Canonical URL
You might say
Keep the product's campaign URLs accessible, but declare the parameter-free URL as canonical and use it in the sitemap.
A preferred representative URL for pages with the same or very similar contentSeveral product URLs with campaign parameters can remain accessible while each page declares a parameter-free representative URL in its head and the sitemap lists that same address. A canonical is usually a hint to search systems, not a browser redirect; use a redirect when visitors must move.
Also calledrel=canonical
Further reading