We propose a new mechanism of spontaneous supersymmetry breaking in noncomm
utative gauge theories. We find that in N = 1 noncommutative gauge theories
both supersymmetry and gauge invariance are dynamically broken. Supersymme
try is broken spontaneously by a Fayet-Iliopoulos D-term which naturally ar
ises in a noncommutative U(n) theory. For a non-chiral matter content the F
ayet-Iliopoulos term is not renormalized and its tree-level value can be ch
osen to be much smaller than the relevant string/noncommutativity scale. In
the low energy theory, the noncommutative U(n) gauge symmetry is broken do
wn to a commutative U(I) x SU(n). This breaking is triggered by the IR/UV m
ixing and manifests itself at and below the noncommutativity mass scale M-N
C similar to theta (-1/2). In particular, the U(I) degrees of freedom decou
ple from the SU(n) in the infrared and become arbitrarily weakly coupled, t
hus playing the role of the hidden sector for supersymmetry breaking. (C) 2
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