particle 0.3.0

Utilities to deal with PDG data tables and particle IDs

Particle: PDG particle data and identification codes

Particle provides a pythonic interface to the Particle Data Group (PDG) particle data tables and particle identification codes.

The PDG defines the standard particle identification (ID) numbering scheme. The package provides the PDGID class implementing queries on those PDG IDs. The queries are also accessible through free standing functions mimicking the HepPID C++ interface.

The Particle class wraps the information in the PDG particle data tables and provides an object-oriented interface and powerful search and look-up utilities.

The current version of the package reflects a pythonic version of the utility functions defined in HepPID and HepPDT versions 3.04.01, see http://lcgapp.cern.ch/project/simu/HepPDT/.

Installation

Install particle like any other Python package:

pip install particle

or similar (use --user, virtualenv, etc. if you wish).

Strict dependencies

• Python (2.7+, 3.5+)

• importlib_resources backport if using Python < 3.7

• attrs provides classes without boilerplate (similar to DataClasses in Python 3.7)

Getting started: PDGIDs

>>> from particle.pdgid import PDGID
>>>
>>> pid = PDGID(211)
>>> pid
<PDGID: 211>
>>> pid.is_meson
True
>>> pid = PDGID(99999999)
>>> pid
<PDGID: 99999999 (is_valid==False)>

For convenience, all properties of the PDGID class are available as standalone functions:

>>> from particle.pdgid import is_meson
>>>
>>> is_meson(211)
True

PDGID literals provide (PDGID class) aliases for the most common particles, with easily recognisable names. For example:

>>> from particle.pdgid import literals as lid
>>>
>>> lid.pi_plus
<PDGID: 211>
>>>
>>> from particle.pdgid.literals import Lambda_b_0
>>>> Lambda_b_0
<PDGID: 5122>
>>> Lambda_b_0.has_bottom
True

You can quickly display PDGID info from the command line with:

$ python -m particle pdgid 323
<PDGID: 323>
A              None
J              1.0
L              0
S              1
Z              None
abspid         323
charge         1.0
has_bottom     False
...

Getting started: Particles

You can use a variety of methods to get particles. If you know the PDGID number you can get a particle directly, or you can use a search:

>>> from particle import Particle
>>> Particle.from_pdgid(211)
<Particle: pdgid=211, fullname='pi+', mass=139.57061 ± 0.00024 MeV>
>>>
>>> Particle.from_search_list('pi')[0]
<Particle: pdgid=111, fullname='pi0', mass=134.9770 ± 0.0005 MeV>

You can search for the properties using keyword arguments, which include name, fullname, mass, width, charge, anti, rank, I, J, G, P, quarks, status, latex, mass_upper, mass_lower, width_upper, and width_lower. You can pass a callable or an exact match for any property. particle can be set to True/False, as well, to limit the search to particles or antiparticles. You can also build the search yourself with the first positional argument, which accepts a callable that is given the particle object itself. If the first positional argument is a string, that will match against the particle’s fullname. The alternative .from_search() requires only one match returned by the search, and will throw an error if more or less than one match is found.

Once you have a particle, any of the properties can be accessed, along with several methods. Though they are not real properties, you can access bar, radius, and spin_type. You can also .invert() a particle.

There are lots of printing choices for particles: describe(), programmatic_name, html_name, HTML printing outs in notebooks, and of course repr and str support.

You can get the .pdgid from a particle, as well. Sorting particles will put lowest abs(PDGID) first.

Particle literals provide (Particle class) aliases for the most common particles, with easily recognisable names. For example:

>>> from particle.particle import literals as lp
>>> lp.pi_plus
<Particle: pdgid=211, fullname='pi+', mass=139.57061 ± 0.00024 MeV>
>>>
>>> from particle.particle.literals import Lambda_b_0
>>>> Lambda_b_0
<Particle: pdgid=5122, fullname='Lambda(b)0', mass=5619.60 ± 0.17 MeV>
>>> Lambda_b_0.J
0.5

You can quickly search for particles from the command line with:

$ python -m particle search 'K*0'
<Particle: pdgid=313, fullname='K*(892)0', mass=895.55 ± 0.20 MeV>
<Particle: pdgid=30313, fullname='K*(1680)0', mass=1718 ± 18 MeV>
<Particle: pdgid=100313, fullname='K*(1410)0', mass=1421 ± 9 MeV>

If you only select one particle, either by a search or by giving the PDGID number, you can see more information about the particle:

$ python -m particle search 311
Name: K          ID: 311          Fullname: K0             Latex: $K^{0}$
Mass  = 497.611 ± 0.013 MeV
Width = -1.0 MeV
I (isospin)       = 1/2    G (parity)        = 0      Q (charge)       = 0
J (total angular) = 0.0    C (charge parity) = 0      P (space parity) = ?
    Quarks: dS
    Antiparticle status: Full (antiparticle name: K~0)