thermalfist::ParticleDecaysMC Namespace Reference

Contains functions for Monte Carlo generation of decays. More...

Functions
double	ThreeBodym12F2 (double m12, double M, double m1, double m2, double m3)
	Square of the \(m_{12}\) probability density function used in a three-body decay (unnormalized) More...
double	TernaryThreeBodym12Maximum (double M, double m1, double m2, double m3)
	Determines the maximum of the \(m_{12}\) probability density function used in a three-body decay. More...
double	GetRandomThreeBodym12 (double M, double m1, double m2, double m3, double fm12max)
	Sample the invariant mass \(m_{12}\) of the leading two daughter particles in a three-body decay. More...
SimpleParticle	LorentzBoost (const SimpleParticle &part, double vx, double vy, double vz)
	Lorentz boost of the 4-momentum of a particle. More...
std::vector< SimpleParticle >	TwoBodyDecay (const SimpleParticle &Mother, double m1, long long pdg1, double m2, long long pdg2)
	Samples the decay products of a two-body decay. More...
std::vector< SimpleParticle >	ManyBodyDecay (const SimpleParticle &Mother, std::vector< double > masses, std::vector< long long > pdgs)
	Samples the decay products of a many-body decay. More...
void	ShuffleDecayProducts (std::vector< double > &masses, std::vector< long long > &pdgs)
	Shuffles the decay products. More...

Variables
int	threebodysucc = 0
	Used for debugging the succes rate in the rejection sampling of \(m_{12}\). More...
int	threebodytot = 0

Detailed Description

Contains functions for Monte Carlo generation of decays.

Function Documentation

double thermalfist::ParticleDecaysMC::GetRandomThreeBodym12	(	double	M,
		double	m1,
		double	m2,
		double	m3,
		double	fm12max
	)

Sample the invariant mass \(m_{12}\) of the leading two daughter particles in a three-body decay.

Parameters

M	Mass of the decaying particle
m1	Mass of the first daughter particle
m2	Mass of the first daughter particle
m3	Mass of the first daughter particle
fm12max	The maximum of the \(m_{12}\) probability density (precomputed with TernaryThreeBodym12Maximum())

Returns

The sampled value of \(m_{12}\)

Definition at line 47 of file ParticleDecaysMC.cpp.

SimpleParticle thermalfist::ParticleDecaysMC::LorentzBoost	(	const SimpleParticle &	part,
		double	vx,
		double	vy,
		double	vz
	)

Lorentz boost of the 4-momentum of a particle.

Parameters

[in]	part	Input particle with a 4-momentum
[in]	vx	Lorentz boost velocity x component
[in]	vy	Lorentz boost velocity y component
[in]	vz	Lorentz boost velocity z component

Returns

SimpleParticle Particle with Lorentz-boosted 4-momentum

Definition at line 63 of file ParticleDecaysMC.cpp.

std::vector< SimpleParticle > thermalfist::ParticleDecaysMC::ManyBodyDecay	(	const SimpleParticle &	Mother,
		std::vector< double >	masses,
		std::vector< long long >	pdgs
	)

Samples the decay products of a many-body decay.

---

NOTE

While the decay kinematics of a three-body decay here are exact, decay kinematics for (4+)-body decays are approximate and should be taken into consideration.

---

Parameters

Mother	The decaying particle
masses	Masses of the decay products (in GeV)
pdgs	Pdg codes of the decay products

Returns

std::vector<SimpleParticle>

Definition at line 121 of file ParticleDecaysMC.cpp.

void thermalfist::ParticleDecaysMC::ShuffleDecayProducts	(	std::vector< double > &	masses,
		std::vector< long long > &	pdgs
	)

Shuffles the decay products.

Currently used for four+ body decays to avoid having asymmetry in momentum distributions of decay products due to non-exact current implementation of these decays.

Parameters

masses	Masses of the decay products (in GeV)
pdgs	Pdg codes of the decay products

Definition at line 175 of file ParticleDecaysMC.cpp.

double thermalfist::ParticleDecaysMC::TernaryThreeBodym12Maximum	(	double	M,
		double	m1,
		double	m2,
		double	m3
	)

Determines the maximum of the \(m_{12}\) probability density function used in a three-body decay.

Uses ternary search.

Parameters

M	Mass of the decaying particle
m1	Mass of the first daughter particle
m2	Mass of the first daughter particle
m3	Mass of the first daughter particle

Returns

Maximum of the \(m_{12}\) probability density function

Definition at line 24 of file ParticleDecaysMC.cpp.

double thermalfist::ParticleDecaysMC::ThreeBodym12F2	(	double	m12,
		double	M,
		double	m1,
		double	m2,
		double	m3
	)

Square of the \(m_{12}\) probability density function used in a three-body decay (unnormalized)

Parameters

m12	Invariant mass of the leading two daughter particles in a three-body decay
M	Mass of the decaying particle
m1	Mass of the first daughter particle
m2	Mass of the first daughter particle
m3	Mass of the first daughter particle

Returns

Square of the probability density for \(m_{12}\)

Definition at line 18 of file ParticleDecaysMC.cpp.

std::vector< SimpleParticle > thermalfist::ParticleDecaysMC::TwoBodyDecay	(	const SimpleParticle &	Mother,
		double	m1,
		long long	pdg1,
		double	m2,
		long long	pdg2
	)

Samples the decay products of a two-body decay.

Parameters

Mother	The decaying particle
m1	Mass of the first daughter (in GeV)
pdg1	Pdg code of the first daughter
m2	Mass of the second daughter (in GeV)
pdg2	Pdg code of the second daughter

Returns

std::vector<SimpleParticle> Two-component vector of decay products

Definition at line 77 of file ParticleDecaysMC.cpp.

Variable Documentation

int thermalfist::ParticleDecaysMC::threebodysucc = 0

Used for debugging the succes rate in the rejection sampling of \(m_{12}\).

Definition at line 44 of file ParticleDecaysMC.cpp.

int thermalfist::ParticleDecaysMC::threebodytot = 0

Definition at line 44 of file ParticleDecaysMC.cpp.