What is 'Jazz' ?
Accepted answer
The author of "The Jazz Process" is Adrian Cho, who is also the director of Rational CLM Development, so I think they are very much related. IBM's Jazz-based tools support the ideas in "The Jazz Process", I believe. (However, Adrian is referring to jazz music, and drawing an analogy between its practices and other team-based human endeavors.)
One other answer
"The Jazz Platform" is a software development platform developed by IBM that, amongst other things, enables collaboration across teams. Tools like Rational Team Concert, Rational Quality Manager and Rational Requirements Composer build on the Jazz Platform and because all these tools are integrated on the same foundation, they facilitate collaboration across disciplines in the software lifecycle (e.g. developing, testing, requirements analysis, etc.)
If you're looking at some link on "pic.dhe.ibm" you're likely reading something in the documentation which is referring to the "Jazz process" framework that is implemented in the Jazz Platform and surfaced through tools such as Rational Team Concert. It allows you to define and evolve software development process that the tools can help you enforce. I discussed process management in the Jazz Platform in "The Jazz Process" in terms of the importance of having "just enough rules" that give people the freedom to innovate while ensuring that things don't devolve into chaos.