Macroeconomics

Quantum mechanics

Pion

Meson

Nuclear physics

Particle physics

Omega

Atomic physics

Hadron

Economics

Branching fraction

Physics

Resonance (particle physics)

Production (economics)

Physical Review

A report is made of the study of production and decay properties of the ${\ensuremath{\eta}}^{0}$, ${\ensuremath{\omega}}^{0}$, ${\ensuremath{\rho}}^{0}$, and ${\ensuremath{\pi}}^{0}$ mesons produced in ${\ensuremath{\pi}}^{+}\ensuremath{-}d$ collisions at 1.23 BeV/c in the Berkeley 72-in. bubble chamber. The production processes are analyzed in terms of ${\ensuremath{\pi}}^{+}$-neutron interactions through the use of an impulse model. A clear enhancement due to the ${{N}_{\frac{1}{2}}}^{*} (1688)$ resonance is observed in the ${\ensuremath{\pi}}^{0}$ (charge exchange) production cross section. The mass of the ${\ensuremath{\eta}}^{0}$ meson is found to be (${m}_{\ensuremath{\eta}0}=552\ifmmode\pm\else\textpm\fi{}3$ MeV), with a branching ratio of $\frac{({\ensuremath{\eta}}^{0}\ensuremath{\rightarrow}\mathrm{all}\mathrm{neutrals})}{({\ensuremath{\eta}}^{0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0})}=3.6\ifmmode\pm\else\textpm\fi{}0.8$, and the partial width $\ensuremath{\Gamma}({{N}_{\frac{1}{2}}}^{*} (1688)\ensuremath{\rightarrow}p+{\ensuremath{\eta}}^{0})&lt;2$ MeV. The central value of the ${\ensuremath{\omega}}^{0}$-meson peak is found to be (${m}_{\ensuremath{\omega}0}=781\ifmmode\pm\else\textpm\fi{}2$ MeV), with a branching ratio $\frac{({\ensuremath{\omega}}^{0}\ensuremath{\rightarrow}\mathrm{all}\mathrm{neutrals})}{({\ensuremath{\omega}}^{0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0})}=8\ifmmode\pm\else\textpm\fi{}3%$, and an upper limit of 5% for decay into two charged pions. The production of the ${\ensuremath{\omega}}^{0}$ is found to be inconsistent with the single-vector-meson exchange model.

Meson Resonance Production in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi>π</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:mrow><mml:mo>−</mml:mo><mml:mi>d</mml:mi></mml:math>Interactions at 1.23 BeV/<i>c</i>

Meson Resonance Production inπ+−dInteractions at 1.23 BeV/c