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ENERGY DEPENDENCE OF ${{\mathit \eta}}$ $\rightarrow$ 3 ${{\mathit \pi}}$ DALITZ PLOTS

$\alpha $ PARAMETER FOR ${{\mathit \eta}}$ $\rightarrow$ 3 ${{\mathit \pi}^{0}}$

INSPIRE   JSON  (beta) PDGID:

S014A0

See the “Note on ${{\mathit \eta}}$ Decay Parameters” in our 1994 edition, Phys.Rev.$\mathbf {D50}$, 1 August 1994, Part$~$I, p.$~$1454. The value here is of $\alpha $ in $\vert $matrix element$\vert ^2$ = 1 + 2${}\alpha {}\mathit z$.

VALUE EVTS DOCUMENT ID TECN  COMMENT $\bf{ -0.0296 \pm0.0016}$ OUR AVERAGE  Error includes scale factor of 1.7.  See the ideogram below. $-0.0406$ $\pm0.0035$ $\pm0.0008$ 272k ABLIKIM 02 AN   BES3 ${{\mathit J / \psi}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \eta}}$ $-0.0265$ $\pm0.0010$ $\pm0.0009$ 7M PRAKHOV 01   CRYB ${{\mathit \gamma}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit p}}{{\mathit \eta}}$ $-0.055$ $\pm0.014$ $\pm0.004$ 33k ABLIKIM 01 G   BES3 ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit J / \psi}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \eta}}$ $-0.0301$ $\pm0.0035$ ${}^{+0.0022}_{-0.0035}$ 512k AMBROSINO 01 A   KLOE ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \phi}}$ $\rightarrow$ ${{\mathit \eta}}{{\mathit \gamma}}$ $-0.027$ $\pm0.008$ $\pm0.005$ 120k 1 ADOLPH 00   WASA ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit p}}{{\mathit p}}{{\mathit \eta}}$ $-0.0322$ $\pm0.0012$ $\pm0.0022$ 3M 2 PRAKHOV 00   CRYB ${{\mathit \gamma}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit p}}{{\mathit \eta}}$ $-0.032$ $\pm0.002$ $\pm0.002$ 1.8M 2 UNVERZAGT 00   CRYB ${{\mathit \gamma}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit p}}{{\mathit \eta}}$ $-0.026$ $\pm0.010$ $\pm0.010$ 75k BASHKANOV 00   WASA ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit p}}{{\mathit p}}{{\mathit \eta}}$ $-0.010$ $\pm0.021$ $\pm0.010$ 12k ACHASOV 00 C   SND ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \phi}}$ $\rightarrow$ ${{\mathit \eta}}{{\mathit \gamma}}$ $-0.031$ $\pm0.004$ 1M TIPPENS 00   CRYB ${{\mathit \pi}^{-}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit n}}{{\mathit \eta}}$, 720 MeV $-0.052$ $\pm0.017$ $\pm0.010$ 98k ABELE 99 C   CBAR ${{\overline{\mathit p}}}$ ${{\mathit p}}$ $\rightarrow$ 5 ${{\mathit \pi}^{0}}$ $-0.022$ $\pm0.023$ 50k ALDE 98   GAM2 • • We do not use the following data for averages, fits, limits, etc. • • $-0.038$ $\pm0.003$ ${}^{+0.012}_{-0.008}$ 1.34M 3 AMBROSINO 00 D   KLOE $-0.32$ $\pm0.37$ 192 BAGLIN 97   HLBC 1  This ADOLPH 2009 result is independent of the BASHKANOV 2007 result. 2  The PRAKHOV 2009 and UNVERZAGT 2009 results are independent. 3  This AMBROSINO 2008D value is an indirect result using ${{\mathit \eta}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{0}}{{\mathit \pi}^{-}}$ events and a$~$rescattering matrix that mixes isospin decay amplitudes.

$\alpha $ PARAMETER FOR ${{\mathit \eta}}$ $\rightarrow$ 3 ${{\mathit \pi}^{0}}$

References

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