Large distance asymptotic behavior of the emptiness formation   probability of the XXZ spin-1/2 Heisenberg chain
  Using its multiple integral representation, we compute the large distance asymptotic behavior of the emptiness formation probability of the XXZ spin-1/2 Heisenberg chain in the massless regime. 
N. Kitanine, J. M. Maillet, N. A. Slavnov, V. Terras