New heterotic string theories in uncompactified dimensions < 10
Abstract
It is shown that infinitely many heterotic string theories exist in uncompactified dimensions less than 10, that are oneloop finite (for massless external legs). Tachyons are removed by compactifying into tori (10  d) and (26 d) dimensions of the rightmoving superstring and leftmoving bosonic string sectors, respectively. The condition for modular invariance is shown to be equivalent to selfduality condition on even lorentzian lattices with (10 d) and (26 d) timelike and spacelike directions, respectively. The construction results in a (10 d)(26 d) parameter family of oneloop finite string theories. The zero mass sector of these theories for d = 4 and 6 correspond to N = 4 and 2 supergravity coupled to super YangMills with many possible groups, some of which cannot be obtained by compactifying d = 10 heterotic string theory.
 Publication:

Physics Letters B
 Pub Date:
 March 1986
 DOI:
 10.1016/03702693(86)906829
 Bibcode:
 1986PhLB..169...41N