# ${{\boldsymbol \rho}{(770)}}$ WIDTH

We no longer list ${\mathit S}{\mathrm -wave}$ Breit-Wigner fits, or data with high combinatorial background.

# NEUTRAL ONLY, ${{\boldsymbol e}^{+}}{{\boldsymbol e}^{-}}$ INSPIRE search

VALUE (MeV) EVTS DOCUMENT ID TECN  COMMENT
$\bf{ 147.8 \pm0.9}$ OUR AVERAGE  Error includes scale factor of 2.0.
$149.59$ $\pm0.67$ 1
 2012 G
BABR ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \gamma}}$
$145.98$ $\pm0.75$ $\pm0.50$ 900k 2
 2007
${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$
$146.1$ $\pm0.8$ $\pm1.5$ 800k 3, 4
 2006
SND ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$
$143.85$ $\pm1.33$ $\pm0.80$ 114k 5, 6
 2004
CMD2 ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$
$147.3$ $\pm1.5$ $\pm0.7$ 1.98M 7
 2003
KLOE 1.02 ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}$
$151.1$ $\pm2.6$ $\pm3.0$ 500k 7
 2002
SND 1.02 ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}$
$150.5$ $\pm3.0$ 8
 1985
OLYA ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$
• • • We do not use the following data for averages, fits, limits, etc. • • •
$144.06$ $\pm0.85$ 9
 2017
RVUE ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$
$144.56$ $\pm0.80$ 10
 2017 A
RVUE ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$
$143.9$ $\pm1.3$ $\pm1.1$ 1.98M 11
 2003
KLOE 1.02 ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}$
$147.4$ $\pm1.5$ $\pm0.7$ 1.98M 12
 2003
KLOE 1.02 ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}$
$149.8$ $\pm2.2$ $\pm2.0$ 500k 13
 2002
SND 1.02 ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}$
$147.9$ $\pm1.5$ $\pm7.5$ 14
 1998
RVUE ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ , ${{\mathit \mu}^{+}}{{\mathit \mu}^{-}}$
$153.5$ $\pm1.3$ $\pm4.6$ 15
 1998
RVUE $0.28 - 0.92$ ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$
$145.0$ $\pm1.7$ 16
 1997
RVUE ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$
$142.5$ $\pm3.5$ 17
 1994
RVUE ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$
$138$ $\pm1$ 18
 1989
RVUE ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$
1  Using the GOUNARIS 1968 parametrization with the complex phase of the ${{\mathit \rho}}−{{\mathit \omega}}$ interference and leaving the masses and widths of the ${{\mathit \rho}{(1450)}}$, ${{\mathit \rho}{(1700)}}$, and ${{\mathit \rho}{(2150)}}$ resonances as free parameters of the fit.
2  A combined fit of AKHMETSHIN 2007 , AULCHENKO 2006 , and AULCHENKO 2005 .
3  Supersedes ACHASOV 2005A.
4  A fit of the SND data from 400 to 1000 MeV using parameters of the ${{\mathit \rho}{(1450)}}$ and ${{\mathit \rho}{(1700)}}$ from a fit of the data of BARKOV 1985 , BISELLO 1989 and ANDERSON 2000A.
5  Using the GOUNARIS 1968 parametrization with the complex phase of the ${{\mathit \rho}}-{{\mathit \omega}}$ interference.
6  From a fit in the energy range 0.61 to 0.96 GeV. Update of AKHMETSHIN 2002 .
7  Assuming ${\mathit m}_{{{\mathit \rho}^{+}}}$ = ${\mathit m}_{{{\mathit \rho}^{-}}}$, $\Gamma _{{{\mathit \rho}^{+}}}$ = $\Gamma _{{{\mathit \rho}^{-}}}$.
8  From the GOUNARIS 1968 parametrization of the pion form factor.
9  Applies the Unitary $\&$ Analytic Model of the pion electromagnetic form factor of DUBNICKA 2010 to analyze the data of LEES 2012G and ABLIKIM 2016C.
10  Applies the Unitary $\&$ Analytic Model of the pion electromagnetic form factor of DUBNICKA 2010 to analyze the data of ACHASOV 2006 , AKHMETSHIN 2007 , AUBERT 2009AS, and AMBROSINO 2011A.
11  Assuming ${\mathit m}_{{{\mathit \rho}^{+}}}$ = ${\mathit m}_{{{\mathit \rho}^{-}}}$ = ${\mathit m}_{{{\mathit \rho}^{0}}}$, $\Gamma _{{{\mathit \rho}^{+}}}$ = $\Gamma _{{{\mathit \rho}^{-}}}$ = $\Gamma _{{{\mathit \rho}^{0}}}$.
12  Without limitations on masses and widths.
13  Assuming ${\mathit m}_{{{\mathit \rho}^{0}}}$ = ${\mathit m}_{{{\mathit \rho}^{\pm}}}$, $\mathit g_{ {{\mathit \rho}^{0}} {{\mathit \pi}} {{\mathit \pi}} }$ = $\mathit g_{ {{\mathit \rho}^{\pm}} {{\mathit \pi}} {{\mathit \pi}} }$.
14  Using the data of BARKOV 1985 in the hidden local symmetry model.
15  From the fit to ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ data from the compilations of HEYN 1981 and BARKOV 1985 , including the GOUNARIS 1968 parametrization of the pion form factor.
16  A fit of BARKOV 1985 data assuming the direct ${{\mathit \omega}}{{\mathit \pi}}{{\mathit \pi}}$ coupling.
17  Applying the S-matrix formalism to the BARKOV 1985 data.
18  Includes BARKOV 1985 data. Model-dependent width definition.

Neutral only, ${{\mathit e}^{+}}{{\mathit e}^{-}}$ (MeV)
References:
 BARTOS 2017A
IJMP A32 1750154 The Mass and Width Differences of the Neutral and Charged ${{\mathit \rho}{(770)}}$, ${{\mathit \rho}{(1450 )}}$ and ${{\mathit \rho}{(1700)}}$ Mesons from ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ and ${{\mathit \nu}}{{\mathit \tau}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}$ Processes
 BARTOS 2017
PR D96 113004 What are the Correct ${{\mathit \rho}{(770)}^{0}}$ Meson Mass and Width Values?
 LEES 2012G
PR D86 032013 Precise Measurement of the ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$( ${{\mathit \gamma}}$) Cross Section with the Initial-State Radiation Method at BABAR
 AKHMETSHIN 2007
PL B648 28 High-Statistics Measurement of the Pion Form Factor in the ${{\mathit \rho}}$-Meson Energy Range with the CMD-2 Detector
 ACHASOV 2006
JETP 103 380 Update of the ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ ${{\mathit \pi}^{+}}$ ${{\mathit \pi}^{-}}$ Cross-Section Measured by SND Detector in the Energy Region 400 < $\sqrt {s }$ < 1000 MeV
 AKHMETSHIN 2004
PL B578 285 Reanalysis of Hadronic Cross Section Measurements at CMD-2
 ALOISIO 2003
PL B561 55 Study of the Decay ${{\mathit \phi}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}$ with the Detector
 ACHASOV 2002
PR D65 032002 Study of the ${{\mathit \pi}}{{\mathit \pi}}$ Mass Spectra in the Process ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}$ at $\sqrt {s }$ = 1020 MeV
 BENAYOUN 1998
EPJ C2 269 New Results in ${{\mathit \rho}^{0}}$ Meson Physics
 GARDNER 1998
PR D57 2716 ${{\mathit \rho}}$ $\leftrightarrow$ ${{\mathit \omega}}$ Mixing and the Pion Formfactor in the Timelike Region
 O'CONNELL 1997
NP A623 559 Extracting the ${{\mathit \rho}}$ $\leftrightarrow$ ${{\mathit \omega}}$ Mixing Amplitude from the Pion Formfactor
 BERNICHA 1994
PR D50 4454 Mass and Width of the ${{\mathit \rho}^{0}}$ from an S Matrix Approach to ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$
 GESHKENBEIN 1989
ZPHY C45 351 Analysis of Experiments on Measurement of the Pion Electromagnetic Formfactor
 BARKOV 1985
NP B256 365 Electromagnetic Pion Form Factor in the Timelike Region