Heterotic M ( atrix ) Strings and Their Interactions 1 Soo - Jong Rey

Following recent proposal of Dijkgraaf, Verlinde and Verlinde, we show that the M(atrix) theory compactified on S1/Z2 provides with a non-perturbative description of second-quantized light-cone heterotic string. This so-called heterotic M(atrix) string theory is defined by twodimensional (8,0) supersymmetric chiral gauge theory with gauge group SO(2N) in the large N limit. We argue that at strong coupling fixed point the chiral gauge theory flows to a (8,0) superconformal field theory defined via SN symmetric product space orbifold. We show that the leading order correction to the strong coupling expansion corresponds to a unique irrelevant operator of scaling dimension three and describes joining and splitting cubic interactions of light-cone heterotic string. We also speculate on M(atrix) description of bosonic strings via dimensional reduction of d=26 Yang-Mills theory. Submitted to Nuclear Physics B 1 Work supported in part by the DOE DE-FG-02-90ER40542, NSF Grant PHY-9513835, NSF-KOSEF Bilateral Grant, KOSEF Purpose-Oriented Research Grant 94-1400-04-01-3 and SRC-Program, Ministry of Education Grant BSRI 97-2410, the Monell Foundation and the Seoam Foundation Fellowships.