SearcharxivSearch

arXiv · hep-ph/0602079

Hyperon Polarization in a Quark-Quark Scattering Model

Abstract

A continuing mystery in particle physics is the large polarization observed in inclusive hyperon production in high energy p-p collisions. In this paper the authors advance the concept that the polarization effects can be accounted for in a simple model based on quarks becoming polarized in the direct q-q scattering process and where, at a fundamental level, the s quark is treated no differently than the u and d, except that it is required to have been created as part of a s-sbar pair prior to the collision. The q-q polarization parameters are extracted from p-p elastic scattering using a previous model and these are used to predict the Lambda polarization from the p-p data. Remarkably good agreement is obtained, raising the possibility that the large hyperon polarizations are no more of a mystery than the p-p polarization itself and that, at least at small pt, the two may be simply related. This concept is extended in an attempt to explain the polarizations observed in other inclusive hyperon processes with the finding that hyperon and elastic polarizations, which previously seemed almost unrelated, may have a simple and common origin.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Homer A. Neal, Eduard De La Cruz Burelo. 2006-02-09. Hyperon Polarization in a Quark-Quark Scattering Model. https://doi.org/10.1063/1.2750818

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Axionic Wormholes in Metric-Affine Gravity

The axion is a promising candidate for solving the strong CP problem. To solve this problem, the global U(1) symmetry must be preserved to a high degree of accuracy. However, it is well known that global symmetries are explicitly violated by quantum gravity effects, giving rise to what is referred to as the axion quality problem. In this paper, we investigate axionic wormholes as a source of explicit U(1) violation in Metric-Affine Gravity. This framework allows for spacetime torsion and non-metricity, which accommodate additional curvature-like and topological terms, such as the Holst and Nieh--Yan terms, that are absent from the metric and Palatini formalisms. We show that non-minimal couplings to these terms modify the wormhole dynamics and enhance the Euclidean wormhole action, thereby alleviating the axion quality problem. We also find that the viable parameter space is enlarged when two of these couplings are simultaneously present. We further identify representative parameter regions where the alleviation of the axion quality problem is compatible with inflationary constraints.

hep-ph

Qubit-Qutrit Quantum Tomography of hadronic $\Lambda\phi$ and $\Lambda K^{\ast 0}$ systems

Quantum-information observables have emerged in recent years as new tools in nuclear and particle physics, from entanglement in top-quark pairs to spin correlations in $\Lambda\bar{\Lambda}$ production. Extending these studies to unequal-spin hadronic final states poses a fundamental challenge: the $6\times6$ density matrix of a qubit-qutrit system contains 35 independent spin parameters, but the decays of $\Lambda V$ pairs, with $V=\phi$ or $K^{*0}$, provide access to only 23 due to the hidden vector polarization from the strong decay. In this Letter, we formulate a qubit-qutrit quantum tomography (QQQT) technique for these spin-$\tfrac{1}{2}\otimes1$ systems and establish exact criteria for entanglement certification from the \textit{incomplete} density matrix. Compared with the $\Lambda\bar{\Lambda}$ system, QQQT of $\Lambda\phi$ and $\Lambda K^{*0}$ provides a new probe of nonperturbative QCD hadronization, enabling a direct comparison of the spin evolution of entangled quark pairs produced from the vacuum as they hadronize into a baryon or a vector meson.

hep-ph

Twist decomposition of exclusive heavy meson production cross sections

We study the twist decomposition of the total cross sections for exclusive heavy vector meson electroproduction and photoproduction in the $\gamma^\ast p$ processes, within the leading logarithmic $1/x$ BFKL formalism. The Mellin transforms of the impact factors of the vector meson are calculated. We show that the higher twist contributions are strongly suppressed in the low-$x$ kinematical regime. Possible enhancement of the higher twists effects for nuclei targets is discussed.

hep-ph