS Collaboration
• DOE Contract Number: FG02-87ER40315; AC05-06OR23177; ST/J000175
• OSTI ID: 1256692
• Report Number(s): JLAB-PHY-16-2270; DOE/OR/23177-3815; arXiv:1604.07425; PRVCAN
• Journal Information: Physical Review C, Vol. 93, Issue 6; ISSN 2469-9985
• Country of Publication: United States
• Language: English