Limits are for the modulus of the axion-two-photon coupling $\mathit G_{{{\mathit A}} {{\mathit \gamma}} {{\mathit \gamma}}}$ defined by $\mathit L~=~−\mathit G_{{{\mathit A}} {{\mathit \gamma}} {{\mathit \gamma}}}\phi _{\mathit A}\mathbf {E}\mathbf {\cdot{}}\mathbf {B}$. For scalars ${{\mathit S}^{0}}$ the limit is on the coupling constant in $\mathit L~=~\mathit G_{{{\mathit S}} {{\mathit \gamma}} {{\mathit \gamma}}}\phi _{S}(\mathbf {E}{}^{2}−\mathbf {B}{}^{2}$). The relation between $\mathit G_{{{\mathit A}} {{\mathit \gamma}} {{\mathit \gamma}}}$ and ${\mathit m}_{{{\mathit A}^{0}}}$ is not used unless stated otherwise, i.e., many of these bounds apply to low-mass axion-like particles (ALPs), not to QCD axions.

VALUE (GeV${}^{-1}$) CL% DOCUMENT ID TECN  COMMENT • • We do not use the following data for averages, fits, limits, etc. • • $<2.2 \times 10^{-4}$ 95 1 ABLIKIM 2024 AD BES3 ${\mathit m}_{{{\mathit A}^{0}}}$ = $0.18 - 2.85$ GeV $<5.8 \times 10^{-11}$ 95 2 ALTENMULLER 2024 CAST ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ 0.02 eV $<7 \times 10^{-12}$ 95 3 DEV 2024 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $0.01 - 100$ MeV $<5 \times 10^{-11}$ 4 DIAMOND 2024 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $1 - 300$ MeV $<1.38 \times 10^{-10}$ 95 5 FORDHAM 2024 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ keV $<2 \times 10^{-11}$ 95 6 GAO 2024 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $10^{-9} - 10^{-7}$ eV $<2 \times 10^{-11}$ 95 7 GAO 2024 A ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $10^{-10} - 2 \times 10^{-7}$ eV $<4 \times 10^{-9}$ 95 8 GUO 2024 DM ${\mathit m}_{{{\mathit A}^{0}}}$ = $4.15 - 6.06$ or $8.3 - 12.2$ $\mu $eV $<1.5 \times 10^{-11}$ 95 9 LI 2024 A ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $5 \times 10^{-10} - 1 \times 10^{-7}$ eV $<7.5 \times 10^{-11}$ 95 10 LI 2024 B ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $2 \times 10^{-8} - 2 \times 10^{-6}$ eV $<4 \times 10^{-12}$ 99 11 LI 2024 D ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $10^{-9} - 10^{-8}$ eV $<3 \times 10^{-12}$ 95 12 MANZARI 2024 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ 0.01 eV $<3 \times 10^{-11}$ 95 13 PANT 2024 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $0.3 - 1$ neV $<8 \times 10^{-4}$ 95 14 PYBUS 2024 GLUX ${\mathit m}_{{{\mathit A}^{0}}}$ = $200 - 450$ MeV $<3 \times 10^{-11}$ 95 15 RAVENSBURG 2024 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ 0.5 MeV $<3 \times 10^{-13}$ 95 16 TODARELLO 2024 DM ${\mathit m}_{{{\mathit A}^{0}}}$ = $2.7 - 5.3$ eV $<1.1 \times 10^{-12}$ 17 WANG 2024 A DM ${\mathit m}_{{{\mathit A}^{0}}}$ = $2.8 - 12.4$ eV $<5.5 \times 10^{-11}$ 95 18 BATTYE 2023 DM ${\mathit m}_{{{\mathit A}^{0}}}$ = $3.9 - 4.7$ $\mu $eV $<2 \times 10^{-13}$ 95 19 BEAUFORT 2023 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $3 - 38$ keV $<2 \times 10^{-12}$ 99 20 BERNAL 2023 COSM ${\mathit m}_{{{\mathit A}^{0}}}$ = $8 - 25$ eV $<4 \times 10^{-14}$ 99 21 CAPOZZI 2023 COSM ${\mathit m}_{{{\mathit A}^{0}}}$ = $30 - 800$ eV $<1.3 \times 10^{-7}$ 95 22 CAPOZZI 2023 A DUMP ${\mathit m}_{{{\mathit A}^{0}}}$ = $10^{3} - 2 \times 10^{8}$ eV $<5 \times 10^{-12}$ 95 23 DAVIES 2023 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $5 - 200$ neV $<1.7 \times 10^{-10}$ 24 DIAMOND 2023 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $2 - 56$ MeV $<6 \times 10^{-29}$ 95 25 FILZINGER 2023 Dilaton-like dark matter $<4.5 \times 10^{-12}$ 95 26 HOOF 2023 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $4 \times 10^{-10}$ eV $<3 \times 10^{-12}$ 95 27 HOOF 2023 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = 60 MeV $<2.7 \times 10^{-11}$ 99.7 28 JACOBSEN 2023 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ $3 \times 10^{-7}$ eV $<2 \times 10^{-11}$ 99 29 LI 2023 H ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $1 - 100$ neV $<3.0 \times 10^{-12}$ 95 30 NOORDHUIS 2023 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $10^{-9} - 10^{-5}$ eV $<5 \times 10^{-11}$ 95 31 PANT 2023 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $0.1 - 1000$ neV $<5 \times 10^{-26}$ 95 32 SHERRILL 2023 DM Dilaton-like dark matter $<8 \times 10^{-9}$ 95 33 SULAI 2023 DM ${\mathit m}_{{{\mathit A}^{0}}}$ = $0.25 - 2 \times 10^{-14}$ eV $<7.9 \times 10^{-12}$ 34 YAO 2023 ASTR ${\mathit m}_{{{\mathit A}^{0}}}{ {}\lesssim{} }$ $10^{-13}$ eV $<3.8 \times 10^{-22}$ 95 35 ZHANG 2023 A Dilaton-like dark matter $<5 \times 10^{-10}$ 90 36 APRILE 2022 B XENT Solar axions $<1.45 \times 10^{-9}$ 95 37 ARNQUIST 2022 MAJD ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ 100 eV $<7 \times 10^{-11}$ 95 38 ARZA 2022 DM ${\mathit m}_{{{\mathit A}^{0}}}=0.2 - 7 \times 10^{-17}$eV $3 - 6 \times 10^{-11}$ 95 39 BERNAL 2022 COSM ${\mathit m}_{{{\mathit A}^{0}}}$ = $8 - 20$ eV $<3.76 \times 10^{-11}$ 95 40 CALORE 2022 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ $10^{-11}$ eV $<2 \times 10^{-10}$ 41 CAPUTO 2022 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $1 - 500$ MeV $<3 \times 10^{-14}$ 95 42 CASTILLO 2022 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $3 \times 10^{-23}$ eV $<6 \times 10^{-12}$ 90 43 DEROCCO 2022 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $5 - 30$ keV $<5.4 \times 10^{-12}$ 95 44 DESSERT 2022 A ASTR ${\mathit m}_{{{\mathit A}^{0}}}{ {}\lesssim{} }$ $3 \times 10^{-7}$ eV $<2.1 \times 10^{-11}$ 95 45 ECKNER 2022 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ $2 \times 10^{-7}$ eV $<1 \times 10^{-11}$ 95 46 FOSTER 2022 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $16.5 - 32.5$ $\mu $eV $<1.14 \times 10^{-5}$ 95 47 KIRITA 2022 SAPH ${\mathit m}_{{{\mathit A}^{0}}}$ = $0.5 - 500$ meV $<2 \times 10^{-16}$ 48 LANGHOFF 2022 COSM ${\mathit m}_{{{\mathit A}^{0}}}$ = $0.1 - 3 \times 10^{4}$ keV $<6 \times 10^{-12}$ 95 49 LI 2022 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $0.2 - 20$ neV $<1.3 \times 10^{-11}$ 95 50 LI 2022 C ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $8 - 200$ neV $<1 \times 10^{-5}$ 51 LUCENTE 2022 ASTR ${\mathit m}_{{{\mathit A}^{0}}}{ {}\lesssim{} }$ 0.4 MeV $<9.2 \times 10^{-11}$ 95 52 BASU 2021 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $3.6 \times 10^{-21}$ eV $<1.8 \times 10^{-10}$ 95 53 BI 2021 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $2 - 6 \times 10^{-7}$ eV $<1.6 \times 10^{-10}$ 95 54 DOLAN 2021 A ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $1 - 570$ keV $<5 \times 10^{-11}$ 95 55 GUO 2021 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $8 - 23$ neV $<1.2 \times 10^{-4}$ 95 56 HOMMA 2021 SAPH ${\mathit m}_{{{\mathit A}^{0}}}$ = $0.4 - 600$ meV $<1.2 \times 10^{-11}$ 95 57 LI 2021 B ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $0.5 - 500$ neV 58 LLOYD 2021 ASTR Magnetars $<1 \times 10^{-13}$ 95 59 REGIS 2021 DM ${\mathit m}_{{{\mathit A}^{0}}}$ = $2.7 - 5.3$ eV $<1.8 \times 10^{-11}$ 95 60 XIAO 2021 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ $3.5 \times 10^{-11}$eV $<7 \times 10^{-4}$ 95 61 ABUDINEN 2020 BEL2 ${\mathit m}_{{{\mathit A}^{0}}}$ = $0.2 - 1$ GeV $<2 \times 10^{-4}$ 90 62 BANERJEE 2020 A NA64 ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ 55 MeV $<1.0 \times 10^{-11}$ 95 63 BUEHLER 2020 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ 3 neV $<5 \times 10^{-10}$ 64 CALORE 2020 ASTR ${\mathit m}_{{{\mathit A}^{0}}}{ {}\lesssim{} }$ $10^{-11}$ eV 65 CARENZA 2020 ASTR Globular clusters $2 - 4 \times 10^{-10}$ 95 66 DENT 2020 A ASTR Solar axions 67 DEPTA 2020 COSM Axion-like particles $<3.6 \times 10^{-12}$ 95 68 DESSERT 2020 A ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ $5 \times 10^{-11}$ eV 69 ESTEBAN 2020 ANIT Axion-like particles $4 - 6 \times 10^{-10}$ 90 70 GAO 2020 ASTR Solar axions $<2.8 \times 10^{-11}$ 95 71 KOROCHKIN 2020 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = 25 eV $\text{none } 6.0 \times 10^{-9} - 1.3 \times 10^{-5}$ 72 LUCENTE 2020 A ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ 270 MeV $<2.6 \times 10^{-11}$ 95 73 MEYER 2020 FLAT ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ $3 \times 10^{-10}$ eV $<8.4 \times 10^{-8}$ 99 74 YAMAMOTO 2020 COSM ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ $4 \times 10^{-6}$ eV $<1 \times 10^{-3}$ 95 75 ALONI 2019 PRMX ${\mathit m}_{{{\mathit A}^{0}}}$ = 0.16 GeV $<1.4 \times 10^{-14}$ 95 76 CAPUTO 2019 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $5 \times 10^{-24}$ eV $<9.6 \times 10^{-14}$ 95 77 FEDDERKE 2019 CMB ${\mathit m}_{{{\mathit A}^{0}}}$ = $10^{-22}$ eV $<7 \times 10^{-13}$ 95 78 IVANOV 2019 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $5 \times 10^{-23}$ eV $<4 \times 10^{-11}$ 95 79 LIANG 2019 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $1.2 \times 10^{-7}$ eV 80 FORTIN 2018 ASTR Axion-like particles $<3 \times 10^{-12}$ 81 JAECKEL 2018 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $30 - 100$ MeV $<5.0 \times 10^{-3}$ 90 82 YAMAJI 2018 LSW ${\mathit m}_{{{\mathit A}^{0}}}$ = $46 - 1020$ eV $<1 \times 10^{-11}$ 99.9 83 ZHANG 2018 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $0.6 - 4$ neV 84 ADE 2017 CMB Axion-like particles $<6.6 \times 10^{-11}$ 95 85 ANASTASSOPOUL.. 2017 CAST ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ 0.02 eV 86 DOLAN 2017 RVUE Axion-like particles $<2.51 \times 10^{-4}$ 95 87 INADA 2017 LSW ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ 0.1 eV $>1.5 \times 10^{-11}$ 95 88 KOHRI 2017 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $0.7 - 50$ neV $<2.6 \times 10^{-12}$ 95 89 MARSH 2017 ASTR ${\mathit m}_{{{\mathit A}^{0}}}{}\leq{}$ $10^{-13}$ eV $<6 \times 10^{-13}$ 90 TIWARI 2017 COSM ${\mathit m}_{{{\mathit A}^{0}}}{}\leq{}$ $10^{-15}$ eV $<5 \times 10^{-12}$ 95 91 AJELLO 2016 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $0.5 - 5$ neV $<1.2 \times 10^{-7}$ 95 92 DELLA-VALLE 2016 LASR ${\mathit m}_{{{\mathit A}^{0}}}$ = 1.3 meV $<7.2 \times 10^{-8}$ 95 93 DELLA-VALLE 2016 LASR ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ 0.5 meV $<8 \times 10^{-4}$ 94 JAECKEL 2016 ALPS ${\mathit m}_{{{\mathit A}^{0}}}$ = $0.1 - 100$ GeV $<6 \times 10^{-21}$ 95 LEEFER 2016 ${\mathit m}_{{{\mathit S}^{0}}}$ $<$ $10^{-18}$ eV 96 ANASTASSOPOUL.. 2015 CAST Chameleons $<1.47 \times 10^{-10}$ 95 97 ARIK 2015 CAST ${\mathit m}_{{{\mathit A}^{0}}}$ = $0.39 - 0.42$ eV $<3.5 \times 10^{-8}$ 95 98 BALLOU 2015 LSW ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ $2 \times 10^{-4}$ eV 99 BRAX 2015 ASTR ${\mathit m}_{{{\mathit S}^{0}}}$ $<$ $4 \times 10^{-12}$ eV $<5.42 \times 10^{-4}$ 95 100 HASEBE 2015 LASR ${\mathit m}_{{{\mathit A}^{0}}}$ = 0.15 eV 101 MILLEA 2015 COSM Axion-like particles 102 VANTILBURG 2015 Dilaton-like dark matter $<4.1 \times 10^{-10}$ 99.7 103 VINYOLES 2015 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ = $0.6 - 185$ eV $<3.3 \times 10^{-10}$ 95 104 ARIK 2014 CAST ${\mathit m}_{{{\mathit A}^{0}}}$ = $0.64 - 1.17$ eV $<6.6 \times 10^{-11}$ 95 105 AYALA 2014 ASTR Globular clusters $<1.4 \times 10^{-7}$ 95 106 DELLA-VALLE 2014 LASR ${\mathit m}_{{{\mathit A}^{0}}}$ = 1 meV 107 EJLLI 2014 COSM ${\mathit m}_{{{\mathit A}^{0}}}$ = $2.66 - 48.8$ $\mu $eV $<8 \times 10^{-8}$ 95 108 PUGNAT 2014 LSW ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ 0.3 meV $<1 \times 10^{-11}$ 109 REESMAN 2014 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ $1 \times 10^{-10}$ eV $<2.1 \times 10^{-11}$ 95 110 ABRAMOWSKI 2013 A IACT ${\mathit m}_{{{\mathit A}^{0}}}$ = $15 - 60$ neV $<2.15 \times 10^{-9}$ 95 111 ARMENGAUD 2013 EDEL ${\mathit m}_{{{\mathit A}^{0}}}<$ 200 eV $<4.5 \times 10^{-8}$ 95 112 BETZ 2013 LSW ${\mathit m}_{{{\mathit A}^{0}}}$ = $7.2 \times 10^{-6}$ eV $<8 \times 10^{-11}$ 113 FRIEDLAND 2013 ASTR Red giants $>2 \times 10^{-11}$ 114 MEYER 2013 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ $1 \times 10^{-7}$ eV $<8.3 \times 10^{-12}$ 95 115 WOUTERS 2013 ASTR ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ $7 \times 10^{-12}$ eV 116 CADAMURO 2012 COSM Axion-like particles $<2.5 \times 10^{-13}$ 95 117 PAYEZ 2012 ASTR ${\mathit m}_{{{\mathit A}^{0}}}<4.2 \times 10^{-14}$ eV $<2.3 \times 10^{-10}$ 95 118 ARIK 2011 CAST ${\mathit m}_{{{\mathit A}^{0}}}$ = $0.39 - 0.64$ eV $<6.5 \times 10^{-8}$ 95 119 EHRET 2010 ALPS ${\mathit m}_{{{\mathit A}^{0}}}<$ 0.7 meV $<2.4 \times 10^{-9}$ 95 120 AHMED 2009 A CDMS ${\mathit m}_{{{\mathit A}^{0}}}<$ 100 eV $<1.2 - 2.8 \times 10^{-10}$ 95 121 ARIK 2009 CAST ${\mathit m}_{{{\mathit A}^{0}}}$ = $0.02 - 0.39$ eV 122 CHOU 2009 Chameleons $<7 \times 10^{-10}$ 123 GONDOLO 2009 ASTR ${\mathit m}_{{{\mathit A}^{0}}}<$ few keV $<1.3 \times 10^{-6}$ 95 124 AFANASEV 2008 ${\mathit m}_{{{\mathit S}^{0}}}<$ 1 meV $<3.5 \times 10^{-7}$ 99.7 125 CHOU 2008 ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ 0.5 meV $<1.1 \times 10^{-6}$ 99.7 126 FOUCHE 2008 ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ 1 meV $<5.6 - 13.4 \times 10^{-10}$ 95 127 INOUE 2008 ${\mathit m}_{{{\mathit A}^{0}}}$ = $0.84 - 1.00$ eV $<5 \times 10^{-7}$ 128 ZAVATTINI 2008 ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ 1 meV $<8.8 \times 10^{-11}$ 95 129 ANDRIAMONJE 2007 CAST ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ 0.02 eV $<1.25 \times 10^{-6}$ 95 130 ROBILLIARD 2007 ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ 1 meV $2 - 5 \times 10^{-6}$ 131 ZAVATTINI 2006 ${\mathit m}_{{{\mathit A}^{0}}}$ = $1 - 1.5$ meV $<1.1 \times 10^{-9}$ 95 132 INOUE 2002 ${\mathit m}_{{{\mathit A}^{0}}}$= $0.05 - 0.27$ eV $<2.78 \times 10^{-9}$ 95 133 MORALES 2002 B ${\mathit m}_{{{\mathit A}^{0}}}<$1 keV $<1.7 \times 10^{-9}$ 90 134 BERNABEI 2001 B ${\mathit m}_{{{\mathit A}^{0}}}<$100 eV $<1.5 \times 10^{-4}$ 90 135 ASTIER 2000 B NOMD ${\mathit m}_{{{\mathit A}^{0}}}<$40 eV 136 MASSO 2000 THEO induced ${{\mathit \gamma}}$ coupling $<2.7 \times 10^{-9}$ 95 137 AVIGNONE 1998 SLAX ${\mathit m}_{{{\mathit A}^{0}}}<1$ keV $<6.0 \times 10^{-10}$ 95 138 MORIYAMA 1998 ${\mathit m}_{{{\mathit A}^{0}}}<0.03$ eV $<3.6 \times 10^{-7}$ 95 139 CAMERON 1993 ${\mathit m}_{{{\mathit A}^{0}}}<10^{-3}$ eV, optical rotation $<6.7 \times 10^{-7}$ 95 140 CAMERON 1993 ${\mathit m}_{{{\mathit A}^{0}}}<10^{-3}$ eV, photon regeneration $<3.6 \times 10^{-9}$ 99.7 141 LAZARUS 1992 ${\mathit m}_{{{\mathit A}^{0}}}<0.03$ eV $<7.7 \times 10^{-9}$ 99.7 141 LAZARUS 1992 ${\mathit m}_{{{\mathit A}^{0}}}$= eV $<7.7 \times 10^{-7}$ 99 142 RUOSO 1992 ${\mathit m}_{{{\mathit A}^{0}}}<10^{-3}$ eV $<2.5 \times 10^{-6}$ 143 SEMERTZIDIS 1990 ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ $7 \times 10^{-4}$ eV 1  ABLIKIM 2024AD constrain the axion-photon coupling through radiative ${{\mathit J / \psi}}$ decays in the BESIII detector at the Beijing electron-positron collider. See their Fig. 5 for mass-dependent limits. 2  ALTENMULLER 2024 report an extended search for solar axions using the CAST experiment. The experiment employed a new xenon-based microMEGAS detector - a pathfinder for the future International Axion Observatory (IAXO). This limit improves upon ANASTASSOPOULOS 2017. See Fig. 4 for mass-dependent limits. 3  DEV 2024 use Fermi gamma-ray observations of the neutron star merger GW170817 to constrain the production and subsequent decay of high-mass axion-like particles. Constraint extends diagonally in mass-coupling space, reaching $7 \times 10^{-12}$ GeV${}^{-1}$ at 100 MeV. See Fig. 4 for mass-dependent limits. 4  DIAMOND 2024 use multi-messenger observations of the neutron star merger GW170817 to constrain the production and radiative decay of axions in the event. Limits shown in their Fig. 3 extend diagonally in mass-coupling space. 5  FORDHAM 2024 use asteroseismology observations of a solar-like star, KIC 6933899, to constrain axion emission from its interior via the photon coupling. Bound applies to all axion masses up to around the core temperature of the star $\sim{}$keV. 6  GAO 2024 constrain ALP-photon oscillations via their imprint on the gamma-ray spectrum of the blazar Mrk 421, as observed by MAGIC and Fermi-LAT. See their Fig. 5 for mass-dependent limits. 7  GAO 2024A constrain ALP-photon oscillations using the high-energy gamma-ray spectrum observed by LHAASO of the brightest gamma-ray burst so far detected, GRB 221009A. See their Fig. 5 for mass-dependent limits. The strength of the limit depends on the magnetic field of the host galaxy. 8  GUO 2024 search for axion dark matter decaying or converting into photons in the Coma Berenices dwarf galaxy using the radio telescope FAST. The quoted limit is for the case of axions decaying, including stimulated emission. See their Fig. 2 for mass-dependent limits. 9  LI 2024A constrain the imprint of ALP-photon oscillations on the TeV gamma-ray spectrum of the BL Lac blazar 1ES 1215+303 using VERITAS and Fermi-LAT data. See their Fig. 4 for mass-dependent limits. 10  LI 2024B constrain the imprint of ALP-photon oscillations on the very-high-energy gamma-ray spectrum of various galactic sources detected by the LHAASO air-shower array. Best limits are obtained from the Crab Nebula after combining several observations from different gamma-ray observatories in addition to LHAASO. See their Fig. 5 for mass-dependent limits. 11  LI 2024D search for evidence of axion-photon oscillations imprinted on the gamma-ray spectrum of the nearby BL Lac blazar Markarian 421. They set upper limits using data from Fermi-LAT and HAWC. The quoted limit applies for ${\mathit m}_{{{\mathit A}^{0}}}$ $\simeq{}$ $3 \times 10^{-9}$ eV. See their Fig. 3 for mass-dependent limits. 12  MANZARI 2024 search for evidence of axions produced in SN1987A converting into gamma-rays that would have been detectable by the Solar Maximum Mission. This analysis improves upon previous studies of axion-photon conversion after SN1987A (e.g. HOOF 2023) by including the magnetic field of the progenitor star. Quoted limit applies for masses below 0.1 neV and rises towards larger masses. See their Fig. 1 for mass-dependent limits. 13  PANT 2024 searches for the imprint of axion-photon oscillations in the very-high-energy gamma-ray spectrum of the quasar QSO B1420+326 observed by the MAGIC telescope. Three small disconnected regions of mass-coupling parameter space below 1 neV are ruled out. See Fig. 4 for the limits. 14  PYBUS 2024 report results from the GlueX detector, which has searched for the two-photon decay of heavy axions produced through the nuclear Primakoff effect due to a beam of photons incident on a Carbon target. See their Fig. 8 for mass-dependent limits. 15  RAVENSBURG 2024 search for heavy axions decaying to two photons using the recent nearby type-II supernova SN 2023ixf. Constraint extends diagonally downwards in mass-coupling space, see their Fig. 2 for full limits. Quoted limit is the most constraining point for the most conservative choices for supernova parameters. 16  TODARELLO 2024 search for axions decaying to two photons in the halos of Milky Way dwarf galaxies observed in the MUSE-Faint survey. This study improves upon an earlier one presented in REGIS 2021. See their Fig. 5 for compiled mass-dependent limits. 17  WANG 2024A search for axions decaying into two photons assuming that they make up the dark matter halos of galaxies. They use data from the Dark Energy Spectroscopic Instrument, searching for the axion decay line in optical wavelengths with their Bright Galaxy and Luminous Red Galaxy samples. See their Fig. 8 for mass-dependent limits on the axion to photon decay rate. Their constraint is quoted as a 5$\sigma $ detection limit. 18  BATTYE 2023 look for dark-matter axions falling into pulsar magnetospheres and converting into narrow radio lines. Unlike the earlier FOSTER 2022 they search for evidence of conversion in the time-domain signal of a single pulsar, using 1 hour of MeerKAT data on the pulsar PSR J2144-3933. The quoted limit applies to an assumed magnetic field of $2 \times 10^{12}$ G and a dark matter density of 0.45 GeV/cm${}^{3}$. 19  BEAUFORT 2023 extends DEROCCO 2022 who searched for the X-ray decay of axions that build up in the gravitational well of the Sun over its lifetime, the 'solar basin'. They use data from NuSTAR and SphinX telescopes and extends the previous study by accounting for the axion production via photon coalescence. 20  BERNAL 2023 use gamma-ray data from 739 blazars observed by FermiLAT and 38 blazars by Cherenkov observatories. They estimate optical depth, subtract the astrophysical component, and attribute the residual to axion two-photon decay. The quoted limit is for ${\mathit m}_{{{\mathit A}^{0}}}$ $\simeq{}$ 25 eV. See their Fig. 3 for the mass-dependent limits. 21  CAPOZZI 2023 use Planck CMB and Lyman-$\alpha $ observations to set limits on early energy injection by decaying dark matter axions that would affect CMB anisotropies and the reionisation history of the Universe. The quoted limit applies to ${\mathit m}_{{{\mathit A}^{0}}}$ = 100 eV and the reionization model of Fauchere-Giguere. See Fig. 4 for mass-dependent constraints from different reionization models. 22  CAPOZZI 2023A search for axions produced in electromagnetic showers in proton beam dumps and fixed target experiments. In this case, they reinterpret MiniBoone data. Quoted limit applies at 100 MeV but the limit does not extend to arbitrarily large couplings. See Fig. 7 for mass-dependent limits. 23  DAVIES 2023 is analogous to AJELLO 2016, and use the Fermi-LAT data from three quasars (3C454.3, CTA 102, and 3C279), considering the blazer jets as the regions where the axion-photon oscillations occur. See Fig. 8 for the mass-dependent limits. 24  DIAMOND 2023 demonstrate that a window of decaying 10-MeV-mass ALP parameter space previously thought to be excluded by the lack of gamma-ray emission from the SN 1987A explosion is actually unconstrained because of the formation of a fireball that would prevent decay photons from escaping. They nevertheless re-exclude this window by considering the non-detection of the sub-MeV emission by the Pioneer Venus Orbiter. The quoted limit is at ${\mathit m}_{{{\mathit A}^{0}}}$ = 56 MeV. See their Fig. 2 for mass-dependent limits. 25  FILZINGER 2023 searched for oscillations in the fine structure constant induced by dilaton-like dark matter by measuring the frequency ratio between the E3 and E2 transitions of ${}^{171}\mathrm {Yb}{}^{+}$. They assume the local dark matter density ${{\mathit \rho}_{{{S}}}}$ = 0.4 GeV/cm${}^{3}$. The quoted limit is set at ${\mathit m}_{{{\mathit S}^{0}}}$ $\simeq{}$ $4 \times 10^{-23}$ eV. See their Fig. 4 for the limits over ${\mathit m}_{{{\mathit S}^{0}}}$ = $1 \times 10^{-24} - 1 \times 10^{-17}$ eV. 26  HOOF 2023 consider axions emitted from SN1987A converting to gamma rays in Galactic magnetic fields, using temporal information of the Solar Maximum Mission data. They set a limit $\mathit G_{{{\mathit A}} {{\mathit \gamma}} {{\mathit \gamma}}}{ {}\lesssim{} }$ $5 \times 10^{-12}$ for masses ${\mathit m}_{{{\mathit A}^{0}}}{ {}\lesssim{} }$ $2 \times 10^{-10}$ eV. See left panel in Fig. 3 for mass-dependent limits. 27  HOOF 2023 look for gamma rays resulting from the decay of axions produced from SN1987A, using the Solar Maximum Mission data. See right panel in Fig. 3 for mass-dependent limits. 28  JACOBSEN 2023 search for the imprints of axion-photon mixing on the TeV spectra of several blazars using data from the HAWC air shower detector. 29  LI 2023H look for gamma-ray spectral irregularities induced by axion-photon oscillations from AGN VER J0521+211, using the Fermi-LAT and VERITAS data. See their Fig. 4 for mass-dependent limits. 30  NOORDHUIS 2023 places strong constraints on the axion-photon coupling over a broad mass window using the fact that the polar cap regions of pulsars can generate a population of axions, which would then convert into an observable outgoing radio flux in the presence of the neutron star's B-field. They search for this signal in 27 pulsars and set mass-dependent limits shown in their Fig. 2. 31  PANT 2023 study the effect of axion-photon oscillations on the gamma-ray spectrum from the extragalactic neutrino source, TXS 0506+056. The quoted limit is at ${\mathit m}_{{{\mathit A}^{0}}}$ $\simeq{}$ $2.7 \times 10^{-7}$ eV. See their Fig. 2 for mass-dependent limits. 32  SHERRILL 2023 search for scalar dilaton-like dark matter via oscillations in the fundamental constants. Their most competitive constraint is on the scalar photon coupling (Fig. 6, upper panel) that affects the fine-structure constant, which they extract using an optical-to-optical clock comparison between ${}^{171}\mathrm {Yb}{}^{+}$ and ${}^{87}\mathrm {Sr}$. Quoted limit applies at the smallest mass in their search window for this case of $10^{-20}$ eV. 33  SULAI 2023 looked for ultralight axion dark matter using the ``Earth as a transducer" concept over the 0.5 to 5 Hz frequency range. They situate several magnetometers at magnetically quiet places and search for spatially-correlated magnetic field patterns induced by axion dark matter interacting in the effective cavity formed between the Earth's surface and the ionosphere. See their Fig. 12 for mass-dependent limits in context. This limit extends to higher-frequencies than their previous limit using archival geomagnetic field data collected by the SuperMAG collaboration, see ARZA 2022 34  YAO 2023 study an optical circular polarization in blazers induced by the axion-photon mixing. The quoted limit assumes the transverse magnetic field at the jet's emission site, with $\mathit B_{T}$ = 1 G, and this limit inversely scales with $\mathit B_{T}$. See their Fig. 3 for the limits' dependence on $\mathit B_{T}$ and electron density. 35  ZHANG 2023A searched for oscillations in the fine structure constant induced by dilaton-like dark matter by measuring the frequencies of a hyperfine-structure transition in ${}^{87}\mathrm {Rb}$ and an electronic transition in ${}^{164}\mathrm {Dy}$, and by comparing them with that of a quartz oscillator. They assume the local dark matter density ${{\mathit \rho}_{{{S}}}}$ $\simeq{}$ 0.4 GeV/cm${}^{3}$. The quoted limit is set at ${\mathit m}_{{{\mathit S}^{0}}}$ $\simeq{}$ $1 \times 10^{-17}$ eV. See their Fig. 3 for the limits over ${\mathit m}_{{{\mathit S}^{0}}}$ = $1 \times 10^{-17} - 8.3 \times 10^{-13}$ eV. 36  APRILE 2022B is an update of APRILE 2020 based on a similar solar axion modeling to DENT 2020A and GAO 2020. They exclude the XENON1T excess found in APRILE 2020. The quoted limit holds for small $\mathit g_{{{\mathit A}} {{\mathit e}} {{\mathit e}}}$. See Fig. 6 for correlation between $\mathit G_{{{\mathit A}} {{\mathit \gamma}} {{\mathit \gamma}}}$ and $\mathit g_{{{\mathit A}} {{\mathit e}} {{\mathit e}}}$. 37  ARNQUIST 2022 is analogous to AVIGNONE 1998, and supersedes ANASTASSOPOULOS 2017 for ${\mathit m}_{{{\mathit A}^{0}}}{ {}\gtrsim{} }$ 1.2 eV. 38  ARZA 2022 search for low-mass axions as dark matter using the Earth as a transducer for axion-photon conversion. The concept works because the region between the Earth and the ionosphere forms an insulating cavity that parametrically enhances the axion signal by the radius of the Earth. The result is an oscillating and spatially correlated magnetic field induced via the interaction between axion dark matter and the geomagnetic field, which they searched for using archival magnetometer field data over 20 years compiled by the SuperMAG collaboration. Quoted limit applies for masses $3 - 4 \times 10^{-17}$ eV, see Fig. 1 for mass-dependent limits. 39  BERNAL 2022 explored the possibility that the excess in the cosmic optical background measured by New Horizonss Long Range Reconnaisance Imager was due to axion dark matter decaying into monoenergetic photons. See their Fig. 2 for the axion-photon coupling to explain the excess. 40  CALORE 2022 update CALORE 2020 by evaluating axion fluxes from progenitors of various masses and performing a template-based analysis using 12 years of Fermi-LAT data in the energy range from 50 MeV to 500 GeV. See their Fig. 10 for mass-dependent limits. 41  CAPUTO 2022 study the effect of energy deposition by radiative decay of axions produced via the Primakoff process and photon coalescence in the supernova core, and set the limits by the radiative energy deposition $<$ $10^{50}$ erg and progenitor radius = $5 \times 10^{13}$ cm. The quoted limit is at ${\mathit m}_{{{\mathit A}^{0}}}$ = 150 MeV. See their Fig. 2 for mass-dependent limits. 42  CASTILLO 2022 update CAPUTO 2019 using the polarization measurements of the Crab Pulsar by the QUIJOTE MFI instrument and 20 Galactic pulsars from the PPTA project. See their Table 1 for the assumed local axion energy density ${{\mathit \rho}_{{{A}}}}$ for each pulsar and their Fig. 7 for the mass-dependent limits in the range of $3 \times 10^{-23}$ eV ${}\leq{}{\mathit m}_{{{\mathit A}^{0}}}{}\leq{}$ $10^{-19}$ eV. 43  DEROCCO 2022 uses the NuSTAR data to search for monochromatic X-ray lines produced by the decay of solar axions trapped on bound orbits. The quoted limit applies to ${\mathit m}_{{{\mathit A}^{0}}}$ $\simeq{}$ 9 keV. They also derive limits in the plane of $\mathit g_{{{\mathit A}} {{\mathit e}} {{\mathit e}}}$ and $\mathit G_{{{\mathit A}} {{\mathit \gamma}} {{\mathit \gamma}}}$. See their Figs. 2 and 4 for mass-dependent limits. 44  DESSERT 2022A look for an axion-induced linear polarization using data from multiple magnetic white dwarf stars. See their Figs. 1 and 8 for the mass-dependent limits. 45  ECKNER 2022 set limits by using sub-PeV diffuse gamma-ray data from HAWC and Tibet AS${{\mathit \gamma}}$ by assuming that gamma rays produced simultaneously with high-energy neutrinos from extragalactic sources suggested by IceCube are converted to axions in the magnetic field at the source and reconverted to gamma rays in the Galactic magnetic field. See their Fig. 4 for mass-dependent limits. 46  FOSTER 2022 is an update of FOSTER 2020 in the list of limits on relic invisible axions. They search for axion-photon transitions generated by neutron stars in the Galactic center region. They use improved population models of the Galactic center neutron stars and a Navarro-Frenk-White (NFW) model of the galactic dark matter distribution. The quoted limit applies to ${\mathit m}_{{{\mathit A}^{0}}}$ $\simeq{}$ $17 - 25$ $\mu $eV. See their Fig. 1 for mass-dependent limits. 47  KIRITA 2022 update HOMMA 2021 by increasing the laser energy and developing a background discrimination method using the beam cross-section dependence of the background originated from optical elements. The quoted limits applies to ${\mathit m}_{{{\mathit A}^{0}}}$ = 0.18 eV. See their Fig. 11 for mass-dependent limits. 48  LANGHOFF 2022 set limits by considering the freeze-in production of axions coupled only to photons. The quoted limit applies to ${\mathit m}_{{{\mathit A}^{0}}}$ = 2 MeV for the reheating temperature equal to 5 MeV. See their Fig. 1 for mass-dependent limits. 49  LI 2022 is analogous to LI 2021B, and use the spectra of the blazar FSRQ 4C+21.35 measured by MAGIC, VERITAS, and Fermi-LAT. The quoted limit applies to ${\mathit m}_{{{\mathit A}^{0}}}$ $\simeq{}$ $8 \times 10^{-10}$ eV. See their Fig. 1 for mass-dependent limits. 50  LI 2022C is analogous to LI 2021B, and use the spectra of the blazars Mrk 421 and PG 1553+113 measured by MAGIC and Fermi-LAT. The quoted limit applies to ${\mathit m}_{{{\mathit A}^{0}}}$ $\simeq{}$ $1 \times 10^{-8}$ eV. See their Fig. 4 for mass-dependent limits. 51  LUCENTE 2022 developed a method to correctly incorporate the effects of axions decaying into photons inside the core of horizontal-branch stars. They update CARENZA 2020 by evaluating axion energy transfer in the range of axion mean free path where the diffusive energy transport and free streaming approximations are not applicable. See their Fig. 1 for the limits. 52  BASU 2021 searched for birefringence induced by axion dark matter using multiple images of the polarized source in the strongly gravitationally lensed system CLASS B1152+199. They assume the axion makes up all dark matter, and used the axion density in the emitting region, ${{\mathit \rho}_{{{A}}}}$ = 20 GeV/cm${}^{3}$. Limits between $9.2 \times 10^{-11} - 7.7 \times 10^{-8}$ GeV${}^{-1}$ are obtained for ${\mathit m}_{{{\mathit A}^{0}}}$ = $3.6 \times 10^{-21} - 4.6 \times 10^{-18}$eV. See their Fig. 2 for mass-dependent limits. 53  BI 2021 look for the gamma-ray spectral distortions induced by axion-photon oscillations in the presence of the Galactic magnetic field, using the measurements of sub-PeV gamma-rays from the Crab Nebula by the Tibet AS${{\mathit \gamma}}$ and HAWC experiments, together with MAGIC and HEGRA gamma-ray data. See their Fig. 3 for mass-dependent limits. 54  DOLAN 2021A study the effect of axion production on the evolution of asymptotic giant branch stars, and use the white-dwarf initial-final mass relation to set the limits. See their Fig. 1 for mass-dependent limits. 55  GUO 2021 is analogous to AJELLO 2016, and use the Fermi-LAT and H.E.S.S. II measurements of PG 1553+113 and PKS 2155-304. See their Fig. 6 for mass-dependent limits. 56  HOMMA 2021 look for the production of axion resonance states and their subsequent stimulated decays by combining linearly polarized creation laser pulses and circularly polarized inducing laser pulses. The quoted limit is at ${\mathit m}_{{{\mathit A}^{0}}}$ $\simeq{}$ 0.178 eV. See their Fig. 14 for mass-dependent limits. 57  LI 2021B is analogous to AJELLO 2016, and use the spectra of the blazar Mrk 421 measured by ARGO-YBJ and Fermi-LAT. They consider ALP-photon mixing in the magnetic fields of both the blazar jet and the Galaxy. The quoted limit applies to ${\mathit m}_{{{\mathit A}^{0}}}$ $\simeq{}$ $1 \times 10^{-9}$ eV. See their Fig. 5 for mass-dependent limits. 58  LLOYD 2021 is analogous to FORTIN 2018, and set limits on the product of the axion couplings to photons and nucleons as $\mathit g_{{{\mathit A}} {{\mathit N}} {{\mathit N}}}$ $\mathit G_{{{\mathit A}} {{\mathit \gamma}} {{\mathit \gamma}}}{ {}\lesssim{} }$ $4.6 \times 10^{-19}$ GeV${}^{-1}$ for ${\mathit m}_{{{\mathit A}^{0}}}{ {}\lesssim{} }$ $10^{-5}$ eV by using the quiescent soft gamma-ray flux upper limits in five magnetars. We use $\mathit g_{{{\mathit A}} {{\mathit N}} {{\mathit N}}}$ = $\mathit G_{{{\mathit A}} {{\mathit N}}}$ 2${\mathit m}_{{{\mathit N}}}$ to translate their limits. See their Table II and Fig. 3 for the limits. 59  REGIS 2021 look for monochromatic photons from axion decay, using the MUSE spectroscopic data on the Leo T dwarf spheroidal galaxy. They assume that axions make up all of dark matter and use the integrated dark matter density along the line of sight determined by observations. 60  XIAO 2021 use X-ray data from Betelgeuse to look for signals from axions produced in the stellar core that were converted to X-rays by the Galactic magnetic field. See their Fig. 1 for the mass-dependent limit. 61  ABUDINEN 2020 look for the process ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit A}^{0}}$ (${{\mathit A}^{0}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}$) and set upper limits of around $10^{-3}$ over the mass range. The quoted limit is at ${\mathit m}_{{{\mathit A}^{0}}}$ = 0.3 GeV. See their Fig. 5 for mass dependent limits. 62  BANERJEE 2020A look for axions produced from high-energy bremsstrahlung photons through the Primakoff effect with the electric field of the target nuclei. They exclude $\mathit G_{{{\mathit A}} {{\mathit \gamma}} {{\mathit \gamma}}}$= $2 \times 10^{-4} - 5 \times 10^{-2}$ GeV${}^{-1}$ for ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ 55 MeV. See their Fig. 5 for mass-dependent limits. 63  BUEHLER 2020 look for the ${{\mathit \gamma}}$-ray transparency due to axion-photon oscillations using high-energy photon events from 79 sources in the Second Fermi-LAT Catalog of High-Energy Sources. The quoted limit is for the intergalactic magnetic field strength and coherence length of $\mathit B$ = 1 nG and $\mathit s$ = 1 Mpc. See their Figs. 4 and 5 for mass-dependent limits and for different magnetic-field parameters. 64  CALORE 2020 use the isotropic diffuse ${{\mathit \gamma}}$-ray background measured by the Fermi-LAT to constrain the ${{\mathit \gamma}}$-ray flux converted in the Galactic magnetic field from axions produced from past core-collapse supernovae. They also derive a limit on a heavier axion with ${\mathit m}_{{{\mathit A}^{0}}}{ {}\gtrsim{} }$ keV decaying into two photons of $\mathit G_{{{\mathit A}} {{\mathit \gamma}} {{\mathit \gamma}}}{ {}\lesssim{} }$ $5 \times 10^{-11}$ GeV${}^{-1}$ for ${\mathit m}_{{{\mathit A}^{0}}}$ = 5 keV. See their Figs. 5 and 7 for the limits as well as limits in the presence of axion-nucleon couplings. 65  CARENZA 2020 extend the globular cluster bound of AYALA 2014 to heavier masses (${\mathit m}_{{{\mathit A}^{0}}}{}\leq{}$ a few 100 keV) by taking account of the coalescence process ${{\mathit \gamma}}$ ${+}$ ${{\mathit \gamma}}$ $\rightarrow$ ${{\mathit A}^{0}}$ as well as the decay of the ALP inside the stellar core. See their Fig.4 for mass-dependent limits. 66  DENT 2020A is analogous to GAO 2020. The quoted limit is from their arXiv:2006.15118v3 (v2 is their published version), using the relativistic Hartree-Fock form factor. The limit is up to two times weaker than the published one. See Fig. 4 in their arXiv version 3 for the correlation between $\mathit G_{{{\mathit A}} {{\mathit \gamma}} {{\mathit \gamma}}}$ and $\mathit g_{{{\mathit A}} {{\mathit e}} {{\mathit e}}}$ corresponding to the excess reported in APRILE 2020. 67  DEPTA 2020 correct the underestimated ${}^{}\mathrm {D}$ abundance in MILLEA 2015, and derive robust cosmological bounds by allowing the reheating temperature, $\mathit N_{{\mathrm {eff}}}$, and neutrino chemical potential to vary. See their Fig. 6 for mass-dependent limits. 68  DESSERT 2020A use the NuSTAR data of the Quintuplet and Westerlund 1 super star clusters to look for X-rays converted in the Galactic magnetic field from the axions produced in stellar cores. See their Fig. 3 for the mass-dependent limits. 69  ESTEBAN 2020 show that the two anomalous ANITA events can be explained by the reflected radio pulses that are resonantly produced in the ionosphere via axion-photon conversion for ${\mathit m}_{{{\mathit A}^{0}}}{ {}\lesssim{} }$ $1 \times 10^{-7}$ eV , if an axion clump passes the Earth about once a month. See their Fig.5 for the region consistent with this interpretation for different values of the axion density inside the clumps. 70  GAO 2020 correct the limit of APRILE 2020 by including inverse Primakoff scattering in the XENON1T detector. The quoted limit is from their arXiv:2006.14598v4 (v3 is their published version), taking account of the atomic form factor of ${}^{}\mathrm {Xe}$ as pointed out in ABE 2020J. The limit is weaker by a factor of $1.5 - 2$ than the published one. See Fig. 3 in their arXiv version 4 for correlation between $\mathit G_{{{\mathit A}} {{\mathit \gamma}} {{\mathit \gamma}}}$ and $\mathit g_{{{\mathit A}} {{\mathit e}} {{\mathit e}}}$ corresponding to the excess reported in APRILE 2020. 71  KOROCHKIN 2020 assume the axion makes up all dark matter, and look for a dip in the observed gamma-ray spectrum of the blazer 1ES 1218+304 by Fermi/LAT and VERITAS due to the extragalactic background light produced by the axion decay. Their analysis favors nonzero axion-induced absorption with $\mathit G_{{{\mathit A}} {{\mathit \gamma}} {{\mathit \gamma}}}$ = $3 \times 10^{-11} - 2 \times 10^{-10}$ GeV${}^{-1}$ over a range of ${\mathit m}_{{{\mathit A}^{0}}}$ = $2 - 18$ eV. See their Fig. 1 for mass-dependent limits between 0.25 $<$ ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ 25 eV. 72  LUCENTE 2020A study the SN 1987A energy-loss argument on the axion-like particle production. In addition to the Primakoff process, they take account of photon coalescence as well as gravitational trapping that become relevant at ${\mathit m}_{{{\mathit A}^{0}}}$ $>$ 100 MeV. See their Fig. 12 for the mass-dependent limit. 73  MEYER 2020 look for prompt $\gamma $-rays converted in the Galactic magnetic fields from axions produced via the Primakoff process in a sample of 20 extragalactic core-collapse supernovae. The limits assume a progenitor mass of 10 times the solar mass and certain models for the optical emission and the galactic magnetic field. See their Figs. 2 and 6 in the erratum for mass- and model-dependent limits. 74  YAMAMOTO 2020 look for X-ray photons converted by the Earth's magnetic field from the axions produced by the two-body decay of dark matter, and set the limits by using the Suzaku data. The quoted limit is for the monochromatic X-ray line from the galactic dark matter with lifetime $\tau $ = $4.32 \times 10^{17}$ sec. They also derive limits on the continuum spectrum from the extragalactic component. See their Fig. 7 for the limits. 75  ALONI 2019 used the data collected by the PRIMEX experiment to derive a limit based on a data-driven method. See their Fig. 2 for mass-dependent limits. 76  CAPUTO 2019 look for an oscillating variation of the polarization angle of the pulsar J0437-4715, where they assume the local axion energy density ${{\mathit \rho}_{{{A}}}}$ = 0.3 GeV/cm${}^{3}$. See their Fig. 2 for mass-dependent limits for $5 \times 10^{-24}$ eV ${}\leq{}{\mathit m}_{{{\mathit A}^{0}}}{}\leq{}$ $2 \times 10^{-19}$ eV. 77  FEDDERKE 2019 look for a uniform reduction of the CMB polarization at large scales, which is induced by the oscillating axion background during CMB decoupling. The quoted limit is based on the assumption that axions make up all of the dark matter. See their Fig. 3 for mass-dependent limits for ${\mathit m}_{{{\mathit A}^{0}}}$ = $10^{-22} - 10^{-19}$ eV. 78  IVANOV 2019 look for the axion-induced periodic changes in the polarization angle of parsec-scale jets in active galactic nuclei observed by the MOJAVE program, where they use the axion energy density ${{\mathit \rho}_{{{A}}}}$ = 20 GeV/cm${}^{3}$. See their Fig. 6 for mass-dependent limits for $5 \times 10^{-23}$ eV ${}\leq{}{\mathit m}_{{{\mathit A}^{0}}}{}\leq{}$ $1.2 \times 10^{-21}$ eV. 79  LIANG 2019 look for spectral irregularities in the spectrum of 10 bright H.E.S.S. sources in the Galactic plane, assuming photon-ALP mixing in the Galactic magnetic fields. See their Fig. 2 for mass-dependent limits with different Galactic magnetic field models. 80  FORTIN 2018 studied the conversion of axion-like particles produced in the core of a magnetar to hard X-rays in the magnetosphere. See their Fig. 5 for mass-dependent limits with different values of the magnetar core temperature. 81  JAECKEL 2018 study axions produced through the Primakoff process from SN 1987A, which subsequently decay into photon pairs. See their Fig. 1 for the mass-dependent limits in the range of ${\mathit m}_{{{\mathit A}^{0}}}$ = $0.01 - 100$ MeV. 82  YAMAJI 2018 search for axions with an x-ray LSW at Spring-8, using the Laue-case conversion in a silicon crystal. They also obtain $\mathit G_{{{\mathit A}} {{\mathit \gamma}} {{\mathit \gamma}}}$ $<$ $4.2 \times 10^{-3}$ GeV${}^{-1}$ for ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ 10 eV. See their Fig. 5 for mass-dependent limits. 83  ZHANG 2018 look for spectral irregularities in the spectrum of PKS 2155-304 measured by Fermi LAT, assuming photon-ALP mixing in the intercluster and Galactic magnetic fields. See their Figs. 2 and 3 for mass-dependent limits with different values of the intercluster magnetic field parameters. 84  ADE 2017 look for cosmic birefringence from axion-like particles using CMB polarization data taken by the BICEP2 and Keck Array experiments. They set a limit $\mathit G_{{{\mathit A}} {{\mathit \gamma}} {{\mathit \gamma}}}\mathit H_{I}$ $<$ $7.2 \times 10^{-2}$ at 95 $\%$CL for ${\mathit m}_{{{\mathit A}^{0}}}$ $<$ $10^{-28}$ eV, where $\mathit H_{I}$ is the Hubble parameter during inflation. 85  ANASTASSOPOULOS 2017 looked for solar axions by the CAST axion helioscope in the vacuum phase, and supersedes ANDRIAMONJE 2007. 86  DOLAN 2017 update existing limits on $\mathit G_{{{\mathit A}} {{\mathit \gamma}} {{\mathit \gamma}}}$ for axion-like particles. The limits from the proton beam dump experiments in their Fig. 2 contained an error, and the corrected version is shown in Fig. 1 of DOLAN 2021. 87  INADA 2017 search for axions with an x-ray LSW at Spring-8. See their Fig. 4 for mass-dependent limits. 88  KOHRI 2017 attributed to axion-photon oscillations the excess of cosmic infrared background observed by the CIBER experiment. See their Fig. 5 for the region preferred by their scenario. 89  MARSH 2017 is similar to WOUTERS 2013, using Chandra observations of M87. See their Fig. 6 for mass-dependent limits. 90  TIWARI 2017 use observed limits of the cosmic distance-duality relation to constrain the photon-ALP mixing based on 3D simulations of the magnetic field configuration. The quoted value is for the averaged magnetic field of 1nG with a coherent length of 1 Mpc. See their Fig. 5 for mass-dependent limits. 91  AJELLO 2016 look for irregularities in the energy spectrum of the NGC1275 measured by Fermi LAT, assuming photon-ALP mixing in the intra-cluster and Galactic magnetic fields. See their Fig. 2 for mass-dependent limits. 92  DELLA-VALLE 2016 look for the birefringence induced by axion-like particles. See their Fig. 14 for mass-dependent limits. 93  DELLA-VALLE 2016 look for the dichroism induced by axion-like particles. See their Fig. 14 for mass-dependent limits. 94  JAECKEL 2016 use the LEP data of ${{\mathit Z}}$ $\rightarrow$ 2 ${{\mathit \gamma}}$ and ${{\mathit Z}}$ $\rightarrow$ 3 ${{\mathit \gamma}}$ to constrain the ALP production via ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit Z}}$ $\rightarrow$ ${{\mathit A}^{0}}$ ${{\mathit \gamma}}$ (${{\mathit A}^{0}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}$), assuming the ALP coupling with two hypercharge bosons. See their Fig. 4 for mass-dependent limits. 95  LEEFER 2016 derived limits by using radio-frequency spectroscopy of dysprosium and atomic clock measurements. See their Fig. 1 for mass-dependent limits as well as limits on Yukawa-type couplings of the scalar to the electron and nucleons. 96  ANASTASSOPOULOS 2015 search for solar chameleons with CAST and derived limits on the chameleon coupling to photons and matter. See their Fig. 12 for the exclusion region. 97  ARIK 2015 is analogous to ARIK 2009, and search for solar axions for ${\mathit m}_{{{\mathit A}^{0}}}$ around 0.2 and 0.4 eV. See their Figs. 1 and 3 for the mass-dependent limits. 98  Based on OSQAR photon regeneration experiment. See their Fig. 6 for mass-dependent limits on scalar and pseudoscalar bosons. 99  BRAX 2015 derived limits on conformal and disformal couplings of a scalar to photons by searching for a chaotic absorption pattern in the X-ray and UV bands of the Hydra A galaxy cluster and a BL lac object, respectively. See their Fig. 8. 100  HASEBE 2015 look for an axion via a four-wave mixing process at quasi-parallel colliding laser beams. They also derived limits on a scalar coupling to photons $\mathit G_{{{\mathit S}} {{\mathit \gamma}} {{\mathit \gamma}}}$ $<$ $2.62 \times 10^{-4}$ GeV${}^{-1}$ at ${\mathit m}_{{{\mathit S}^{0}}}$ = 0.15 eV. See their Figs. 11 and 12 for mass-dependent limits. 101  MILLEA 2015 is similar to CADAMURO 2012, including the Planck data and the latest inferences of primordial deuterium abundance. See their Fig. 3 for mass-dependent limits. 102  VANTILBURG 2015 look for harmonic variations in the dyprosium transition frequency data, induced by coherent oscillations of the fine-structure constant due to dilaton-like dark matter, and set the limits, $\mathit G_{{{\mathit S}} {{\mathit \gamma}} {{\mathit \gamma}}}$ $<$ $6 \times 10^{-27}$ GeV${}^{-1}$ at ${\mathit m}_{{{\mathit S}^{0}}}$ = $6 \times 10^{-23}$ eV. See their Fig. 4 for mass-dependent limits between $1 \times 10^{-24}<$ ${\mathit m}_{{{\mathit S}^{0}}}<$ $1 \times 10^{-15}$ eV. 103  VINYOLES 2015 performed a global fit analysis based on helioseismology and solar neutrino observations. See their Fig. 9. 104  ARIK 2014 is similar to ARIK 2011. See their Fig. 2 for mass-dependent limits. 105  AYALA 2014 derived the limit from the helium-burning lifetime of horizontal-branch stars based on number counts in globular clusters. 106  DELLA-VALLE 2014 use the new PVLAS apparatus to set a limit on vacuum magnetic birefringence induced by axion-like particles. See their Fig. 6 for the mass-dependent limits. 107  EJLLI 2014 set limits on a product of primordial magnetic field and the axion mass using CMB distortion induced by resonant axion production from CMB photons. See their Fig.$~$1 for limits applying specifically to the DFSZ and KSVZ axion models. 108  PUGNAT 2014 is analogous to EHRET 2010. See their Fig. 5 for mass-dependent limits on scalar and pseudoscalar bosons. 109  REESMAN 2014 derive limits by requiring effects of axion-photon interconversion on gamma-ray spectra from distant blazars to be no larger than errors in the best-fit optical depth based on a certain extragalactic background light model. See their Fig. 5 for mass-dependent limits. 110  ABRAMOWSKI 2013A look for irregularities in the energy spectrum of the BL Lac object PKS 2155--304 measured by H.E.S.S. The limits depend on assumed magnetic field around the source. See their Fig. 7 for mass-dependent limits. 111  ARMENGAUD 2013 is analogous to AVIGNONE 1998. See Fig. 6 for the limit. 112  BETZ 2013 performed a microwave-based light shining through the wall experiment. See their Fig. 13 for mass-dependent limits. 113  FRIEDLAND 2013 derived the limit by considering blue-loop suppression of the evolution of red giants with $7 - 12$ solar masses. 114  MEYER 2013 attributed to axion-photon oscillations the observed excess of very high-energy ${{\mathit \gamma}}$-rays with respect to predictions based on extragalactic background light models. See their Fig.4 for mass-dependent lower limits for various magnetic field configurations. 115  WOUTERS 2013 look for irregularities in the X-ray spectrum of the Hydra cluster observed by Chandra. See their Fig. 4 for mass-dependent limits. 116  CADAMURO 2012 derived cosmological limits on $\mathit G_{{{\mathit A}}{{\mathit \gamma}}{{\mathit \gamma}}}$ for axion-like particles. See their Fig. 1 for mass-dependent limits. 117  PAYEZ 2012 derive limits from polarization measurements of quasar light (see their Fig.$~$3). The limits depend on assumed magnetic field strength in galaxy clusters. The limits depend on assumed magnetic field and electron density in the local galaxy supercluster. 118  ARIK 2011 search for solar axions using ${}^{3}\mathrm {He}$ buffer gas in CAST, continuing from the ${}^{4}\mathrm {He}$ version of ARIK 2009. See Fig.$~$2 for the exact mass-dependent limits. 119  ALPS is a photon regeneration experiment. See their Fig.$~$4 for mass-dependent limits on scalar and pseudoscalar bosons. 120  AHMED 2009A is analogous to AVIGNONE 1998. 121  ARIK 2009 is the ${}^{4}\mathrm {He}$ filling version of the CAST axion helioscope in analogy to INOUE 2002 and INOUE 2008. See their Fig.$~$7 for mass-dependent limits. 122  CHOU 2009 use the GammeV apparatus in the afterglow mode to search for chameleons, (pseudo)scalar bosons with a mass depending on the environment. For pseudoscalars they exclude at 3$\sigma $ the range $2.6 \times 10^{-7}$ GeV${}^{-1}<$ ${{\mathit G}}_{A{{\mathit \gamma}}{{\mathit \gamma}}}<$ $4.2 \times 10^{-6}$ GeV${}^{-1}$ for vacuum ${\mathit m}_{{{\mathit A}^{0}}}$ roughly below 6 meV for density scaling index exceeding 0.8. 123  GONDOLO 2009 use the all-flavor measured solar neutrino flux to constrain solar interior temperature and thus energy losses. 124  LIPSS photon regeneration experiment, assuming scalar particle ${{\mathit S}^{0}}$. See Fig.$~$4 for mass-dependent limits. 125  CHOU 2008 perform a variable-baseline photon regeneration experiment. See their Fig.$~$3 for mass-dependent limits. Excludes the PVLAS result of ZAVATTINI 2006. 126  FOUCHE 2008 is an update of ROBILLIARD 2007. See their Fig. 12 for mass-dependent limits. 127  INOUE 2008 is an extension of INOUE 2002 to larger axion masses, using the Tokyo axion helioscope. See their Fig. 4 for mass-dependent limits. 128  ZAVATTINI 2008 is an upgrade of ZAVATTINI 2006, see their Fig.$~$8 for mass-dependent limits. They now exclude the parameter range where ZAVATTINI 2006 had seen a positive signature. 129  ANDRIAMONJE 2007 looked for Primakoff conversion of solar axions in 9T superconducting magnet into X-rays. Supersedes ZIOUTAS 2005. 130  ROBILLIARD 2007 perform a photon regeneration experiment with a pulsed laser and pulsed magnetic field. See their Fig. 4 for mass-dependent limits. Excludes the PVLAS result of ZAVATTINI 2006 with a CL exceeding 99.9$\%$. 131  ZAVATTINI 2006 propagate a laser beam in a magnetic field and observe dichroism and birefringence effects that could be attributed to an axion-like particle. This result is now excluded by ROBILLIARD 2007, ZAVATTINI 2008, and CHOU 2008. 132  INOUE 2002 looked for Primakoff conversion of solar axions in 4T superconducting magnet into X$~$ray. 133  MORALES 2002B looked for the coherent conversion of solar axions to photons via the Primakoff effect in Germanium detector. 134  BERNABEI 2001B looked for Primakoff coherent conversion of solar axions into photons via Bragg scattering in NaI crystal in DAMA dark matter detector. 135  ASTIER 2000B looked for production of axions from the interaction of high-energy photons with the horn magnetic field and their subsequent re-conversion to photons via the interaction with the NOMAD dipole magnetic field. 136  MASSO 2000 studied limits on axion-proton coupling using the induced axion-photon coupling through the proton loop and CAMERON 1993 bound on the axion-photon coupling using optical rotation. They obtained the bound $\mathit g{}^{2}_{{{\mathit p}}}/4{{\mathit \pi}}<1.7 \times 10^{-9}$ for the coupling $\mathit g_{{{\mathit p}}}{{\overline{\mathit p}}}\gamma _{5}{{\mathit p}}\phi _{\mathit A}$. 137  AVIGNONE 1998 result is based on the coherent conversion of solar axions to photons via the Primakoff effect in a single crystal germanium detector. 138  Based on the conversion of solar axions to $\mathit X$-rays in a strong laboratory magnetic field. 139  Experiment based on proposal by MAIANI 1986. 140  Experiment based on proposal by VANBIBBER 1987. 141  LAZARUS 1992 experiment is based on proposal found in VANBIBBER 1989. 142  RUOSO 1992 experiment is based on the proposal by VANBIBBER 1987. 143  SEMERTZIDIS 1990 experiment is based on the proposal of MAIANI 1986. The limit is obtained by taking the noise amplitude as the upper limit. Limits extend to ${\mathit m}_{{{\mathit A}^{0}}}$ = $4 \times 10^{-3}$ where $\mathit G_{{{\mathit A}} {{\mathit \gamma}} {{\mathit \gamma}}}$ $<$ $1 \times 10^{-4}$ GeV${}^{-1}$.

References