2017/09/30 by Daniël Boer, Tom van Daal, Jonathan R. Gaunt +3 · 7 citations
Mathematics · Physics and Astronomy · #Algorithm #Combinatorics #Computation #Computer science #Context (archaeology) #Drell–Yan process #Factorization #Geometry #Glauber #Gluon #Graph #Hadron #High-Energy Particle Collisions Research #Mathematics #Particle physics #Particle physics theoretical and experimental studies #Parton #Physics #Quantum Chromodynamics and Particle Interactions #Quantum chromodynamics #Quantum mechanics #Scaling #Scattering #Transverse plane #Vertex (graph theory) #hep-ph
paper · pdf · doi:10.21468/scipostphys.3.6.040
published in SciPost Physics 3(6) (SciPost.org) · 36 pages, 11 figures; v2: typos corrected/ reference added, v3: minor corrections/ small explanations added/ references added, v4: very minor correction/ small explanations added/ references added (this version has been accepted for publication in SciPost)
openalex created_date 2017/09/25 · arxiv created 2017/12/18 · openalex publication_date 2017/12/19 · arxiv updated 2018/01/19 · openalex updated_date 2026/08/05
It has been suggested that a colour-entanglement effect exists in the Drell-Yan cross section for the ‘double T-odd’ contributions at low transverse momentum \bmQ_\st , rendering the colour structure different from that predicted by the usual factorisation formula . These T-odd contributions can come from the Boer-Mulders or Sivers transverse momentum dependent distribution functions. The different colour structure should be visible already at the lowest possible order that gives a contribution to the double Boer-Mulders (dBM) or double Sivers (dS) effect, that is at the level of two gluon exchanges. To discriminate between the different predictions, we compute the leading-power contribution to the low- \bmQ_\st dBM cross section at the two-gluon exchange order in the context of a spectator model. The computation is performed using a method of regions analysis with Collins subtraction terms implemented. The results conform with the predictions of the factorisation formula. In the cancellation of the colour entanglement, diagrams containing the three-gluon vertex are essential. Furthermore, the Glauber region turns out to play an important role – in fact, it is possible to assign the full contribution to the dBM cross section at the given order to the region in which the two gluons have Glauber scaling. A similar disentanglement of colour is found for the dS effect.