${{\mathit \eta}_{{{c}}}{(1S)}}$ MASS

INSPIRE   PDGID:
M026M
VALUE (MeV) EVTS DOCUMENT ID TECN  COMMENT
$\bf{ 2984.1 \pm0.4}$ OUR AVERAGE  Error includes scale factor of 1.2.
$2985.01$ $\pm0.17$ $\pm0.89$ 35k
AAIJ
2023AH
LHCB ${{\mathit B}^{+}}$ $\rightarrow$ ${{\mathit K}^{+}}$( ${{\mathit K}_S^0}$ ${{\mathit K}}{{\mathit \pi}}$)
$2983.9$ $\pm0.7$ $\pm0.1$ 1
AAIJ
2020H
LHCB ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit b}}{{\mathit X}}$ $\rightarrow$ ${{\mathit p}}{{\overline{\mathit p}}}{{\mathit X}}$
$2985.9$ $\pm0.7$ $\pm2.1$ 1705
ABLIKIM
2019AV
BES3 ${{\mathit J / \psi}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \omega}}{{\mathit \omega}}$
$2984.6$ $\pm0.7$ $\pm2.2$ 2673
XU
2018
BELL ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}{{\mathit \eta}^{\,'}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$
$2986.7$ $\pm0.5$ $\pm0.9$ 11k 2
AAIJ
2017AD
LHCB ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit B}^{+}}{{\mathit X}}$ $\rightarrow$ ${{\mathit p}}{{\overline{\mathit p}}}{{\mathit K}^{+}}{{\mathit X}}$
$2982.8$ $\pm1.0$ $\pm0.5$ 6.4k 3
AAIJ
2017BB
LHCB ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit b}}{{\overline{\mathit b}}}{{\mathit X}}$ $\rightarrow$ 2( ${{\mathit K}^{+}}{{\mathit K}^{-}}$) ${{\mathit X}}$
$2982.2$ $\pm1.5$ $\pm0.1$ 2.0k 4
AAIJ
2015BI
LHCB ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \eta}_{{{c}}}}$(1 ${{\mathit S}}$) ${{\mathit X}}$
$2983.5$ $\pm1.4$ ${}^{+1.6}_{-3.6}$ 5
ANASHIN
2014
KEDR ${{\mathit J / \psi}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \eta}_{{{c}}}}$
$2979.8$ $\pm0.8$ $\pm3.5$ 4.5k 6, 7
LEES
2014E
BABR ${{\mathit \gamma}}$ ${{\mathit \gamma}}$ $\rightarrow$ ${{\mathit K}^{+}}{{\mathit K}^{-}}{{\mathit \pi}^{0}}$
$2984.1$ $\pm1.1$ $\pm2.1$ 900 6, 8, 7
LEES
2014E
BABR ${{\mathit \gamma}}$ ${{\mathit \gamma}}$ $\rightarrow$ ${{\mathit K}^{+}}{{\mathit K}^{-}}{{\mathit \eta}}$
$2984.3$ $\pm0.6$ $\pm0.6$ 9, 10
ABLIKIM
2012F
BES3 ${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \eta}_{{{c}}}}$
$2984.49$ $\pm1.16$ $\pm0.52$ 832 6
ABLIKIM
2012N
BES3 ${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \pi}^{0}}{{\mathit \gamma}}$ hadrons
$2982.7$ $\pm1.8$ $\pm2.2$ 486
ZHANG
2012A
BELL ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}{{\mathit \eta}^{\,'}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$
$2984.5$ $\pm0.8$ $\pm3.1$ 11k
DEL-AMO-SANCH..
2011M
BABR ${{\mathit \gamma}}$ ${{\mathit \gamma}}$ $\rightarrow$ ${{\mathit K}^{+}}{{\mathit K}^{-}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}$
$2985.4$ $\pm1.5$ ${}^{+0.5}_{-2.0}$ 920 10
VINOKUROVA
2011
BELL ${{\mathit B}^{\pm}}$ $\rightarrow$ ${{\mathit K}^{\pm}}({{\mathit K}_S^0}$ ${{\mathit K}^{\pm}}{{\mathit \pi}^{\mp}}$)
$2982.2$ $\pm0.4$ $\pm1.6$ 14k 11
LEES
2010
BABR 10.6 ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}{{\mathit K}_S^0}$ ${{\mathit K}^{\pm}}{{\mathit \pi}^{\mp}}$
$2985.8$ $\pm1.5$ $\pm3.1$ 0.9k
AUBERT
2008AB
BABR ${{\mathit B}}$ $\rightarrow$ ${{\mathit \eta}_{{{c}}}{(1S)}}{{\mathit K}^{(*)}}$ $\rightarrow$ ${{\mathit K}}{{\overline{\mathit K}}}{{\mathit \pi}}{{\mathit K}^{(*)}}$
$2986.1$ $\pm1.0$ $\pm2.5$ 7.5k
UEHARA
2008
BELL ${{\mathit \gamma}}$ ${{\mathit \gamma}}$ $\rightarrow$ ${{\mathit \eta}_{{{c}}}}$ $\rightarrow$ hadrons
$2970$ $\pm5$ $\pm6$ 501 12
ABE
2007
BELL ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit J / \psi}}$( ${{\mathit c}}{{\overline{\mathit c}}}$)
$2971$ $\pm3$ ${}^{+2}_{-1}$ 195
WU
2006
BELL ${{\mathit B}^{+}}$ $\rightarrow$ ${{\mathit p}}{{\overline{\mathit p}}}{{\mathit K}^{+}}$
$2974$ $\pm7$ ${}^{+2}_{-1}$ 20
WU
2006
BELL ${{\mathit B}^{+}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\overline{\mathit \Lambda}}}{{\mathit K}^{+}}$
$2981.8$ $\pm1.3$ $\pm1.5$ 592
ASNER
2004
CLEO ${{\mathit \gamma}}$ ${{\mathit \gamma}}$ $\rightarrow$ ${{\mathit \eta}_{{{c}}}^{\,'}}$ $\rightarrow$ ${{\mathit K}_S^0}$ ${{\mathit K}^{\pm}}{{\mathit \pi}^{\mp}}$
$2984.1$ $\pm2.1$ $\pm1.0$ 190 13
AMBROGIANI
2003
E835 ${{\overline{\mathit p}}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \eta}_{{{c}}}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}$
• • We do not use the following data for averages, fits, limits, etc. • •
$2982.5$ $\pm0.4$ $\pm1.4$ 12k 14
DEL-AMO-SANCH..
2011M
BABR ${{\mathit \gamma}}$ ${{\mathit \gamma}}$ $\rightarrow$ ${{\mathit K}_S^0}$ ${{\mathit K}^{\pm}}{{\mathit \pi}^{\mp}}$
$2982.2$ $\pm0.6$ 15
MITCHELL
2009
CLEO ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit X}}$
$2982$ $\pm5$ 270 16
AUBERT
2006E
BABR ${{\mathit B}^{\pm}}$ $\rightarrow$ ${{\mathit K}^{\pm}}{{\mathit X}}_{{{\mathit c}} {{\overline{\mathit c}}}}$
$2982.5$ $\pm1.1$ $\pm0.9$ 2.5k 17
AUBERT
2004D
BABR ${{\mathit \gamma}}$ ${{\mathit \gamma}}$ $\rightarrow$ ${{\mathit \eta}_{{{c}}}{(1S)}}$ $\rightarrow$ ${{\mathit K}}{{\overline{\mathit K}}}{{\mathit \pi}}$
$2977.5$ $\pm1.0$ $\pm1.2$ 18, 15
BAI
2003
BES ${{\mathit J / \psi}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \eta}_{{{c}}}}$
$2979.6$ $\pm2.3$ $\pm1.6$ 180 19
FANG
2003
BELL ${{\mathit B}}$ $\rightarrow$ ${{\mathit \eta}_{{{c}}}}{{\mathit K}}$
$2976.3$ $\pm2.3$ $\pm1.2$ 20, 15
BAI
2000F
BES ${{\mathit J / \psi}}$ , ${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \eta}_{{{c}}}}$
$2976.6$ $\pm2.9$ $\pm1.3$ 140 21, 15
BAI
2000F
BES ${{\mathit J / \psi}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \eta}_{{{c}}}}$
$2980.4$ $\pm2.3$ $\pm0.6$ 22
BRANDENBURG
2000B
CLE2 ${{\mathit \gamma}}$ ${{\mathit \gamma}}$ $\rightarrow$ ${{\mathit \eta}_{{{c}}}}$ $\rightarrow$ ${{\mathit K}^{\pm}}{{\mathit K}_S^0}$ ${{\mathit \pi}^{\mp}}$
$2975.8$ $\pm3.9$ $\pm1.2$ 21
BAI
1999B
BES Sup. by BAI 2000F
$2999$ $\pm8$ 25
ABREU
1998O
DLPH ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}$ +hadrons
$2988.3$ ${}^{+3.3}_{-3.1}$
ARMSTRONG
1995F
E760 ${{\overline{\mathit p}}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}$
$2974.4$ $\pm1.9$ 23, 15
BISELLO
1991
DM2 ${{\mathit J / \psi}}$ $\rightarrow$ ${{\mathit \eta}_{{{c}}}}{{\mathit \gamma}}$
$2969$ $\pm4$ $\pm4$ 80 15
BAI
1990B
MRK3 ${{\mathit J / \psi}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit K}^{+}}{{\mathit K}^{-}}{{\mathit K}^{+}}{{\mathit K}^{-}}$
$2956$ $\pm12$ $\pm12$ 15
BAI
1990B
MRK3 ${{\mathit J / \psi}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit K}^{+}}{{\mathit K}^{-}}{{\mathit K}_S^0}$ ${{\mathit K}_L^0}$
$2982.6$ ${}^{+2.7}_{-2.3}$ 12
BAGLIN
1987B
SPEC ${{\overline{\mathit p}}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}$
$2980.2$ $\pm1.6$ 23, 15
BALTRUSAITIS
1986
MRK3 ${{\mathit J / \psi}}$ $\rightarrow$ ${{\mathit \eta}_{{{c}}}}{{\mathit \gamma}}$
$2984$ $\pm2.3$ $\pm4.0$ 15
GAISER
1986
CBAL ${{\mathit J / \psi}}$ $\rightarrow$ ${{\mathit \gamma}}$ X, ${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}$ X
$2976$ $\pm8$ 24, 15
BALTRUSAITIS
1984
MRK3 ${{\mathit J / \psi}}$ $\rightarrow$ 2 ${{\mathit \phi}}{{\mathit \gamma}}$
$2982$ $\pm8$ 18 25
HIMEL
1980B
MRK2 ${{\mathit e}^{+}}{{\mathit e}^{-}}$
$2980$ $\pm9$ 25
PARTRIDGE
1980B
CBAL ${{\mathit e}^{+}}{{\mathit e}^{-}}$
1  AAIJ 2020H report ${\mathit m}_{{{\mathit J / \psi}}}–{\mathit m}_{{{\mathit \eta}_{{{c}}}{(1S)}}}$ = $113.0$ $\pm0.7$ $\pm0.1$ MeV. We use the current value ${\mathit m}_{{{\mathit J / \psi}}}$ = $3096.900$ $\pm0.006$ MeV to obtain the quoted mass.
2  AAIJ 2017AD report ${\mathit m}_{{{\mathit J / \psi}}}–{\mathit m}_{{{\mathit \eta}_{{{c}}}{(1S)}}}$ = $110.2$ $\pm0.5$ $\pm0.9$ MeV. We use the current value ${\mathit m}_{{{\mathit J / \psi}}}$ = $3096.900$ $\pm0.006$ MeV to obtain the quoted mass.
3  From a fit of the ${{\mathit \phi}}{{\mathit \phi}}$ invariant mass with the mass and width of ${{\mathit \eta}_{{{c}}}{(1S)}}$ as free parameters.
4  AAIJ 2015BI reports ${\mathit m}_{{{\mathit J / \psi}}}$ $−$ ${\mathit m}_{{{\mathit \eta}_{{{c}}}{(1S)}}}$ = $114.7$ $\pm1.5$ $\pm0.1$ MeV from a sample of ${{\mathit \eta}_{{{c}}}{(1S)}}$ and ${{\mathit J / \psi}}$ produced in ${{\mathit b}}$-hadron decays. We have used current value of ${\mathit m}_{{{\mathit J / \psi}}}$ = $3096.900$ $\pm0.006$ MeV to arrive at the quoted ${\mathit m}_{{{\mathit \eta}_{{{c}}}{(1S)}}}$ result.
5  Taking into account an asymmetric photon lineshape.
6  With floating width.
7  Ignoring possible interference with the non-resonant 0${}^{-}$ amplitude.
8  Using both, ${{\mathit \eta}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}$ and ${{\mathit \eta}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}$ decays.
9  From a simultaneous fit to six decay modes of the ${{\mathit \eta}_{{{c}}}}$.
10  Accounts for interference with non-resonant continuum.
11  Taking into account interference with the non-resonant $\mathit J{}^{P} = 0-$ amplitude.
12  From a fit of the ${{\mathit J / \psi}}$ recoil mass spectrum. Supersedes ABE,K 2002 and ABE 2004G.
13  Using mass of ${{\mathit \psi}{(2S)}}$ = $3686.00$ MeV.
14  Not independent from the measurements reported by LEES 2010.
15  MITCHELL 2009 observes a significant asymmetry in the lineshapes of ${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \eta}_{{{c}}}}$ and ${{\mathit J / \psi}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \eta}_{{{c}}}}$ transitions. If ignored, this asymmetry could lead to significant bias whenever the mass and width are measured in ${{\mathit \psi}{(2S)}}$ or ${{\mathit J / \psi}}$ radiative decays.
16  From the fit of the kaon momentum spectrum. Systematic errors not evaluated.
17  Superseded by LEES 2010.
18  From a simultaneous fit of five decay modes of the ${{\mathit \eta}_{{{c}}}}$.
19  Superseded by VINOKUROVA 2011.
20  Weighted average of the ${{\mathit \psi}{(2S)}}$ and ${{\mathit J / \psi}{(1S)}}$ samples. Using an ${{\mathit \eta}_{{{c}}}}$ width of $13.2$ MeV.
21  Average of several decay modes. Using an ${{\mathit \eta}_{{{c}}}}$ width of $13.2$ MeV.
22  Superseded by ASNER 2004.
23  Average of several decay modes.
24  ${{\mathit \eta}_{{{c}}}}$ $\rightarrow$ ${{\mathit \phi}}{{\mathit \phi}}$.
25  Mass adjusted by us to correspond to ${{\mathit J / \psi}{(1S)}}$ mass = 3097 MeV.
References