Upsilons in U+U - paper status (report #18)

Upsilons in U+U paper status report.

HF PWG report #18b
, corresponding to paper version v3
Corresponding documents are here:
https://drupal.star.bnl.gov/STAR/content/upsilons-uu-paper-and-note

updated from collab. meeting report #18, see here:
https://drupal.star.bnl.gov/STAR/system/files/UUUpaperstatus18.pdf