### Abstract

Current all-orders proofs of factorization of hard processes are made by extracting the leading power behavior of Feynman graphs, i.e., by extracting asymptotics strictly order-by-order in perturbation theory. The resulting parton densities and fragmentation functions include nonperturbative effects. I show how there are missing elements in the proofs; these are related to and exemplified by string and cluster models of hadronization. The proofs rely on large rapidity differences between different parts of graphs for the process; but in reality large rapidity gaps are filled in.

Original language | English (US) |
---|---|

Journal | Proceedings of Science |

Volume | Part F128562 |

State | Published - Jan 1 2016 |

Event | 2016 QCD Evolution Workshop, QCDEV 2016 - Amsterdam, Netherlands Duration: May 30 2016 → Jun 3 2016 |

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### All Science Journal Classification (ASJC) codes

- General

### Cite this

*Proceedings of Science*,

*Part F128562*.

}

*Proceedings of Science*, vol. Part F128562.

**Do fragmentation functions in factorization theorems correctly treat non-perturbative effects?** / Collins, John.

Research output: Contribution to journal › Conference article

TY - JOUR

T1 - Do fragmentation functions in factorization theorems correctly treat non-perturbative effects?

AU - Collins, John

PY - 2016/1/1

Y1 - 2016/1/1

N2 - Current all-orders proofs of factorization of hard processes are made by extracting the leading power behavior of Feynman graphs, i.e., by extracting asymptotics strictly order-by-order in perturbation theory. The resulting parton densities and fragmentation functions include nonperturbative effects. I show how there are missing elements in the proofs; these are related to and exemplified by string and cluster models of hadronization. The proofs rely on large rapidity differences between different parts of graphs for the process; but in reality large rapidity gaps are filled in.

AB - Current all-orders proofs of factorization of hard processes are made by extracting the leading power behavior of Feynman graphs, i.e., by extracting asymptotics strictly order-by-order in perturbation theory. The resulting parton densities and fragmentation functions include nonperturbative effects. I show how there are missing elements in the proofs; these are related to and exemplified by string and cluster models of hadronization. The proofs rely on large rapidity differences between different parts of graphs for the process; but in reality large rapidity gaps are filled in.

UR - http://www.scopus.com/inward/record.url?scp=85026405414&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85026405414&partnerID=8YFLogxK

M3 - Conference article

AN - SCOPUS:85026405414

VL - Part F128562

JO - Proceedings of Science

JF - Proceedings of Science

SN - 1824-8039

ER -