Triple (and quadruple) soft-gluon radiation in QCD hard scattering
Abstract We consider the radiation of three soft gluons in a generic process for multi- parton hard scattering in QCD. In the soft limit the corresponding scattering amplitude has a singular behaviour that is factorized and controlled by a colorful soft current. We compute the tree-level current for...
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| Format: | Article |
| Language: | English |
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SpringerOpen
2020-01-01
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| Series: | Journal of High Energy Physics |
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| Online Access: | https://doi.org/10.1007/JHEP01(2020)118 |
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| author | Stefano Catani Dimitri Colferai Alessandro Torrini |
| author_facet | Stefano Catani Dimitri Colferai Alessandro Torrini |
| author_sort | Stefano Catani |
| collection | DOAJ |
| description | Abstract We consider the radiation of three soft gluons in a generic process for multi- parton hard scattering in QCD. In the soft limit the corresponding scattering amplitude has a singular behaviour that is factorized and controlled by a colorful soft current. We compute the tree-level current for triple soft-gluon emission from both massless and massive hard partons. The three-gluon current is expressed in terms of maximally non-abelian irreducible correlations. We compute the soft behaviour of squared amplitudes and the colour correlations produced by the squared current. The radiation of one and two soft gluons leads to colour dipole correlations. Triple soft-gluon radiation produces in addition colour quadrupole correlations between the hard partons. We examine the soft and collinear singularities of the squared current in various energy ordered and angular ordered regions. We discuss some features of soft radiation to all-loop orders for processes with two and three hard partons. Considering triple soft-gluon radiation from three hard partons, colour quadrupole interactions break the Casimir scaling symmetry between quarks and gluons. We also present some results on the radiation of four soft gluons from two hard partons, and we discuss the colour monster contribution and its relation with the violation (and generalization) of Casimir scaling. We also compute the first correction of 𝒪(1/ N c 2 $$ {N}_c^2 $$ ) to the eikonal formula for multiple soft-gluon radiation with strong energy ordering from two hard gluons. |
| format | Article |
| id | doaj-art-2381cfcdab084c9fb60c0bf23ede9617 |
| institution | Kabale University |
| issn | 1029-8479 |
| language | English |
| publishDate | 2020-01-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Journal of High Energy Physics |
| spelling | doaj-art-2381cfcdab084c9fb60c0bf23ede96172025-02-09T12:06:30ZengSpringerOpenJournal of High Energy Physics1029-84792020-01-012020117010.1007/JHEP01(2020)118Triple (and quadruple) soft-gluon radiation in QCD hard scatteringStefano Catani0Dimitri Colferai1Alessandro Torrini2INFN, Sezione di Firenze and Dipartimento di Fisica e Astronomia, Università di FirenzeINFN, Sezione di Firenze and Dipartimento di Fisica e Astronomia, Università di FirenzeINFN, Sezione di Firenze and Dipartimento di Fisica e Astronomia, Università di FirenzeAbstract We consider the radiation of three soft gluons in a generic process for multi- parton hard scattering in QCD. In the soft limit the corresponding scattering amplitude has a singular behaviour that is factorized and controlled by a colorful soft current. We compute the tree-level current for triple soft-gluon emission from both massless and massive hard partons. The three-gluon current is expressed in terms of maximally non-abelian irreducible correlations. We compute the soft behaviour of squared amplitudes and the colour correlations produced by the squared current. The radiation of one and two soft gluons leads to colour dipole correlations. Triple soft-gluon radiation produces in addition colour quadrupole correlations between the hard partons. We examine the soft and collinear singularities of the squared current in various energy ordered and angular ordered regions. We discuss some features of soft radiation to all-loop orders for processes with two and three hard partons. Considering triple soft-gluon radiation from three hard partons, colour quadrupole interactions break the Casimir scaling symmetry between quarks and gluons. We also present some results on the radiation of four soft gluons from two hard partons, and we discuss the colour monster contribution and its relation with the violation (and generalization) of Casimir scaling. We also compute the first correction of 𝒪(1/ N c 2 $$ {N}_c^2 $$ ) to the eikonal formula for multiple soft-gluon radiation with strong energy ordering from two hard gluons.https://doi.org/10.1007/JHEP01(2020)118Perturbative QCDScattering Amplitudes |
| spellingShingle | Stefano Catani Dimitri Colferai Alessandro Torrini Triple (and quadruple) soft-gluon radiation in QCD hard scattering Journal of High Energy Physics Perturbative QCD Scattering Amplitudes |
| title | Triple (and quadruple) soft-gluon radiation in QCD hard scattering |
| title_full | Triple (and quadruple) soft-gluon radiation in QCD hard scattering |
| title_fullStr | Triple (and quadruple) soft-gluon radiation in QCD hard scattering |
| title_full_unstemmed | Triple (and quadruple) soft-gluon radiation in QCD hard scattering |
| title_short | Triple (and quadruple) soft-gluon radiation in QCD hard scattering |
| title_sort | triple and quadruple soft gluon radiation in qcd hard scattering |
| topic | Perturbative QCD Scattering Amplitudes |
| url | https://doi.org/10.1007/JHEP01(2020)118 |
| work_keys_str_mv | AT stefanocatani tripleandquadruplesoftgluonradiationinqcdhardscattering AT dimitricolferai tripleandquadruplesoftgluonradiationinqcdhardscattering AT alessandrotorrini tripleandquadruplesoftgluonradiationinqcdhardscattering |