8. A computer program product for query processing based on normalized search terms, the computer program product comprising: a non-transitory computer-readable storage medium having computer-readable program code embodied therewith, the computer-readable program code comprising: computer-readable program code configured to, responsive to receiving a query, generate a normalized search term for a concept in the query based on a first language model, of a plurality of language models each having a predefined association with a respective concept; computer-readable program code configured to modify the query to include the normalized search term; computer-readable program code configured to execute the modified query against the indexed corpus of evidence, where the corpus of evidence is indexed based on the plurality of language models to include a set of normalized terms for each respective item of evidence in the corpus, wherein the indexed corpus of evidence includes a first item of evidence used to support a first candidate answer, of a plurality of candidate answers; and computer-readable program code configured to, upon determining that the set of normalized terms for the first item of evidence includes the normalized search term, returning the first candidate answer as responsive to the query.
12. The computer program product of claim 8 , wherein the concept is separately expressed by each of a plurality of variants.