arXiv subjects

J. G. K"orner

Publications and source records attributed to J. G. K"orner.

5 recordsLinked to original sources

arXiv1996

Current, Pion and Photon Transitions between Heavy Baryons

I discuss the structure of current-induced bottom baryon to charm baryon transitions, and the structure of pion and photon transitions between heavy charm or bottom baryons in the Heavy Quark Symmetry limit as $m_Q\rightarrow\infty$. The emphasis is on the structural similarity of the Heavy Quark Symmetry predictions for the three types of transitions. The discussion involves the ground state $s$-wave heavy baryons as well as the excited $p$-wave heavy baryon states. Using a constituent quark model picture for the light diquark system with an underlying $SU(2N_f)\otimes O(3)$ symmetry one arrives at a number of new predictions that go beyond the Heavy Quark Symmetry predictions.

hep-ph↗

arXiv1996

Polar Angle Dependence of the Alignment Polarization of Quarks Produced in e^+e^- Annihilation

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 alignment (or longitudinal) polarization of light and heavy quarks produced in e^+e^- annihilations. We present analytical and numerical results for the alignment 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.

hep-ph↗

arXiv1995

Lambda_b-Polarization from its Inclusive Semileptonic Decay

We discuss the Lambda_b-polarization of the bottom baryon Lambda_b in its production and in its decay. Standard Model predictions for b-quark polarization on the Z-peak are reviewed, including beam-quark orientation effects and O(as) radiative corrections to the polarization. The b-quark polarization is expected to be handed over to the Lambda_b into which it fragments with a high degree of efficiency. We present several spin-momentum correlation measures of the spin of the Λ_b with the momenta of its decay products in its inclusive semileptonic decay. We estimate the strengths of the spin-momentum correlations in the Free Quark Decay (FQD) model and find that some of the measures provide good or very good analyzing power for measuring the polarization of the Lambda_b.

hep-ph↗

arXiv1995

Longitudinal Contribution to the Alignment Polarization of Quarks Produced in e+ e- Annihilation: An O(alpha_s) Effect

We calculate the longitudinal contribution to the alignment polarization $\Pl$ of quarks produced in $e^+e^-$ annihilation. In the Standard Model, the longitudinal alignment polarization vanishes at the Born term level and thus receives its first non-zero contribution from the $O(\as)$ tree graph process. We provide analytical and numerical results for the longitudinal alignment polarization of massless and massive quarks, in particular for the recently discovered top quark.

hep-ph↗

arXiv1993

One-Loop QCD Mass Effects in the Production of Polarized Bottom and Top Quarks

The analytic expressions for the production cross sections of polarized bottom and top quarks in $e^+e^-$ annihilation are explicitly derived at the one-loop order of strong interactions. Chirality-violating mass effects will reduce the longitudinal spin polarization for the light quark pairs by an amount of $3\%$, when one properly considers the massless limit for the final quarks. Numerical estimates of longitudinal spin polarization effects in the processes $e^+e^-\to b\bar{b}(g)$ and $e^+e^- \to t\bar{t}(g)$ are presented.

hep-ph↗