arXiv subjects

Nicolas Bernal

Publications and source records attributed to Nicolas Bernal.

22 records · Page 2Linked to original sources

arXiv2009

BMSSM Implications for Cosmology

The addition of non-renormalizable terms involving the Higgs fields to the MSSM (BMSSM) ameliorates the little hierarchy problem of the MSSM. We analyze in detail the two main cosmological issues affected by the BMSSM: dark matter and baryogenesis. The regions for which the relic abundance of the LSP is consistent with WMAP and collider constraints are identified, showing that the bulk region and other previously excluded regions are now permitted. Requiring vacuum stability limits the allowed regions. Based on a two-loop finite temperature effective potential analysis, we show that the electroweak phase transition can be sufficiently first order in regions that for the MSSM are incompatible with the LEP Higgs mass bound, including parameter values of \tanβ\lsim 5, m_{\tilde{t}_{1}} > m_t, m_Q << TeV.

hep-ph↗

arXiv2009

Dark matter direct detection in the MSSM with heavy scalars

We explore the dark matter detection prospects in the Minimal Supersymmetric Standard Model in the scenario where the scalar partners of the fermions and the Higgs particles (except for the Standard-Model-like one) are assumed to be very heavy and are removed from the low-energy spectrum. We analyse the neutralino LSP ($χ_1^0$) in scenarios where the gaugino mass parameters are universal at the GUT scale and also the case where they are non-universal. This analysis is carried out in the framework of a Xenon-like 100 kg experiment. In general, an important fraction of the parameter space giving rise to the dark matter relic density measured by WMAP can be probed and excluded in the case of not detecting any WIMP. In the opposite case, once a WIMP signal has been found, we show that for a light $χ_1^0$ which is a higgsino-gaugino mixture it is possible to reconstruct efficiently the mass and the scattering cross-section of the neutralino LSP. Moreover, we show that it is also feasible to put strong constraints over some of the parameters of the Lagrangian, e.g. the higgsino and the gaugino mass parameters.

hep-ph↗

arXiv2009

Single Higgs-boson production through gamma-gamma scattering within the general 2HDM

The production of a single neutral Higgs boson h through (loop-induced) gamma-gamma collisions is explored in the context of the linear colliders within the general Two-Higgs-Doublet Model (2HDM). Two different mechanisms are analyzed: on the one hand, the scattering gamma gamma-> h of two real photons in a gamma-gamma collider; on the other, the more traditional mechanism of virtual photon fusion, e+e- -->e+e- + h. Owing to the peculiar properties of the Higgs boson self-interactions within the general 2HDM, we find that the overall production rates can be boosted up significantly, provided the charged Higgs mass is not too heavy. For example, if the latter is slightly above 100 GeV and, in addition, the lightest CP-even Higgs boson falls in the ballpark of the LEP bound on the SM Higgs mass up to a few hundred GeV, the cross-sections may typically render σ(gamma gamma-> h)= 0.1-1 pb and σ(e+e- --> e+e- + h)\sim 0.01 pb -- in both cases well above the SM prediction. Although for charged Higgs masses above 300 GeV the rates become virtually insensitive to the Higgs boson self-couplings, a significant tail of non-SM effects produced by the combined contribution of the Yukawa couplings and gauge bosons could still reveal a smoking gun.

hep-ph↗

arXiv2008

WIMP mass from direct, indirect dark matter detection experiments and colliders: A complementary and model-independent approach

We study the possibility of identifying dark matter properties from direct (XENON100) and indirect (GLAST) detection experiments. In the same way, we examine the perspectives given by the next generation of colliders (ILC). All this analysis is done following a model-independent approach. We have shown that the three detection techniques can act in a highly complementary way. whereas direct detection experiments will probe efficiently light WIMPs, given a positive detection (at the 10% level for $m_χ \sim 50$ GeV), GLAST will be able to confirm and even increase the precision in the case of a NFW profile, for a WIMP-nucleon cross-section $σ_{χ-p}<10^{-8}$ pb. However, for heavier WIMP ($\sim 175$ GeV), the ILC will lead the reconstruction of the mass.

hep-ph↗