#### ${{\boldsymbol \chi}_{{c1}}{(3872)}}$ MASS FROM ${{\boldsymbol J / \psi}}{{\boldsymbol X}}$ MODE

VALUE (MeV) EVTS DOCUMENT ID TECN  COMMENT
 $\bf{ 3871.65 \pm0.06}$ OUR AVERAGE
$3871.64$ $\pm0.06$ $\pm0.01$ 19.8k 1
 2020 S
LHCB ${{\mathit B}^{+}}$ $\rightarrow$ ${{\mathit J / \psi}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit K}^{+}}$
$3871.9$ $\pm0.7$ $\pm0.2$ 20
 2014
BES3 ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit J / \psi}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \gamma}}$
$3871.95$ $\pm0.48$ $\pm0.12$ 0.6k
 2012 H
LHCB ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit J / \psi}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit X}}$
$3871.85$ $\pm0.27$ $\pm0.19$ 170 2
 2011
BELL ${{\mathit B}}$ $\rightarrow$ ${{\mathit K}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit J / \psi}}$
$3873$ ${}^{+1.8}_{-1.6}$ $\pm1.3$ 27 3
 2010 B
BABR ${{\mathit B}}$ $\rightarrow$ ${{\mathit \omega}}{{\mathit J / \psi}}{{\mathit K}}$
$3871.61$ $\pm0.16$ $\pm0.19$ 6k 4, 3
 2009 AU
CDF2 ${{\mathit p}}$ ${{\overline{\mathit p}}}$ $\rightarrow$ ${{\mathit J / \psi}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit X}}$
$3871.4$ $\pm0.6$ $\pm0.1$ 93.4
 2008 Y
BABR ${{\mathit B}^{+}}$ $\rightarrow$ ${{\mathit K}^{+}}{{\mathit J / \psi}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$
$3868.7$ $\pm1.5$ $\pm0.4$ 9.4
 2008 Y
BABR ${{\mathit B}^{0}}$ $\rightarrow$ ${{\mathit K}_S^0}$ ${{\mathit J / \psi}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$
$3871.8$ $\pm3.1$ $\pm3.0$ 522 5, 3
 2004 F
D0 ${{\mathit p}}$ ${{\overline{\mathit p}}}$ $\rightarrow$ ${{\mathit J / \psi}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit X}}$
• • We do not use the following data for averages, fits, limits, etc. • •
$3871.695$ $\pm0.067$ $\pm0.068$ 15.6k 6
LHCB ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit J / \psi}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit X}}$
$3871.59$ $\pm0.06$ $\pm0.03$ 4.2k 7
 2020 S
LHCB ${{\mathit B}^{+}}$ $\rightarrow$ ${{\mathit J / \psi}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit K}^{+}}$
$3873.3$ $\pm1.1$ $\pm1.0$ 45 8
 2019 V
BES ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \omega}}{{\mathit J / \psi}}$
$3860.0$ $\pm10.4$ 13.6 9, 3
 2018 A
COMP ${{\mathit \gamma}^{*}}$ ${{\mathit N}}$ $\rightarrow$ ${{\mathit X}}{{\mathit \pi}^{\pm}}{{\mathit N}^{\,'}}$
$3868.6$ $\pm1.2$ $\pm0.2$ 8 10
 2006
BABR ${{\mathit B}^{0}}$ $\rightarrow$ ${{\mathit K}_S^0}$ ${{\mathit J / \psi}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$
$3871.3$ $\pm0.6$ $\pm0.1$ 61 10
 2006
BABR ${{\mathit B}^{-}}$ $\rightarrow$ ${{\mathit K}^{-}}{{\mathit J / \psi}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$
$3873.4$ $\pm1.4$ 25 11
 2005 R
BABR ${{\mathit B}^{+}}$ $\rightarrow$ ${{\mathit K}^{+}}{{\mathit J / \psi}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$
$3871.3$ $\pm0.7$ $\pm0.4$ 730 3, 12
 2004
CDF2 ${{\mathit p}}$ ${{\overline{\mathit p}}}$ $\rightarrow$ ${{\mathit J / \psi}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit X}}$
$3872.0$ $\pm0.6$ $\pm0.5$ 36 13
 2003
BELL ${{\mathit B}}$ $\rightarrow$ ${{\mathit K}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit J / \psi}}$
$3836$ $\pm13$ 58 3, 14
 1994
E705 300 ${{\mathit \pi}^{\pm}}$ ${}^{}\mathrm {Li}$ $\rightarrow$ ${{\mathit J / \psi}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit X}}$
 1 Calculated from ${\mathit m}_{{{\mathit \chi}_{{c1}}{(3872)}}}–{\mathit m}_{{{\mathit \psi}{(2S)}}}$ = $185.54$ $\pm0.06$ MeV obtained by combining the data with ${{\mathit \chi}_{{c1}}{(3872)}}$ produced in ${{\mathit B}^{+}}$ decays from AAIJ 2020S and inclusive ${{\mathit b}}$-hadron decays from AAIJ 2020AD and using ${\mathit m}_{{{\mathit \psi}{(2S)}}}$ = 3686.097 MeV. Breit-Wigner parametrization.
 2 The mass difference for the ${{\mathit \chi}_{{c1}}{(3872)}}$ produced in ${{\mathit B}^{+}}$ and ${{\mathit B}^{0}}$ decays is ($-0.71$ $\pm0.96$ $\pm0.19$) MeV.
 3 Width consistent with detector resolution.
 4 A possible equal mixture of two states with a mass difference greater than 3.6 MeV/c${}^{2}$ is excluded at 95$\%$ CL.
 5 Calculated from the corresponding ${\mathit m}_{{{\mathit \chi}_{{c1}}{(3872)}}}$ $−$ ${\mathit m}_{{{\mathit J / \psi}}}$ using ${\mathit m}_{{{\mathit J / \psi}}}$=3096.916 MeV.
 6 Using ${{\mathit \chi}_{{c1}}{(3872)}}$ produced in inclusive ${{\mathit b}}$-hadron decays and ${\mathit m}_{{{\mathit \psi}{(2S)}}}$ = $3686.097$ $\pm0.010$ MeV. Breit-Wigner parametrization. Superseded by the combined value in AAIJ 2020S.
 7 Using Breit-Wigner parametrization. Superseded by the combined value in AAIJ 2020S.
 8 Fit with fixed width and including two resonances, ${{\mathit X}{(3915)}}$ and ${{\mathit X}{(3960)}}$.
 9 Could be a different state.
 10 Calculated from the corresponding ${\mathit m}_{{{\mathit \chi}_{{c1}}{(3872)}}}–{\mathit m}_{{{\mathit \psi}{(2S)}}}$ using ${\mathit m}_{{{\mathit \psi}{(2S)}}}$ = 3686.093 MeV. Superseded by AUBERT 2008Y.
 11 Calculated from the corresponding ${\mathit m}_{{{\mathit \chi}_{{c1}}{(3872)}}}–{\mathit m}_{{{\mathit \psi}{(2S)}}}$ using ${\mathit m}_{{{\mathit \psi}{(2S)}}}$ = 3685.96MeV. Superseded by AUBERT 2006 .
 12 Superseded by AALTONEN 2009AU.
 13 Superseded by CHOI 2011 .
 14 A lower mass value can be due to an incorrect momentum scale for soft pions.
References:
 AAIJ 2020S
JHEP 2008 123 Study of the $\psi_2(3823)$ and $\chi_{c1}(3872)$ states in $B^+ \rightarrow \left( J\psi\pi^+\pi^-\right)K^+$ decays
PR D102 092005 Study of the lineshape of the $\chi_{c1}(3872)$ state
 ABLIKIM 2019V
PRL 122 232002 Study of $e^+e^- \to \gamma \omega J/\psi$ and Observation of $X(3872) \to \omega J/\psi$
 AGHASYAN 2018A
PL B783 334 Search for muoproduction of $X (3872)$ at COMPASS and indication of a new state $\widetilde{X}(3872)$
 ABLIKIM 2014
PRL 112 092001 Observation of ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit X}{(3872)}}$ at BESIII
 AAIJ 2012H
EPJ C72 1972 Observation of ${{\mathit X}{(3872)}}$ Production in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 7 TeV
 CHOI 2011
PR D84 052004 Bounds on the Width, Mass Difference and other Properties of ${{\mathit X}{(3872)}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit J / \psi}}$ Decays
 DEL-AMO-SANCHEZ 2010B
PR D82 011101 Evidence for the Decay ${{\mathit X}{(3872)}}$ $\rightarrow$ ${{\mathit J / \psi}}{{\mathit \omega}}$
 AALTONEN 2009AU
PRL 103 152001 Precision Measurement of the ${{\mathit X}{(3872)}}$ Mass in ${{\mathit J / \psi}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ Decays
 AUBERT 2008Y
PR D77 111101 Study of ${{\mathit B}}$ $\rightarrow$ ${{\mathit X}{(3872)}}{{\mathit K}}$ , with ${{\mathit X}{(3872)}}$ $\rightarrow$ ${{\mathit J / \psi}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$
 AUBERT 2006
PR D73 011101 Study of the ${{\mathit X}{(3872)}}$ and ${{\mathit Y}{(4260)}}$ in ${{\mathit B}^{0}}$ $\rightarrow$ ${{\mathit J / \psi}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit K}^{0}}$ and ${{\mathit B}^{-}}$ $\rightarrow$ ${{\mathit J / \psi}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit K}^{-}}$ Decays
 AUBERT 2005R
PR D71 071103 Study of the ${{\mathit B}}$ $\rightarrow$ ${{\mathit J / \psi}}{{\mathit K}^{-}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ Decay and Measurement of the ${{\mathit B}}$ $\rightarrow$ ${{\mathit X}{(3872)}}{{\mathit K}^{-}}$ Branching Fraction
 ABAZOV 2004F
PRL 93 162002 Observation and Properties of the ${{\mathit X}{(3872)}}$ Decaying to ${{\mathit J / \psi}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ in ${{\mathit p}}{{\overline{\mathit p}}}$ Collisions at $\sqrt {s }$ = 1.96 TeV
 ACOSTA 2004
PRL 93 072001 Observation of the Narrow State ${{\mathit X}{(3872)}}$ $\rightarrow$ ${{\mathit J / \psi}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ in ${{\overline{\mathit p}}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 1.96 TeV
 CHOI 2003
PRL 91 262001 Observation of a Narrow Charmoniumlike State in Exclusive ${{\mathit B}^{+}}$ $\rightarrow$ ${{\mathit K}^{\pm}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit J / \psi}}$ Decay
 ANTONIAZZI 1994
PR D50 4258 Search for Hidden Charm Resonance States Decaying into ${{\mathit J / \psi}}$ or ${{\mathit \psi}^{\,'}}$ Plus Pions