2024 journal article
Exploring the Strong Interaction of Three-Body Systems at the LHC
Physical Review X.
open access via doi.org (publisher)Deuterons are atomic nuclei composed of a neutron and a proton held together by the strong interaction. Unbound ensembles composed of a deuteron and a third nucleon have been investigated in the past using scattering experiments, and they constitute a fundamental reference in nuclear physics to constrain nuclear interactions and the properties of nuclei. In this work, <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:msup><a:mrow><a:mi>K</a:mi></a:mrow><a:mrow><a:mo>+</a:mo></a:mrow></a:msup><a:mtext>−</a:mtext><a:mi>d</a:mi></a:mrow></a:math> and <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mrow><c:mi>p</c:mi><c:mtext>−</c:mtext><c:mi>d</c:mi></c:mrow></c:math> femtoscopic correlations measured by the ALICE Collaboration in proton-proton (<e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mi>p</e:mi><e:mi>p</e:mi></e:math>) collisions at <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"><g:mrow><g:msqrt><g:mrow><g:mi>s</g:mi></g:mrow></g:msqrt><g:mo>=</g:mo><g:mn>13</g:mn><g:mtext> </g:mtext><g:mtext> </g:mtext><g:mi>TeV</g:mi></g:mrow></g:math> at the Large Hadron Collider (LHC) are presented. It is demonstrated that correlations in momentum space between deuterons and kaons or protons allow us to study three-hadron systems at distances comparable with the proton radius. The analysis of the <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"><i:mrow><i:msup><i:mrow><i:mi>K</i:mi></i:mrow><i:mrow><i:mo>+</i:mo></i:mrow></i:msup><i:mtext>−</i:mtext><i:mi>d</i:mi></i:mrow></i:math> correlation shows that the relative distances at which deuterons and protons or kaons are produced are around 2 fm. The analysis of the <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"><k:mrow><k:mi>p</k:mi><k:mtext>−</k:mtext><k:mi>d</k:mi></k:mrow></k:math> correlation shows that only a full three-body calculation that accounts for the internal structure of the deuteron can explain the data. In particular, the sensitivity of the observable to the short-range part of the interaction is demonstrated. These results indicate that correlations involving light nuclei in <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" display="inline"><m:mi>p</m:mi><m:mi>p</m:mi></m:math> collisions at the LHC will also provide access to any three-body system in the strange and charm sectors. Published by the American Physical Society 2024