Hidden strangeness in meson weak decays to baryon pair

Our study focuses on the weak decay of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:msubsup><a:mi>D</a:mi><a:mi>s</a:mi><a:mo>+</a:mo></a:msubsup><a:mo stretchy="false">→</a:mo><a:mi>p</a:mi><a:mover accent="true"><a:mi>n</a:mi><a:mo stretchy="false">¯</a:mo></a:mover></a:math>, which is the only possible two-body baryonic decay in the <f:math xmlns:f="http://www.w3.org/1998/Math/MathML" display="inline"><f:mi>D</f:mi></f:math> meson system. An analysis using perturbative quantum chromodynamics (pQCD) is challenging in this decay due to the small amount of energy released. In particular, naive factorization, suppressed by the light quark masses, results in a minor contribution to this channel. In the framework of final state interactions, the hidden strangeness in the intermediate state naturally avoids this chiral suppression from light quark masses. The branching fraction is predicted to be <h:math xmlns:h="http://www.w3.org/1998/Math/MathML" display="inline"><h:mi mathvariant="script">B</h:mi><h:mo stretchy="false">(</h:mo><h:msubsup><h:mi>D</h:mi><h:mi>s</h:mi><h:mo>+</h:mo></h:msubsup><h:mo stretchy="false">→</h:mo><h:mi>p</h:mi><h:mover accent="true"><h:mi>n</h:mi><h:mo stretchy="false">¯</h:mo></h:mover><h:mo stretchy="false">)</h:mo><h:mo>=</h:mo><h:mo stretchy="false">(</h:mo><h:mn>1.43</h:mn><h:mo>±</h:mo><h:mn>0.10</h:mn><h:mo stretchy="false">)</h:mo><h:mo>×</h:mo><h:msup><h:mn>10</h:mn><h:mrow><h:mo>−</h:mo><h:mn>3</h:mn></h:mrow></h:msup></h:math>, in agreement with the experimental value of <r:math xmlns:r="http://www.w3.org/1998/Math/MathML" display="inline"><r:mo stretchy="false">(</r:mo><r:mn>1.22</r:mn><r:mo>±</r:mo><r:mn>0.11</r:mn><r:mo stretchy="false">)</r:mo><r:mo>×</r:mo><r:msup><r:mn>10</r:mn><r:mrow><r:mo>−</r:mo><r:mn>3</r:mn></r:mrow></r:msup></r:math>. We also analyze the decays of <v:math xmlns:v="http://www.w3.org/1998/Math/MathML" display="inline"><v:mi>B</v:mi></v:math> mesons into two charmed baryons involving annihilation-type topological diagrams. In these decays, we conduct a joint analysis of naive factorization and final state interactions. Using the experimental upper bound of <x:math xmlns:x="http://www.w3.org/1998/Math/MathML" display="inline"><x:mi mathvariant="script">B</x:mi><x:mo stretchy="false">(</x:mo><x:msubsup><x:mi>B</x:mi><x:mi>s</x:mi><x:mn>0</x:mn></x:msubsup><x:mo stretchy="false">→</x:mo><x:msubsup><x:mi mathvariant="normal">Λ</x:mi><x:mi>c</x:mi><x:mo>+</x:mo></x:msubsup><x:msubsup><x:mover accent="true"><x:mi mathvariant="normal">Λ</x:mi><x:mo stretchy="false">¯</x:mo></x:mover><x:mi>c</x:mi><x:mo>−</x:mo></x:msubsup><x:mo stretchy="false">)</x:mo><x:mo>&lt;</x:mo><x:mn>8</x:mn><x:mo>×</x:mo><x:msup><x:mn>10</x:mn><x:mrow><x:mo>−</x:mo><x:mn>5</x:mn></x:mrow></x:msup></x:math>, we set a constraint on the coupling constant <hb:math xmlns:hb="http://www.w3.org/1998/Math/MathML" display="inline"><hb:msub><hb:mi>g</hb:mi><hb:mrow><hb:msup><hb:mi>D</hb:mi><hb:mo>+</hb:mo></hb:msup><hb:msubsup><hb:mi mathvariant="normal">Λ</hb:mi><hb:mi>c</hb:mi><hb:mo>+</hb:mo></hb:msubsup><hb:mi>n</hb:mi></hb:mrow></hb:msub><hb:mo>&lt;</hb:mo><hb:mn>7.5</hb:mn></hb:math>. Final state interactions lead to a prediction of the decay parameter <kb:math xmlns:kb="http://www.w3.org/1998/Math/MathML" display="inline"><kb:mi>γ</kb:mi><kb:mo stretchy="false">(</kb:mo><kb:msubsup><kb:mi>B</kb:mi><kb:mi>s</kb:mi><kb:mn>0</kb:mn></kb:msubsup><kb:mo stretchy="false">→</kb:mo><kb:msubsup><kb:mi mathvariant="normal">Λ</kb:mi><kb:mi>c</kb:mi><kb:mo>+</kb:mo></kb:msubsup><kb:msubsup><kb:mover accent="true"><kb:mi mathvariant="normal">Λ</kb:mi><kb:mo stretchy="false">¯</kb:mo></kb:mover><kb:mi>c</kb:mi><kb:mo>−</kb:mo></kb:msubsup><kb:mo stretchy="false">)</kb:mo><kb:mo>&gt;</kb:mo><kb:mn>0.8</kb:mn></kb:math>, whereas pQCD predicts it to be negative. We propose future measurements of <tb:math xmlns:tb="http://www.w3.org/1998/Math/MathML" display="inline"><tb:msup><tb:mi>B</tb:mi><tb:mn>0</tb:mn></tb:msup><tb:mo stretchy="false">→</tb:mo><tb:msubsup><tb:mi mathvariant="normal">Ξ</tb:mi><tb:mi>c</tb:mi><tb:mo>+</tb:mo></tb:msubsup><tb:msubsup><tb:mover accent="true"><tb:mi mathvariant="normal">Ξ</tb:mi><tb:mo stretchy="false">¯</tb:mo></tb:mover><tb:mi>c</tb:mi><tb:mo>−</tb:mo></tb:msubsup></tb:math>, predicting a significant <ac:math xmlns:ac="http://www.w3.org/1998/Math/MathML" display="inline"><ac:mi>S</ac:mi><ac:mi>U</ac:mi><ac:mo stretchy="false">(</ac:mo><ac:mn>3</ac:mn><ac:msub><ac:mo stretchy="false">)</ac:mo><ac:mi>F</ac:mi></ac:msub></ac:math> breaking effect with <ec:math xmlns:ec="http://www.w3.org/1998/Math/MathML" display="inline"><ec:mfrac><ec:mrow><ec:mi mathvariant="script">B</ec:mi><ec:mo stretchy="false">(</ec:mo><ec:msup><ec:mi>B</ec:mi><ec:mn>0</ec:mn></ec:msup><ec:mo stretchy="false">→</ec:mo><ec:msubsup><ec:mi mathvariant="normal">Ξ</ec:mi><ec:mi>c</ec:mi><ec:mo stretchy="false">+</ec:mo></ec:msubsup><ec:msubsup><ec:mover accent="true"><ec:mi mathvariant="normal">Ξ</ec:mi><ec:mo stretchy="false">¯</ec:mo></ec:mover><ec:mi>c</ec:mi><ec:mo stretchy="false">−</ec:mo></ec:msubsup><ec:mo stretchy="false">)</ec:mo></ec:mrow><ec:mrow><ec:mi mathvariant="script">B</ec:mi><ec:mo stretchy="false">(</ec:mo><ec:msubsup><ec:mi>B</ec:mi><ec:mi>s</ec:mi><ec:mn>0</ec:mn></ec:msubsup><ec:mo stretchy="false">→</ec:mo><ec:msubsup><ec:mi mathvariant="normal">Λ</ec:mi><ec:mi>c</ec:mi><ec:mo stretchy="false">+</ec:mo></ec:msubsup><ec:msubsup><ec:mover accent="true"><ec:mi mathvariant="normal">Λ</ec:mi><ec:mo stretchy="false">¯</ec:mo></ec:mover><ec:mi>c</ec:mi><ec:mo stretchy="false">−</ec:mo></ec:msubsup><ec:mo stretchy="false">)</ec:mo></ec:mrow></ec:mfrac><ec:mo>=</ec:mo><ec:mn>1.4</ec:mn><ec:mo>%</ec:mo></ec:math>, contrary to the naive estimate of 5.3%. We strongly recommend future measurements. Published by the American Physical Society 2024