Exotic <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msubsup> <mml:mi>T</mml:mi> <mml:mrow> <mml:mi>c</mml:mi> <mml:mover accent="true"> <mml:mi>s</mml:mi> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> <mml:mn>0</

We employ the Born-Oppenheimer approximation to the <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:msubsup> <a:mi>T</a:mi> <a:mrow> <a:mi>c</a:mi> <a:mover accent="true"> <a:mi>s</a:mi> <a:mo stretchy="false">¯</a:mo> </a:mover> <a:mn>0</a:mn> </a:mrow> <a:mi>a</a:mi> </a:msubsup> <a:mo stretchy="false">(</a:mo> <a:mn>2900</a:mn> <a:msup> <a:mo stretchy="false">)</a:mo> <a:mn>0</a:mn> </a:msup> </a:math> and <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"> <g:msubsup> <g:mi>T</g:mi> <g:mrow> <g:mi>c</g:mi> <g:mover accent="true"> <g:mi>s</g:mi> <g:mo stretchy="false">¯</g:mo> </g:mover> <g:mn>0</g:mn> </g:mrow> <g:mi>a</g:mi> </g:msubsup> <g:mo stretchy="false">(</g:mo> <g:mn>2900</g:mn> <g:msup> <g:mo stretchy="false">)</g:mo> <g:mrow> <g:mo>+</g:mo> <g:mo>+</g:mo> </g:mrow> </g:msup> </g:math> states observed by the LHCb Collaboration and study mass spectrum and root-mean-square radius values. For this purpose, we use the dynamical diquark model. We assume that a strange quark is heavy for the usage of the Born-Oppenheimer approximation. Our results strongly indicate that the <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" display="inline"> <m:msubsup> <m:mi>T</m:mi> <m:mrow> <m:mi>c</m:mi> <m:mover accent="true"> <m:mi>s</m:mi> <m:mo stretchy="false">¯</m:mo> </m:mover> <m:mn>0</m:mn> </m:mrow> <m:mi>a</m:mi> </m:msubsup> <m:mo stretchy="false">(</m:mo> <m:mn>2900</m:mn> <m:mo stretchy="false">)</m:mo> </m:math> states are best described as composed of axial-vector (spin-1) diquark pairs. Furthermore, the calculated root-mean-square radius, <s:math xmlns:s="http://www.w3.org/1998/Math/MathML" display="inline"> <s:mrow> <s:mo stretchy="false">⟨</s:mo> <s:msup> <s:mrow> <s:mi>r</s:mi> </s:mrow> <s:mrow> <s:mn>2</s:mn> </s:mrow> </s:msup> <s:msup> <s:mrow> <s:mo stretchy="false">⟩</s:mo> </s:mrow> <s:mrow> <s:mn>1</s:mn> <s:mo>/</s:mo> <s:mn>2</s:mn> </s:mrow> </s:msup> <s:mo>≈</s:mo> <s:mn>0.70</s:mn> <s:mi>–</s:mi> <s:mn>0.80</s:mn> <s:mtext> </s:mtext> <s:mtext> </s:mtext> <s:mi>fm</s:mi> </s:mrow> </s:math> , which is significantly less than 1 fm, provides compelling evidence that these are compact tetraquarks rather than loosely bound hadronic molecules.