Towards a tensionless string field theory for six-dimensional (2,0) CFT

Low energy dynamics of coincident M5 branes, which are important but elusive objects in M-theory, is conjectured to be described by a conformal field theory in six-dimensions with (2,0) supersymmetry. To obtain the Lagrangian description of the theory is an open problem. I will describe our attempt to obtain such a description by means of formulating interacting field theory of tensionless strings, which arises from M2 branes stretching between the M5 branes. The talk will be based on a work, arxiv:1805.10927, done in collaboration with Sudarshan Ananth(IISER Pune), Stefano Kovacs(Dublin IAS), Yuki Sato(Nagoya Univ. and Chulalongkorn Univ.).