A COSMIC STRING-SPECIFIC SIGNATURE ON THE COSMIC MICROWAVE BACKGROUND

Using an analytical model for the string network, we show that the kur tosis of cosmic microwave background (CMB) temperature gradient maps i s a good statistic to distinguish between the cosmic string model and inflationary models of structure formation. The difference between the stringy and the inflationary value for the kurtosis is inversely prop ortional to the angular resolution and to the number of strings per Hu bble volume of the strings' scaling solution. If strings are indeed re sponsible for CMB anisotropies, then experiments with resolutions of a couple of arcminutes or smaller could determine it using this statist ic.