DarkCapPy

Written by: Adam Green (agree019@ucr.edu) and Philip Tanedo (flip.tanedo@ucr.edu)

DarkCapPy is a Python 3/Jupyter package for calculating rates associated with dark matter capture in the Earth, annihilation into light mediators, and the subsequent observable decay of the light mediators near the surface of the Earth. The package includes a calculation of the Sommerfeld enhancement at the center of the Earth and the timescale for capture--annihilation equilibrium. The code is open source and can be modified for other compact astronomical objects and mediator spins. The reference paper can be found at: https://arxiv.org/abs/1509.07525v3. Along with being included in the package, the manual can be found at https://arxiv.org/abs/1808.03700.

Version 2.0

In this update, we extended the functionality of DarkCapPy to allow the dark matter capture process to be calculated from any planetary body with data matching the AGSS09 solar composition dataset, found at: http://www.ice.csic.es/personal/aldos/Solar_Data.html. Previously, DarkCapPy was able only able to calculate the capture process for Earth. We have since adapted DarkCapPy to accept the AGSS09 solar dataset and modified the original Earth dataset to match the format of the AGSS09 set.

We also change the way DarkCapPy handles the Dark Matter velocity distribution. In version 1, the velocity distributions in both the galactic and planetary frame were calculated within DarkCapPy. In version 2, these distributions must be included as separate csv files.

DarkCapPy Dependencies

Python 3.6.2

Python Packages

• Numpy 1.14.3
• Scipy 0.19.1
• Pandas 0.22.0

Installation with PIP

To download the main repository: pip install git+https://github.com/agree019/DarkCapPy

To download a specific branch: pip install git+https://github.com/agree019/DarkCapPy.git@<brach name>

Package Structure

DarkCapPy/
||DarkPhoton.py
||Configure/
||--AtomicData.py
||--Constants.py
||--PlanetData.py
||--PREM500.csv
||--PREM500_Mod.csv
||--struct_b16_agss09.csv
||--EarthDMVelDist.csv
||--SunDmVelDist.csv
||Template_Calculation/
||--DarkCapPy_Template.ipynb
||--Branching_Ratio/
||----Branching_Ratio.READ_ME.txt
||----brtoe.csv
||--Signal/
||----Signal_READ_ME.txt
||----100GeVSignal.csv
||----Signal_Backups/
||------Signal_Backups_Read_ME.txt
||--Sommerfeld/
||----Sommerfeld_READ_ME.txt
||----100GeVSommerfeld.csv

File Descriptions

DarkPhoton.py

This file contains all the function definitions to calculate the "Earthshine" scenario.

AtomicData.py

This file contains information about elements, eg: atomic mass, number of protons.

Constants.py

This file initializes all constants used in this calculation.

PlanetData.py

This file initializes the planet-dependent quantities, eg: enclosed mass, escape velocity. The input comma separated file (csv) file defines the planet.

PREM500.csv

This csv file contains radius and density information about Earth.

PREM500_Mod.csv

This csv file contains the radius, enclosed mass, and elemental composition of Earth and is formatted to match struct_b16_agss09.csv

struct_b16_agss09.csv

This csv file contains the structural information and elemental composition of the sun

EarthDMVelDist.csv

This csv file contains the dark matter velocity distributions in the galactic frame and the Earth frame.

SunDMVelDist.csv

This csv file contains the dark matter velocity distributions in the galactic frame and the Sun frame.

DarkCapPy_Template.ipynb

This Jupyter notebook contains an example implementation of DarkCapPy

brtoe.csv

This file stores the branching ratio to electron-positron pairs as a function of mediator mass.

100GeVSignal.csv

This file is a completed Signal file for dark matter with a mass of 100 GeV.

100GeVSommerfeld.csv

This file is a completed Sommerfeld file for dark matter with a mass of 100 GeV.

Example use

import numpy as np
import pandas as pd
from scipy.interpolate import interpolate

from DarkCapPy import *
import DarkCapPy.DarkPhoton as DP

mx = 1000
ma = 1
epsilon = 1e-8
alpha = 1/137
alphax = 0.035
tauCross = DP.tauCross

cap1 = DP.cCap(mx, ma, epsilon, alpha, alphax)
kappa0 = DP.kappa_0(mx, alpha)
cap2 = DP.cCapQuick(mx, ma, epsilon, alphax, kappa0)


sommerfeld = DP.thermAvgSommerfeld(mx, ma, alphax)
sigma = DP.sigmaVtree(mx, ma, alphax)
ann = DP.cAnn(mx, sigma, sommerfeld)

tau = DP.tau(cap1, ann)

gammaAnn = DP.gammaAnn(cap1, ann)
L = DP.decayLength(mx, ma, epsilon, 1)
Edecay = DP.epsilonDecay(L)

signal = DP.iceCubeSignal(gammaAnn, Edecay, DP.yr2s(10))

Output

Capture_1            : 110079473.7575132
Kappa_0              : 3.1452272427969017e+25
Capture_2            : 110082953.49789158
Therm Avg Sommerfeld : 238.71863691039448
Sigma V              : 3.8484490764205524e-09
Annihilation         : 1.8311290915841913e-46
EQ Time              : 7.04348098392085e+18
Gamma_ann            : 22336.873085842682
Decay Length         : 87324480.0
Epsilon_decay        : 5.100088114082073e-07
N_signal             : 0.012594031678514129