Structure of open-flavor four-quark states in the charm and bottom region

We present quantitative results for masses and the internal structure of four-quark states with two heavy quarks, i.e., <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mi>Q</a:mi><a:msup><a:mi>Q</a:mi><a:mo>′</a:mo></a:msup><a:mover accent="true"><a:mi>q</a:mi><a:mo stretchy="false">¯</a:mo></a:mover><a:msup><a:mover accent="true"><a:mi>q</a:mi><a:mo stretchy="false">¯</a:mo></a:mover><a:mo>′</a:mo></a:msup></a:mrow></a:math> with <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"><g:mi>Q</g:mi><g:mo>,</g:mo><g:msup><g:mi>Q</g:mi><g:mo>′</g:mo></g:msup><g:mo>∈</g:mo><g:mo stretchy="false">{</g:mo><g:mi>c</g:mi><g:mo>,</g:mo><g:mi>b</g:mi><g:mo stretchy="false">}</g:mo></g:math> and <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"><k:mi>q</k:mi><k:mo>,</k:mo><k:msup><k:mi>q</k:mi><k:mo>′</k:mo></k:msup><k:mo>∈</k:mo><k:mo stretchy="false">{</k:mo><k:mi>u</k:mi><k:mo>,</k:mo><k:mi>d</k:mi><k:mo>,</k:mo><k:mi>s</k:mi><k:mo stretchy="false">}</k:mo></k:math>, and <o:math xmlns:o="http://www.w3.org/1998/Math/MathML" display="inline"><o:msup><o:mi>J</o:mi><o:mi>P</o:mi></o:msup><o:mo>∈</o:mo><o:msup><o:mn>1</o:mn><o:mo>+</o:mo></o:msup></o:math>. The composition of these states in terms of meson-meson and diquark-antidiquark pairs, extracted from a relativistic four-body Faddeev-Yakubowski equation, is dynamically determined from underlying QCD forces. We find states at energy levels in very good agreement with lattice QCD and, where available, with experimental states. Their internal structure, most notably between the <q:math xmlns:q="http://www.w3.org/1998/Math/MathML" display="inline"><q:msubsup><q:mi>T</q:mi><q:mrow><q:mi>c</q:mi><q:mi>c</q:mi></q:mrow><q:mo>+</q:mo></q:msubsup></q:math>, <s:math xmlns:s="http://www.w3.org/1998/Math/MathML" display="inline"><s:msub><s:mi>T</s:mi><s:mrow><s:mi>b</s:mi><s:mi>c</s:mi></s:mrow></s:msub></s:math> and <u:math xmlns:u="http://www.w3.org/1998/Math/MathML" display="inline"><u:msubsup><u:mi>T</u:mi><u:mrow><u:mi>b</u:mi><u:mi>b</u:mi></u:mrow><u:mo>−</u:mo></u:msubsup></u:math>, show significant and sizeable variations.