Proceedings of the *Particle Physics and Early Universe
Conference * (PPEUC).

**For this paper:**
postscript
PPEUC CMB index
1 Introduction ...

# A New Statistic for the Detection of Long Strings in Microwave
Background Maps

Leandros Perivolaropoulos

*Department of Physics,
University of Crete,*

71003 Heraklion, GREECE

## Abstract:

A new statistic is discussed, designed to detect isolated coherent step-like
discontinuities produced by cosmic strings present at late times. As a
background I superpose a scale invariant Gaussian random field which could have
been produced by a superposition of seeds on all scales and/or by inflationary
quantum fluctuations. The effects of uncorrelated Gaussian random noise are
also included. The statistical variable considered is the Sample Mean
Difference (SMD) between large neighbouring sectors of CMB maps, separated by
straight lines in two dimensional maps and points in one dimensional maps. I
find that the SMD statistics can detect * at the level* the
presense of a long string with while more conventional statistics
like the skewness or the kurtosis require a value of almost an order of
magnitude larger for detectability at a comparable level.

*PPEUC Proceedings*

Fri Jul 25 11:45:54 BST 1997