# ${{\boldsymbol a}_{{1}}{(1260)}}$ MASS INSPIRE search

VALUE (MeV) EVTS DOCUMENT ID TECN  COMMENT
$\bf{ 1230 \pm40}$ OUR ESTIMATE
$1299$ ${}^{+12}_{-28}$ 46M 1
 2018 B
COMP 190 ${{\mathit \pi}^{-}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \pi}^{-}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit p}}$
• • • We do not use the following data for averages, fits, limits, etc. • • •
$1195.05$ $\pm1.05$ $\pm6.33$ 894k
 2018 AI
LHCB ${{\mathit D}^{0}}$ $\rightarrow$ ${{\mathit K}^{\mp}}{{\mathit \pi}^{\pm}}{{\mathit \pi}^{\pm}}{{\mathit \pi}^{\mp}}$
$1209$ $\pm4$ ${}^{+12}_{-9}$ 2
 2018
RVUE ${{\mathit \tau}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{-}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \nu}_{{\tau}}}$
$1225$ $\pm9$ $\pm20$ 7k 3
 2017
RVUE ${{\mathit D}^{0}}$ $\rightarrow$ ${{\mathit \pi}^{-}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{+}}$
$1255$ $\pm6$ ${}^{+7}_{-17}$ 420k 4
 2010
COMP 190 ${{\mathit \pi}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{-}}{{\mathit \pi}^{-}}{{\mathit \pi}^{+}}{{\mathit P}}{{\mathit b}^{\,'}}$
$1243$ $\pm12$ $\pm20$ 5
 2007 AU
BABR 10.6 ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \rho}^{0}}{{\mathit \rho}^{\pm}}{{\mathit \pi}^{\mp}}{{\mathit \gamma}}$
$\text{1230 - 1270}$ 6360 6
 2007 A
FOCS ${{\mathit D}^{0}}$ $\rightarrow$ ${{\mathit \pi}^{-}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{+}}$
$1203$ $\pm3$ 7
 2004
RVUE ${{\mathit \tau}^{+}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \nu}_{{\tau}}}$
$1330$ $\pm24$ 90k
 2004
OBLX ${{\overline{\mathit p}}}$ ${{\mathit p}}$ $\rightarrow$ 2 ${{\mathit \pi}^{+}}$2 ${{\mathit \pi}^{-}}$
$1331$ $\pm10$ $\pm3$ 37k 8
 2000
CLE2 $10.6$ ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \tau}^{+}}{{\mathit \tau}^{-}}$ , ${{\mathit \tau}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{-}}{{\mathit \pi}^{0}}{{\mathit \pi}^{0}}{{\mathit \nu}_{{\tau}}}$
$1255$ $\pm7$ $\pm6$ 5904 9
 1998 G
DLPH ${{\mathit e}^{+}}{{\mathit e}^{-}}$
$1207$ $\pm5$ $\pm8$ 5904 10
 1998 G
DLPH ${{\mathit e}^{+}}{{\mathit e}^{-}}$
$1196$ $\pm4$ $\pm5$ 5904 11, 12
 1998 G
DLPH ${{\mathit e}^{+}}{{\mathit e}^{-}}$
$1240$ $\pm10$
 1998 B
450 ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit p}_{{f}}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}{{\mathit p}_{{s}}}$
$1262$ $\pm9$ $\pm7$ 9, 13
 1997 R
OPAL ${\it{}E}^{\it{}ee}_{\rm{}cm}$= $88 - 94$, ${{\mathit \tau}}$ $\rightarrow$ 3 ${{\mathit \pi}}{{\mathit \nu}}$
$1210$ $\pm7$ $\pm2$ 10, 13
 1997 R
OPAL ${\it{}E}^{\it{}ee}_{\rm{}cm}$= $88 - 94$, ${{\mathit \tau}}$ $\rightarrow$ 3 ${{\mathit \pi}}{{\mathit \nu}}$
$1211$ $\pm7$ ${}^{+50}_{-0}$ 10
 1993 C
ARG ${{\mathit \tau}^{+}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \nu}}$
$1121$ $\pm8$ 14
 1992
SPEC 8 ${{\mathit \pi}^{-}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}{{\mathit n}}$
$1242$ $\pm37$ 15
 1991
RVUE ${{\mathit \tau}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \nu}}$
$1260$ $\pm14$ 16
 1991
RVUE ${{\mathit \tau}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \nu}}$
$1250$ $\pm9$ 17
 1991
RVUE ${{\mathit \tau}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \nu}}$
$1208$ $\pm15$
 1990
OMEG 300.0 ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit p}}{{\mathit p}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}$
$1220$ $\pm15$ 18
 1989
RVUE ${{\mathit \tau}^{+}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \nu}}$
$1260$ $\pm25$ 19
 1988
RVUE
$1166$ $\pm18$ $\pm11$
 1987
MAC ${{\mathit \tau}^{+}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \nu}}$
$1164$ $\pm41$ $\pm23$
 1987
MAC ${{\mathit \tau}^{+}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{0}}{{\mathit \pi}^{0}}{{\mathit \nu}}$
$1250$ $\pm40$ 18
 1987
RVUE
$1046$ $\pm11$
 1986 B
ARG ${{\mathit \tau}^{+}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \nu}}$
$1056$ $\pm20$ $\pm15$
 1986
DLCO ${{\mathit \tau}^{+}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \nu}}$
$1194$ $\pm14$ $\pm10$
 1986
MRK2 ${{\mathit \tau}^{+}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \nu}}$
$1255$ $\pm23$
 1985
SPEC 40 ${{\mathit \pi}^{-}}$ ${{\mathit A}}$ $\rightarrow$ ${{\mathit \pi}^{-}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit A}}$
$1240$ $\pm80$ 20
 1981
SPEC 8.45 ${{\mathit \pi}^{-}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit n}}$3 ${{\mathit \pi}}$
$1280$ $\pm30$ 20
 1981 B
CNTR 63,94 ${{\mathit \pi}^{-}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit p}}$3 ${{\mathit \pi}}$
$1041$ $\pm13$ 21
 1977
HBC 4.2 ${{\mathit K}^{-}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \Sigma}}$3 ${{\mathit \pi}}$
1  Statistical error negligible.
2  From the pole position. Using an amplitude analysis based on approximate three-body unitary of ${{\mathit \tau}}$ data from SCHAEL 2005C.
3  Reanalysis of CLEO data using Breit-Wigner parameterization.
4  Superseded by AGHASYAN 2018B.
5  The ${{\mathit \rho}^{\pm}}{{\mathit \pi}^{\mp}}$ state can be also due to the ${{\mathit \pi}{(1300)}}$.
6  Using the Breit-Wigner parameterization; strong correlation between mass and width.
7  Using the data of BARATE 1998R.
8  From a fit to the 3${{\mathit \pi}}$ mass spectrum including the ${{\mathit K}}{{\overline{\mathit K}}^{*}{(892)}}$ threshold.
9  Uses the model of KUHN 1990 .
10  Uses the model of ISGUR 1989 .
11  Includes the effect of a possible ${{\mathit a}_{{1}}^{\,'}}$ state.
12  Uses the model of FEINDT 1990 .
13  Supersedes AKERS 1995P.
14  Average and spread of values using 2 variants of the model of BOWLER 1975 .
15  Reanalysis of RUCKSTUHL 1986 .
16  Reanalysis of SCHMIDKE 1986 .
17  Reanalysis of ALBRECHT 1986B.
18  From a combined reanalysis of ALBRECHT 1986B, SCHMIDKE 1986 , and RUCKSTUHL 1986 .
19  From a combined reanalysis of ALBRECHT 1986B and DAUM 1981B.
20  Uses the model of BOWLER 1975 .
21  Produced in ${{\mathit K}^{-}}$ backward scattering.
References:
 AAIJ 2018AI
EPJ C78 443 Studies of the resonance structure in $D^{0} \rightarrow K^\mp \pi ^\pm \pi ^\pm \pi ^\mp$ decays
 AGHASYAN 2018B
PR D98 092003 Light isovector resonances in $\pi^- p \to \pi^-\pi^-\pi^+ p$ at 190 GeV/${\it c}$
 MIKHASENKO 2018
PR D98 096021 Pole position of the $a_1(1260)$ from $\tau$-decay
 DARGENT 2017
JHEP 1705 143 Amplitude Analyses of ${{\mathit D}^{0}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ and ${{\mathit D}^{0}}$ $\rightarrow$ ${{\mathit K}^{+}}{{\mathit K}^{-}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ Decays
 ALEKSEEV 2010
PRL 104 241803 Observation of a $\mathit J{}^{PC} = 1-+$ Exotic Resonance in Diffractive Dissociation of 190 GeV/$\mathit c$ ${{\mathit \pi}^{-}}$ into ${{\mathit \pi}^{-}}{{\mathit \pi}^{-}}{{\mathit \pi}^{+}}$
 AUBERT 2007AU
PR D76 092005 The ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ 2( ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$) ${{\mathit \pi}^{0}}$ , 2( ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$) ${{\mathit \eta}}$ , ${{\mathit K}^{+}}{{\mathit K}^{-}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}$ and ${{\mathit K}^{+}}{{\mathit K}^{-}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \eta}}$ Cross Sections Measured with Initial-State Radiation
PR D75 052003 Study of the ${{\mathit D}^{0}}$ $\rightarrow$ ${{\mathit \pi}^{-}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{+}}$ Decay
 GOMEZ-DUMM 2004
PR D69 073002 ${{\mathit \tau}}$ $\rightarrow$ ${{\mathit \pi}}{{\mathit \pi}}{{\mathit \pi}}{{\mathit \nu}_{{\tau}}}$ Decays in the Resonance Effective Theory
 SALVINI 2004
EPJ C35 21 ${{\overline{\mathit p}}}{{\mathit p}}$ Annihilation into Four Charged Pions at Rest and in Flight
 ASNER 2000
PR D61 012002 Hadronic Structure in the Decay ${{\mathit \tau}^{-}}$ $\rightarrow$ ${{\mathit \nu}_{{\tau}}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}{{\mathit \pi}^{0}}$ and the Sign of the ${{\mathit \nu}_{{\tau}}}$ Helicity
 ABREU 1998G
PL B426 411 A Study of the Hadronic Resonance Structure in the Decay ${{\mathit \tau}}$ $\rightarrow$ 3 ${{\mathit \pi}}{{\mathit \nu}_{{\tau}}}$
 BARBERIS 1998B
PL B422 399 A Study of the Centrally Produced ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}$ Channel in ${{\mathit p}}{{\mathit p}}$ Interactions at 450 ${\mathrm {GeV/}}\mathit c$
 ACKERSTAFF 1997R
ZPHY C75 593 A Measurement of the Hadronic Decay Current and the ${{\mathit \nu}_{{\tau}}}$ Helicity in ${{\mathit \tau}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{-}}{{\mathit \pi}^{-}}{{\mathit \pi}^{+}}{{\mathit \nu}_{{\tau}}}$
 ALBRECHT 1993C
ZPHY C58 61 Analysis of the Decay ${{\mathit \tau}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{-}}{{\mathit \pi}^{-}}{{\mathit \pi}^{+}}{{\mathit \nu}_{{\tau}}}$ and Determination of the ${{\mathit a}_{{1}}{(1260)}}$ Resonance Parameters
 ANDO 1992
PL B291 496 Experimental Study of the Axial-Vector Resonances of ${{\mathit a}_{{1}}}$ and ${{\mathit h}_{{1}}}$ in the ${{\mathit \pi}^{-}}{{\mathit p}}$ Charge Exchange Reaction
 IVANOV 1991
ZPHY C49 563 The Decay ${{\mathit \tau}}$ $\rightarrow$ 3 ${{\mathit \pi}}{{\mathit \nu}_{{\tau}}}$ and Characteristics of ${{\mathit a}_{{1}}}$ Meson
 ARMSTRONG 1990
ZPHY C48 213 A Study of the Centrally Produced ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}$ System Formed in the Reaction ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit p}_{{f}}}$( ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}$) ${{\mathit p}_{{s}}}$ at 300 ${\mathrm {GeV/}}\mathit c$
 ISGUR 1989
PR D39 1357 The ${{\mathit a}_{{1}}}$ in ${{\mathit \tau}}$ Decay
 BOWLER 1988
PL B209 99 The Parameters of the ${{\mathit a}_{{1}}}$ Meson
 BAND 1987
PL B198 297 Measurements of ${{\mathit \tau}}$ Decays to Three Pions
 TORNQVIST 1987
ZPHY C36 695 The ${{\mathit a}_{{1}}}$ Mass from ${{\mathit \tau}}$ $\rightarrow$ ${{\mathit a}_{{1}}}$ Decay
 ALBRECHT 1986B
ZPHY C33 7 Measurement of ${{\mathit \tau}}$ Decays into Three Charged Pions
 RUCKSTUHL 1986
PRL 56 2132 Study of Three Prong ${{\mathit \tau}}$ Decays and Determination of the $\mathit A_{1}$ Parameters
 SCHMIDKE 1986
PRL 57 527 Study of the Decay ${{\mathit \tau}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{-}}{{\mathit \pi}^{-}}{{\mathit \pi}^{+}}{{\mathit \nu}_{{\tau}}}$
 BELLINI 1985
SJNP 41 781 $2{}^{-}{}^{}$ Resonances in the ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{-}}$ Systems
 DANKOWYCH 1981
PRL 46 580 Evidence for $\mathit I = 1$ (${{\mathit A}_{{1}}}$) and $\mathit I = 0$ (${{\mathit H}}$) Axial Vector Resonances in Charge Exchange
 DAUM 1981B
NP B182 269 Diffractive Production of 3${{\mathit \pi}}$ States at 63 and 94 GeV
 GAVILLET 1977
PL 69B 119 Backward Production of a Spin Parity $1{}^{+}{}^{}{{\mathit \rho}}{{\mathit \pi}}$ Enhancement at 1.04 GeV