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Observation of psi (3686) -> n(n)over-bar and improved measurement of psi (3686) -> p(p)over-bar

BESIII Collaboration, Haddadi, Z., Kalantar-Nayestanaki, N., Kavatsyuk, M., Löhner, H., Messchendorp, J. G. & Tiemens, M., 10-Aug-2018, In : Physical Review D. 98, 3, 13 p., 032006.

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We observe the decay psi (3686) -> n (n) over bar for the first time and measure psi (3686) -> p (p) over bar with improved accuracy by using 1.07 x 10(8) psi (3686) events collected with the BESIII detector. The measured branching fractions are B(psi(3686) -> n (n) over bar) = (3.06 +/- 0.06 +/- 0.14) x 10(-4) and B(psi(3686) -> p (p) over bar) = (3.05 +/- 0.02 +/- 0.12) x 10(-4). Here, the first uncertainties are statistical, and the second ones are systematic. With the hypothesis that the polar angular distributions of the neutron and proton in the center-of-mass system obey 1 + alpha cos(2) theta, we determine the a parameters to be alpha(n (n) over bar) = 0.68 +/- 0.12 +/- 0.11 and alpha(p (p) over bar) = 1.03 +/- 0.06 +/- 0.03 for psi(3686) -> n (n) over bar and psi(3686) -> p (p) over bar, respectively.
Original languageEnglish
Article number032006
Number of pages13
JournalPhysical Review D
Volume98
Issue number3
Publication statusPublished - 10-Aug-2018

    Keywords

  • BARYON-ANTIBARYON PAIRS, J/PSI DECAYS, AMPLITUDES, BESIII, ANNIHILATION, TESTS, PHASE

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