# More on large-momentum effective theory approach to parton physics

## Abstract

Large-Momentum Effective Theory (or LaMET) advocated by the present authors provides a direct ap-proach to simulate parton physics in Euclidean lattice QCD theory. Recently, there has been much interest in this theory in the literature, with some questioning its validity and effectiveness. Here we provide some discussions aiming at a further exposition of this approach. In particular, we explain why it does not have the usual power divergence problem in lattice QCD calculations for the moments of parton distributions. Here the only power divergence in the LaMET approach comes from the self-energy of the Wilson lines which can be properly factorized. We show that although the Ioffe-time distribution provides an alternative way to extract the parton distribution from the same lattice observables, it also requires the same large momentum (or short distance) limit as in LaMET to obtain a precision calculation. In conclusion, with a proper quantification of errors, both extraction methods shall be compared with the same lattice data.

- Authors:

- Publication Date:

- Research Org.:
- Univ. of Maryland, College Park, MD (United States); Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

- Sponsoring Org.:
- USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)

- OSTI Identifier:
- 1437732

- Alternate Identifier(s):
- OSTI ID: 1502433

- Grant/Contract Number:
- FG02-93ER-40762; SC0011090; SFB/TRR-55; 16DZ2260200; FG02-93ER40762

- Resource Type:
- Published Article

- Journal Name:
- Nuclear Physics. B

- Additional Journal Information:
- Journal Name: Nuclear Physics. B Journal Volume: 924 Journal Issue: C; Journal ID: ISSN 0550-3213

- Publisher:
- Elsevier

- Country of Publication:
- Netherlands

- Language:
- English

- Subject:
- 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

### Citation Formats

```
Ji, Xiangdong, Zhang, Jian-Hui, and Zhao, Yong. More on large-momentum effective theory approach to parton physics. Netherlands: N. p., 2017.
Web. doi:10.1016/j.nuclphysb.2017.09.001.
```

```
Ji, Xiangdong, Zhang, Jian-Hui, & Zhao, Yong. More on large-momentum effective theory approach to parton physics. Netherlands. doi:10.1016/j.nuclphysb.2017.09.001.
```

```
Ji, Xiangdong, Zhang, Jian-Hui, and Zhao, Yong. Wed .
"More on large-momentum effective theory approach to parton physics". Netherlands. doi:10.1016/j.nuclphysb.2017.09.001.
```

```
@article{osti_1437732,
```

title = {More on large-momentum effective theory approach to parton physics},

author = {Ji, Xiangdong and Zhang, Jian-Hui and Zhao, Yong},

abstractNote = {Large-Momentum Effective Theory (or LaMET) advocated by the present authors provides a direct ap-proach to simulate parton physics in Euclidean lattice QCD theory. Recently, there has been much interest in this theory in the literature, with some questioning its validity and effectiveness. Here we provide some discussions aiming at a further exposition of this approach. In particular, we explain why it does not have the usual power divergence problem in lattice QCD calculations for the moments of parton distributions. Here the only power divergence in the LaMET approach comes from the self-energy of the Wilson lines which can be properly factorized. We show that although the Ioffe-time distribution provides an alternative way to extract the parton distribution from the same lattice observables, it also requires the same large momentum (or short distance) limit as in LaMET to obtain a precision calculation. In conclusion, with a proper quantification of errors, both extraction methods shall be compared with the same lattice data.},

doi = {10.1016/j.nuclphysb.2017.09.001},

journal = {Nuclear Physics. B},

number = C,

volume = 924,

place = {Netherlands},

year = {2017},

month = {11}

}

DOI: 10.1016/j.nuclphysb.2017.09.001

*Citation information provided by*

Web of Science

Web of Science