Search for prompt production of pentaquarks in charm hadron final states

A search for hidden-charm pentaquark states decaying to a range of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:msub><a:mrow><a:mi mathvariant="normal">Σ</a:mi></a:mrow><a:mrow><a:mi>c</a:mi></a:mrow></a:msub><a:mover accent="true"><a:mrow><a:mi>D</a:mi></a:mrow><a:mrow><a:mo stretchy="false">¯</a:mo></a:mrow></a:mover></a:mrow></a:math> and <f:math xmlns:f="http://www.w3.org/1998/Math/MathML" display="inline"><f:mrow><f:msubsup><f:mrow><f:mi mathvariant="normal">Λ</f:mi></f:mrow><f:mrow><f:mi>c</f:mi></f:mrow><f:mrow><f:mo>+</f:mo></f:mrow></f:msubsup><f:mover accent="true"><f:mrow><f:mi>D</f:mi></f:mrow><f:mrow><f:mo stretchy="false">¯</f:mo></f:mrow></f:mover></f:mrow></f:math> final states, as well as doubly charmed pentaquark states to <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"><k:msub><k:mi mathvariant="normal">Σ</k:mi><k:mi>c</k:mi></k:msub><k:mi>D</k:mi></k:math> and <n:math xmlns:n="http://www.w3.org/1998/Math/MathML" display="inline"><n:msubsup><n:mi mathvariant="normal">Λ</n:mi><n:mi>c</n:mi><n:mo>+</n:mo></n:msubsup><n:mi>D</n:mi></n:math>, is made using samples of proton-proton collision data corresponding to an integrated luminosity of <q:math xmlns:q="http://www.w3.org/1998/Math/MathML" display="inline"><q:mn>5.7</q:mn><q:mtext> </q:mtext><q:mtext> </q:mtext><q:msup><q:mi>fb</q:mi><q:mrow><q:mo>−</q:mo><q:mn>1</q:mn></q:mrow></q:msup></q:math> recorded by the LHCb detector at <s:math xmlns:s="http://www.w3.org/1998/Math/MathML" display="inline"><s:msqrt><s:mi>s</s:mi></s:msqrt><s:mo>=</s:mo><s:mn>13</s:mn><s:mtext> </s:mtext><s:mtext> </s:mtext><s:mi>TeV</s:mi></s:math>. Since no significant signals are found, upper limits are set on the pentaquark yields relative to that of the <u:math xmlns:u="http://www.w3.org/1998/Math/MathML" display="inline"><u:msubsup><u:mi mathvariant="normal">Λ</u:mi><u:mi>c</u:mi><u:mo>+</u:mo></u:msubsup></u:math> baryon in the <x:math xmlns:x="http://www.w3.org/1998/Math/MathML" display="inline"><x:msubsup><x:mi mathvariant="normal">Λ</x:mi><x:mi>c</x:mi><x:mo>+</x:mo></x:msubsup><x:mo stretchy="false">→</x:mo><x:mrow><x:mi>p</x:mi><x:msup><x:mi>K</x:mi><x:mo>−</x:mo></x:msup><x:msup><x:mi>π</x:mi><x:mo>+</x:mo></x:msup></x:mrow></x:math> decay mode. The known pentaquark states are also investigated, and their signal yields are found to be consistent with zero in all cases.