Diffusion Monte Carlo calculation of fully heavy pentaquarks

Using a diffusion Monte Carlo algorithm, we calculated the spectra of all possible <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>S</a:mi></a:math>-wave fully heavy pentaquarks within the framework of the quark model. Our aim was to compare the masses of different spin-color configurations corresponding to the same spatial wave function for each quark composition. In particular, we computed the masses of the configuration with the maximum number of undistinguishable quarks and those of all the possible <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mrow><c:mi>baryon</c:mi><c:mo>+</c:mo><c:mi>meson</c:mi></c:mrow></c:math> splittings compatible with the total number of <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mi>b</e:mi></e:math>’s and <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"><g:mi>c</g:mi></g:math>’s for a given pentaquark. What we found was that, in all cases, compact <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"><i:mrow><i:mi>baryon</i:mi><i:mo>+</i:mo><i:mi>meson</i:mi></i:mrow></i:math> configurations had lower masses than their more symmetric counterparts. Moreover, those “molecular” associations were unstable (with larger masses) that their infinitely separated noninteracting pieces except in the case of <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"><k:mo stretchy="false">(</k:mo><k:mi>c</k:mi><k:mi>c</k:mi><k:mi>b</k:mi><k:mo stretchy="false">)</k:mo><k:mo stretchy="false">(</k:mo><k:mi>c</k:mi><k:mover accent="true"><k:mi>b</k:mi><k:mo stretchy="false">¯</k:mo></k:mover><k:mo stretchy="false">)</k:mo></k:math> and <s:math xmlns:s="http://www.w3.org/1998/Math/MathML" display="inline"><s:mo stretchy="false">(</s:mo><s:mi>b</s:mi><s:mi>b</s:mi><s:mi>c</s:mi><s:mo stretchy="false">)</s:mo><s:mo stretchy="false">(</s:mo><s:mi>b</s:mi><s:mover accent="true"><s:mi>c</s:mi><s:mo stretchy="false">¯</s:mo></s:mover><s:mo stretchy="false">)</s:mo></s:math> pentaquarks. In any case, even for unstable arrangements, the excess masses are so small (<ab:math xmlns:ab="http://www.w3.org/1998/Math/MathML" display="inline"><ab:mrow><ab:mo>∼</ab:mo><ab:mn>20</ab:mn><ab:mi>–</ab:mi><ab:mn>60</ab:mn><ab:mtext> </ab:mtext><ab:mtext> </ab:mtext><ab:mi>MeV</ab:mi></ab:mrow></ab:math>) as to make those compact molecular structures serious candidates to be experimentally detected. Published by the American Physical Society 2024