Theoretical study of the π+p→pa0+ϕ reaction

We study the production of hyperon resonances in the <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:msup><a:mi>π</a:mi><a:mo>+</a:mo></a:msup><a:mi>p</a:mi><a:mo stretchy="false">→</a:mo><a:mi>p</a:mi><a:msubsup><a:mi>a</a:mi><a:mn>0</a:mn><a:mo>+</a:mo></a:msubsup><a:mi>ϕ</a:mi></a:math> reaction within an effective Lagrangian approach. The model includes the production of <d:math xmlns:d="http://www.w3.org/1998/Math/MathML" display="inline"><d:mi mathvariant="normal">Δ</d:mi><d:mo stretchy="false">(</d:mo><d:mn>1940</d:mn><d:mo stretchy="false">)</d:mo></d:math> and <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"><i:mi mathvariant="normal">Δ</i:mi><i:mo stretchy="false">(</i:mo><i:mn>1920</i:mn><i:mo stretchy="false">)</i:mo></i:math> in the intermediate state excited by the <n:math xmlns:n="http://www.w3.org/1998/Math/MathML" display="inline"><n:mi>ρ</n:mi></n:math> and <p:math xmlns:p="http://www.w3.org/1998/Math/MathML" display="inline"><p:mi>p</p:mi></p:math> exchanges between the initial proton and <r:math xmlns:r="http://www.w3.org/1998/Math/MathML" display="inline"><r:mi>π</r:mi></r:math> meson. Because of the large contribution of <t:math xmlns:t="http://www.w3.org/1998/Math/MathML" display="inline"><t:mi>ρ</t:mi></t:math> exchange in <v:math xmlns:v="http://www.w3.org/1998/Math/MathML" display="inline"><v:mi mathvariant="normal">Δ</v:mi><v:mo stretchy="false">(</v:mo><v:mn>1940</v:mn><v:mo stretchy="false">)</v:mo></v:math> production, <ab:math xmlns:ab="http://www.w3.org/1998/Math/MathML" display="inline"><ab:mi mathvariant="normal">Δ</ab:mi><ab:mo stretchy="false">(</ab:mo><ab:mn>1940</ab:mn><ab:mo stretchy="false">)</ab:mo></ab:math> is found to be a significant contribution near the threshold in this reaction. We provide total and differential cross section predictions for the reaction and discuss the possible influence of model parameters, off-shell effects, and branching ratios for <fb:math xmlns:fb="http://www.w3.org/1998/Math/MathML" display="inline"><fb:mi mathvariant="normal">Δ</fb:mi><fb:mo stretchy="false">(</fb:mo><fb:mn>1940</fb:mn><fb:mo stretchy="false">)</fb:mo><fb:mo stretchy="false">→</fb:mo><fb:mi>p</fb:mi><fb:msub><fb:mi>a</fb:mi><fb:mn>0</fb:mn></fb:msub></fb:math> and <lb:math xmlns:lb="http://www.w3.org/1998/Math/MathML" display="inline"><lb:mi mathvariant="normal">Δ</lb:mi><lb:mo stretchy="false">(</lb:mo><lb:mn>1920</lb:mn><lb:mo stretchy="false">)</lb:mo><lb:mo stretchy="false">→</lb:mo><lb:mi>p</lb:mi><lb:msub><lb:mi>a</lb:mi><lb:mn>0</lb:mn></lb:msub></lb:math> decays, which will be useful in future experimental studies. This reaction can provide a platform for studying the features of <rb:math xmlns:rb="http://www.w3.org/1998/Math/MathML" display="inline"><rb:mi mathvariant="normal">Δ</rb:mi><rb:mo stretchy="false">(</rb:mo><rb:mn>1940</rb:mn><rb:mo stretchy="false">)</rb:mo></rb:math> resonance, especially the coupling to the <wb:math xmlns:wb="http://www.w3.org/1998/Math/MathML" display="inline"><wb:mi>p</wb:mi><wb:msub><wb:mi>a</wb:mi><wb:mn>0</wb:mn></wb:msub></wb:math> channel.