Parton species and their charge conjugation #
For a hadron whose quarks come in the flavours of a type Flavor, the parton species are the
quark and the antiquark of each flavour and the gluon. This file names that index type,
Species Flavor, so that the quark, antiquark and gluon distributions of a hadron (collinear
densities, TMDs, fragmentation functions) are indexed by one type, and a species sum such as the
momentum sum rule ∑ₛ ∫₀¹ x fₛ(x) dx = 1 runs over all of them, the gluon included.
Charge conjugation exchanges the quark and the antiquark of each flavour and fixes the gluon
(Species.conj); it is an involution.
Main definitions #
EpsilonEridani.Particles.Parton.Species Flavor: a quark or antiquark of a flavour, or the gluon.EpsilonEridani.Particles.Parton.Species.equivSum:Species Flavor ≃ (Flavor ⊕ Flavor) ⊕ Unit.EpsilonEridani.Particles.Parton.Species.conj: charge conjugation of species.
Main statements #
Species.card: there are2 * Fintype.card Flavor + 1species.Species.sum_univ: a sum over all species is the quark sum, the antiquark sum and the gluon term.Species.conj_involutive: charge conjugation is an involution.
References #
- J. C. Collins, Foundations of Perturbative QCD, Cambridge University Press (2011), ch. 6.
A parton species over the quark-flavour type Flavor: the quark of a flavour, the antiquark
of a flavour, or the gluon.
- quark
{Flavor : Type}
(i : Flavor)
: Species Flavor
The quark of flavour
i. - antiquark
{Flavor : Type}
(i : Flavor)
: Species Flavor
The antiquark of flavour
i. - gluon
{Flavor : Type}
: Species Flavor
The gluon.
Instances For
Equations
- One or more equations did not get rendered due to their size.
- EpsilonEridani.Particles.Parton.instDecidableEqSpecies.decEq (EpsilonEridani.Particles.Parton.Species.quark i) (EpsilonEridani.Particles.Parton.Species.antiquark i_1) = isFalse ⋯
- EpsilonEridani.Particles.Parton.instDecidableEqSpecies.decEq (EpsilonEridani.Particles.Parton.Species.quark i) EpsilonEridani.Particles.Parton.Species.gluon = isFalse ⋯
- EpsilonEridani.Particles.Parton.instDecidableEqSpecies.decEq (EpsilonEridani.Particles.Parton.Species.antiquark i) (EpsilonEridani.Particles.Parton.Species.quark i_1) = isFalse ⋯
- EpsilonEridani.Particles.Parton.instDecidableEqSpecies.decEq (EpsilonEridani.Particles.Parton.Species.antiquark i) EpsilonEridani.Particles.Parton.Species.gluon = isFalse ⋯
- EpsilonEridani.Particles.Parton.instDecidableEqSpecies.decEq EpsilonEridani.Particles.Parton.Species.gluon (EpsilonEridani.Particles.Parton.Species.quark i) = isFalse ⋯
- EpsilonEridani.Particles.Parton.instDecidableEqSpecies.decEq EpsilonEridani.Particles.Parton.Species.gluon (EpsilonEridani.Particles.Parton.Species.antiquark i) = isFalse ⋯
- EpsilonEridani.Particles.Parton.instDecidableEqSpecies.decEq EpsilonEridani.Particles.Parton.Species.gluon EpsilonEridani.Particles.Parton.Species.gluon = isTrue ⋯
Instances For
The species over Flavor are equivalent to (Flavor ⊕ Flavor) ⊕ Unit: the quark of flavour
i goes to .inl (.inl i), the antiquark of flavour i to .inl (.inr i), and the gluon to
.inr (). It carries the Fintype instance on species and sum_univ.
Equations
- One or more equations did not get rendered due to their size.
Instances For
Equations
There are two species, a quark and an antiquark, for each flavour, and the gluon.
A sum over all parton species is the sum over the quarks, the sum over the antiquarks, and the gluon term.
Charge conjugation of parton species: the quark and the antiquark of each flavour are exchanged, and the gluon is its own antiparticle.
Equations
- (EpsilonEridani.Particles.Parton.Species.quark i).conj = EpsilonEridani.Particles.Parton.Species.antiquark i
- (EpsilonEridani.Particles.Parton.Species.antiquark i).conj = EpsilonEridani.Particles.Parton.Species.quark i
- EpsilonEridani.Particles.Parton.Species.gluon.conj = EpsilonEridani.Particles.Parton.Species.gluon