New determination of ST < N vertical bar(q)over-barD(mu)D(v)q vertical bar N > based on recent experimental constraints

作者：Gubler Philipp^*; Jeong Kie Sang; Lee Su Houng

来源：Physical Review D - Particles, Fields, Gravitation and Cosmology, 2015, 92(1): 014010.

DOI：10.1103/PhysRevD.92.014010

The symmetric and traceless part of the matrix element ST < N vertical bar(q) over barD(mu)D(v)q vertical bar N > can be determined from the second moment of the twist-3 parton distribution function e(x). Recently, novel experimental data on e(x) have become available, which enables us to evaluate the magnitude of the above matrix element with considerably reduced systematic uncertainties. Based on the new experimental data, we show that ST < N vertical bar(q) over barD(mu)D(v)q vertical bar N > is likely to be at least an order of magnitude smaller than what previous model-based estimates have so far suggested. We discuss the consequences of this observation for the analysis of deep inelastic scattering and QCD sum rules studies at finite density for the vector meson and the nucleon in which this matrix element is being used as an input parameter.

• 出版日期2015-7-7