arXiv subjects

J. A. R. Cembranos

Publications and source records attributed to J. A. R. Cembranos.

65 records · Page 4Linked to original sources

arXiv2004

Branon search in hadronic colliders

In the context of the brane-world scenarios with compactified extra dimensions, we study the production of brane fluctuations (branons) in hadron colliders ($p \bar p$, $pp$ and $e^\pm p$) in terms of the brane tension parameter $f$, the branon mass $M$ and the number of branons $N$. From the absence of monojets events at HERA and Tevatron (run I), we set bounds on these parameters and we also study how such bounds could be improved at Tevatron (run II) and the future LHC. The single photon channel is also analyzed for the two last colliders.

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arXiv2004

Branon dark matter

In the brane-world scenario, our universe is understood as a three dimensional hypersurface embedded in a higher dimensional space-time. The fluctuations of the brane along the extra dimensions are seen from the four-dimensional point of view as new fields whose properties are determined by the geometry of the extra space. We show that such branon fields can be massive, stable and weakly interacting, and accordinlgy they are natural candidates to explain the universe missing mass problem. We also consider the possibility of producing branons non-thermally and their relevance in the cosmic coincidence problem. Finally we show that some of the branon distinctive signals could be detected in future colliders and in direct or indirect dark matter searches.

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arXiv2004

Dark Geometry

Extra-dimensional theories contain additional degrees of freedom related to the geometry of the extra space which can be interpreted as new particles. Such theories allow to reformulate most of the fundamental problems of physics from a completely different point of view. In this essay we concentrate on the brane fluctuations which are present in brane-worlds, and how such oscillations of the own space-time geometry along curved extra dimensions can help to resolve the Universe missing mass problem. The energy scales involved in these models are low compared to the Planck scale, and this means that some of the brane fluctuations distinctive signals could be detected in future colliders and in direct or indirect dark matter searches.

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arXiv2004

Branons as dark matter

In the brane-world scenario with low tension, brane fluctuations (branons) together with the Standard Model particles are the only relevant degrees of freedom at low energies. Branons are stable, weakly interacting, massive particles and their relic abundance can account for the dark matter of the universe. In a certain range of the parameter space, they could be detectable by future direct search experiments.

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arXiv2003

Cosmological and astrophysical limits on brane fluctuations

We consider a general brane-world model parametrized by the brane tension scale $f$ and the branon mass $M$. For low tension compared to the fundamental gravitational scale, we calculate the relic branon abundance and its contribution to the cosmological dark matter. We compare this result with the current observational limits on the total and hot dark matter energy densities and derive the corresponding bounds on $f$ and $M$. Using the nucleosynthesis bounds on the number of relativistic species, we also set a limit on the number of light branons in terms of the brane tension. Finally, we estimate the bounds coming from the energy loss rate in supernovae explosions due to massive branon emission.

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arXiv2003

Living on a brane

We briefly review the distinctive signals of brane world models with low tension. We pay special attention to the brane fluctuations (branons), whose phenomenological consequences could be important both in high energy particle physics experiments and in astrophysical and cosmological observations.

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arXiv2003

Brane-world dark matter

We show that, in the context of brane-world scenarios with low tension $τ=f^4$, massive brane fluctuations are natural dark matter candidates. We calculate the present abundances for both hot(warm) and cold branons in terms of the branon mass $M$ and the tension scale $f$. The results are compared with the current experimental bounds on these parameters. We also study the prospects for their detection in direct search experiments and comment on their characteristic signals in the indirect ones.

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arXiv2003

Limits on the brane fluctuations mass and on the brane tension scale from electron-positron colliders

In the context of the brane-world scenarios with compactified large extra dimensions, we study the production of the possible massive brane oscillations (branons) in electron-positron colliders. We compute their contribution to the electroweak gauge bosons decay width and to the single-photon and single-Z processes. With LEP-I results and assuming non observation at LEP-II, we present exclusion plots for the brane tension $τ= f^4$ and the branon mass $M$. Prospects for the next generation of electron-positron colliders are also considered.

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arXiv2003

Phenomenological implications of brane world scenarios with low tension

The recent proposal of theories with compactified large extra dimensions is reviewed. We pay especial attention to brane world models with low tension where the only relevant degrees of freedom at low energies are the Standard Model (SM) particles and the branons, which are transversal brane oscillations. By using an effective Lagrangian, we study some phenomenological consequences of these scenarios in a model independent way.

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arXiv2001

Brane-skyrmions and wrapped states

In the context of a brane world and including an induced curvature term in the brane action, we obtain the effective lagrangian for the Goldstone bosons (branons) associated with the spontaneous breaking of the translational invariance in the bulk. In addition to the branons, this effective action has Skyrmion-like solitonic states which can be understood as holes in the brane. We study their main properties such as mass and size, the Skyrmion-branon interaction and their possible fermionic quantization. We also consider states where the brane is wrapped around the extra dimensions and their relation with the brane-skyrmions. Finally, we extend our results to higher-dimensional branes, such as those appearing in M-theory, where brane-skyrmions could also be present.

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arXiv2001

Goldstone bosons and solitons on the brane

In this work we compute the effective action describing the low-energy brane Goldstone-boson dynamics. The Goldstone bosons or branons appear because the brane spontaneously breaks the translational invariance along the extra dimensions. We discuss the Higgs-like mechanism in which the Kaluza-Klein gauge fields absorb the Goldstone bosons and acquire mass. We also present the explicit form of the effective action describing the low-energy interactions between the three-brane Goldstone bosons and the Standard Model fields. In addition to the branons, two new kinds of states arise corresponding to Skyrmion-like solutions and wrapped states. We study the main properties of these states, their geometrical interpretation and the relations between them.

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