PDG - A Particle Properties Database in Ruby
Essentially a port of PyPDT, PDG is a Ruby gem for accessing particle properties, as defined by the Particle Data Group.
The units are millimetres (mm) for distance, picoseconds (ps) for time, and gigaelectronvolts (GeV) for energy.
An example usage:
ruby
> require "pdg"
> PDG[4122]
=> Lambda(c): ID=4122, m=2.28646 GeV, q=1.0, width=3.3e-12 GeV
# Or alternatively
> particles = PDG.particles
> lc = particles[4122]
=> Lambda(c): ID=4122, m=2.28646 GeV, q=1.0, width=3.3e-12 GeV
> lc.mass
=> 2.28646
> lc.width
=> 3.3e-12
> lc.mean_distance(20)
=> 0.5196155433341929
> puts particles.pretty_print(4122)
+------+------+-------------+--------+-------+----------+
| id | name | mass | charge | width | lifetime |
+------+------+-------------+--------+-------+----------+
| 2212 | p | 0.938272046 | 1.0 | 0.0 | 0.0 |
+------+------+-------------+--------+-------+----------+
> puts particles.pretty_print(1..100)
+----+-------+----------------+---------------------+---------------+------------------------+
| id | name | mass | charge | width | lifetime |
+----+-------+----------------+---------------------+---------------+------------------------+
| 1 | d | 0.0048 | -0.3333333333333333 | 0.0 | 0.0 |
| 2 | u | 0.0023 | 0.6666666666666666 | 0.0 | 0.0 |
| 3 | s | 0.095 | -0.3333333333333333 | 0.0 | 0.0 |
| 4 | c | 1.275 | 0.6666666666666666 | 0.0 | 0.0 |
| 5 | b | 4.18 | -0.3333333333333333 | 0.0 | 0.0 |
| 6 | t | 173.5 | 0.6666666666666666 | 2.0 | 3.29105965e-13 |
| 11 | e | 0.000510998928 | -1.0 | 0.0 | 0.0 |
| 13 | mu | 0.105658372 | -1.0 | 2.9959848e-19 | 2196980.2049730024 |
| 15 | tau | 1.77682 | -1.0 | 2.265e-12 | 0.290601293598234 |
| 21 | g | 0.0 | 0.0 | 0.0 | 0.0 |
| 22 | gamma | 0.0 | 0.0 | 0.0 | 0.0 |
| 23 | Z | 91.1876 | 0.0 | 2.4952 | 2.6379125120230843e-13 |
| 24 | W | 80.385 | 1.0 | 2.085 | 3.1568917505995203e-13 |
+----+-------+----------------+---------------------+---------------+------------------------+
All available particle properties are given as instance methods in the Particle class.
The ParticleTable class, which is returned by PDG.particles, inherits from Hash and so has all of its parent’s methods, including an ability to select objects with a Range.
ruby
> particles = PDG.particles
> particles[1..100].length
=> 13
Alternative Data Sources
Note that not all particles are included by default. This is due to them not being present in the PDG-provided source data (the PDG have been contacted about this). There is an older version available with more particles but outdated properties. This can be used as an alternative source file.
``` $ irb
require “pdg” PDG[12] => nil exit
$ wget http://pdg.lbl.gov/rpp/mcdata/mass_width_02.mc $ irb
require “pdg” particles = PDG.particles(“mass_width_02.mc”) PDG[12] => ```
Testing
You can run the tests on the gem source.
bash
$ git clone git://github.com/alexpearce/pdg.git
$ cd pdg
$ bundle install --path=vendor/bundle
$ rake
Contributions
This gem is very much in its infancy. If there are features you would like to see, or incorrect implementations that need fixing, do submit an issue or email me.
Other
