Spin asymmetry Ad1 and the spin-dependent structure function gd1 of the deuteron at low values of x and Q2

We present a precise measurement of the deuteron longitudinal spin asymmetry A(1)(d) and of the deuteron spin-dependent structure function g(1)(d) at Q(2) < 1 (GeV/c)(2) and 4 x 10(-5) < x < 2.5 x 10(-2) based on the data collected by the COMPASS experiment at CERN during the years 2002 and 2003. The statistical precision is tenfold better than that of the previous measurement in this region. The measured A(1)(d) and g(1)(d) are found to be consistent with zero in the whole range of x. (c) 2007 Elsevier B.V. All rights reserved.