Challenges and concepts for design of an interaction region with push-pull arrangement of detectors - An interface document by Parker, B, Herve, A, Osborne, J, Mikhailichenko, A, Buesser, K, Ashmanskas, B, Kuchler, V, Mokhov, N, Enomoto, A, Sugimoto, Y, Tauchi, T, Tsuchiya, K, Weisend, J, Burrows, P, Markiewicz, T, Oriunno, M, Seryi, A, Sullivan, M, Angal-Kalinin, D, Sanuki, T, Yamamoto, H