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String Formation Beyond Leading Colour
We present a new model for the hadronisation of multi-parton systems, in which colour correlations beyond leading $N_C$ are allowed to influence the formation of confining potentials (strings). The multiplet structure of $SU(3)$ is combined with a minimisation of the string potential energy, to deci...
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Lenguaje: | eng |
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2015
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Acceso en línea: | https://dx.doi.org/10.1007/JHEP08(2015)003 http://cds.cern.ch/record/2014847 |
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author | Christiansen, Jesper R. Skands, Peter Z. |
author_facet | Christiansen, Jesper R. Skands, Peter Z. |
author_sort | Christiansen, Jesper R. |
collection | CERN |
description | We present a new model for the hadronisation of multi-parton systems, in which colour correlations beyond leading $N_C$ are allowed to influence the formation of confining potentials (strings). The multiplet structure of $SU(3)$ is combined with a minimisation of the string potential energy, to decide between which partons strings should form, allowing also for "baryonic" configurations (e.g., two colours can combine coherently to form an anticolour). In $e^+e^-$collisions, modifications to the leading-colour picture are small, suppressed by both colour and kinematics factors. But in $pp$ collisions, multi-parton interactions increase the number of possible subleading connections, counteracting their naive $1/N_C^2$ suppression. Moreover, those that reduce the overall string lengths are kinematically favoured. The model, which we have implemented in the PYTHIA 8 generator, is capable of reaching agreement not only with the important $\left<p_\perp\right>(n_\mathrm{charged})$ distribution but also with measured rates (and ratios) of kaons and hyperons, in both $ee$ and $pp$ collisions. Nonetheless, the shape of their $p_\perp$ spectra remains challenging to explain. |
id | cern-2014847 |
institution | Organización Europea para la Investigación Nuclear |
language | eng |
publishDate | 2015 |
record_format | invenio |
spelling | cern-20148472022-08-10T13:08:00Zdoi:10.1007/JHEP08(2015)003http://cds.cern.ch/record/2014847engChristiansen, Jesper R.Skands, Peter Z.String Formation Beyond Leading ColourParticle Physics - PhenomenologyWe present a new model for the hadronisation of multi-parton systems, in which colour correlations beyond leading $N_C$ are allowed to influence the formation of confining potentials (strings). The multiplet structure of $SU(3)$ is combined with a minimisation of the string potential energy, to decide between which partons strings should form, allowing also for "baryonic" configurations (e.g., two colours can combine coherently to form an anticolour). In $e^+e^-$collisions, modifications to the leading-colour picture are small, suppressed by both colour and kinematics factors. But in $pp$ collisions, multi-parton interactions increase the number of possible subleading connections, counteracting their naive $1/N_C^2$ suppression. Moreover, those that reduce the overall string lengths are kinematically favoured. The model, which we have implemented in the PYTHIA 8 generator, is capable of reaching agreement not only with the important $\left<p_\perp\right>(n_\mathrm{charged})$ distribution but also with measured rates (and ratios) of kaons and hyperons, in both $ee$ and $pp$ collisions. Nonetheless, the shape of their $p_\perp$ spectra remains challenging to explain.We present a new model for the hadronisation of multi-parton systems, in which colour correlations beyond leading N$_{C}$ are allowed to influence the formation of confining potentials (strings). The multiplet structure of SU(3) is combined with a minimisation of the string potential energy, to decide between which partons strings should form, allowing also for “baryonic” configurations (e.g., two colours can combine coherently to form an anticolour). In e$^{+}$ e$^{−}$collisions, modifications to the leading-colour picture are small, suppressed by both colour and kinematics factors. But in pp collisions, multi-parton interactions increase the number of possible subleading connections, counteracting their naive 1/N$_{C}^{2}$ suppression. Moreover, those that reduce the overall string lengths are kinematically favoured. The model, which we have implemented in the PYTHIA 8 generator, is capable of reaching agreement not only with the important 〈p$_{⊥}$〉 (n$_{charged}$) distribution but also with measured rates (and ratios) of kaons and hyperons, in both ee and pp collisions. Nonetheless, the shape of their p$_{⊥}$ spectra remains challenging to explain.We present a new model for the hadronisation of multi-parton systems, in which colour correlations beyond leading $N_C$ are allowed to influence the formation of confining potentials (strings). The multiplet structure of $SU(3)$ is combined with a minimisation of the string potential energy, to decide between which partons strings should form, allowing also for "baryonic" configurations (e.g., two colours can combine coherently to form an anticolour). In $e^+e^-$collisions, modifications to the leading-colour picture are small, suppressed by both colour and kinematics factors. But in $pp$ collisions, multi-parton interactions increase the number of possible subleading connections, counteracting their naive $1/N_C^2$ suppression. Moreover, those that reduce the overall string lengths are kinematically favoured. The model, which we have implemented in the PYTHIA 8 generator, is capable of reaching agreement not only with the important $\left<p_\perp\right>(n_\mathrm{charged})$ distribution but also with measured rates (and ratios) of kaons and hyperons, in both $ee$ and $pp$ collisions. Nonetheless, the shape of their $p_\perp$ spectra remains challenging to explain.arXiv:1505.01681COEPP-MN-15-1LU-TP-15-16MCNET-15-09COEPP-MN-15-1LU-TP-15-16MCNET-15-09COEPP-MN-15-1LU-TP-15-16MCNET-15-09oai:cds.cern.ch:20148472015-05-07 |
spellingShingle | Particle Physics - Phenomenology Christiansen, Jesper R. Skands, Peter Z. String Formation Beyond Leading Colour |
title | String Formation Beyond Leading Colour |
title_full | String Formation Beyond Leading Colour |
title_fullStr | String Formation Beyond Leading Colour |
title_full_unstemmed | String Formation Beyond Leading Colour |
title_short | String Formation Beyond Leading Colour |
title_sort | string formation beyond leading colour |
topic | Particle Physics - Phenomenology |
url | https://dx.doi.org/10.1007/JHEP08(2015)003 http://cds.cern.ch/record/2014847 |
work_keys_str_mv | AT christiansenjesperr stringformationbeyondleadingcolour AT skandspeterz stringformationbeyondleadingcolour |