The Validity of the Cosmic String Pattern Search with the Cosmic Microwave Background

We introduce a new technique to detect the discrete temperature steps thatcosmic strings might have left in the cosmic microwave background (CMB)anisotropy map. The technique provides a validity test on the pattern search ofcosmic strings that could serve as the groundwork for future pattern searches.The detecting power of the technique is only constrained by two unavoidablefeatures of CMB data: (1) the finite pixelization of the sky map and (2) theGaussian fluctuation from instrumental noise and primordial anisotropy. We setthe upper limit on the cosmic string parameter as $G\mu\lesssim 3.7\times10^{-6}$ at the 95% confidence level (CL) and find that the amplitude of thetemperature step has to be greater than $44\mu K$ in order to be detected forthe {\it{Wilkinson Microwave Anisotropy Probe (WMAP)}} 3 year data.Comment: 9 pages, 3 figures. Revised for publicatio