Ref Arxiv: 1605.02684
Ref. & Cit.: NASA ADS
Résumé:

We present the activities of the 'New Physics' working group for the 'Physics at TeV Colliders' workshop (Les Houches, France, 1-19 June, 2015). Our report includes new physics studies connected with the Higgs boson and its properties, direct search strategies, reinterpretation of the LHC results in the building of viable models and new computational tool developments. Important signatures for searches for natural new physics at the LHC and new assessments of the interplay between direct dark matter searches and the LHC are also considered.

Commentaires: Proceedings of the New Physics Working Group of the 2015 Les Houches Workshop, Physics at TeV Colliders, Les Houches 1-19 June 2015. 197 pages

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Commentaires: Status of lepton physics as of 2015

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PMID 25983647
Ref Arxiv: 1409.0659
DOI: 10.1140/epjc/s10052-014-3252-1
WoS: WOS:000348993400003
Ref. & Cit.: NASA ADS
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40 Citations
Résumé:

We show that novel paths to dark matter generation and baryogenesis are open when the Standard Model is extended with three sterile neutrinos $N_i$ and a charged scalar $\delta^+$. Specifically, we propose a new production mechanism for the dark matter particle --a multi-keV sterile neutrino, $N_1$-- that does not depend on the active-sterile mixing angle and does not rely on a large primordial lepton asymmetry. Instead, $N_1$ is produced, via freeze-in, by the decays of $\delta^+$ while it is in equilibrium in the early Universe. In addition, we demonstrate that, thanks to the couplings between the heavier sterile neutrinos $N_{2,3}$ and $\delta^+$, baryogenesis via leptogenesis can be realized close to the electroweak scale. The lepton asymmetry is generated either by $N_{2,3}$-decays for masses $M_{2,3}\gtrsim$ TeV, or by $N_{2,3}$-oscillations for $M_{2,3}\sim$ GeV. Experimental signatures of this scenario include an X-ray line from dark matter decays, and the direct production of $\delta^+$ at the LHC. This model thus describes a minimal, testable scenario for neutrino masses, the baryon asymmetry, and dark matter.

Commentaires: 15 pages

Ref HAL: hal-00803544_v1
Ref Arxiv: 1303.5284
DOI: 10.1007/JHEP07(2013)146
WoS: 000323202900059
Ref. & Cit.: NASA ADS
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2 Citations
Résumé:

Present data prefer a large but non-maximal 2-3 mixing in the lepton sector. We argue that this value, in connection with $\sin\theta_{13}\simeq 0.15$, is the generic outcome of minimal flavour structures. We present a few different incarnations of this statement, in terms of lepton mass matrices depending on a small number of parameters, that can be justified by discrete flavour symmetries. We also propose a general procedure to study the correlation between $\theta_{23}$, the absolute scale and ordering of the neutrino masses, and the leptonic CP-violating phases.

Commentaires: 24 pages, 10 figures

Ref HAL: hal-00820347_v1
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Résumé:

I will argue that pseudo Nambu-Goldstone bosons (pNGBs) may be natural candidates for the dark matter (DM). I will present two scenarios where the mass and the interactions of the pNGBs are connected to the electroweak scale. In this case the DM properties are interlaced with the properties of the Higgs boson. The computation of the DM relic density and the detection perspectives will be discussed.

Ref HAL: hal-00820342_v1
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Résumé:

Light scalars can be natural without supersymmetry, if they are not elementary particles, rather composite states emerging from a strongly-coupled sector. I will show that the Higgs and the dark matter could be the lightest states of such a sector. Indeed, they are the pseudo Nambu-Goldstone bosons of composite models based on the coset $O(6)/O(5)$. Their low-energy interactions are determined by symmetry considerations. I will identify the region of parameters where composite scalar dark matter has the required relic density, satisfying at the same time the constraints from Higgs searches at the LHC, as well as dark matter searches. Compositeness can enhance the dark matter scattering rates and lead to an excellent discovery prospect for the near future.

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Ref Arxiv: 1204.2808
DOI: 10.1007/JHEP07(2012)015
WoS: 000307298400015
Ref. & Cit.: NASA ADS
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122 Citations
Résumé:

We show that the dark matter (DM) could be a light composite scalar $\eta$, emerging from a TeV-scale strongly-coupled sector as a pseudo Nambu-Goldstone boson (pNGB). Such state arises naturally in scenarios where the Higgs is also a composite pNGB, as in $O(6)/O(5)$ models, which are particularly predictive, since the low-energy interactions of $\eta$ are determined by symmetry considerations. We identify the region of parameters where $\eta$ has the required DM relic density, satisfying at the same time the constraints from Higgs searches at the LHC, as well as DM direct searches. Compositeness, in addition to justify the lightness of the scalars, can enhance the DM scattering rates and lead to an excellent discovery prospect for the near future. For a Higgs mass $m_h\simeq 125$ GeV and a pNGB characteristic scale $f \lesssim 1$ TeV, we find that the DM mass is either $m_\eta \simeq 50-70$ GeV, with DM annihilations driven by the Higgs resonance, or in the range 100-500 GeV, where the DM derivative interaction with the Higgs becomes dominant. In the former case the invisible Higgs decay to two DM particles could weaken the LHC Higgs signal.

Commentaires: 19 pages + appendices, 16 figures