3.5 kev X-ray line and Supersymmetry

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1 Miami-2014, Fort Lauderdale, Florida Bartol Research Institute Department Physics and Astronomy University of Delaware, USA in collaboration with Bhaskar Dutta, Rizwan Khalid and Qaisar Shafi, JHEP 1411, 018 (2014)

2 X-ray Multi Mirror Mission - Newton (XMM-Newton) Chandra X-ray Observatory (0.1-10) kev energy range

3 Un-identified X-ray line around 3.5 kev from Perseus galaxy cluster and the Andromeda galaxy E. Bulbul, M. Markevitch, A. Foster, R. K. Smith, M. Loewenstein and S. W. Randall, Astrophys. J. 789, 13 (2014) A. Boyarsky, O. Ruchayskiy, D. Iakubovskyi and J. Franse, Phys. Rev. Lett. 113,

4 Observed X-ray line with energy of approximately 3.5 kev can not be associated with any known atomic transition that could be consistent with the observed intensity. In the absence of a clear astrophysical explanation, the possibility that this line is associated with DM is tantalizing. E. Bulbul, M. Markevitch, A. Foster, R. K. Smith, M. Loewenstein and S. W. Randall, Astrophys. J. 789, 13 (2014) A. Boyarsky, O. Ruchayskiy, D. Iakubovskyi and J. Franse, Phys. Rev. Lett. 113, m DM 7 kev τ DM sec.

5 Possible dark matter candidate 1) If DM is bosonic, it decays to two photons. This requires that it is a scalar or pseudoscalar. Because a massive spin-1 particle cannot decay to two massless photons due to the Landau-Yang theorem. Axion, or axion like particle or just very light scalar particle φ f F µνf µν or a f F µν F µν. 2) In the fermionic case, the final state must be a photon and a neutrino, and the most plausible option is a spin-1/2 fermion ψ (which could be thought of as a sterile neutrino): v f 2 ψ σ µν νf µν

6 Supersymmetry Possible kev mass dark matter candidates: Neutralino (mostly bino) Gravitino Axino Singlino...

7 Massless neutralino in the MSSM L χ 0 = 1 2 M 1 B B 1 2 M 2 W 0 W 0 + µ h 0 d h 0 u g 2 2 W 0 (v 1 h0 d v 2 h0 u ) + g 1 2 B(v 1 h0 d v 2 h0 u ) 1 2 ψt 0 M χ 0ψ 0 M χ 0 = M 1 0 M Z s w c β M Z c w s β 0 M 2 M Z c w c β M Z c w s β M Z s w c β M Z c w c β 0 µ M Z s w s β M Z c w s β µ 0 ψ T 0 ( ) B, W 0, h0 d, h0 u

8 Massless neutralino M 1 = M 2M 2 Z sin(2β)s2 w µm 2 M 2 Z sin(2β)c2 w 2M2 Z s2 w µ tan β. I. Gogoladze, J. D. Lykken, C. Macesanu and S. Nandi, Phys. Rev. D 68, (2003) A massless neutralino is allowed by all existing experimental data and astrophysical and cosmological observations H. K. Dreiner et.al., Eur. Phys. J. C 62, 547 (2009). The cosmological data are suggesting the presence for an extra relativistic component with an effective neutrino number N eff = at 95% c.l. (Without Planck data) A. Melchiorri et. al,. J. Phys. Conf. Ser. 485, (2014). N eff = at 95% c.l. (Including Planck data)

9 Decaying 7 kev bino LSP C. Kolda and J. Unwin, arxiv: R-parity violation couplings: λlle c + λ QLd c + ɛh u L χ 0 1 ν + γ ( ) 10 τ B ( ) 4 ( sec. m f 7 kev λ 2 TeV m B The problem is that 7 kev bino, been either thermal or non-thermal, as dark matter does not works. ) 3

10 Gravitino dark matter and massless bino General GMSB scenarios gravitino can have mass between 1 ev to 100 TeV. We assume m G 7 kev and massless Bino. G χ γ Γ( G χ 0 1 γ) = cos θ2 W m3 G 8πm 2 Pl For τ( G χ 0 1 γ) 1027 sec. We need m Pl GeV.

11 Gravitino dark matter and massless bino The gravitino relic density : ( ) ( ) 100 GeV TR ( ) m g 2 Ω G h2 = GeV 1 TeV m G Ω Gh and m g 1.4 TeV requires T R 170 GeV.

12 Axino dark matter and massless bino Combination of PQ mechanism with low scale SUSY predicts the SUSY partner of the axion (a), the axino (ã) and saxion (s). A = 1 (s + ia) + 2 ã θ + F A θ θ 2 Axino couples to the gauginos and gauge bosons via anomaly induced term. i α Y C Y ã γ 5 [γ µ, γ ν ] 16π f B B µν a Assuming 7 kev axino and massless bino then we can have ã χ γ.

13 Axino dark matter and massless bino Γ(ã χ 0 1 γ) = α2 emc 2 aχγ 128π 3 m 3 ã f 2 a Axino lifetime can be written as: ( ) τ(ã χ 0 1 γ) = f 2 ( a 7.1 kev sec GeV mã We need to have f a GeV for τ(ã χ 0 1 γ) 1027 sec. ) 3

14 Axino dark matter and massless bino On the other hand, in order not to overproduce axion dark matter, is preferred to have f a < GeV. Small initial axion mis-alignment angle θ Massive fields with late decays properties Assuming to have axion like particle. The axino relic density : Ωãh 2 ( mã 0.1GeV ) ( GeV f a ) 2 ( TR ) 10 4 GeV Ωãh and f a GeV requires T R GeV.

15 NMSSM, Decaying singlino dark matter L m χ 0 = 1 2 Ψ0T M χ 0Ψ 0 + h.c., Ψ 0T ( B 0, W 0 3, h 0 d, h 0 u, s, ν i ) M 1 0 m Z c β s W m Z s β s W 0 0 M 2 m Z c β c W m Z s β c W 0 M N = m Z c β s W m Z c β c W 0 µ eff λvs β m Z s β s W m Z s β c W µ eff 0 λvc β 0 0 λvs β λvc β 2κx κ = λ 1 2 ( ) λv 2 0.6m 2 zm 2 0.5µM2 2 sin 2β µ µm 1 M 2

16 NMSSM, Decaying singlino dark matter R-parity (lepton number) breaking terms: L R = λ 1 LH u S + λ ijk L i L j E c k + λ ijk Q il j d c k + ɛ ih u L i L m χ 0 = 1 2 Ψ0T M χ 0Ψ 0 + h.c., Ψ 0T ( B 0, W 0 3, h 0 d, h 0 u, s, ν i ) ξ R = M χ 0 = ( MN ξ T R ξ R M ν 3 3 ) g v 1 2 gv µ 1 + λ 1 s λ 1 v u g v 2 2 gv µ 2 + λ 2 s λ 2 v u g v 3 2 gv µ 3 + λ 3 s λ 3 v u.

17 NMSSM, Decaying singlino dark matter M H (m χ + i Γ( χ 0 1 ν γ) 1 8π m H +) τ( χ 0 1 ν γ) = sec ( ) λy 2 2 χ 3 1 4π 2 M 2 H ( MH ) 2 ( GeV λ ) 2

18 NMSSM, Decaying singlino dark matter Because of small coupling singlinos are out of equilibrium at high temperature. They are not produced in the freeze-out from the equilibrium. Singlinos can be produced for instance from modulus decay from out of equilibrium. The thermal abundance gets diluted by (T R /T f ) 3.

19 Conclusion We show that in low scale supersymmety it is possible to accommodate 3.5 kev X-ray line, satisfy the WMAP bound on dark matter abundance and captivate all experimental constraints.