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Significant effects of second KK particles on LKP dark matter physics

Collaborated with Mitsuru Kakizaki (ICRR) Shigeki Matsumoto (ICRR) Yoshio Sato (Saitama U.). Significant effects of second KK particles on LKP dark matter physics. Masato Senami (ICRR, University of Tokyo) senami@icrr.u-tokyo.ac.jp. hep-ph/0502059. Kaluza-Klein dark matter.

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Significant effects of second KK particles on LKP dark matter physics

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  1. Collaborated with Mitsuru Kakizaki (ICRR) Shigeki Matsumoto (ICRR) Yoshio Sato (Saitama U.) Significant effects of second KK particles on LKP dark matter physics Masato Senami (ICRR, University of Tokyo) senami@icrr.u-tokyo.ac.jp hep-ph/0502059

  2. Kaluza-Klein dark matter • WMAP result establish the existence of non-baryonic cold dark matter • Weakly Interacting Massive Particle (WIMP) is excellent candidate • Lightest supersymmetric particle • Lightest Kaluza-Klein particle (LKP) in universal extra dimension (UED) models • … http://lambda.gsfc.nasa.gov

  3. Mass spectrum Universal Extra Dimension model Universal means all SM particles propagate in spatial extra dimensions Eq. of motion Momentum conservation in higher dim. = KK number conservation In 4 dim. viewpoint To obtain chiral fermion at zero mode, the extra dimension is compactified by S1/Z2 KK parity conservation LKP is stable LKP is a good candidate of DM

  4. Mass spectrum Mass of KK particle • Each KK mode has degenerate mass • Radiative corrections remove the degeneracy Lightest KK particle (SM massless particles are exactly degenerate) m = mass of LKP 1/R=500 GeV, ΛR=20, mh=120 GeV Cheng, Matchev and Schmaltz

  5. Tree level annihilation diagrams Dark matter relic abundance • After annihilation rate dropped below the Hubble parameter, LKP can not annihilate and the density per comoving volume is fixed. • Large cross section ⇒ small relic abundance DM relic abundance ⇒Large mass of DM particle Servant and Tait They consider only the first KK modes

  6. does not couple with SM particle at tree level Second KK s-channel We find • Since DM is non-relativistic, the incident energy of two LKPs is almost degenerate with the mass of second KK modes • In particular, s-channel LKP annihilation process mediated by competes with tree level diagrams because oftheresonance We calculate these type of diagrams One of the resonant diagrams

  7. Cross section • Parameters • For δ～ 0.01, incident energy matches the pole and averaged cross section is significantly enhanced (10% ~ 100%) • δ～0.01 is realized for after the inclusion of the radiative corrections in the minimal UED

  8. Dark matter abundance • The mass of the KK dark matter consistent with the WMAP data is around 950 GeV • This result is about 100 GeV above compared to the tree-level result • The resonant annihilation process mediated by causes this increase

  9. `natural resonance’ Second KK resonance • The s-channel annihilation • First KK mass ~ m Second KK mass ~ 2m • Energy of two first KK mode second KK mass • second KK particle 　⇒　s-channel resonance This resonance is natural!

  10. Conclusion • Second KK particle effect : `natural resonance’ • Relic abundance of the LKP, • s-channel resonance • KK dark matter mass consistent with WMAP ~950 GeV(about 100 GeV above the tree result) • `Natural resonance’ affects • coannihilation • indirect detection • collider signature

  11. Second KK resonance • Coannihilation • If degenerate with in mass, coannihilates with • tree level coannihilation rate is small • s-channel : dipole type interaction • Indirect detection • DM is almost at rest • : good accuracy • s-channel second KK B-boson • Collider signature • Future linear e+e- collider • s-channel second KK W-boson • M. Battaglia et al. hep-ph/0502041 missing

  12. -0.5 % 0 % 1 % 0.5 % m 1.5 % 2 % mh Second KK Higgs mass difference (GeV) (GeV)

  13. Cross sections

  14. Some diagrams

  15. Radiative corrections Weak mixing angles Tree level mass spectrum

  16. first KK mode, 1/R mass superparticle, soft mass stable LKP stable LSP KK mode : tower identical spin superpartner : single different spin Lepton collider! Compact Linear Collider (CLIC) angular distribution energy spectrum total cross-section Abstract SUSY UED similarity LHCでnew physics を発見しても区別できない

  17. 0 1 n=2 1 1 0 Radiative corrections • Radiative corrections remove the degeneracy • Lightest KK particle • Second KK particles couple to SM particles (KK number violating interaction is forbidden by the momentum conservation) 1/R=500 GeV, ΛR=20, mh=120 GeV

  18. Comparison of UED and SUSY • UED parameter is chosen naturally • MSSM parameter is adjusted to UED parameter • Back ground • Events ～20fb small polar angle missing energy > 2.5 TeV transverse energy < 150 GeV event sphericity > 0.05

  19. UED SUSY UED 14.4 fb 2.76 fb SUSY Angular distribution and spin measurements Background free!!

  20. Threshold scans New particle の質量決定 confirm に利用 cross section include beamstrahlung

  21. UED SUSY Muon energy spectrum UED,SUSYの区別には使えない UED SUSY For UED,

  22. is mostly -like and predominantly couple to Resonance Resonance!! • SUSY Z,γs-channel • UED Z2,γ2 s-channel is kinematically forbidden. is kinematically allowed. Weak mixing angle for second KK mode is very small 1/R = 1350 GeV

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