An alternative explanation for the Θ(1540) pentaquark peak

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We have studied the γd → K+ K- n p reaction in which the LEPS collaboration found a signal in the K+ n invariant mass for the claimed Θ(1540) pentaquark peak. Our study reveal that the procedure used at LEPS to reconstruct the K+n invariant mass generates an artificial strength in the Θ(1540) region and that the LEPS collaboration underestimated the background in that region, such that the signal observed for the Θ(1540) is compatible with a fluctuation of 2σ over the calculated background.