Isocurvature modes in the CMB bispectrum

David Langlois , Bartjan van Tent

We study the angular bispectrum of local type arising from the (possibly correlated) combination of a primordial adiabatic mode with an isocurvature one. Generically, this bispectrum can be decomposed into six elementary bispectra. We estimate how precisely CMB data, including polarization, can enable us to measure or constrain the six corresponding amplitudes, considering separately the four types of isocurvature modes (CDM, baryon, neutrino density, neutrino velocity). Finally, we discuss how the model-independent constraints on the bispectrum can be combined to get constraints on the parameters of multiple-field inflation models.

Domaines: Relativité Générale et Cosmologie Quantique [gr-qc]; Physique des Hautes Energies - Théorie [hep-th]; Astrophysique [astro-ph]

David Langlois, Bartjan van Tent. Isocurvature modes in the CMB bispectrum. Journal of Cosmology and Astroparticle Physics, 2012, 07, pp.040. ⟨10.1088/1475-7516/2012/07/040⟩. ⟨hal-00692526⟩