Study of excited Ξ states in ψ(3686)→K−</mml:msup…

Based on a sample of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mo stretchy="false">(</a:mo><a:mn>448.1</a:mn><a:mo>±</a:mo><a:mn>2.9</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>6</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 at BEPCII, the decays of <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"><i:mrow><i:mi>ψ</i:mi><i:mo stretchy="false">(</i:mo><i:mn>3686</i:mn><i:mo stretchy="false">)</i:mo><i:mo stretchy="false">→</i:mo><i:msup><i:mrow><i:mi>K</i:mi></i:mrow><i:mrow><i:mo>−</i:mo></i:mrow></i:msup><i:mi mathvariant="normal">Λ</i:mi><i:msup><i:mrow><i:mover accent="true"><i:mrow><i:mi mathvariant="normal">Ξ</i:mi></i:mrow><i:mrow><i:mo stretchy="false">¯</i:mo></i:mrow></i:mover></i:mrow><i:mrow><i:mo>+</i:mo></i:mrow></i:msup><i:mo>+</i:mo><i:mi mathvariant="normal">c</i:mi><i:mo>.</i:mo><i:mi mathvariant="normal">c</i:mi><i:mo>.</i:mo></i:mrow></i:math> with <t:math xmlns:t="http://www.w3.org/1998/Math/MathML" display="inline"><t:mrow><t:msup><t:mrow><t:mover accent="true"><t:mrow><t:mi mathvariant="normal">Ξ</t:mi></t:mrow><t:mrow><t:mo stretchy="false">¯</t:mo></t:mrow></t:mover></t:mrow><t:mrow><t:mo>+</t:mo></t:mrow></t:msup><t:mo stretchy="false">→</t:mo><t:mover accent="true"><t:mrow><t:mi mathvariant="normal">Λ</t:mi></t:mrow><t:mrow><t:mo stretchy="false">¯</t:mo></t:mrow></t:mover><t:msup><t:mrow><t:mi>π</t:mi></t:mrow><t:mrow><t:mo>+</t:mo></t:mrow></t:msup></t:mrow></t:math>, <cb:math xmlns:cb="http://www.w3.org/1998/Math/MathML" display="inline"><cb:mrow><cb:mover accent="true"><cb:mrow><cb:mi mathvariant="normal">Λ</cb:mi></cb:mrow><cb:mrow><cb:mo stretchy="false">¯</cb:mo></cb:mrow></cb:mover><cb:mo stretchy="false">→</cb:mo><cb:mover accent="true"><cb:mrow><cb:mi>p</cb:mi></cb:mrow><cb:mrow><cb:mo stretchy="false">¯</cb:mo></cb:mrow></cb:mover><cb:msup><cb:mrow><cb:mi>π</cb:mi></cb:mrow><cb:mrow><cb:mo>+</cb:mo></cb:mrow></cb:msup></cb:mrow></cb:math> are studied. We investigate the two excited resonances, <kb:math xmlns:kb="http://www.w3.org/1998/Math/MathML" display="inline"><kb:mrow><kb:mi mathvariant="normal">Ξ</kb:mi><kb:mo stretchy="false">(</kb:mo><kb:mn>1690</kb:mn><kb:msup><kb:mrow><kb:mo stretchy="false">)</kb:mo></kb:mrow><kb:mrow><kb:mo>−</kb:mo></kb:mrow></kb:msup></kb:mrow></kb:math> and <pb:math xmlns:pb="http://www.w3.org/1998/Math/MathML" display="inline"><pb:mrow><pb:mi mathvariant="normal">Ξ</pb:mi><pb:mo stretchy="false">(</pb:mo><pb:mn>1820</pb:mn><pb:msup><pb:mrow><pb:mo stretchy="false">)</pb:mo></pb:mrow><pb:mrow><pb:mo>−</pb:mo></pb:mrow></pb:msup></pb:mrow></pb:math>, which are each observed with large significance (<ub:math xmlns:ub="http://www.w3.org/1998/Math/MathML" display="inline"><ub:mrow><ub:mo form="prefix">≫</ub:mo><ub:mn>10</ub:mn><ub:mi>σ</ub:mi></ub:mrow></ub:math>) in the <xb:math xmlns:xb="http://www.w3.org/1998/Math/MathML" display="inline"><xb:mrow><xb:msup><xb:mrow><xb:mi>K</xb:mi></xb:mrow><xb:mrow><xb:mo>−</xb:mo></xb:mrow></xb:msup><xb:mi mathvariant="normal">Λ</xb:mi></xb:mrow></xb:math> invariant mass distributions. A partial wave analysis is performed, and the spin-parities of <ac:math xmlns:ac="http://www.w3.org/1998/Math/MathML" display="inline"><ac:mi mathvariant="normal">Ξ</ac:mi><ac:mo stretchy="false">(</ac:mo><ac:mn>1690</ac:mn><ac:msup><ac:mo stretchy="false">)</ac:mo><ac:mo>−</ac:mo></ac:msup></ac:math> and <fc:math xmlns:fc="http://www.w3.org/1998/Math/MathML" display="inline"><fc:mi mathvariant="normal">Ξ</fc:mi><fc:mo stretchy="false">(</fc:mo><fc:mn>1820</fc:mn><fc:msup><fc:mo stretchy="false">)</fc:mo><fc:mo>−</fc:mo></fc:msup></fc:math> are measured to be <kc:math xmlns:kc="http://www.w3.org/1998/Math/MathML" display="inline"><kc:msup><kc:mfrac><kc:mn>1</kc:mn><kc:mn>2</kc:mn></kc:mfrac><kc:mo>−</kc:mo></kc:msup></kc:math> and <mc:math xmlns:mc="http://www.w3.org/1998/Math/MathML" display="inline"><mc:msup><mc:mfrac><mc:mn>3</mc:mn><mc:mn>2</mc:mn></mc:mfrac><mc:mo>−</mc:mo></mc:msup></mc:math>, respectively. The masses, widths, and product branching fractions of <oc:math xmlns:oc="http://www.w3.org/1998/Math/MathML" display="inline"><oc:mi mathvariant="normal">Ξ</oc:mi><oc:mo stretchy="false">(</oc:mo><oc:mn>1690</oc:mn><oc:msup><oc:mo stretchy="false">)</oc:mo><oc:mo>−</oc:mo></oc:msup></oc:math> and <tc:math xmlns:tc="http://www.w3.org/1998/Math/MathML" display="inline"><tc:mi mathvariant="normal">Ξ</tc:mi><tc:mo stretchy="false">(</tc:mo><tc:mn>1820</tc:mn><tc:msup><tc:mo stretchy="false">)</tc:mo><tc:mo>−</tc:mo></tc:msup></tc:math> are also measured. Published by the American Physical Society 2024