# ${{\boldsymbol A}^{0}}$ (Axion) and Other Light Boson (${{\boldsymbol X}^{0}}$) Searches in Nuclear Transitions INSPIRE search

Limits are for branching ratio.
VALUE CL% DOCUMENT ID TECN  COMMENT
• • • We do not use the following data for averages, fits, limits, etc. • • •
$<8.5 \times 10^{-6}$ 90 1
 2002
CNTR ${}^{125}\mathrm {mTe}$ decay
2
 1997 C
RVUE M1 transitions
$<5.5 \times 10^{-10}$ 95 3
 1995
CNTR ${}^{252}\mathrm {Cf}$ fission, ${{\mathit A}^{0}}$ $\rightarrow$ ${{\mathit e}}{{\mathit e}}$
$<1.2 \times 10^{-6}$ 95 4
 1993
CNTR ${}^{139}\mathrm {La}^{*}$ $\rightarrow$ ${}^{139}\mathrm {La}$ ${{\mathit A}^{0}}$
$<2 \times 10^{-4}$ 90 5
 1992
CNTR ${}^{35}\mathrm {S}$ decay, ${{\mathit A}^{0}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}$
$<1.5 \times 10^{-9}$ 95 6
 1990
CNTR ${}^{241}\mathrm {Am}$ decay
$<(0.4 - 10){\times }\text{ 10^}{-3}$ 95 7
 1990
CNTR ${}^{8}\mathrm {Be}^{*}$ $\rightarrow$ ${}^{8}\mathrm {Be}$ ${{\mathit A}^{0}}$ , ${{\mathit A}^{0}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}$
$<(0.2 - 1){\times }\text{ 10^}{-3}$ 90 8
 1989
CNTR ${}^{16}\mathrm {O}^{*}$ $\rightarrow$ ${}^{16}\mathrm {O}$ ${{\mathit X}^{0}}$ , ${{\mathit X}^{0}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}$
9
 1988
CNTR ${}^{}\mathrm {Cu}^{*}$ $\rightarrow$ ${}^{}\mathrm {Cu}$ ${{\mathit A}^{0}}$ ( ${{\mathit A}^{0}}$ $\rightarrow$ 2 ${{\mathit \gamma}}$ , ${{\mathit A}^{0}}$ ${{\mathit e}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit e}}$ , ${{\mathit A}^{0}}$ ${{\mathit Z}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit Z}}$ )
$<1.5 \times 10^{-4}$ 90 10
 1988
CNTR ${}^{12}\mathrm {C}^{*}$ $\rightarrow$ ${}^{12}\mathrm {C}$ ${{\mathit A}^{0}}$ , ${{\mathit A}^{0}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}$
$<5 \times 10^{-3}$ 90 11
 1988 C
CNTR ${}^{16}\mathrm {O}^{*}$ $\rightarrow$ ${}^{16}\mathrm {O}$ ${{\mathit X}^{0}}$ , ${{\mathit X}^{0}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}$
$<3.4 \times 10^{-5}$ 95 12
 1988
SPEC ${}^{2}\mathrm {H}^{*}$, ${{\mathit A}^{0}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}$
$<4 \times 10^{-4}$ 95 13
 1988
CNTR Nuclear decay (isovector)
$<3 \times 10^{-3}$ 95 13
 1988
CNTR Nuclear decay (isoscalar)
$<0.106$ 90 14
 1986
SPEC ${}^{6}\mathrm {Li}$ isovector decay
$<10.8$ 90 14
 1986
SPEC ${}^{10}\mathrm {B}$ isoscalar decays
$<2.2$ 90 14
 1986
SPEC ${}^{14}\mathrm {N}$ isoscalar decays
$<4 \times 10^{-4}$ 90 15
 1986 B
CNTR ${}^{14}\mathrm {N}^{*}$
16
 1985
CNTR ${}^{}\mathrm {Li}^{*}$, deut${}^{*}$ ${{\mathit A}^{0}}$ $\rightarrow$ 2 ${{\mathit \gamma}}$
17
 1983
CNTR ${}^{97}\mathrm {Nb}^{*}$, deut${}^{*}$ transition ${{\mathit A}^{0}}$ $\rightarrow$ 2 ${{\mathit \gamma}}$
18
 1982 B
CNTR ${}^{}\mathrm {Li}^{*}$, deut${}^{*}$ transition ${{\mathit A}^{0}}$ $\rightarrow$ 2 ${{\mathit \gamma}}$
19
 1982
CNTR ${}^{}\mathrm {Cu}^{*}$ $\rightarrow$ ${}^{}\mathrm {Cu}$ ${{\mathit A}^{0}}$ ( ${{\mathit A}^{0}}$ $\rightarrow$ 2 ${{\mathit \gamma}}$ )
20
 1982
CNTR ${}^{}\mathrm {Li}^{*}$, ${}^{}\mathrm {Nb}^{*}$ decay, ${{\mathit n}}$-capt.
21
 1981
CNTR ${}^{}\mathrm {Ba}^{*}$ $\rightarrow$ ${}^{}\mathrm {Ba}$ ${{\mathit A}^{0}}$ ( ${{\mathit A}^{0}}$ $\rightarrow$ 2 ${{\mathit \gamma}}$ )
22
 1979
Carbon
1  DERBIN 2002 looked for the axion emission in an M1 transition in ${}^{125}\mathrm {mTe}$ decay. They looked for a possible presence of a shifted energy spectrum in gamma rays due to the undetected axion.
2  DEBOER 1997C reanalyzed the existent data on Nuclear M1 transitions and find that a 9$~$MeV boson decaying into ${{\mathit e}^{+}}{{\mathit e}^{-}}$ would explain the excess of events with large opening angles. See also DEBOER 2001 for follow-up experiments.
3  TSUNODA 1995 looked for axion emission when ${}^{252}\mathrm {Cf}$ undergoes a spontaneous fission, with the axion decaying into ${{\mathit e}^{+}}{{\mathit e}^{-}}$ . The bound is for ${\mathit m}_{{{\mathit A}^{0}}}$=40 MeV. It improves to $2.5 \times 10^{-5}$ for ${\mathit m}_{{{\mathit A}^{0}}}$=200 MeV.
4  MINOWA 1993 studied chain process, ${}^{139}\mathrm {Ce}$ $\rightarrow$ ${}^{139}\mathrm {La}^{*}$ by electron capture and M1 transition of ${}^{139}\mathrm {La}^{*}$ to the ground state. It does not assume decay modes of ${{\mathit A}^{0}}$. The bound applies for ${\mathit m}_{{{\mathit A}^{0}}}<166$ keV.
5  HICKS 1992 bound is applicable for ${\mathit \tau}_{{{\mathit X}^{0}}}$ $<4 \times 10^{-11}$ sec.
6  The ASANUMA 1990 limit is for the branching fraction of ${{\mathit X}^{0}}$ emission per ${}^{241}\mathrm {Am}$ ${{\mathit \alpha}}$ decay and valid for ${\mathit \tau}_{{{\mathit X}^{0}}}$ $<$ $3 \times 10^{-11}~$s.
7  The DEBOER 1990 limit is for the branching ratio ${}^{8}\mathrm {Be}^{*}$ ($18.15$ MeV, 1${}^{+}$) $\rightarrow$ ${}^{8}\mathrm {Be}$ ${{\mathit A}^{0}}$ , ${{\mathit A}^{0}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}$ for the mass range ${\mathit m}_{{{\mathit A}^{0}}}$ = 4$-$15 MeV.
8  The BINI 1989 limit is for the branching fraction of ${}^{16}\mathrm {O}^{*}$ ($6.05$ MeV, 0${}^{+}$) $\rightarrow$ ${}^{16}\mathrm {O}$ ${{\mathit X}^{0}}$ , ${{\mathit X}^{0}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}$ for ${\mathit m}_{{{\mathit X}}}$ = $1.5-3.1$ MeV. ${\mathit \tau}_{{{\mathit X}^{0}}}{ {}\lesssim{} }$ $10^{-11}~$s is assumed. The spin-parity of ${{\mathit X}}$ is restricted to 0${}^{+}$ or 1${}^{−}$.
9  AVIGNONE 1988 looked for the 1115 keV transition ${}^{}\mathrm {C}^{*}$ $\rightarrow$ ${}^{}\mathrm {Cu}$ ${{\mathit A}^{0}}$ , either from ${{\mathit A}^{0}}$ $\rightarrow$ 2 ${{\mathit \gamma}}$ in-flight decay or from the secondary ${{\mathit A}^{0}}$ interactions by Compton and by Primakoff processes. Limits for axion parameters are obtained for ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ $1.1$ MeV.
10  DATAR 1988 rule out light pseudoscalar particle emission through its decay ${{\mathit A}^{0}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}$ in the mass range $1.02-2.5$ MeV and lifetime range $10^{-13}-10^{-8}~$s. The above limit is for $\tau$ = $5 \times 10^{-13}~$s and $\mathit m$ = $1.7$ MeV; see the paper for the $\tau -\mathit m$ dependence of the limit.
11  The limit is for the branching fraction of ${}^{16}\mathrm {O}^{*}$ ($6.05$ MeV, 0${}^{+}$) $\rightarrow$ ${}^{16}\mathrm {O}$ ${{\mathit X}^{0}}$ , ${{\mathit X}^{0}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}$ against internal pair conversion for ${\mathit m}_{{{\mathit X}^{0}}}$ = $1.7$ MeV and ${\mathit \tau}_{{{\mathit X}^{0}}}$ $<$ $10^{-11}~$s. Similar limits are obtained for ${\mathit m}_{{{\mathit X}^{0}}}$ = $1.3-3.2$ MeV. The spin parity of ${{\mathit X}^{0}}$ must be either 0${}^{+}$ or 1${}^{−}$. The limit at $1.7$ MeV is translated into a limit for the ${{\mathit X}^{0}}$-nucleon coupling constant: $\mathit g{}^{2}_{ {{\mathit X}^{0}} }/4{{\mathit \pi}}$ $<$ $2.3 \times 10^{-9}$.
12  The DOEHNER 1988 limit is for ${\mathit m}_{{{\mathit A}^{0}}}$ = $1.7$ MeV, $\tau\mathrm {({{\mathit A}^{0}})}$ $<$ $10^{-10}~$s. Limits less than $10^{-4}$ are obtained for ${\mathit m}_{{{\mathit A}^{0}}}$ = $1.2-2.2$ MeV.
13  SAVAGE 1988 looked for ${{\mathit A}^{0}}$ that decays into ${{\mathit e}^{+}}{{\mathit e}^{-}}$ in the decay of the $9.17$ MeV $\mathit J{}^{P}$ = $2{}^{+}{}^{}$ state in ${}^{14}\mathrm {N}$, $17.64$ MeV state $\mathit J{}^{P}$ = $1{}^{+}{}^{}$ in ${}^{8}\mathrm {Be}$, and the $18.15$ MeV state $\mathit J{}^{P}$ = $1{}^{+}{}^{}$ in ${}^{8}\mathrm {Be}$. This experiment constrains the isovector coupling of ${{\mathit A}^{0}}$ to hadrons, if ${\mathit m}_{{{\mathit A}^{0}}}$ = ($1.1$ $\rightarrow$ $2.2$) MeV and the isoscalar coupling of ${{\mathit A}^{0}}$ to hadrons, if ${\mathit m}_{{{\mathit A}^{0}}}$ = ($1.1$ $\rightarrow$ $2.6$) MeV. Both limits are valid only if $\tau\mathrm {({{\mathit A}^{0}})}{ {}\lesssim{} }$ $1 \times 10^{-11}$ s.
14  Limits are for $\Gamma\mathrm {({{\mathit A}^{0}}(1.8 MeV))}/\Gamma\mathrm {({{\mathit \pi}}M1)}$; i.e., for 1.8 MeV axion emission normalized to the rate for internal emission of ${{\mathit e}^{+}}{{\mathit e}^{-}}$ pairs. Valid for ${\mathit \tau}_{{{\mathit A}^{0}}}$ $<$ $2 \times 10^{-11}$s. ${}^{6}\mathrm {Li}$ isovector decay data strongly disfavor PECCEI 1986 model I, whereas the ${}^{10}\mathrm {B}$ and ${}^{14}\mathrm {N}$ isoscalar decay data strongly reject PECCEI 1986 model II and III.
15  SAVAGE 1986B looked for ${{\mathit A}^{0}}$ that decays into ${{\mathit e}^{+}}{{\mathit e}^{-}}$ in the decay of the 9.17 MeV $\mathit J{}^{P} = 2+$ state in ${}^{14}\mathrm {N}$. Limit on the branching fraction is valid if ${\mathit \tau}_{{{\mathit A}^{0}}}{ {}\lesssim{} }1. \times 10^{-11}$s for ${\mathit m}_{{{\mathit A}^{0}}}$ = (1.1$-$1.7) MeV. This experiment constrains the iso-vector coupling of ${{\mathit A}^{0}}$ to hadrons.
16  ANANEV 1985 with IBR-2 pulsed reactor exclude standard ${{\mathit A}^{0}}$ at CL = 95$\%$ masses below 470 keV (${}^{}\mathrm {Li}^{*}$ decay) and below 2${}{\mathit m}_{{{\mathit e}}}$ for deuteron* decay.
17  CAVAIGNAC 1983 at Bugey reactor exclude axion at any ${\mathit m}_{\mathrm {{}^{97}\mathrm {Nb}^{*}decay}}$ and axion with ${\mathit m}_{{{\mathit A}^{0}}}$ between 275 and 288 keV (deuteron* decay).
18  ALEKSEEV 1982 with IBR-2 pulsed reactor exclude standard ${{\mathit A}^{0}}$ at CL = 95$\%$ mass-ranges ${\mathit m}_{{{\mathit A}^{0}}}$ $<$400 keV (${}^{}\mathrm {Li}^{*}$ decay) and 330 keV $<{\mathit m}_{{{\mathit A}^{0}}}$ $<$2.2 MeV. (deuteron* decay).
19  LEHMANN 1982 obtained ${{\mathit A}^{0}}$ $\rightarrow$ 2 ${{\mathit \gamma}}$ rate $<6.2 \times 10^{-5}$/s (CL = 95$\%$) excluding ${\mathit m}_{{{\mathit A}^{0}}}$ between 100 and 1000 keV.
20  ZEHNDER 1982 used Gosgen 2.8GW light-water reactor to check ${{\mathit A}^{0}}$ production. No 2${{\mathit \gamma}}$ peak in ${}^{}\mathrm {Li}^{*}$, ${}^{}\mathrm {Nb}^{*}$ decay (both single ${{\mathit p}}$ transition) nor in ${{\mathit n}}$ capture (combined with previous ${}^{}\mathrm {Ba}^{*}$ negative result) rules out standard ${{\mathit A}^{0}}$. Set limit ${\mathit m}_{{{\mathit A}^{0}}}$ $<$60 keV for any ${{\mathit A}^{0}}$.
21  ZEHNDER 1981 looked for ${}^{}\mathrm {Ba}^{*}$ $\rightarrow$ ${{\mathit A}^{0}}{}^{}\mathrm {Ba}$ transition with ${{\mathit A}^{0}}$ $\rightarrow$ 2 ${{\mathit \gamma}}$ . Obtained 2${{\mathit \gamma}}$ coincidence rate $<2.2 \times 10^{-5}$/s (CL = 95$\%$) excluding ${\mathit m}_{{{\mathit A}^{0}}}$ $>$160 keV (or 200 keV depending on Higgs mixing). However, see BARROSO 1981 .
22  CALAPRICE 1979 saw no axion emission from excited states of carbon. Sensitive to axion mass between 1 and 15 MeV.
References:
 DERBIN 2002
PAN 65 1302 Search for Axions Emitted in Nuclear Magnetic Transitions
 DEBOER 1997C
JP G23 L85 Excess in Nuclear ${{\mathit e}^{+}}{{\mathit e}^{-}}$ Pairs near 9 ${\mathrm {MeV}}/\mathit c{}^{2}$ Invariant Mass
 TSUNODA 1995
EPL 30 273 A Search for Back-to-Back ${{\mathit e}^{+}}{{\mathit e}^{-}}$ Pairs in the Spontaneous Fission Disintegration of ${}^{252}\mathrm {Cf}$
 MINOWA 1993
PRL 71 4120 Invisible Axion Search in ${}^{139}\mathrm {La}$ $\mathit M$1 Transition
 HICKS 1992
PL B276 423 Search for a Light Neutral Boson Associated with $\beta$ Decay
 ASANUMA 1990
PL B237 588 A Search for Correlated ${{\mathit e}^{+}}{{\mathit e}^{-}}$ Pairs in the Decay of ${}^{241}\mathrm {Am}$
 DEBOER 1990
JP G16 L1 Search for a Short Lived Isoscalar Axion with Mass between 4 ${\mathrm {GeV/}}\mathit c{}^{-2}$ and 15 ${\mathrm {MeV}}/\mathit c{}^{-2}$
 BINI 1989
PL B221 99 A Sensitive Search for the Emission of a Neutral Particle in the Decay of the First Excited State in ${}^{16}\mathrm {O}$
 AVIGNONE 1988
PR D37 618 Search for Axions from 1115 keV Transition of ${}^{65}\mathrm {Cu}$
 DATAR 1988
PR C37 250 Search for Short Lived Neutral Particle in the 15.1 MeV Isovector Transition of ${}^{12}\mathrm {C}$
 DEBOER 1988C
JP G14 L131 Search for Elusive Neutral Particles in Nuclear Decay
 DOEHNER 1988
PR D38 2722 Pair Decay of the 2.2 MeV Excited State of the Deuteron: Limits on Light Particle Emission
 SAVAGE 1988
PR D37 1134 New Limit on Light Scalar and Pseudoscalar Particles Produced in Nuclear Decay
 HALLIN 1986
PRL 57 2105 Restrictions on a 1.7 MeV Axion from Nuclear Pair Transitions
 SAVAGE 1986B
PRL 57 178 A Search for a Short Lived Neutral Particle Produced in Nuclear Decay
 ANANEV 1985
SJNP 41 585 Search for axion at the Impulsive Reactor IBR-2
 CAVAIGNAC 1983
PL 121B 193 A Search for Axions at a Power Reactor
 ALEKSEEV 1982B
JETPL 36 116 Search for Axion on IBR-2 Pulse Reactor
 LEHMANN 1982
PL 115B 270 Axion Search in the Monochromatic M1 Transition of ${}^{65}\mathrm {Cu}$
 ZEHNDER 1982
PL 110B 419 Search for Axions in Specific Nuclear ${{\mathit \gamma}}$ Transitions at a Power Reactor
 ZEHNDER 1981
PL 104B 494 Axion Search in a Monochromatic ${{\mathit \gamma}}$ transition: a New Lower Limit for the Axion Mass
 CALAPRICE 1979
PR D20 2708 Search for Axion Emission in the Decay of Excited States of ${}^{12}\mathrm {C}$
 BARROSO 1981
PL 106B 91 Axions: to be or not to be?
 PECCEI 1986
PL B172 435 A Viable Axion Model