# Positivity conditions on the spin density matrix: A simple parametrization

@article{Chung1975PositivityCO,
title={Positivity conditions on the spin density matrix: A simple parametrization},
author={S. U. Chung and T. Laurence Trueman},
journal={Physical Review D},
year={1975},
volume={11},
pages={633-646}
}
• Published 1 February 1975
• Physics
• Physical Review D
A simple parametrization of the spin density matrix $\ensuremath{\rho}$ is given which ensures that $\ensuremath{\rho}$ is a positive, Hermitian matrix which satisfies the parity symmetry conditions. There is a minimal number of parameters and they can vary independently; no complicated constraints on their allowed region of variation are required. A similar parametrization is given for the real part of $\ensuremath{\rho}$. Rank conditions, polarized targets, and angular distributions are also…
53 Citations
Status of exotic-quantum-number mesons
• Physics
• 2010
The search for mesons with non-quark-antiquark (exotic) quantum numbers has gone on for nearly 30 years. Currently there is experimental evidence of three isospin one states, the
Spin correlations in polarizations of P-wave charmonia $\chi_{cJ}$ and impact on $J/\psi$ polarization
• Physics
• 2014
Based on a general form of the effective vertex functions for the decays of P-wave charmonia $\chicj$, angular distribution formulas for the subsequent decays $\chicj\rightarrow \jpsi \gamma$ and
Moments of angular distribution and beam asymmetries in ηπ0 photoproduction at GlueX
In the search for exotic mesons, the GlueX collaboration will soon extract moments of the $\eta\pi^0$ angular distribution. In the perspective of these results, we generalize the formalism of moment
Spin-parity analysis of the ƒ1(1285)π− system in the reaction π−p → ƒ1(1285)π−p at 18 GeV / c
Abstract We have carried out a study of the reaction π − p → ƒ 1 (1285) π − p at 18 GeV / c , with ƒ 1 (1285) → K + K 0 π − This reaction is almost entirely mediated by the natural-parity exchange,
The generators of Lorentz transformation in momentum space
In the momentum space, the angular momentum operator and the boost vector operator, i.e. the generators for the Lorentz transformation of a particle with arbitrary spin and nonzero mass are
Model Selection for and Partial-Wave Analysis of a Five-Pion Final State at the COMPASS Experiment at CERN
The light-meson spectrum is an important ingredient to understand quantum chromodynamics, the theory of strong interaction at low energies, where quarks and gluons are confined into hadrons. However,
Light Scalar Mesons in Central Production at COMPASS
• Physics
• 2016
COMPASS is a fixed-target experiment at the CERN SPS that studies the spectrum of light-quark hadrons. In 2009, it collected a large dataset using a 190 GeV/c positive hadron beam impinging on a
The beam-helicity asymmetry for γp → pK+K− and γp → pπ+ π−
• Physics
• 2016
The first-time measurement of the angular dependence of the beam-helicity asymmetry for γp → pK+ K− is shown and compared to γp → pπ+ π−. The data obtained were from the CLAS g12 experiment at
Analysis of the reaction π−Be → π−π0π0Be at VES
We present the results of the analysis of diffractive reaction π−Be → π−π0π0Be measured with upgraded VES detector with the statistics of about 16 · 106 events. The mass-independent partial-wave
Ambiguities in model-independent partial-wave analysis
• Physics
Physical Review D
• 2018
Partial wave analysis is an important tool for analyzing large data sets in hadronic decays of light and heavy mesons. It commonly relies on the isobar model, which assumes multihadron final states