Double-scattering contribution tob1(x,Q2)in the deuteron

Abstract

We study the tensor structure function b 1 (x, Q 2 ) in deep inelastic scattering (DIS) of an electron from a polarized deuteron target. We model the electron-nucleon cross section at the starting point for Q 2 evolution by vector-meson-dominance (VMD). Shadowing due to the double-scattering of vector mesons, along with the presence of a d-state admixture in ground state deuteron wave function gives rise to a non-vanishing contribution to b 1 (x, Q 2 ).We find a large enhancement at low-x in qualitative agreement with other recent estimates of double-scattering contributions to b 1 (x, Q 2 ). If the model is valid, it should apply within the range of present fixed target experiments.

Projections of structure functions in a spin-one hadron

“…The data indicated a finite distribution at x < 0.1, which roughly agrees with a double scattering contribution estimated in Ref. [11]. The data are also consistent with the quark-parton model sum rule for b 1 [13] although experimental errors are still large.…”

“…It should be noted that b 1 vanishes if spin-1/2 constituents are in the orbital S state, so that it is sensitive to dynamical aspects of spin and orbital structure and possibly to non-nucleonic degrees of freedom, for example, in the deuteron. In conventional approaches, such tensor structure arises due to the D state admixture [3,4], pions [9], and shadowing effects [10,11] in a nucleus. However, as it became obvious in the nucleon spin, it is likely that high-energy tensor structure would not be simply described by such conventional models.…”

Target mass effects in deep-inelastic scattering on the deuteron

“…Their results show it to be significantly different from zero, rising as x → 0, and consistent with coherent double scattering model predictions [3,4,5]. However, these measurements were necessarily at a relatively low Q 2 and power corrections may be important in the interpretation of the data.…”

Measurement of the Tensor Structure Functionb1of the Deuteron

“…0, and its magnitude could reach about 1% of the unpolarized structure function F d 1 , due to the same mechanism that leads to the well-known effect of nuclear shadowing in unpolarized scattering [22]. This feature is described by coherent double-scattering models [15,[23][24][25][26][27][28]. The observed b d 1 confirms qualitatively the double-scattering model predictions, except for the negative value at hxi 0:452, which, however, is still compatible with zero at the 2 level.…”