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${{\mathit \eta}}$ MASS

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S014M

Recent measurements resolve the obvious inconsistency in previous ${{\mathit \eta}}$ mass measurements in favor of the higher value first reported by NA48 (LAI 2002). We use only precise measurements consistent with this higher mass value for our ${{\mathit \eta}}$ mass average.

VALUE (MeV) EVTS DOCUMENT ID TECN  COMMENT $\bf{ 547.862 \pm0.017}$ OUR AVERAGE $547.865$ $\pm0.031$ $\pm0.062$ NIKOLAEV 2014 CRYB ${{\mathit \gamma}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit p}}{{\mathit \eta}}$ $547.873$ $\pm0.005$ $\pm0.027$ 1M GOSLAWSKI 2012 SPEC ${{\mathit d}}$ ${{\mathit p}}$ $\rightarrow$ ${}^{3}\mathrm {He}{{\mathit \eta}}$ $547.874$ $\pm0.007$ $\pm0.029$ AMBROSINO 2007 B KLOE ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \phi}}$ $\rightarrow$ ${{\mathit \eta}}{{\mathit \gamma}}$ $547.785$ $\pm0.017$ $\pm0.057$ 16k MILLER 2007 CLEO ${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit J / \psi}}{{\mathit \eta}}$ $547.843$ $\pm0.030$ $\pm0.041$ 1134 LAI 2002 NA48 ${{\mathit \eta}}$ $\rightarrow$ 3 ${{\mathit \pi}^{0}}$ • • We do not use the following data for averages, fits, limits, etc. • • $547.311$ $\pm0.028$ $\pm0.032$ 1 ABDEL-BARY 2005 SPEC ${{\mathit d}}$ ${{\mathit p}}$ $\rightarrow$ ${}^{3}\mathrm {He}{{\mathit \eta}}$ $547.12$ $\pm0.06$ $\pm0.25$ KRUSCHE 1995 D SPEC ${{\mathit \gamma}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \eta}}{{\mathit p}}$, threshold $547.30$ $\pm0.15$ PLOUIN 1992 SPEC ${{\mathit d}}$ ${{\mathit p}}$ $\rightarrow$ ${}^{3}\mathrm {He}{{\mathit \eta}}$ $547.45$ $\pm0.25$ DUANE 1974 SPEC ${{\mathit \pi}^{-}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit n}}$ neutrals $548.2$ $\pm0.65$ FOSTER 1965 C HBC $549.0$ $\pm0.7$ 148 FOELSCHE 1964 HBC $548.0$ $\pm1.0$ 91 ALFF-STEINBER.. 1962 HBC $549.0$ $\pm1.2$ 53 BASTIEN 1962 HBC 1  ABDEL-BARY 2005 disagrees significantly with recent measurements of similar or better precision. See comment in the header.

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