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${{\mathit a}_{{0}}{(980)}}$ MASS

${{\mathit \eta}}{{\mathit \pi}}$ FINAL STATE ONLY

INSPIRE   PDGID:

M036M1

VALUE (MeV) EVTS DOCUMENT ID TECN CHG  COMMENT • • We do not use the following data for averages, fits, limits, etc. • • $1004.1$ $\pm1.5$ $\pm6.5$ 1 ALBRECHT 2020 CBAR 0.9 ${{\overline{\mathit p}}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \pi}^{0}}{{\mathit \pi}^{0}}{{\mathit \eta}}$ , ${{\mathit \pi}^{0}}{{\mathit \eta}}{{\mathit \eta}}$ , ${{\mathit \pi}^{0}}{{\mathit K}^{+}}{{\mathit K}^{-}}$ $982.5$ $\pm1.6$ $\pm1.1$ 16.9k 2 AMBROSINO 2009 F KLOE 1.02 ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \eta}}{{\mathit \pi}^{0}}{{\mathit \gamma}}$ $986$ $\pm4$ ANISOVICH 2009 RVUE 0.0 ${{\overline{\mathit p}}}{{\mathit p}}$ , ${{\mathit \pi}}{{\mathit N}}$ $982.3$ ${}^{+0.6}_{-0.7}$ ${}^{+3.1}_{-4.7}$ 3 UEHARA 2009 A BELL ${{\mathit \gamma}}$ ${{\mathit \gamma}}$ $\rightarrow$ ${{\mathit \pi}^{0}}{{\mathit \eta}}$ $985$ $\pm4$ $\pm6$ 318 ACHARD 2002 B L3 $183 - 209$ ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ ${{\mathit e}^{-}}$ ${{\mathit \eta}}$ ${{\mathit \pi}^{+}}$ ${{\mathit \pi}^{-}}$ $995$ ${}^{+52}_{-10}$ 36 4 ACHASOV 2000 F SND ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \eta}}{{\mathit \pi}^{0}}{{\mathit \gamma}}$ $994$ ${}^{+33}_{-8}$ 36 5 ACHASOV 2000 F SND ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \eta}}{{\mathit \pi}^{0}}{{\mathit \gamma}}$ $975$ $\pm7$ BARBERIS 2000 H 450 ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit p}_{{f}}}{{\mathit \eta}}{{\mathit \pi}^{0}}{{\mathit p}_{{s}}}$ $988$ $\pm8$ BARBERIS 2000 H 450 ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \Delta}_{{f}}^{++}}{{\mathit \eta}}{{\mathit \pi}^{-}}{{\mathit p}_{{s}}}$ $\sim{}\text{ 1055}$ 6 OLLER 1999 RVUE ${{\mathit \eta}}{{\mathit \pi}}$ , ${{\mathit K}}{{\overline{\mathit K}}}$ $\sim{}\text{ 1009.2}$ 6 OLLER 1999 B RVUE ${{\mathit \pi}}$ ${{\mathit \pi}}$ $\rightarrow$ ${{\mathit \pi}}{{\mathit \pi}}$ , ${{\mathit K}}{{\overline{\mathit K}}}$ $993.1$ $\pm2.1$ 7 TEIGE 1999 B852 $18.3$ ${{\mathit \pi}^{-}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \eta}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit n}}$ $988$ $\pm6$ 6 ANISOVICH 1998 B RVUE Compilation $987$ TORNQVIST 1996 RVUE ${{\mathit \pi}}$ ${{\mathit \pi}}$ $\rightarrow$ ${{\mathit \pi}}{{\mathit \pi}}$ , ${{\mathit K}}{{\overline{\mathit K}}}$ , ${{\mathit K}}{{\mathit \pi}}$ , ${{\mathit \eta}}{{\mathit \pi}}$ $991$ JANSSEN 1995 RVUE ${{\mathit \eta}}$ ${{\mathit \pi}}$ $\rightarrow$ ${{\mathit \eta}}{{\mathit \pi}}$ , ${{\mathit K}}{{\overline{\mathit K}}}$ , ${{\mathit K}}{{\mathit \pi}}$ , ${{\mathit \eta}}{{\mathit \pi}}$ $984.45$ $\pm1.23$ $\pm0.34$ AMSLER 1994 C CBAR $0.0$ ${{\overline{\mathit p}}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \omega}}{{\mathit \eta}}{{\mathit \pi}^{0}}$ $982$ $\pm2$ 8 AMSLER 1992 CBAR 0.0 ${{\overline{\mathit p}}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \eta}}{{\mathit \eta}}{{\mathit \pi}^{0}}$ $984$ $\pm4$ 1040 8 ARMSTRONG 1991 B OMEG $\pm{}$ 300 ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit p}}{{\mathit p}}{{\mathit \eta}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ $976$ $\pm6$ ATKINSON 1984 E OMEG $\pm{}$ 25$-$55 ${{\mathit \gamma}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \eta}}{{\mathit \pi}}{{\mathit n}}$ $986$ $\pm3$ 500 9 EVANGELISTA 1981 OMEG $\pm{}$ 12 ${{\mathit \pi}^{-}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \eta}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{-}}{{\mathit p}}$ $990$ $\pm7$ 145 9 GURTU 1979 HBC $\pm{}$ 4.2 ${{\mathit K}^{-}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\mathit \eta}}$2 ${{\mathit \pi}}$ $980$ $\pm11$ 47 CONFORTO 1978 OSPK - 4.5 ${{\mathit \pi}^{-}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit p}}{{\mathit X}^{-}}$ $978$ $\pm16$ 50 CORDEN 1978 OMEG $\pm{}$ 12$-$15 ${{\mathit \pi}^{-}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit n}}{{\mathit \eta}}$2 ${{\mathit \pi}}$ $977$ $\pm7$ GRASSLER 1977 HBC - 16 ${{\mathit \pi}^{\mp}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit p}}{{\mathit \eta}}$3 ${{\mathit \pi}}$ $989$ $\pm4$ 70 WELLS 1975 HBC - 3.1$-$6 ${{\mathit K}^{-}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\mathit \eta}}$2 ${{\mathit \pi}}$ $972$ $\pm10$ 150 DEFOIX 1972 HBC $\pm{}$ 0.7 ${{\overline{\mathit p}}}$ ${{\mathit p}}$ $\rightarrow$ 7 ${{\mathit \pi}}$ $970$ $\pm15$ 20 BARNES 1969 C HBC - 4$-$5 ${{\mathit K}^{-}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\mathit \eta}}$2 ${{\mathit \pi}}$ $980$ $\pm10$ CAMPBELL 1969 DBC $\pm{}$ 2.7 ${{\mathit \pi}^{+}}{{\mathit d}}$ $980$ $\pm10$ 15 MILLER 1969 B HBC - 4.5 ${{\mathit K}^{-}}$ ${{\mathit N}}$ $\rightarrow$ ${{\mathit \eta}}{{\mathit \pi}}{{\mathit \Lambda}}$ $980$ $\pm10$ 30 AMMAR 1968 HBC $\pm{}$ 5.5 ${{\mathit K}^{-}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\mathit \eta}}$2 ${{\mathit \pi}}$ 1  T-matrix pole with 2 poles, 2 channels, pole mass on adjacent sheet $1002.4$ $\pm1.4$ $\pm6.6$ MeV. 2  Using the model of ACHASOV 1989 and ACHASOV 2003B. 3  From a fit with the S-wave amplitude including two interfering Breit-Wigners plus a background term. 4  Using the model of ACHASOV 1989 . Supersedes ACHASOV 1998B. 5  Using the model of JAFFE 1977 . Supersedes ACHASOV 1998B. 6  T-matrix pole. 7  Breit-Wigner fit, average between ${{\mathit a}_{{0}}^{\pm}}$ and ${{\mathit a}_{{0}}^{0}}$. The fit favors a slightly heavier ${{\mathit a}_{{0}}^{\pm}}$. 8  From a single Breit-Wigner fit. 9  From ${{\mathit f}_{{1}}{(1285)}}$ decay.

References:

ALBRECHT 2020 EPJ C80 453 Coupled channel analysis of ${\bar{p}p}\,\rightarrow \,\pi ^0\pi ^0\eta $, ${\pi ^0\eta \eta }$ and ${K^+K^-\pi ^0}$ at 900 MeV/c and of ${\pi \pi }$-scattering data AMBROSINO 2009F PL B681 5 Study of the ${{\mathit a}_{{0}}{(980)}}$ Meson via the Radiative Decay ${{\mathit \phi}}$ $\rightarrow$ ${{\mathit \eta}}{{\mathit \pi}^{0}}{{\mathit \gamma}}$ with the KLOE Detector ANISOVICH 2009 IJMP A24 2481 The Combined Analysis of ${{\mathit \pi}}$ ${{\mathit N}}$ $\rightarrow$ two mesons ${+}$ ${{\mathit N}}$ Reactions within Reggeon Exchanges and Data for ${{\mathit p}}$ ${{\overline{\mathit p}}}$ (at rest) $\rightarrow$ three mesons UEHARA 2009A PR D80 032001 High-Statistics Study of ${{\mathit \eta}}{{\mathit \pi}^{0}}$ Production in Two-Photon Collisions ACHARD 2002B PL B526 269 ${{\mathit f}_{{1}}{(1285)}}$ Formation in Two Photon Collisions at LEP ACHASOV 2000F PL B479 53 The ${{\mathit \phi}}$ $\rightarrow$ ${{\mathit \eta}}{{\mathit \pi}^{0}}{{\mathit \gamma}}$ Decay BARBERIS 2000H PL B488 225 A Study of the Centrally Produced ${{\mathit \eta}}{{\mathit \pi}^{0}}$ and ${{\mathit \eta}}{{\mathit \pi}^{-}}$ Systems in ${{\mathit p}}{{\mathit p}}$ Interactions at 450 ${\mathrm {GeV/}}\mathit c$ OLLER 1999 PR D60 099906 (erratum) Meson-Meson Interaction in a Nonperturbative Chiral Approach OLLER 1999B NP A652 407 (erratum) Chiral Symmetry Amplitudes in the S-wave Isoscalar and Isovector Channels and the ${{\mathit \sigma}}$, ${{\mathit f}_{{0}}{(980)}}$, ${{\mathit a}_{{0}}{(980)}}$ Scalar Mesons TEIGE 1999 PR D59 012001 Properties of the ${{\mathit a}_{{0}}{(980)}}$ Meson ANISOVICH 1998B SPU 41 419 The Lightest Scalar Glueball TORNQVIST 1996 PRL 76 1575 Resurrection of the ${{\mathit \sigma}}$ Meson JANSSEN 1995 PR D52 2690 On the Structure of the Scalar Mesons ${{\mathit f}_{{0}}{(975)}}$ and ${{\mathit a}_{{0}}{(980)}}$ AMSLER 1994C PL B327 425 Study of ${{\overline{\mathit p}}}{{\mathit p}}$ Annihilation at Rest into ${{\mathit \omega}}{{\mathit \eta}}{{\mathit \pi}^{0}}$ AMSLER 1992 PL B291 347 Proton Antiproton Annihilation into ${{\mathit \eta}}{{\mathit \eta}}{{\mathit \pi}}$: Observation of a Scalar Resonance Decaying into ${{\mathit \eta}}{{\mathit \eta}}$ ARMSTRONG 1991B ZPHY C52 389 Study of the ${{\mathit \eta}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ System Centrally Produced in the Reaction ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit p}_{{f}}}$( ${{\mathit \eta}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$) ${{\mathit p}_{{s}}}$ at 300 ${\mathrm {GeV/}}\mathit c$ ATKINSON 1984E PL 138B 459 Inclusive Photoproduction of ${{\mathit \delta}{(980)}}$ and ${{\mathit B}{(1235)}}$ at High x$_{F}$ EVANGELISTA 1981 NP B178 197 Results from a ${{\mathit \pi}^{-}}{{\mathit p}}$ Slow Proton Trigger Experiment at 12 ${\mathrm {GeV/}}\mathit c$ Also NP B186 594 Results from a ${{\mathit \pi}^{-}}{{\mathit p}}$ Slow Proton Trigger Experiment at 12 ${\mathrm {GeV/}}\mathit c$ GURTU 1979 NP B151 181 Production and Decay Properties of the ${{\mathit D}{(1285)}}$ Meson in ${{\mathit K}^{-}}{{\mathit p}}$ Interactions at 4.2 ${\mathrm {GeV/}}\mathit c$ CONFORTO 1978 LNC 23 419 Study of the ${{\mathit \delta}{(970)}}$ Meson CORDEN 1978 NP B144 253 Observation of the ${{\mathit D}}$, ${{\mathit E}}$ and ${{\mathit \delta}}$ Mesons in ${{\mathit \pi}^{-}}{{\mathit p}}$ Interactions at 12 and 15 ${\mathrm {GeV/}}\mathit c$ GRASSLER 1977 NP B121 189 Production and Decay of the ${{\mathit \delta}{(970)}}$ and ${{\mathit D}{(1285)}}$ Mesons in ${{\mathit \pi}^{\pm}}{{\mathit p}}$ Interactions at 16 ${\mathrm {GeV/}}\mathit c$ WELLS 1975 NP B101 333 $\delta $ Production in $3.1 - 3.6$ ${\mathrm {GeV/}}\mathit c$ ${{\mathit K}^{-}}{{\mathit p}}$ Interactions DEFOIX 1972 NP B44 125 Evidence for Decays of the ${{\mathit D}}$- and ${{\mathit E}}$-Mesons into ${{\mathit \sigma}}{{\mathit \pi}}$ in ${{\overline{\mathit p}}}{{\mathit p}}$ Annihilation at 700 ${\mathrm {MeV}}/\mathit c$ BARNES 1969C PRL 23 610 Evidence for a ${{\mathit \pi}}{{\mathit \eta}}$ Resonance at 970 MeV Produced in ${{\mathit \pi}^{-}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ Missing Mass at 3.9, 4.6, and 5.0 ${\mathrm {GeV/}}\mathit c$ CAMPBELL 1969 PRL 22 1204 Study of ${{\mathit D}^{0}}$ $\rightarrow$ ${{\mathit \pi}^{\pm}}{{\mathit \delta}^{\mp}}$ and ${{\mathit \delta}^{\mp}}$ $\rightarrow$ ${{\mathit \pi}^{\mp}}{{\mathit \eta}}$ in the Reaction ${{\mathit \pi}^{+}}$ ${{\mathit d}}$ $\rightarrow$ ${{\mathit p}}$ $_{spect.}$ ${{\mathit p}}{{\mathit D}^{0}}$ at 2.7 ${\mathrm {GeV/}}\mathit c$ MILLER 1969B PL 29B 255 Production of a ${{\mathit \pi}}-{{\mathit \eta}}$ Resonance at a Mass of 0.98 GeV in ${{\mathit K}^{-}}$ ${{\mathit n}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\mathit \pi}^{-}}{{\mathit \eta}}$ at 4.5 ${\mathrm {GeV/}}\mathit c$ Also PR 188 2011 Final States with a Single Charged Particle and Visible ${{\mathit \Lambda}}$ from ${{\mathit K}}{{\mathit n}}$ Interactions at 4.5 ${\mathrm {GeV/}}\mathit c$ AMMAR 1968 PRL 21 1832 Boson Resonance of Mass 980 MeV Decaying into ${{\mathit \pi}}{{\mathit \eta}}$

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