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Plan of my talk Littlest Higgs Model with T-parity Relic abundance of LTP dark matter

Dark matter in the little Higgs model ~ Indirect detection of LTP (Lightest T-odd Particle) dark matter using cosmic positron measurement ~. Collaborated with Masaki Asano (KEK) Nobuchika Okada (KEK) Yasuhiro Okada (KEK). Shigeki Matsumoto (KEK, Theory).

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Plan of my talk Littlest Higgs Model with T-parity Relic abundance of LTP dark matter

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  1. Dark matter in the little Higgs model~ Indirect detection of LTP (Lightest T-odd Particle) dark matter using cosmic positron measurement ~ Collaborated with Masaki Asano (KEK) Nobuchika Okada (KEK) Yasuhiro Okada (KEK) Shigeki Matsumoto (KEK, Theory) • Plan of my talk • Littlest Higgs Model with T-parity • Relic abundance of LTP dark matter • 3. Cosmic positron signature from LTP annihilation

  2. New-Phys.(10TeV) & EW(0.1TeV) 1. Higgs field = pseudo NG boson 2. Special arrangement for the cancellation of Λ2 at 1-loop. ① Little Higgs scenario Arkani-Hamed, Cohen, Katz and Nelson (2002) SU(5)⊃[SU(2)×U(1)]2(gauged) ② Littlest Higgs Model (LHM) (VEV = f ~ O(1) TeV) SO(5)⊃SU(2)×U(1) (diagonal) ③ Higgs potential Based on non-linear σ-model (Σ=e2iΠ/fΣ0) generated radiatively through the Colman-Weinberg potential e.g) W WH Dμ: (B1, W1 ; B2, W2) (g1, g’1 ; g2, g’2) Heavy & SM Gauge bosons h h h h – g2 g2 V(φ) = －μ2φ2 + λφ4 Σ：(24 – 10) pions Triplet Higgs 1-loop log Λ 2-loop Λ2 1-loop log Λ eaten SM Higgs under SM gauge group

  3. Spectrum 10 (T-even) (T-odd) Φ WH , ZH 1 (TeV) h AH W, Z 0.1 impose T - parity B1(W1) ⇔ B2(W2) Π⇔－ΩΠΩ Ω= diag.(1,1,–1,1,1) (no heavy gauge boson exchange, no triplet VEV.) ④ LHM with T-parity Original LHM is suffered from severe constraints from EWPM. (Tree-level corrections due to the exchange of additional heavy gauge bosons and non-vanishing VEV of triplet higgs.) f must be larger than 5 TeV !!  fine-tuning again Constraint from EWPO (S,T,U) Sample point Lightest T-odd Particle (LTP) is stable  Good Candidate of Cold Dark Matter !! Hubisz, Meade, Noble, Perelstein (2005)

  4. Relic abundance of LTP dark matter Dominant contribution to Calculation of Relic Abundance ( If mAH > mh ) Relic abundance of the dark matter can be explained by LTP naturally in the usual thermal relic scenario. Ωｈ２= 0.111 ± 0.006 Signatures of LTP dark matter in indirect detection measurement using e+. Sample point 0.8

  5. Annihilate 1~2 kpc e+ e+ Sun Halo LTP dark matter annihilates into e+ in the galactic halo Indirect detection of LTP using e+ LTP dark matter annihilation Astrophysical ambiguity on the signal (and background) is small compared to other indirect detections. (20 ~ 30 %) e+ do not travel in straight line, the signal is observed as the Positron excess in cosmic rays. e+ is absorbed and loses its energy by the propagation in ISM. The flux at earth mostly originates within a few kpc. N-body simulation suggest the possibility to enhance the signal due to the inhomogeneity in the local DM dist. ( parameterized as BF = ratio of signal with inhomogeneity and without one. The factor may reach 2 ~ 10. )

  6. Possibility to detect the signal in PAMELA Not only DM ann. but also C.R. produces high-energy e+ PAMELA (satellite-borne exp.) e+ : 50 (MeV) ~ 270 (GeV) acceptance : 20.5cm2sr energy res. : 12%/E1/2 + 2% contamination : 10-4 level Background positrons C.R. (primary e-)  secondary e+ during propagation in Galaxy 0.20 PAMELA covers the interesting range of LTP dark matter. To detect the signal, the B.G. estimation is important. positron fraction e+/(e+ + e– ) HEAT PAMELA (expected) 0.10 B.G. will be measure accurately at PAMELA (at 1 ~ 5 GeV) and astrophysical ambiguity will be very small !! 0.05 Background (GeV) 0.01 The LTP dark matter signal can be detected at the range ~ 100 GeV. 1 10 5 50 100

  7. Positron Signature from LTP DM Deviation from B.G. Energy bins of width Δ(log E) = 0.60 (E < 40 GeV) Δ(log E) = 0.64 (E > 40 GeV) χ2/d.o.f. = 2.11 > 95% C.L. ( = 1.3) Positron Fraction : e+/(e+ + e– ) 0.024 PAMELA f = 1.4 TeV mh = 340 GeV m = 220 GeV (sample point) bins 0.020 Signal + B.G. Background 0.016 BF = 5 Hooper & Silk (2004) 50 100 200 500 E (GeV) PAMERA may be capable of observing the LTP dark matter. (AMS-02, the sensitivity is improved, can detect the signature even if BF = 1)

  8. Summary • We investigate the possibility to detect the signature of the LTP dark matter in indirect detection using positrons. • PAMER can distinguish the signature from B.G. if BF = 5. • AMS-02, the sensitivity is considerably improved, can detect the signature even if BF = 1. Future directions • Constraint the LHMwT from direct detection of LTP dark matter • Gamma-ray signature from G.C. • Anti-proton excess in C.R. and neutrino flux from the Sun.

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