Nucleon matrix elements of twist-3 and 4 operators from the instanton vacuum
| dc.creator | Balla, J. | |
| dc.creator | Polyakov, M. V. | |
| dc.creator | Weiss, C. | |
| dc.date | 1999-01-26 | |
| dc.date.accessioned | 2026-07-07T04:06:19Z | |
| dc.date.available | 2026-07-07T04:06:19Z | |
| dc.description | The spin-dependent twist-3 and 4 nucleon matrix elements d^(2) and f^(2) describing power corrections to the Bjorken and Ellis-Jaffe sum rules are computed in the instanton vacuum. A systematic expansion in the small packing fraction of the instanton medium, rho / R << 1, is performed. We find that the twist-3 matrix element d^(2) is suppressed [of order (rho / R)^4], while the twist-4 matrix element f^(2) is of order unity. Numerically, d^(2) << f^(2). The small value of d^(2) \sim 10^{-3} obtained from instantons is consistent with the recent E143 measurements of the structure function g_2, where d^(2) enters at the same level as the twist-2 contribution. | |
| dc.description | 6 pages, LaTeX. Oral contribution to the 8th International Conference on the Structure of Baryons (Baryons '98), Bonn, Sep. 22-26, 1998; to appear in the Proceedings | |
| dc.identifier | https://arxiv.org/abs/hep-ph/9901425 | |
| dc.identifier | http://arxiv.org/abs/hep-ph/9901425 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/48721 | |
| dc.subject | High Energy Physics - Phenomenology | |
| dc.title | Nucleon matrix elements of twist-3 and 4 operators from the instanton vacuum | |
| dc.type | text |