Axions and Axion-like Particles Belén Gavela! Univ. Autónoma de Madrid and IFT MORIOND Electroweak 2017 H2020 We will consider the SM plus a generic scalar field a ! ! with derivative couplings to SM particles! ! and free scale fa:! ! an ALP (axion-like particle) general effective couplings This is shift symmetry invariant: ~ Goldstone! boson Brivio, Gavela, Merlo, Mimasu, No, del Rey, Sanz 2017 arXiv:1701.05379 We will consider the SM plus a generic scalar field a ! ! with derivative couplings to SM particles! ! and free scale fa:! ! an ALP (axion-like particle) general effective couplings Why? Brivio, Gavela, Merlo, Mimasu, No, del Rey, Sanz 2017 arXiv:1701.05379 Is the Higgs the only (fundamental?) scalar in nature?! ! ! ! ! Or simply the first one discovered? The spin 0 window Window on spin 0 The SM Higgs is a ~ doublet of SU(2)L The spin 0 window Window on spin 0 The SM Higgs is a ~ doublet of SU(2)L What about a singlet (pseudo) scalar? Strong motivation from fundamental problems of the SM S Φ a Rocio del Rey Strong motivation for singlet (pseudo)scalars from fundamental ! SM problems The nature of DM is unknown It may be a (SM singlet) scalar S! the “Higgs portal” = + S2 δL Φ Φ Silveira+Zee; Veltman+Yndurain; Patt+Wilczek… Strong motivation for singlet (pseudo)scalars from fundamental ! SM problems The nature of DM is unknown The strong CP problem Why is the QCD " parameter! so small? ~μν LQCD⊃θ GμνG It may be a (SM singlet) scalar S! the “Higgs portal” " dynamical U(1)A solution + 2 the axion a δL = Φ ΦS It is a pGB: ~only derivative couplings #$ a Silveira+Zee; Veltman+Yndurain; Patt+Wilczek… Also excellent DM candidate Peccei+Quinn; Wilczek… Strong motivation for singlet (pseudo)scalars from fundamental ! SM problems The nature of DM is unknown The strong CP problem Why is the QCD " parameter! so small? ~ a_ μν LQCD⊃ GμνG fa It may be a (SM singlet) scalar S! the “Higgs portal” " dynamical U(1)A solution + 2 the axion a δL = Φ ΦS It is a pGB: ~only derivative couplings #$ a Silveira+Zee; Veltman+Yndurain; Patt+Wilczek… Also excellent DM candidate Peccei+Quinn; Wilczek… In “true QCD axion” models: ma fa = cte. 1/fa ma ma vs scale fa ga ~1/fa In QCD-like theory because of explicit U(1)A breaking at quantum level (instantons, #) QCD Choi et al. 1986 ma vs scale fa ga ~1/fa In QCD-like theory because of explicit U(1)A breaking at quantum level (instantons, #) QCD Choi et al. 1986 * * Models assuming ! * -5 -2 9 12 SM gauge group: 10 < ma < 10 eV , 10 < fa <10 GeV ma vs scale fa ga ~1/fa In QCD-like theory because of explicit U(1)A breaking at quantum level (instantons, #) QCD Choi et al. 1986 * * Models assuming ! * -5 -2 9 12 SM gauge group: 10 < ma < 10 eV , 10 < fa <10 GeV γ Intensely looked for experimentally… ga$ (GeV-1)! γ (GeV-1) “True” QCD axion ! band = “Invisible axion”! e.g. KSVZ, DFSZ… ! v<< fa —> EW hierarchy problem “True” QCD region ma (eV) … and theoretically https://arxiv.org/pdf/1611.04652.pdf γ ga$ (GeV-1)! γ (GeV-1) Refined KSVZ axion ! band: ! up and thinner! from %DM ! + Landau-poles analysis (Luzio+Mescia+Nardi 2017) ! v<< fa —> EW hierarchy problem “True” QCD region ma (eV) … and theoretically https://arxiv.org/pdf/1611.04652.pdf γ ga$ (GeV-1)! γ (GeV-1) QCD axiflavon ! band ! (creative view) (Calibbi et al. 2016) ! v<< fa —> EW hierarchy problem “True” QCD region ma (eV) … and theoretically https://arxiv.org/pdf/1611.04652.pdf γ ga$ (GeV-1)! γ (GeV-1) QCD axiflavon ! band ! (creative view) (Calibbi et al. 2016) Excluded for axiflavon ! by rare meson decays ! v<< fa —> EW hierarchy problem “True” QCD region ma (eV) … and theoretically https://arxiv.org/pdf/1611.04652.pdf ma vs scale fa ga ~1/fa In QCD-like theory because of explicit U(1)A breaking at quantum level (instantons, #) QCD Choi et al. 1986 * * Models assuming ! * -5 -2 9 12 SM gauge group: 10 < ma < 10 eV , 10 < fa <10 GeV ma vs scale fa ga ~1/fa In QCD-like theory because of explicit U(1)A breaking at quantum level (instantons, #) QCD Choi et al. 1986 * * Models assuming ! * -5 -2 9 12 SM gauge group: 10 < ma < 10 eV , 10 < fa <10 GeV * Models enlarging the strong SM gauge sector, with scale #’ ? ma vs scale fa ga ~1/fa In QCD-like theory because of explicit U(1)A breaking at quantum level (instantons, #) QCD Choi et al. 1986 -5 -2 9 12 10 < ma < 10 eV , 10 < fa <10 GeV * Models enlarging the strong SM gauge sector, with scale #’ ? , ma vs scale fa ga ~1/fa In QCD-like theory because of explicit U(1)A breaking at quantum level (instantons, #) QCD Choi et al. 1986 -5 -2 9 12 10 < ma < 10 eV , 10 < fa <10 GeV * Models enlarging the strong SM gauge sector, with scale #’ ? , ma vs scale fa ga ~1/fa In QCD-like theory because of explicit U(1)A breaking at quantum level (instantons, #) QCD Choi et al. 1986 -6 -3 9 12 10? < ma < 10 eV , 10 < fa <10? GeV * Models enlarging the strong SM gauge sector, with scale #’ ? , relax the parameter space Recent activity on heavy “true” axions * Enlarging the strong SM gauge group, with scale #’: Dimopoulos+Susskind 79, Tye 81…Rubakov 97… Berezhiani+Gianfagna+Gianotti 01… surge since 2016!: : Gherghetta+Nagata+Shifman , Chiang et al., Khobadize… Hook and many collaborators, Dimopoulos et al. … e.g. SU(3)c x SU(N’) both confining #QCD #’ a Recent activity on heavy “true” axions * Enlarging the strong SM gauge group, with scale #’: Dimopoulos+Susskind 79, Tye 81…Rubakov 97… Berezhiani+Gianfagna+Gianotti 01… surge since 2016!: : Gherghetta+Nagata+Shifman , Chiang et al., Khobadize… Hook and many collaborators, Dimopoulos et al. … e.g. SU(3)c x SU(N’) both confining #QCD #’ * The ugly part: " and "’ Recent activity on heavy “true” axions * Enlarging the strong SM gauge group, with scale #’: Dimopoulos+Susskind 79, Tye 81…Rubakov 97… Berezhiani+Gianfagna+Gianotti 01… surge since 2016!: : Gherghetta+Nagata+Shifman , Chiang et al., Khobadize… Hook and many collaborators, Dimopoulos et al. … e.g. SU(3)c x SU(N’) both confining #QCD #’ * The ugly part: " and "’ —>To reabsorb both : unification, and/or SM mirror world related by Z2, ! or other constructions … all require tunings Nothing works very nicely, but there is movement —> e.g. fa ~ TeV, ma ~ MeV - TeV still solve the strong CP problem * Much territory to explore for heavy ‘true” axions and for ALPs e.g. ~ TeV CAST +! SUMICO Jaeckel+ Spannowsky 2015 Log 10ma (eV) “True” QCD axion * Much territory to explore for heavy ‘true” axions and for ALPs e.g. ~ TeV CAST +! SUMICO Jaeckel+ Spannowsky 2015 Log10ma (eV) “True” axion region ! amplifies?? * Much territory to explore for heavy ‘true” axions and for ALPs ~ TeV CAST +! SUMICO Jaeckel+ Spannowsky 2015 Log10ma (eV) “True” axion region ! amplifies?? (Pseudo)Goldstone Bosons also in many BSM theories * e.g. Extra-dim Kaluza-Klein: 5d gauge field compactified to 4d the Wilson line around the circle is a GB, which behaves as an axion in 4d * a Moriond example: the “relaxion" (G. Perez talk) is not a GB but part of its couplings are purely derivative as those of ALPs, e.g. * Much territory to explore for axions and ALPs e.g. ~ TeV ! CAST +! SUMICO Strongderivative case for couplings looking everywhere of a spin 0 forparticle purely ! Jaeckel+ Spannowsky 2015 Log10ma (eV) We will consider the SM plus a generic scalar field a ! ! with derivative couplings to SM particles! ! and free scale fa:! ! an ALP (axion-like particle) general effective couplings THEORY plus NEW SIGNALS at colliders Brivio, Gavela, Merlo, Mimasu, No, del Rey, Sanz 2017 arXiv:1701.05379 Up to date, phenomenological studies have mostly focused on ! ALP couplings to fermions and photons But because of SU(2)xU(1) gauge invariance, ! a-$$ should come together with a-$&, a-Z& and a-W+W- : + …. ALP-Linear= effective Lagrangian at NLO SM EFT If only bosonic ALP-operators are considered: , Georgi, Kaplan, Randall 1986 ALP-Linear= effective Lagrangian at NLO SM EFT If only bosonic ALP-operators are considered: , SM higgs doublet Georgi, Kaplan, Randall 1986 ALP-Linear= effective Lagrangian at NLO SM EFT If only bosonic ALP-operators are considered: , Georgi, Kaplan, Randall 1986 ALP-Linear= effective Lagrangian at NLO SM EFT If only bosonic ALP-operators are considered: , Georgi, Kaplan, Randall 1986 ALP-Linear= effective Lagrangian at NLO SM EFT If only bosonic ALP-operators are considered: a a Only fermionic a-Higgs couplings Georgi, Kaplan, Randall 1986 ALP-Linear= effective Lagrangian at NLO SM EFT If only bosonic ALP-operators are considered: Note: NO a-Higgs purely bosonic couplings Georgi, Kaplan, Randall 1986 ALP-Linear= effective Lagrangian at NLO SM EFT Complete basis (bosons+fermions): where Xψ is a general 3x3 matrix in flavour space Note: NO a-Higgs bosonic couplings Georgi + Kaplan + Randall 1986 Choi + Kang + Kim, 1986 Salvio + Strumia + Shue, 2013 ALP-Linear effective Lagrangian at NLO Complete basis (bosons+fermions): ! analysiswhere parameters: Xψ is a general 3x3 !matrix in flavour space Note: NO a-Higgs bosonic couplings Georgi + Kaplan + Randall 1986 Choi + Kang + Kim, 1986 Salvio + Strumia + Shue, 2013 ALP-Linear effective Lagrangian at NLO Complete basis (bosons+fermions): where Xψ is a general 3x3 matrix in flavour space contain a-$$ and other couplings Georgi + Kaplan + Randall 1986 Choi + Kang + Kim, 1986 Salvio + Strumia + Shue, 2013 Because of SU(2)xU(1) gauge invariance, ! a-$$ comes together with a-$&, a-Z& and a-W+W- : a-$$ studies only bounds this combination of couplings 90% CL: Because of SU(2)xU(1) gauge invariance, ! a-$$ comes together with a-$&, a-Z& and a-W+W- : Largely disregarded up to very very recently only a tiny bit in Jaeckel+Spannowsky