The q T and ∆ ϕ t t ¯ $$ \Delta {\phi}_{t\overline{t}} $$ spectra in top-antitop hadroproduction at NNLL+NNLO: the interplay of soft-collinear resummation and Coulomb singularities
Abstract In this paper, we present the resummation-improved differential transverse momentum and azimuthal decorrelation cross sections, d σ t t ¯ / d q T $$ {\textrm{d}\sigma}_{t\overline{t}}/{\textrm{d}q}_{\textrm{T}} $$ and d σ t t ¯ / d ∆ ϕ t t ¯ $$ {\textrm{d}\sigma}_{t\overline{t}}/\textrm{d}\...
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2025-02-01
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| Series: | Journal of High Energy Physics |
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| Online Access: | https://doi.org/10.1007/JHEP02(2025)020 |
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| author | Wan-Li Ju Marek Schönherr |
| author_facet | Wan-Li Ju Marek Schönherr |
| author_sort | Wan-Li Ju |
| collection | DOAJ |
| description | Abstract In this paper, we present the resummation-improved differential transverse momentum and azimuthal decorrelation cross sections, d σ t t ¯ / d q T $$ {\textrm{d}\sigma}_{t\overline{t}}/{\textrm{d}q}_{\textrm{T}} $$ and d σ t t ¯ / d ∆ ϕ t t ¯ $$ {\textrm{d}\sigma}_{t\overline{t}}/\textrm{d}\Delta {\phi}_{t\overline{t}} $$ , in top-antitop pair production at the LHC. Our calculation is based on the observation that both cross sections are dominated by topologies where the top-quark pair is well separated, expressed in their relative velocity β t t ¯ ∼ O 1 $$ {\beta}_{t\overline{t}}\sim \mathcal{O}(1) $$ , at colliding energies of s $$ \sqrt{s} $$ = 13 TeV or higher. Therefore, the asymptotic behaviour in the limits q T → 0 and ∆ ϕ t t ¯ $$ \Delta {\phi}_{t\overline{t}} $$ → 0 can mostly be captured by the soft and collinear resummation in the HQET+SCET framework. Nevertheless, starting at N2LL, Coulomb singularities emerge in the threshold regime, β t t ¯ $$ {\beta}_{t\overline{t}} $$ → 0, in both the hard sector and its evolution kernels, leading to unphysical results upon integration over the entire β t t ¯ $$ {\beta}_{t\overline{t}} $$ range. To this end, two prescriptions, dubbed the D- and R-prescription, are introduced to regularise these Coulomb singularities. They embody two fundamentally different methods to truncate the threshold enhanced terms, rendering their contribution finite. In the absence of a combined threshold and small-transverse-momentum resummation, we present a quantitative assessment of the ambiguity introduced by the choice of prescription, itself a test of the sensitivity of our calculation to such threshold enhancements, for both the d σ t t ¯ / d q T $$ {\textrm{d}\sigma}_{t\overline{t}}/{\textrm{d}q}_{\textrm{T}} $$ and d σ t t ¯ / d ∆ ϕ t t ¯ $$ {\textrm{d}\sigma}_{t\overline{t}}/\textrm{d}\Delta {\phi}_{t\overline{t}} $$ spectra. |
| format | Article |
| id | doaj-art-9a456dbddf6143efbd076fb291055cd4 |
| institution | DOAJ |
| issn | 1029-8479 |
| language | English |
| publishDate | 2025-02-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Journal of High Energy Physics |
| spelling | doaj-art-9a456dbddf6143efbd076fb291055cd42025-08-20T03:08:02ZengSpringerOpenJournal of High Energy Physics1029-84792025-02-012025216210.1007/JHEP02(2025)020The q T and ∆ ϕ t t ¯ $$ \Delta {\phi}_{t\overline{t}} $$ spectra in top-antitop hadroproduction at NNLL+NNLO: the interplay of soft-collinear resummation and Coulomb singularitiesWan-Li Ju0Marek Schönherr1INFN, Sezione di MilanoInstitute for Particle Physics Phenomenology, Durham UniversityAbstract In this paper, we present the resummation-improved differential transverse momentum and azimuthal decorrelation cross sections, d σ t t ¯ / d q T $$ {\textrm{d}\sigma}_{t\overline{t}}/{\textrm{d}q}_{\textrm{T}} $$ and d σ t t ¯ / d ∆ ϕ t t ¯ $$ {\textrm{d}\sigma}_{t\overline{t}}/\textrm{d}\Delta {\phi}_{t\overline{t}} $$ , in top-antitop pair production at the LHC. Our calculation is based on the observation that both cross sections are dominated by topologies where the top-quark pair is well separated, expressed in their relative velocity β t t ¯ ∼ O 1 $$ {\beta}_{t\overline{t}}\sim \mathcal{O}(1) $$ , at colliding energies of s $$ \sqrt{s} $$ = 13 TeV or higher. Therefore, the asymptotic behaviour in the limits q T → 0 and ∆ ϕ t t ¯ $$ \Delta {\phi}_{t\overline{t}} $$ → 0 can mostly be captured by the soft and collinear resummation in the HQET+SCET framework. Nevertheless, starting at N2LL, Coulomb singularities emerge in the threshold regime, β t t ¯ $$ {\beta}_{t\overline{t}} $$ → 0, in both the hard sector and its evolution kernels, leading to unphysical results upon integration over the entire β t t ¯ $$ {\beta}_{t\overline{t}} $$ range. To this end, two prescriptions, dubbed the D- and R-prescription, are introduced to regularise these Coulomb singularities. They embody two fundamentally different methods to truncate the threshold enhanced terms, rendering their contribution finite. In the absence of a combined threshold and small-transverse-momentum resummation, we present a quantitative assessment of the ambiguity introduced by the choice of prescription, itself a test of the sensitivity of our calculation to such threshold enhancements, for both the d σ t t ¯ / d q T $$ {\textrm{d}\sigma}_{t\overline{t}}/{\textrm{d}q}_{\textrm{T}} $$ and d σ t t ¯ / d ∆ ϕ t t ¯ $$ {\textrm{d}\sigma}_{t\overline{t}}/\textrm{d}\Delta {\phi}_{t\overline{t}} $$ spectra.https://doi.org/10.1007/JHEP02(2025)020Effective Field Theories of QCDFactorizationRenormalization GroupResummationTop Quark |
| spellingShingle | Wan-Li Ju Marek Schönherr The q T and ∆ ϕ t t ¯ $$ \Delta {\phi}_{t\overline{t}} $$ spectra in top-antitop hadroproduction at NNLL+NNLO: the interplay of soft-collinear resummation and Coulomb singularities Journal of High Energy Physics Effective Field Theories of QCD Factorization Renormalization Group Resummation Top Quark |
| title | The q T and ∆ ϕ t t ¯ $$ \Delta {\phi}_{t\overline{t}} $$ spectra in top-antitop hadroproduction at NNLL+NNLO: the interplay of soft-collinear resummation and Coulomb singularities |
| title_full | The q T and ∆ ϕ t t ¯ $$ \Delta {\phi}_{t\overline{t}} $$ spectra in top-antitop hadroproduction at NNLL+NNLO: the interplay of soft-collinear resummation and Coulomb singularities |
| title_fullStr | The q T and ∆ ϕ t t ¯ $$ \Delta {\phi}_{t\overline{t}} $$ spectra in top-antitop hadroproduction at NNLL+NNLO: the interplay of soft-collinear resummation and Coulomb singularities |
| title_full_unstemmed | The q T and ∆ ϕ t t ¯ $$ \Delta {\phi}_{t\overline{t}} $$ spectra in top-antitop hadroproduction at NNLL+NNLO: the interplay of soft-collinear resummation and Coulomb singularities |
| title_short | The q T and ∆ ϕ t t ¯ $$ \Delta {\phi}_{t\overline{t}} $$ spectra in top-antitop hadroproduction at NNLL+NNLO: the interplay of soft-collinear resummation and Coulomb singularities |
| title_sort | q t and ∆ ϕ t t ¯ delta phi t overline t spectra in top antitop hadroproduction at nnll nnlo the interplay of soft collinear resummation and coulomb singularities |
| topic | Effective Field Theories of QCD Factorization Renormalization Group Resummation Top Quark |
| url | https://doi.org/10.1007/JHEP02(2025)020 |
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