Do papers ever get published posthumously? What is the longest discrepancy between death and publication?
The paper 


  Radcliffe, J. M. "Some properties of coherent spin states." Journal of Physics A: General Physics 4.3 (1971): 313


was submitted in 1970, published in 1971, and contains the following:

 

At the time of writing this post, the paper has 951 Google citations. 

There is no hint as to the date of the passing of Prof. Radcliffe but it is the only publication by this author on MathSciNet; it is entirely possible that Prof. Radcliffe could have published in Journals not covered by MathSciNet.  The Mathematical Genealogy project contains references to a single John Radcliffe who graduated from University of London in 1967, but the general area of the thesis and the aforementioned work do not match very well.

Anyways, this is clearly an example of posthumous publication not done in collaboration.