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Post Info TOPIC: SO(5) x U(1) gauge bosons


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Posts: 131433
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Vortons
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Title: Creating vortons and three-dimensional skyrmions from domain wall annihilation with stretched vortices in Bose-Einstein condensates
Authors: Muneto Nitta, Kenichi Kasamatsu, Makoto Tsubota, Hiromitsu Takeuchi

We propose a mechanism to create a vorton or three-dimensional skyrmion in phase-separated two-component BECs with the order parameters Psi_1 and Psi_2 of the two condensates. We consider a pair of a domain wall (brane) and an anti-domain wall (anti-brane) stretched by vortices (strings), where the Psi_2 component with a vortex winding is sandwiched by two domains of the Psi_1 component. The vortons appear when the domain wall pair annihilates. Experimentally, this can be realized by preparing the phase separation in the order Psi_1, Psi_2 and Psi_1 components, where the nodal plane of a dark soliton in Psi_1 component is filled with the Psi_2 component with vorticity. By selectively removing the filling Psi_2 component gradually with a resonant laser beam, the collision of the brane and anti-brane can be made, creating vortons.

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Posts: 131433
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Skyrmions
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Title: Dangerous Skyrmions in Little Higgs Models
Authors: Marc Gillioz

Skyrmions are present in many models of electroweak symmetry breaking where the Higgs is a pseudo-Goldstone boson of some strongly interacting sector. They are stable, composite objects whose mass lies in the range 10-100 TeV and can be naturally abundant in the universe due to their small annihilation cross-section. They represent therefore good dark matter candidates. We show however in this work that the lightest skyrmion states are electrically charged in most of the popular little Higgs models, and hence should have been directly or indirectly observed in nature already. The charge of the skyrmion under the electroweak gauge group is computed in a model-independent way and is related to the presence of anomalies in the underlying theory via the Wess-Zumino-Witten term.

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Posts: 131433
Date:
SO(5) x U(1) gauge bosons
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Title: Collider signatures of the SO(5) x U(1) gauge-Higgs unification
Authors: Yutaka Hosotani, Minoru Tanaka, Nobuhiro Uekusa

Collider signatures of the SO(5) x U(1) gauge-Higgs unification model in the Randall-Sundrum warped space are explored. Gauge couplings of quarks and leptons receive small corrections from the fifth dimension whose effects are tested by the precision data. It is found that the forward-backward asymmetries in e^+e^- collisions on the Z pole are well explained in a wide range of the warp factor z_L, but the model is consistent with the branching fractions of Z decay only for large z_L \simg 10^{15}. Kaluza-Klein (KK) spectra of gauge bosons, quarks, and leptons as well as gauge and Higgs couplings of low-lying KK excited states are determined. Right-handed quarks and leptons have larger couplings to the KK gauge bosons than left-handed ones. Production rates of Higgs bosons and KK states at Tevatron, LHC and ILC are evaluated. The first KK Z has a mass 1130 GeV with a width 415 GeV for z_L = 10^{15}. The model is consistent with the current limit on the Z' production at Tevatron and LHC with z_L \simg 10^{15}. A large effect of parity violation appears in the difference between the rapidity distributions of e^+ and e^- in the decay of the first KK Z. The first KK gauge bosons decay into light and heavy quarks evenly.

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