Is there any common research model for supersonic transport?
According to NASA here:


  This test case is an aircraft concept previously used as an optional
  case (LM1021) in the 1st Sonic Boom Prediction Workshop. This
  configuration is described in the following reference: John
  Morgenstern, Nicole Norstrud, Jack Sokhey, Steve Martins, and Juan J.
  Alonso, “Advanced Concept Studies for Supersonic Commercial Transports
  Entering Service in the 2018 to 2020 Period,” NASA
  CR-2013-217820,DOI:2060/20130010174. See NTRS Record. There is also a
  description in the following reference: John M. Morgenstern, Michael
  Buonanno, and Frank Marconi, “Full Configuration Low Boom Model and
  Grids for 2014 Sonic Boom Prediction Workshop,” AIAA-2013-647.