Stabilite en niveau 0 pour les groupes orthogonaux impairs p-adiques

Abstract

In this paper, we construct stable distributions on the set of elliptic elements of an odd orthogonal groups (over a p-adic field with p large). Theses distributions are of zero level. They are parametrised by Langlands like parameters. In the second part of the paper, we show how to interpret these distributions in term of characters of discrete series; this is conditional to a result of A.-M. Aubert which announces how to reduce the zero level case to the case of unipotent reduction using the Lusztig's induction. But, modulo this explicit hypothesis, we prove that our computation will determine all the stable linear combinations of discrete series of zero level for $SO(2n+1)$. The link between the parameters of stable distributions and stable linear combinations of discrete series is done by using a Fourier like involution on the set of parameters.