# Factorization for hard exclusive electroproduction of mesons in QCD

## Abstract

We formulate and prove a QCD factorization theorem for hard exclusive electroproduction of mesons in QCD. The proof is valid for the leading power in Q and all logarithms. This generalizes previous work on vector meson production in the diffractive region of small x. The amplitude is expressed in terms of off-diagonal generalizations of the usual parton densities. The full theorem applies to all kinds of mesons and not just to vector mesons. The parton densities used include not only the ordinary parton density, but also the helicity density (g{sub 1} or {Delta}q) and the transversity density (h{sub 1} or {delta}q), and these can be probed by measuring the polarization of the produced mesons with unpolarized protons. {copyright} {ital 1997} {ital The American Physical Society}

- Authors:

- Department of Physics, Penn State University, 104 Davey Lab., University Park, Pennsylvania 16802 (United States)
- Physics Department, Tel-Aviv University, Tel Aviv (Israel)

- Publication Date:

- OSTI Identifier:
- 538722

- DOE Contract Number:
- FG02-90ER40577; FG02-93ER40771

- Resource Type:
- Journal Article

- Journal Name:
- Physical Review, D

- Additional Journal Information:
- Journal Volume: 56; Journal Issue: 5; Other Information: PBD: Sep 1997

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 66 PHYSICS; ELECTROPRODUCTION; FACTORIZATION; MESONS; QUANTUM CHROMODYNAMICS; ELECTRON-PROTON INTERACTIONS; PARTON MODEL; EXCLUSIVE INTERACTIONS; VECTOR MESONS; PARTONS; DENSITY; HELICITY; POLARIZATION

### Citation Formats

```
Collins, J.C., Frankfurt, L., and Strikman, M..
```*Factorization for hard exclusive electroproduction of mesons in QCD*. United States: N. p., 1997.
Web. doi:10.1103/PhysRevD.56.2982.

```
Collins, J.C., Frankfurt, L., & Strikman, M..
```*Factorization for hard exclusive electroproduction of mesons in QCD*. United States. doi:10.1103/PhysRevD.56.2982.

```
Collins, J.C., Frankfurt, L., and Strikman, M.. Mon .
"Factorization for hard exclusive electroproduction of mesons in QCD". United States. doi:10.1103/PhysRevD.56.2982.
```

```
@article{osti_538722,
```

title = {Factorization for hard exclusive electroproduction of mesons in QCD},

author = {Collins, J.C. and Frankfurt, L. and Strikman, M.},

abstractNote = {We formulate and prove a QCD factorization theorem for hard exclusive electroproduction of mesons in QCD. The proof is valid for the leading power in Q and all logarithms. This generalizes previous work on vector meson production in the diffractive region of small x. The amplitude is expressed in terms of off-diagonal generalizations of the usual parton densities. The full theorem applies to all kinds of mesons and not just to vector mesons. The parton densities used include not only the ordinary parton density, but also the helicity density (g{sub 1} or {Delta}q) and the transversity density (h{sub 1} or {delta}q), and these can be probed by measuring the polarization of the produced mesons with unpolarized protons. {copyright} {ital 1997} {ital The American Physical Society}},

doi = {10.1103/PhysRevD.56.2982},

journal = {Physical Review, D},

number = 5,

volume = 56,

place = {United States},

year = {1997},

month = {9}

}