High Energy Cosmic Rays from Decaying Supersymmetric Dark Matter

1. High Energy Cosmic Raysfrom Decaying Supersymmetric Dark Matter Koji Ishiwata (Tohoku University) In collaboration with Shigeki Matsumoto (Toyama University) Takeo Moroi (Tohoku University) Based on arXiv:0811.0250(hep-ph),0811.4492(astro-ph), 0903.0242(hep-ph) ICRR, May 8, 2009

2. 1. Introduction

3. Dark Matter (DM) • Very weakly interacting with other particles • Massive • Stable It accounts for 23 % of total energy density in the Universe [WMAP] In the standard model of particle physics, however, there is no candidate for DM Beyond the standard model

4. Supersymmetry (SUSY) is promising model • Motivated by • Hierarchy problem • Gauge coupling unification, etc… • Lightest superparticle (LSP) is viable candidate for DM • under -parity • As LSP, • Lightest neutralino (Bino, Wino, Higgsinos mixed state) • Sneutrino • Gravitino

5. LSP-DM scenarios has been studied in cosmological and astrophysical points of view • Production processes in thermal history (thermal relic for • lightest neutralino, thermal scattering for gravitino, etc…) • Consistency with big-bang neucleosynthesis (BBN) • [Kawasaki,Kohri,Moroi] • Direct detection of DM [DAMA,CDMS-II,XENON10] • Indirect search via cosmic rays Signal from DM might be detected[HEAT,EGRET, etc]

6. Recently, PAMELA (and Fermi) observations have indicated anomalous fluxes in cosmic-ray [Adriani et al.] [Abdo et al.; Chang et al.]

7. Possible candidates for the origins of the anomalies • DM annihilation • DM decay • Pulsars [Hooper,Blasi,Serpico] [Cirelli,Kodastik,Raidal,Strumia; Hisano,Kawasaki, Kohri,Moroi,Nakayama,etc…] [Chen,Nojiri,Takahashi,Yanagida; Hamaguchi,Nakamura, Shirai,etc…] Especially in SUSY, decaying LSP-DM under very weak -parity violation (RPV) has interesting aspects • Lifetime can be much longer than the age of the Universe • PAMELA anomaly can be well reproduced [KI,Matsumoto,Moroi]

8. Our works Focusing on decaying LSP-DM scenarios, we calculate cosmic-ray and found that • The PAMELA anomaly can be well explained • Constraints from cosmic-ray anti-proton observation are • not so severe • Synchrotron radiation from Galactic center is consistent • with foreground emission observedby WMAP DM Cosmic rays time now

9. Contents of my talk 1. Introduction 2. Decaying DM Scenarios 3. Cosmic rays ( ) 4. Summary

10. 2. Decaying DM Scenarios

11. Decaying LSP DM in RPV • LSP • Gravitino • Bino • Sneutrino • RPV • Bi-linear • Leptonic tri-linear (Gaugino/Higgsino – lepton mixing) (lepton – lepton – slepton mixing) Leptonic decay is main mode

12. Gravitino LSP [Takayama,Yamaguchi;Buchmuller,Covi,Hamaguchi,Ibarra, Yanagida] • Advantage for thermal leptogenesis without conflicting BBN ( NLSP decays before BBN) • Cosmic-ray produced by the decay explain • EGRET and HEAT simultaneously when [KI,Matsumoto,Moroi; Ibarra,Tran] Main mode: (under bi-linear RPV) Gravitino NLSP Cosmic rays SM time now BBN

13. Sneutrino LSP • (not excluded by direct detection experiment) • (with purely Dirac type neutrino mass) [Hall,Moroi,Murayama] [Asaka,KI,Moroi] (under tri-linear RPV) Main mode: Sneutrino Thermal relic NLSP llate decay Decay in thermal bath Cosmic rays time now

14. Bino LSP • Thermal relic explains DM abundance (one of the most • popular scenarios) Main mode: (under tri-linear RPV) (under bi-linear RPV) The same as LSP Bino Thermal relic Cosmic rays time now

15. Decay vs. Annihilation Production rate • Decay Parameters: • Annihilation Parameters:

16. 3. Cosmic rays ( )

17. Propagation of Cosmic rays in the Galaxy Mean free path Solve diffusion equation in the Galaxy Sum up the contributions of inside and outside of the Galaxy DM origin flux:

18. flux Diffusion equation: • : Diffusion coefficient • : Energy loss rate • : source term Solar system “Diffusion zone” :speed of light Note: background (BG) is the astrophysical origin flux [Moskalenko,Strong], [Baltz,Edsjo]

19. flux Diffusion equation: • : Convection velocity • : pair annihilation rate ( :half height of Galactic disc ) : velocity of Solar system “Diffusion zone”

20. Propagation models: [Delahaye,Lineros,Donato,Fornengo,Salati] [Tan,Ng; Protheroe] Parameter M1 MED M2 MAX MED MIN • Positron source term: (Annihilation) (Decay)

21. -ray flux • Cosmological distance • Milky Way halo l.o.s. NFW profile : DM energy density (NFW) : -ray energy distribution from single DM decay Note: for BG flux, we interpolate from lower energy data as,

22. NumericalResults • Gravitino LSP PAMELA anomaly can be well explained when irrespective of and final state lepton

23. Electron + Positron Flux PAMELA best-fit value PPB-BETS [Torii et al.] Fermi Final state lepton: electron case may be excluded The other cases may be severely constrained

24. Anti-proton Flux PAMELA best-fit value BESS [Orito et al.; Asaoka et al.; Abe et al.] CAPRICE[Boezio et al.] Constraints from anti-proton flux observations may not be so severe in the decaying gravitino scenario

25. Gamma-ray Flux PAMELA best-fit value EGRET [Sreekumar et al.] Consistent with EGRET irrespective of

26. Sneutrino LSP , irrespective of PAMELA anomaly Severely constrained, except for final state: Fermi

27. Bino LSP , irrespective of PAMELA anomaly Severely constrained, except for final state leptons are only Fermi

28. On the other hand, induces synchrotron radiation under the magnetic field in the Galaxy !!! Image of synchrotron radiation In the frequency band, remnant flux of from the Galactic center, which is called "WMAP Haze", is reported [Hooper,Finkbeiner,Dobler]

29. Numerical Results Solar system Synchrotron Radiation Flux Side view of Galaxy Radiation flux in decaying gravitino-DM scenario is , which is consistent with "WMAP Haze"

30. 4. Summary

31. In decaying LSP-DM scenarios, we calculate cosmic-ray and found that When , • The PAMELA anomaly can be well explained, while some • cases where hard are produced may be excluded by Fermi • Constraints from cosmic-ray anti-proton observation are • not so severe • Synchrotron radiation flux from Galactic center is consistent • with foreground emission observed by WMAP

32. Backup

33. Gravitino decay

34. Decay widths (Large contribution of longitudinal mode)

35. Cosmic-ray Positron Flux

36. Decay vs. Annihilation • Positron source term (Decay) (Annihilation)

37. Decay vs. Annihilation Parameters: For Wino annihilation case, Parameters:

38. Synchrotron Radiation Flux

39. Formalism l.o.s. : Synchrotron radiation energy per unit time and unit frequency from single electron Solar system Side view of Galaxy larger is expected to have a peak at and suppressed by in

40. Numerical Results • Gravitino DM Radio flux in decaying gravitino DM scenario is , which is consistent with WMAP Haze

41. NumericalResults • Final state: ( ) Flux of is expected in leptonically decaying DM scenario

42. NLSP decay at the LHC

43. NLSP decay at LHC In the gravitino DM scenario, NLSP decay can be detected at the LHC although its decay length is much larger than the detector size When , the number of decaying NLSP is expected to be for cases [K.I.,Ito,Moroi] • -NLSP: • -NLSP: The number of NLSP decay is expected to be for the wide parameter region in this scenario

44. Moreover, with the numbers of decaying and total NLSP, lifetime canbe determined when with statistical uncertainty 30% [K.I.,Ito,Moroi] : Number of (decaying/total) NLSP : Momentum distribution of NLSP : Decay probability within In SUSY event, ,which is not sensitive to mass spectrum [simulated by HERWIG and ISAJET packages], thus Observables:

45. NLSP decay at LHC NLSP decay at LHC stau SUSY event simulated by HERWIG package in minimal gauge mediation (mass spectrum is given by ISAJET package)