Study of the decays χcJ→ΛΛ¯ω

Using <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mo stretchy="false">(</a:mo><a:mn>27.12</a:mn><a:mo>±</a:mo><a:mn>0.14</a:mn><a:mo stretchy="false">)</a:mo><a:mo>×</a:mo><a:msup><a:mrow><a:mn>10</a:mn></a:mrow><a:mrow><a:mn>8</a:mn></a:mrow></a:msup></a:mrow></a:math> <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mrow><e:mi>ψ</e:mi><e:mo stretchy="false">(</e:mo><e:mn>3686</e:mn><e:mo stretchy="false">)</e:mo></e:mrow></e:math> events collected with the BESIII detector, we present the first observation of the decays <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"><i:msub><i:mi>χ</i:mi><i:mrow><i:mi>c</i:mi><i:mi>J</i:mi></i:mrow></i:msub><i:mo stretchy="false">→</i:mo><i:mi mathvariant="normal">Λ</i:mi><i:mover accent="true"><i:mi mathvariant="normal">Λ</i:mi><i:mo stretchy="false">¯</i:mo></i:mover><i:mi>ω</i:mi></i:math>, where <p:math xmlns:p="http://www.w3.org/1998/Math/MathML" display="inline"><p:mi>J</p:mi><p:mo>=</p:mo><p:mn>0</p:mn></p:math>, 1, 2, with statistical significances of <r:math xmlns:r="http://www.w3.org/1998/Math/MathML" display="inline"><r:mrow><r:mn>11.7</r:mn><r:mi>σ</r:mi></r:mrow></r:math>, <t:math xmlns:t="http://www.w3.org/1998/Math/MathML" display="inline"><t:mrow><t:mn>11.2</t:mn><t:mi>σ</t:mi></t:mrow></t:math>, and <v:math xmlns:v="http://www.w3.org/1998/Math/MathML" display="inline"><v:mn>11.8</v:mn><v:mi>σ</v:mi></v:math>. The branching fractions of these decays are determined to be <x:math xmlns:x="http://www.w3.org/1998/Math/MathML" display="inline"><x:mrow><x:mi mathvariant="script">B</x:mi><x:mo stretchy="false">(</x:mo><x:msub><x:mrow><x:mi>χ</x:mi></x:mrow><x:mrow><x:mi>c</x:mi><x:mn>0</x:mn></x:mrow></x:msub><x:mo stretchy="false">→</x:mo><x:mi mathvariant="normal">Λ</x:mi><x:mover accent="true"><x:mrow><x:mi mathvariant="normal">Λ</x:mi></x:mrow><x:mrow><x:mo stretchy="false">¯</x:mo></x:mrow></x:mover><x:mi>ω</x:mi><x:mo stretchy="false">)</x:mo><x:mo>=</x:mo><x:mspace linebreak="goodbreak"/><x:mo stretchy="false">(</x:mo><x:mn>2.37</x:mn><x:mo>±</x:mo><x:mn>0.22</x:mn><x:mo>±</x:mo><x:mn>0.25</x:mn><x:mo stretchy="false">)</x:mo><x:mo>×</x:mo><x:msup><x:mrow><x:mn>10</x:mn></x:mrow><x:mrow><x:mo>−</x:mo><x:mn>4</x:mn></x:mrow></x:msup></x:mrow></x:math>, <kb:math xmlns:kb="http://www.w3.org/1998/Math/MathML" display="inline"><kb:mrow><kb:mi mathvariant="script">B</kb:mi><kb:mo stretchy="false">(</kb:mo><kb:msub><kb:mrow><kb:mi>χ</kb:mi></kb:mrow><kb:mrow><kb:mi>c</kb:mi><kb:mn>1</kb:mn></kb:mrow></kb:msub><kb:mo stretchy="false">→</kb:mo><kb:mi mathvariant="normal">Λ</kb:mi><kb:mover accent="true"><kb:mrow><kb:mi mathvariant="normal">Λ</kb:mi></kb:mrow><kb:mrow><kb:mo stretchy="false">¯</kb:mo></kb:mrow></kb:mover><kb:mi>ω</kb:mi><kb:mo stretchy="false">)</kb:mo><kb:mo>=</kb:mo><kb:mo stretchy="false">(</kb:mo><kb:mn>1.01</kb:mn><kb:mo>±</kb:mo><kb:mn>0.10</kb:mn><kb:mo>±</kb:mo><kb:mn>0.11</kb:mn><kb:mo stretchy="false">)</kb:mo><kb:mo>×</kb:mo><kb:msup><kb:mrow><kb:mn>10</kb:mn></kb:mrow><kb:mrow><kb:mo>−</kb:mo><kb:mn>4</kb:mn></kb:mrow></kb:msup></kb:mrow></kb:math>, and <wb:math xmlns:wb="http://www.w3.org/1998/Math/MathML" display="inline"><wb:mrow><wb:mi mathvariant="script">B</wb:mi><wb:mo stretchy="false">(</wb:mo><wb:msub><wb:mrow><wb:mi>χ</wb:mi></wb:mrow><wb:mrow><wb:mi>c</wb:mi><wb:mn>2</wb:mn></wb:mrow></wb:msub><wb:mo stretchy="false">→</wb:mo><wb:mi mathvariant="normal">Λ</wb:mi><wb:mover accent="true"><wb:mrow><wb:mi mathvariant="normal">Λ</wb:mi></wb:mrow><wb:mrow><wb:mo stretchy="false">¯</wb:mo></wb:mrow></wb:mover><wb:mi>ω</wb:mi><wb:mo stretchy="false">)</wb:mo><wb:mo>=</wb:mo><wb:mspace linebreak="goodbreak"/><wb:mo stretchy="false">(</wb:mo><wb:mn>1.40</wb:mn><wb:mo>±</wb:mo><wb:mn>0.13</wb:mn><wb:mo>±</wb:mo><wb:mn>0.17</wb:mn><wb:mo stretchy="false">)</wb:mo><wb:mo>×</wb:mo><wb:msup><wb:mrow><wb:mn>10</wb:mn></wb:mrow><wb:mrow><wb:mo>−</wb:mo><wb:mn>4</wb:mn></wb:mrow></wb:msup></wb:mrow></wb:math>, where the first uncertainties are statistical and the second are systematic. We observe no clear intermediate structures. Published by the American Physical Society 2024