# Connecting dark matter annihilation to the vertex functions of Standard Model fermions

## Abstract

We consider scenarios in which dark matter is a Majorana fermion which couples to Standard Model fermions through the exchange of charged mediating particles. The matrix elements for various dark matter annihilation processes are then related to one-loop corrections to the fermion-photon vertex, where dark matter and the charged mediators run in the loop. In particular, in the limit where Standard Model fermion helicity mixing is suppressed, the cross section for dark matter annihilation to various final states is related to corrections to the Standard Model fermion charge form factor. These corrections can be extracted in a gauge-invariant manner from collider cross sections. Although current measurements from colliders are not precise enough to provide useful constraints on dark matter annihilation, improved measurements at future experiments, such as the International Linear Collider, could improve these constraints by several orders of magnitude, allowing them to surpass the limits obtainable by direct observation.

- Authors:

- Department of Physics and Astronomy, University of Hawaii, Honolulu, HI 96822, Hawaii (United States)

- Publication Date:

- OSTI Identifier:
- 22676099

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2017; Journal Issue: 07; Other Information: Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ANNIHILATION; FORM FACTORS; GAUGE INVARIANCE; HELICITY; INTERNATIONAL LINEAR COLLIDER; MAJORANA FERMIONS; MAJORANA SPINORS; MATRIX ELEMENTS; NONLUMINOUS MATTER; STANDARD MODEL; VERTEX FUNCTIONS

### Citation Formats

```
Kumar, Jason, and Light, Christopher, E-mail: jkumar@hawaii.edu, E-mail: lightc@hawaii.edu.
```*Connecting dark matter annihilation to the vertex functions of Standard Model fermions*. United States: N. p., 2017.
Web. doi:10.1088/1475-7516/2017/07/030.

```
Kumar, Jason, & Light, Christopher, E-mail: jkumar@hawaii.edu, E-mail: lightc@hawaii.edu.
```*Connecting dark matter annihilation to the vertex functions of Standard Model fermions*. United States. doi:10.1088/1475-7516/2017/07/030.

```
Kumar, Jason, and Light, Christopher, E-mail: jkumar@hawaii.edu, E-mail: lightc@hawaii.edu. Sat .
"Connecting dark matter annihilation to the vertex functions of Standard Model fermions". United States.
doi:10.1088/1475-7516/2017/07/030.
```

```
@article{osti_22676099,
```

title = {Connecting dark matter annihilation to the vertex functions of Standard Model fermions},

author = {Kumar, Jason and Light, Christopher, E-mail: jkumar@hawaii.edu, E-mail: lightc@hawaii.edu},

abstractNote = {We consider scenarios in which dark matter is a Majorana fermion which couples to Standard Model fermions through the exchange of charged mediating particles. The matrix elements for various dark matter annihilation processes are then related to one-loop corrections to the fermion-photon vertex, where dark matter and the charged mediators run in the loop. In particular, in the limit where Standard Model fermion helicity mixing is suppressed, the cross section for dark matter annihilation to various final states is related to corrections to the Standard Model fermion charge form factor. These corrections can be extracted in a gauge-invariant manner from collider cross sections. Although current measurements from colliders are not precise enough to provide useful constraints on dark matter annihilation, improved measurements at future experiments, such as the International Linear Collider, could improve these constraints by several orders of magnitude, allowing them to surpass the limits obtainable by direct observation.},

doi = {10.1088/1475-7516/2017/07/030},

journal = {Journal of Cosmology and Astroparticle Physics},

number = 07,

volume = 2017,

place = {United States},

year = {Sat Jul 01 00:00:00 EDT 2017},

month = {Sat Jul 01 00:00:00 EDT 2017}

}