Heavy quark jet production near threshold

Lin Dai, Chul Kim, Adam K. Leibovich

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


In this paper, we study the fragmentation of a heavy quark into a jet near threshold, meaning that final state jet carries most of the energy of the fragmenting heavy quark. Using the heavy quark fragmentation function, we simultaneously resum large logarithms of the jet radius R and 1 − z, where z is the ratio of the jet energy to the initiating heavy quark energy. There are numerically significant corrections to the leading order rate due to this resummation. We also investigate the heavy quark fragmentation to a groomed jet, using the soft drop grooming algorithm as an example. In order to do so, we introduce a collinear-ultrasoft mode sensitive to the grooming region determined by the algorithm’s zcut parameter. This allows us to resum large logarithms of zcut/(1 − z), again leading to large numerical corrections near the endpoint. A nice feature of the analysis of the heavy quark fragmenting to a groomed jet is the heavy quark mass m renders the algorithm infrared finite, allowing a perturbative calculation. We analyze this for EJR ∼ m and EJR » m, where EJ is the jet energy. To do the latter case, we introduce an ultracollinear-soft mode, allowing us to resum large logarithms of EJR/m. Finally, as an application we calculate the rate for e+e collisions to produce a heavy quark jet in the endpoint region, where we show that grooming effects have a sizable contribution near the endpoint.

Original languageEnglish
Article number148
JournalJournal of High Energy Physics
Issue number9
StatePublished - 1 Sep 2021


  • Effective Field Theories
  • Perturbative QCD
  • Resummation

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


Dive into the research topics of 'Heavy quark jet production near threshold'. Together they form a unique fingerprint.

Cite this