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Title: Cosmic positron signature from dark matter in the littlest Higgs model with T parity

Abstract

We calculate the flux of cosmic positrons from the dark matter annihilation in the littlest Higgs model with T parity. The dark matter annihilates mainly into weak gauge bosons in the halo, and high-energy positrons are produced through leptonic and hadronic decays of the bosons. We investigate a possibility to detect the positron signal in upcoming experiments such as PAMELA and AMS-02. We found that the dark matter signal can be distinguished from the background in the PAMELA experiment when the dark matter mass is less than 120 GeV and the signal flux is enhanced due to a small scale clustering of dark matter. Furthermore, the signal from the dark matter annihilation can be detected in the AMS-02 experiment, even if such enhancement does not exist. We also discuss the invisible width of the Higgs boson in this model.

Authors:
; ;  [1];  [2];  [1]
  1. Theory Group, KEK, Oho 1-1 Tsukuba, 305-0801 (Japan)
  2. (Sokendai), Oho 1-1 Tsukuba, 305-0801 (Japan)
Publication Date:
OSTI Identifier:
21020130
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 75; Journal Issue: 6; Other Information: DOI: 10.1103/PhysRevD.75.063506; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ANNIHILATION; COSMIC POSITRONS; GEV RANGE; HADRONIC PARTICLE DECAY; HIGGS BOSONS; HIGGS MODEL; LEPTONIC DECAY; NONLUMINOUS MATTER; PARITY; PARTICLE IDENTIFICATION; PARTICLE WIDTHS; REST MASS

Citation Formats

Asano, Masaki, Okada, Nobuchika, Okada, Yasuhiro, The Graduate University for Advanced Studies, and Matsumoto, Shigeki. Cosmic positron signature from dark matter in the littlest Higgs model with T parity. United States: N. p., 2007. Web. doi:10.1103/PHYSREVD.75.063506.
Asano, Masaki, Okada, Nobuchika, Okada, Yasuhiro, The Graduate University for Advanced Studies, & Matsumoto, Shigeki. Cosmic positron signature from dark matter in the littlest Higgs model with T parity. United States. doi:10.1103/PHYSREVD.75.063506.
Asano, Masaki, Okada, Nobuchika, Okada, Yasuhiro, The Graduate University for Advanced Studies, and Matsumoto, Shigeki. Thu . "Cosmic positron signature from dark matter in the littlest Higgs model with T parity". United States. doi:10.1103/PHYSREVD.75.063506.
@article{osti_21020130,
title = {Cosmic positron signature from dark matter in the littlest Higgs model with T parity},
author = {Asano, Masaki and Okada, Nobuchika and Okada, Yasuhiro and The Graduate University for Advanced Studies and Matsumoto, Shigeki},
abstractNote = {We calculate the flux of cosmic positrons from the dark matter annihilation in the littlest Higgs model with T parity. The dark matter annihilates mainly into weak gauge bosons in the halo, and high-energy positrons are produced through leptonic and hadronic decays of the bosons. We investigate a possibility to detect the positron signal in upcoming experiments such as PAMELA and AMS-02. We found that the dark matter signal can be distinguished from the background in the PAMELA experiment when the dark matter mass is less than 120 GeV and the signal flux is enhanced due to a small scale clustering of dark matter. Furthermore, the signal from the dark matter annihilation can be detected in the AMS-02 experiment, even if such enhancement does not exist. We also discuss the invisible width of the Higgs boson in this model.},
doi = {10.1103/PHYSREVD.75.063506},
journal = {Physical Review. D, Particles Fields},
number = 6,
volume = 75,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}
  • We show that there are regions in the parameter space of the Littlest Higgs model with T-parity, allowed by electroweak precision data, where the Higgs boson can decay invisibly into a pair of heavy photons A{sub H} with a substantial branching ratio. For a symmetry breaking scale f in the range 450-600 GeV, the BR(H{yields}A{sub H}A{sub H}) can be up to 95% for an intermediate mass Higgs, and from 20% down to a few percents for a Higgs boson of mass 200 GeV or above. The total decay width of the Higgs boson can thereby be enhanced by an ordermore » of magnitude compared to the Standard Model for Higgs masses around 130 GeV.« less
  • In the littlest Higgs model with T-parity new flavor-changing interactions between mirror fermions and the standard model (SM) fermions can induce various flavor-changing neutral-current decays for B-mesons, the Z-boson, and the Higgs boson. Since all these decays induced in the littlest Higgs with T-parity model are correlated, in this work we perform a collective study for these decays, namely, the Z-boson decay Z{yields}bs, the Higgs-boson decay h{yields}bs, and the B-meson decays B{yields}X{sub s}{gamma}, B{sub s}{yields}{mu}{sup +}{mu}{sup -}, and B{yields}X{sub s}{mu}{sup +}{mu}{sup -}. We find that under the current experimental constraints from the B-decays, the branching ratios of both Z{yields}bs andmore » h{yields}bs can still deviate from the SM predictions significantly. In the parameter space allowed by the B-decays, the branching ratio of Z{yields}bs can be enhanced up to 10{sup -7} (about one order above the SM prediction) while h{yields}bs can be much suppressed relative to the SM prediction (about one order below the SM prediction)« less
  • We study the collider phenomenology of a littlest Higgs model with T parity. We first stress the important role of the T-odd SU(2)-doublet fermions (introduced to make the model T-parity invariant) in high energy scattering processes, such as qq{yields}W{sub H}{sup +}W{sub H}{sup -} where W{sub H}{sup {+-}} are the T-odd partners of W bosons. Because the mass of the T-odd SU(2)-doublet fermions cannot be too heavy to be consistent with low energy data, they can be copiously produced at the CERN Large Hadron Collider (LHC). Therefore, we study the collider phenomenology of the model with emphasis on the contributions ofmore » the T-odd fermion to the production of the heavy T-parity partners (either bosons or fermions) of the usual particles at the LHC. The production cross sections and the decay branching ratios of the new heavy particles are classified and various experimental signatures are discussed.« less
  • The D{yields}X{sub u}l{sup +}l{sup -} transitions -- branching ratios, forward-backward (FB) asymmetry A{sub FB}{sup c}, the CP asymmetry A{sub CP}{sup c}, and the CP asymmetry in the forward-backward asymmetry A{sub FB}{sup CP} -- have two sources: for D{sup {+-}}they represent a pure {Delta}C=1 and {Delta}Q=0 current interaction whereas neutral D mesons can also communicate via their antihadron. Standard model (SM) contributions to BR(D{yields}X{sub u}l{sup +}l{sup -}) come primarily from long distance dynamics, which overshadow short distance contributions by several orders of magnitude; still they fall much below the present upper experimental bounds. Even the SM contributions to A{sub FB}{sup c},more » A{sub CP}{sup c}, and A{sub FB}{sup CP} are tiny, quite unlike in beauty hadrons. The branching ratios are hardly dented by contributions from the littlest Higgs models with T parity (LHT) even in the short distance regime, let alone in the SM long distances dynamics. Yet the asymmetries A{sub FB}{sup c}, A{sub CP}{sup c}, and A{sub FB}{sup CP} in these new physics models can be enhanced over SM predictions, as they arise purely from short distance dynamics; this can occur, in particular, for A{sub FB}{sup c} and A{sub FB}{sup CP}, which get enhanced by orders of magnitudes. Even such enhancements hardly reach absolute sizes for observable experimental effects for A{sub FB}{sup c} and A{sub CP}{sup c}. However, LHT contributions to A{sub FB}{sup CP} could be measured in experiments like the LHCb and the SuperB Collaboration. These results lead us to draw further conclusions on flavor-changing neutral-current interactions within LHT-like models through some simple scaling arguments that encapsulate the essence of flavor dynamics in and beyond the standard model.« less