hazma.gamma_ray.gamma_ray¶

hazma.gamma_ray.gamma_ray(particles, cme, eng_gams, mat_elem_sqrd=<function <lambda>>, num_ps_pts=1000, num_bins=25)¶

Returns total gamma ray spectrum from a set of particles.

Blah and blah.

Parameters:

particles (array_like) – List of particle names. Availible particles are ‘muon’, ‘electron’ ‘charged_pion’, ‘neutral pion’, ‘charged_kaon’, ‘long_kaon’, ‘short_kaon’. cme (double) – Center of mass energy of the final state in MeV. eng_gams (np.ndarray[double, ndim=1]) – List of gamma ray energies in MeV to evaluate spectra at. mat_elem_sqrd (double(*func)(np.ndarray, )) – Function for the matrix element squared of the proccess. Must be a function taking in a list of four momenta of size (num_fsp, 4). Default value is a flat matrix element. num_ps_pts (int {1000}, optional) – Number of phase space points to use. num_bins (int {25}, optional) – Number of bins to use.

Returns:

spec (np.ndarray) – Total gamma ray spectrum from all final state particles.

Notes

The total spectrum is computed using

\[\frac{dN}{dE}(E_{\gamma}) =\sum_{i,j}P_{i}(E_{j})\frac{dN_i}{dE}(E_{\gamma}, E_{j})\]

where \(i\) runs over the final state particles, \(j\) runs over energies sampled from probability distributions. \(P_{i}(E_{j})\) is the probability that particle \(i\) has energy \(E_{j}\). The probabilities are computed using hazma.phase_space_generator.rambo. The total number of energies used is num_bins.

Examples

Example of generating a spectrum from a muon, charged kaon and long kaon with total energy of 5000 MeV.

>>> from hazma.gamma_ray import gamma_ray
>>> import numpy as np
>>>
>>> particles = np.array(['muon', 'charged_kaon', 'long_kaon'])
>>> cme = 5000.
>>> eng_gams = np.logspace(0., np.log10(cme), num=200, dtype=np.float64)
>>>
>>> spec = gamma_ray(particles, cme, eng_gams)