Pair production by a constant external field in noncommutative QED

In this Letter we study QED on the noncommutative space in the constant ele ctromagnetic field background. Using the explicit solutions of the noncommu tative version of Dirac equation in such background, we show that there are well-defined in- and out-going asymptotic states and also there is a causa l Green's function. We calculate the pair production rate in this case. We show that at tree level noncommutativity will not change the pair productio n and the threshold electric field. We also calculate the pair production r ate considering the first loop corrections. In this case we show that the t hreshold electric field is decreased by the noncommutativity effects. (C) 2 001 Published by Elsevier Science B.V.