Improved method to extract nucleon helicity distributions using event weighting

An improved analysis method to extract quark helicity distributions in leading order (LO) QCD from semi-inclusive double spin asymmetries in deep inelastic scattering is presented. The method relies on the fact that fragmentation functions, describing the fragmentation of a quark into a hadron, have...

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Bibliographic Details
Published in:Journal of instrumentation 2017-02, Vol.12 (2), p.P02007-P02007
Main Author: Pretz, J.
Format: Article
Language:English
Subjects:
Figure of merit
Fragmentation
Hadrons
Helicity
Mathematical analysis
Mathematical models
Quarks
Vectors (mathematics)
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Summary:An improved analysis method to extract quark helicity distributions in leading order (LO) QCD from semi-inclusive double spin asymmetries in deep inelastic scattering is presented. The method relies on the fact that fragmentation functions, describing the fragmentation of a quark into a hadron, have a strong dependence on the energy fraction z of the observed hadron. Hadrons with large z contain more information about the struck quark. This can be used in a weighting procedure to improve the figure of merit (= inverse of variance). In numerical examples it is shown that one could gain 15-39% depending on the quark flavor and cut on z. Mathematically the problem can be described as finding an optimal solution in terms of the figure of merit for parameters [Theta] determined from a system of linear equations B(x) [Theta] =Y(x), where the measured input vector Y(x) is given as event distributions depending on a random variable x, the coefficients of the matrix B(x) depend as well on x, whereas the parameter vector [Theta] to be determined does not.
ISSN:1748-0221
1748-0221
DOI:10.1088/1748-0221/12/02/P02007