  We consider the coincident root loci consisting of the polynomials with at least two double roots andpresent a linear basis of the corresponding ideal in the algebra of symmetric polynomials in terms of the Jack polynomials with special value of parameter $\alpha = -2.$ As a corollary we present an explicit formula for the Hilbert-Poincar\`e series of this ideal and the generator of the minimal degree as a special Jack polynomial.   A generalization to the case of the symmetric polynomials vanishing on the double shifted diagonals and the Macdonald polynomials specialized at $t^2 q = 1$ is also presented. We also give similar results for the interpolation Jack polynomials. 
Coincident root loci and Jack and Macdonald polynomials for special   values of the parameters