Study of the decays χcJ→ΛΛ¯ϕ

Based on <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mo stretchy="false">(</a:mo><a:mn>2712.4</a:mn><a:mo>±</a:mo><a:mn>14.3</a:mn><a:mo stretchy="false">)</a:mo><a:mo>×</a:mo><a:msup><a:mn>10</a:mn><a:mn>6</a:mn></a:msup></a:math> <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:msup><e:mi>e</e:mi><e:mo>+</e:mo></e:msup><e:msup><e:mi>e</e:mi><e:mo>−</e:mo></e:msup><e:mo stretchy="false">→</e:mo><e:mi>ψ</e:mi><e:mo stretchy="false">(</e:mo><e:mn>3686</e:mn><e:mo stretchy="false">)</e:mo></e:math> events collected with the BESIII detector operating at the BEPCII Collider, we report the first evidence of <j:math xmlns:j="http://www.w3.org/1998/Math/MathML" display="inline"><j:msub><j:mi>χ</j:mi><j:mrow><j:mi>c</j:mi><j:mn>0</j:mn></j:mrow></j:msub><j:mo stretchy="false">→</j:mo><j:mi mathvariant="normal">Λ</j:mi><j:mover accent="true"><j:mi mathvariant="normal">Λ</j:mi><j:mo stretchy="false">¯</j:mo></j:mover><j:mi>ϕ</j:mi></j:math> decays and the first observation of <q:math xmlns:q="http://www.w3.org/1998/Math/MathML" display="inline"><q:msub><q:mi>χ</q:mi><q:mrow><q:mi>c</q:mi><q:mn>1</q:mn><q:mo>,</q:mo><q:mn>2</q:mn></q:mrow></q:msub><q:mo stretchy="false">→</q:mo><q:mi mathvariant="normal">Λ</q:mi><q:mover accent="true"><q:mi mathvariant="normal">Λ</q:mi><q:mo stretchy="false">¯</q:mo></q:mover><q:mi>ϕ</q:mi></q:math> decays, with significances of <x:math xmlns:x="http://www.w3.org/1998/Math/MathML" display="inline"><x:mn>4.1</x:mn><x:mi>σ</x:mi></x:math>, <z:math xmlns:z="http://www.w3.org/1998/Math/MathML" display="inline"><z:mn>11.3</z:mn><z:mi>σ</z:mi></z:math> and <bb:math xmlns:bb="http://www.w3.org/1998/Math/MathML" display="inline"><bb:mn>13.0</bb:mn><bb:mi>σ</bb:mi></bb:math>, respectively. The decay branching fractions of <db:math xmlns:db="http://www.w3.org/1998/Math/MathML" display="inline"><db:msub><db:mi>χ</db:mi><db:mrow><db:mi>c</db:mi><db:mn>0</db:mn><db:mo>,</db:mo><db:mn>1</db:mn><db:mo>,</db:mo><db:mn>2</db:mn></db:mrow></db:msub><db:mo stretchy="false">→</db:mo><db:mi mathvariant="normal">Λ</db:mi><db:mover accent="true"><db:mi mathvariant="normal">Λ</db:mi><db:mo stretchy="false">¯</db:mo></db:mover><db:mi>ϕ</db:mi></db:math> are measured to be <kb:math xmlns:kb="http://www.w3.org/1998/Math/MathML" display="inline"><kb:mo stretchy="false">(</kb:mo><kb:mn>2.99</kb:mn><kb:mo>±</kb:mo><kb:mn>1.24</kb:mn><kb:mo>±</kb:mo><kb:mn>0.19</kb:mn><kb:mo stretchy="false">)</kb:mo><kb:mo>×</kb:mo><kb:msup><kb:mn>10</kb:mn><kb:mrow><kb:mo>−</kb:mo><kb:mn>5</kb:mn></kb:mrow></kb:msup></kb:math>, <ob:math xmlns:ob="http://www.w3.org/1998/Math/MathML" display="inline"><ob:mo stretchy="false">(</ob:mo><ob:mn>6.01</ob:mn><ob:mo>±</ob:mo><ob:mn>0.90</ob:mn><ob:mo>±</ob:mo><ob:mn>0.40</ob:mn><ob:mo stretchy="false">)</ob:mo><ob:mo>×</ob:mo><ob:msup><ob:mn>10</ob:mn><ob:mrow><ob:mo>−</ob:mo><ob:mn>5</ob:mn></ob:mrow></ob:msup></ob:math>, and <sb:math xmlns:sb="http://www.w3.org/1998/Math/MathML" display="inline"><sb:mo stretchy="false">(</sb:mo><sb:mn>7.13</sb:mn><sb:mo>±</sb:mo><sb:mn>0.81</sb:mn><sb:mo>±</sb:mo><sb:mn>0.36</sb:mn><sb:mo stretchy="false">)</sb:mo><sb:mo>×</sb:mo><sb:msup><sb:mn>10</sb:mn><sb:mrow><sb:mo>−</sb:mo><sb:mn>5</sb:mn></sb:mrow></sb:msup></sb:math>, where the first uncertainties are statistical and the second systematic. No obvious enhancement near the <wb:math xmlns:wb="http://www.w3.org/1998/Math/MathML" display="inline"><wb:mi mathvariant="normal">Λ</wb:mi><wb:mover accent="true"><wb:mi mathvariant="normal">Λ</wb:mi><wb:mo stretchy="false">¯</wb:mo></wb:mover></wb:math> production threshold or excited <cc:math xmlns:cc="http://www.w3.org/1998/Math/MathML" display="inline"><cc:mi mathvariant="normal">Λ</cc:mi></cc:math> state is found in the <fc:math xmlns:fc="http://www.w3.org/1998/Math/MathML" display="inline"><fc:mi mathvariant="normal">Λ</fc:mi><fc:mi>ϕ</fc:mi></fc:math> (or <ic:math xmlns:ic="http://www.w3.org/1998/Math/MathML" display="inline"><ic:mover accent="true"><ic:mi mathvariant="normal">Λ</ic:mi><ic:mo stretchy="false">¯</ic:mo></ic:mover><ic:mi>ϕ</ic:mi></ic:math>) system.