Probing the isospin structure and low-lying resonances in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msubsup> <mml:mi mathvariant="normal">Λ</mml:mi> <mml:mi>c</mml:mi> <mml:mo>+</mml:mo> </mml:msubsup> <mml:mo st

The Cabibbo-favored decay <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <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:mi>n</a:mi> <a:msup> <a:mover accent="true"> <a:mi>K</a:mi> <a:mo stretchy="false">¯</a:mo> </a:mover> <a:mn>0</a:mn> </a:msup> <a:msup> <a:mi>π</a:mi> <a:mo>+</a:mo> </a:msup> </a:math> offers a unique window to explore unresolved puzzles in the low-energy baryon spectroscopy and the isospin dynamics of the <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"> <g:mover accent="true"> <g:mi>K</g:mi> <g:mo stretchy="false">¯</g:mo> </g:mover> <g:mi>N</g:mi> </g:math> system. Recent experimental results present a, for now, contradiction: LHCb and Belle analyses of <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"> <k:msubsup> <k:mi mathvariant="normal">Λ</k:mi> <k:mi>c</k:mi> <k:mo>+</k:mo> </k:msubsup> <k:mo stretchy="false">→</k:mo> <k:mi>p</k:mi> <k:msup> <k:mi>K</k:mi> <k:mo>−</k:mo> </k:msup> <k:msup> <k:mi>π</k:mi> <k:mo>+</k:mo> </k:msup> </k:math> suggest the <o:math xmlns:o="http://www.w3.org/1998/Math/MathML" display="inline"> <o:mi>p</o:mi> <o:msup> <o:mi>K</o:mi> <o:mo>−</o:mo> </o:msup> </o:math> ( <q:math xmlns:q="http://www.w3.org/1998/Math/MathML" display="inline"> <q:mi>I</q:mi> <q:mo>=</q:mo> <q:mn>0</q:mn> </q:math> ) component dominates, while the Beijing Spectrometer III (BESIII) hints at significant contributions from both isospin 0 and 1 in the <s:math xmlns:s="http://www.w3.org/1998/Math/MathML" display="inline"> <s:mi>n</s:mi> <s:msup> <s:mover accent="true"> <s:mi>K</s:mi> <s:mo stretchy="false">¯</s:mo> </s:mover> <s:mn>0</s:mn> </s:msup> </s:math> system of <w:math xmlns:w="http://www.w3.org/1998/Math/MathML" display="inline"> <w:msubsup> <w:mi mathvariant="normal">Λ</w:mi> <w:mi>c</w:mi> <w:mo>+</w:mo> </w:msubsup> <w:mo stretchy="false">→</w:mo> <w:mi>n</w:mi> <w:msubsup> <w:mi>K</w:mi> <w:mi>S</w:mi> <w:mn>0</w:mn> </w:msubsup> <w:msup> <w:mi>π</w:mi> <w:mo>+</w:mo> </w:msup> </w:math> . Furthermore, the measured branching fraction of <ab:math xmlns:ab="http://www.w3.org/1998/Math/MathML" display="inline"> <ab:msubsup> <ab:mi mathvariant="normal">Λ</ab:mi> <ab:mi>c</ab:mi> <ab:mo>+</ab:mo> </ab:msubsup> <ab:mo stretchy="false">→</ab:mo> <ab:mi>n</ab:mi> <ab:msubsup> <ab:mi>K</ab:mi> <ab:mi>S</ab:mi> <ab:mn>0</ab:mn> </ab:msubsup> <ab:msup> <ab:mi>π</ab:mi> <ab:mo>+</ab:mo> </ab:msup> </ab:math> exceeds SU(3) symmetry predictions by a factor of 3–4, signaling strong contributions from low-lying resonances. In this work, we provide a theoretical analysis of <eb:math xmlns:eb="http://www.w3.org/1998/Math/MathML" display="inline"> <eb:msubsup> <eb:mi mathvariant="normal">Λ</eb:mi> <eb:mi>c</eb:mi> <eb:mo>+</eb:mo> </eb:msubsup> <eb:mo stretchy="false">→</eb:mo> <eb:mi>n</eb:mi> <eb:msup> <eb:mover accent="true"> <eb:mi>K</eb:mi> <eb:mo stretchy="false">¯</eb:mo> </eb:mover> <eb:mn>0</eb:mn> </eb:msup> <eb:msup> <eb:mi>π</eb:mi> <eb:mo>+</eb:mo> </eb:msup> </eb:math> within the coupled-channel chiral unitary approach, where the <kb:math xmlns:kb="http://www.w3.org/1998/Math/MathML" display="inline"> <kb:mi>N</kb:mi> <kb:mo stretchy="false">(</kb:mo> <kb:mn>1535</kb:mn> <kb:mo stretchy="false">)</kb:mo> </kb:math> and <ob:math xmlns:ob="http://www.w3.org/1998/Math/MathML" display="inline"> <ob:mi mathvariant="normal">Λ</ob:mi> <ob:mo stretchy="false">(</ob:mo> <ob:mn>1670</ob:mn> <ob:mo stretchy="false">)</ob:mo> </ob:math> can be dynamically generated. Our calculations show a narrow peak from <tb:math xmlns:tb="http://www.w3.org/1998/Math/MathML" display="inline"> <tb:mi>N</tb:mi> <tb:mo stretchy="false">(</tb:mo> <tb:mn>1535</tb:mn> <tb:mo stretchy="false">)</tb:mo> </tb:math> in the <xb:math xmlns:xb="http://www.w3.org/1998/Math/MathML" display="inline"> <xb:msup> <xb:mi>π</xb:mi> <xb:mo>+</xb:mo> </xb:msup> <xb:mi>n</xb:mi> </xb:math> invariant mass spectrum and a distinct dip from <zb:math xmlns:zb="http://www.w3.org/1998/Math/MathML" display="inline"> <zb:mi mathvariant="normal">Λ</zb:mi> <zb:mo stretchy="false">(</zb:mo> <zb:mn>1670</zb:mn> <zb:mo stretchy="false">)</zb:mo> </zb:math> in the <ec:math xmlns:ec="http://www.w3.org/1998/Math/MathML" display="inline"> <ec:msup> <ec:mover accent="true"> <ec:mi>K</ec:mi> <ec:mo stretchy="false">¯</ec:mo> </ec:mover> <ec:mn>0</ec:mn> </ec:msup> <ec:mi>n</ec:mi> </ec:math> spectrum. The dip structure is qualitatively consistent with the <ic:math xmlns:ic="http://www.w3.org/1998/Math/MathML" display="inline"> <ic:mi mathvariant="normal">Λ</ic:mi> <ic:mo stretchy="false">(</ic:mo> <ic:mn>1670</ic:mn> <ic:mo stretchy="false">)</ic:mo> </ic:math> manifestation in <nc:math xmlns:nc="http://www.w3.org/1998/Math/MathML" display="inline"> <nc:mover accent="true"> <nc:mi>K</nc:mi> <nc:mo stretchy="false">¯</nc:mo> </nc:mover> <nc:mi>N</nc:mi> <nc:mo stretchy="false">→</nc:mo> <nc:mover accent="true"> <nc:mi>K</nc:mi> <nc:mo stretchy="false">¯</nc:mo> </nc:mover> <nc:mi>N</nc:mi> </nc:math> scattering, supporting its molecular interpretation. This study not only connects the experimental observations but also highlights <uc:math xmlns:uc="http://www.w3.org/1998/Math/MathML" display="inline"> <uc:msubsup> <uc:mi mathvariant="normal">Λ</uc:mi> <uc:mi>c</uc:mi> <uc:mo>+</uc:mo> </uc:msubsup>