Polar angle dependence of the longitudinal polarization of quarks produced in e + e - -annihilation

Abstract

We calculate one-loop radiative QCD corrections to the three polarized and unpolarized structure functions that determine the beam-quark polar angle dependence of the longitudinal polarization of light and heavy quarks produced in e>e\-annihilations. We present analytical and numerical results for the longitudinal polarization and its polar angle dependence. We discuss in some detail the zero-mass limit of our results and the role of the anomalous spin-flip contributions to the polarization observables in the zero-mass limit. Our discussion includes transverse and longitudinal beam polarization effects.

Analytical O(αs) corrections to the beam frame double-spin density matrix elements of e<

“…[11,12,13]. This by-product in the present investigation provides a profound cross-check for our calculation.…”

“…In performing these calculations in the beam frame spanned by the momenta of the electron and the quark, it turned out that the integrals necessary for the phase space integration are quite similar to those used by us in former calculations [8,9,10,11,12,13,14,15,16] (see also Ref. [22] for the mathematical background).…”

“…Analytical results for the O(α s ) radiative corrections to longitudinal single-spin polarisation including quark mass effects can be found in Refs. [8,9,10,11,12], and corresponding results for the transverse and normal polarisation components can be found in Ref. [13].…”

“…Ref. [12]). The various components of the lepton tensor L i µν and hadron tensor H i µν are decomposed according to…”

The Z boson spin observables as messengers of new physics

“…At the LEP experiments, this program was exploited for τ leptons [1] and, for general e + e − colliders, proposed for heavy quarks [2][3][4][5]. But for spin-1 vector bosons the number of independent spin observables is eight, requiring a more elaborate discussion.…”