NRQCD reconfronts LHCb data on quarkonium production within jets

We compare LHCb measurements of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mi>J</a:mi> <a:mo>/</a:mo> <a:mi>ψ</a:mi> </a:math> and <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"> <c:mi>ψ</c:mi> <c:mo stretchy="false">(</c:mo> <c:mn>2</c:mn> <c:mi>S</c:mi> <c:mo stretchy="false">)</c:mo> </c:math> transverse-momentum distributions within jets with QCD calculations, which may be crucial in understanding the quarkonium production mechanism. Our theoretical calculations are based on the fragmenting jet function formalism, while the nonperturbative formation of quarkonia is described by the nonrelativistic QCD factorization formalism. We include the newest refinements in the perturbative calculation including resummation of threshold and Dokshitzer-Gribov-Lipatov-Altarelli-Parisi logarithms. We find that the <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"> <g:mi>ψ</g:mi> <g:mo stretchy="false">(</g:mo> <g:mn>2</g:mn> <g:mi>S</g:mi> <g:mo stretchy="false">)</g:mo> </g:math> data have the potential to discriminate between the different production mechanisms proposed in the literature.