Studying the interaction between charm and light-flavor mesons

The two-particle momentum correlation functions between charm mesons (<a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:msup><a:mi mathvariant="normal">D</a:mi><a:mrow><a:mo>*</a:mo><a:mo>±</a:mo></a:mrow></a:msup></a:math> and <d:math xmlns:d="http://www.w3.org/1998/Math/MathML" display="inline"><d:mrow><d:msup><d:mrow><d:mi mathvariant="normal">D</d:mi></d:mrow><d:mrow><d:mo>±</d:mo></d:mrow></d:msup></d:mrow></d:math>) and charged light-flavor mesons (<g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"><g:msup><g:mi>π</g:mi><g:mo>±</g:mo></g:msup></g:math> and <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"><i:mrow><i:msup><i:mrow><i:mi mathvariant="normal">K</i:mi></i:mrow><i:mrow><i:mo>±</i:mo></i:mrow></i:msup></i:mrow></i:math>) in all charge combinations are measured for the first time by the ALICE Collaboration in high-multiplicity proton–proton collisions at a center-of-mass energy of <l:math xmlns:l="http://www.w3.org/1998/Math/MathML" display="inline"><l:msqrt><l:mi>s</l:mi></l:msqrt><l:mo>=</l:mo><l:mn>13</l:mn><l:mtext> </l:mtext><l:mtext> </l:mtext><l:mi>TeV</l:mi></l:math>. For DK and <n:math xmlns:n="http://www.w3.org/1998/Math/MathML" display="inline"><n:msup><n:mi mathvariant="normal">D</n:mi><n:mo>*</n:mo></n:msup><n:mi mathvariant="normal">K</n:mi></n:math> pairs, the experimental results are in agreement with theoretical predictions of the residual strong interaction based on quantum chromodynamics calculations on the lattice and chiral effective field theory. In the case of <r:math xmlns:r="http://www.w3.org/1998/Math/MathML" display="inline"><r:mi mathvariant="normal">D</r:mi><r:mi>π</r:mi></r:math> and <u:math xmlns:u="http://www.w3.org/1998/Math/MathML" display="inline"><u:msup><u:mi mathvariant="normal">D</u:mi><u:mo>*</u:mo></u:msup><u:mi>π</u:mi></u:math> pairs, tension between the calculations including strong interactions and the measurement is observed. For all particle pairs, the data can be adequately described by Coulomb interaction only, indicating a shallow interaction between charm and light-flavor mesons. Finally, the scattering lengths governing the residual strong interaction of the <x:math xmlns:x="http://www.w3.org/1998/Math/MathML" display="inline"><x:mi mathvariant="normal">D</x:mi><x:mi>π</x:mi></x:math> and <ab:math xmlns:ab="http://www.w3.org/1998/Math/MathML" display="inline"><ab:msup><ab:mi mathvariant="normal">D</ab:mi><ab:mo>*</ab:mo></ab:msup><ab:mi>π</ab:mi></ab:math> systems are determined by fitting the experimental correlation functions with a model that employs a Gaussian potential. The extracted values are small and compatible with zero.