Measurement of the absolute branching fraction of the three-body decay Λc+→Ξ0K+π0 and search …

The Cabbibo-favored decay <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:msubsup><a:mi mathvariant="normal">Λ</a:mi><a:mi>c</a:mi><a:mo>+</a:mo></a:msubsup><a:mo stretchy="false">→</a:mo><a:msup><a:mi mathvariant="normal">Ξ</a:mi><a:mn>0</a:mn></a:msup><a:msup><a:mi>K</a:mi><a:mo>+</a:mo></a:msup><a:msup><a:mi>π</a:mi><a:mn>0</a:mn></a:msup></a:mrow></a:math> is studied for the first time using <f:math xmlns:f="http://www.w3.org/1998/Math/MathML" display="inline"><f:mn>6.1</f:mn><f:mtext> </f:mtext><f:mtext> </f:mtext><f:msup><f:mi>fb</f:mi><f:mrow><f:mo>−</f:mo><f:mn>1</f:mn></f:mrow></f:msup></f:math> of <h:math xmlns:h="http://www.w3.org/1998/Math/MathML" display="inline"><h:mrow><h:msup><h:mi>e</h:mi><h:mo>+</h:mo></h:msup><h:msup><h:mi>e</h:mi><h:mo>−</h:mo></h:msup></h:mrow></h:math> collision data at center-of-mass energies between 4.600 and 4.840 GeV, collected with the BESIII detector at the BEPCII collider. With a double-tag method, the branching fraction of the three-body decay <j:math xmlns:j="http://www.w3.org/1998/Math/MathML" display="inline"><j:mrow><j:msubsup><j:mi mathvariant="normal">Λ</j:mi><j:mi>c</j:mi><j:mo>+</j:mo></j:msubsup><j:mo stretchy="false">→</j:mo><j:msup><j:mi mathvariant="normal">Ξ</j:mi><j:mn>0</j:mn></j:msup><j:msup><j:mi>K</j:mi><j:mo>+</j:mo></j:msup><j:msup><j:mi>π</j:mi><j:mn>0</j:mn></j:msup></j:mrow></j:math> is measured to be <o:math xmlns:o="http://www.w3.org/1998/Math/MathML" display="inline"><o:mo stretchy="false">(</o:mo><o:mn>7.79</o:mn><o:mo>±</o:mo><o:mn>1.46</o:mn><o:mo>±</o:mo><o:mn>0.95</o:mn><o:mo stretchy="false">)</o:mo><o:mo>×</o:mo><o:msup><o:mn>10</o:mn><o:mrow><o:mo>−</o:mo><o:mn>3</o:mn></o:mrow></o:msup></o:math>, where the first and second uncertainties are statistical and systematic, respectively. The branching fraction of the two-body decay <s:math xmlns:s="http://www.w3.org/1998/Math/MathML" display="inline"><s:mrow><s:msubsup><s:mi mathvariant="normal">Λ</s:mi><s:mi>c</s:mi><s:mo>+</s:mo></s:msubsup><s:mo stretchy="false">→</s:mo><s:mi mathvariant="normal">Ξ</s:mi><s:mo stretchy="false">(</s:mo><s:mn>1530</s:mn><s:msup><s:mo stretchy="false">)</s:mo><s:mn>0</s:mn></s:msup><s:msup><s:mi>K</s:mi><s:mo>+</s:mo></s:msup></s:mrow></s:math> is <z:math xmlns:z="http://www.w3.org/1998/Math/MathML" display="inline"><z:mo stretchy="false">(</z:mo><z:mn>5.99</z:mn><z:mo>±</z:mo><z:mn>1.04</z:mn><z:mo>±</z:mo><z:mn>0.32</z:mn><z:mo stretchy="false">)</z:mo><z:mo>×</z:mo><z:msup><z:mn>10</z:mn><z:mrow><z:mo>−</z:mo><z:mn>3</z:mn></z:mrow></z:msup></z:math>, which is consistent with the previous result of <db:math xmlns:db="http://www.w3.org/1998/Math/MathML" display="inline"><db:mo stretchy="false">(</db:mo><db:mn>5.02</db:mn><db:mo>±</db:mo><db:mn>0.99</db:mn><db:mo>±</db:mo><db:mn>0.31</db:mn><db:mo stretchy="false">)</db:mo><db:mo>×</db:mo><db:msup><db:mn>10</db:mn><db:mrow><db:mo>−</db:mo><db:mn>3</db:mn></db:mrow></db:msup></db:math>. In addition, the upper limit on the branching fraction of the doubly Cabbibo-suppressed decay <hb:math xmlns:hb="http://www.w3.org/1998/Math/MathML" display="inline"><hb:mrow><hb:msubsup><hb:mi mathvariant="normal">Λ</hb:mi><hb:mi>c</hb:mi><hb:mo>+</hb:mo></hb:msubsup><hb:mo stretchy="false">→</hb:mo><hb:mi>n</hb:mi><hb:msup><hb:mi>K</hb:mi><hb:mo>+</hb:mo></hb:msup><hb:msup><hb:mi>π</hb:mi><hb:mn>0</hb:mn></hb:msup></hb:mrow></hb:math> is <lb:math xmlns:lb="http://www.w3.org/1998/Math/MathML" display="inline"><lb:mn>7.1</lb:mn><lb:mo>×</lb:mo><lb:msup><lb:mn>10</lb:mn><lb:mrow><lb:mo>−</lb:mo><lb:mn>4</lb:mn></lb:mrow></lb:msup></lb:math> at the 90% confidence level. The upper limits on the branching fractions of <nb:math xmlns:nb="http://www.w3.org/1998/Math/MathML" display="inline"><nb:msubsup><nb:mi mathvariant="normal">Λ</nb:mi><nb:mi>c</nb:mi><nb:mo>+</nb:mo></nb:msubsup><nb:mo stretchy="false">→</nb:mo><nb:msup><nb:mi mathvariant="normal">Σ</nb:mi><nb:mn>0</nb:mn></nb:msup><nb:msup><nb:mi>K</nb:mi><nb:mo>+</nb:mo></nb:msup><nb:msup><nb:mi>π</nb:mi><nb:mn>0</nb:mn></nb:msup></nb:math> and <sb:math xmlns:sb="http://www.w3.org/1998/Math/MathML" display="inline"><sb:mi mathvariant="normal">Λ</sb:mi><sb:msup><sb:mi>K</sb:mi><sb:mo>+</sb:mo></sb:msup><sb:msup><sb:mi>π</sb:mi><sb:mn>0</sb:mn></sb:msup></sb:math> are also determined to be <vb:math xmlns:vb="http://www.w3.org/1998/Math/MathML" display="inline"><vb:mn>1.8</vb:mn><vb:mo>×</vb:mo><vb:msup><vb:mn>10</vb:mn><vb:mrow><vb:mo>−</vb:mo><vb:mn>3</vb:mn></vb:mrow></vb:msup></vb:math> and <xb:math xmlns:xb="http://www.w3.org/1998/Math/MathML" display="inline"><xb:mn>2.0</xb:mn><xb:mo>×</xb:mo><xb:msup><xb:mn>10</xb:mn><xb:mrow><xb:mo>−</xb:mo><xb:mn>3</xb:mn></xb:mrow></xb:msup></xb:math>, respectively. Published by the American Physical Society 2024