The default HeavyIon model in Pythia. More...

#include <HeavyIons.h>

Inheritance diagram for Angantyr:

Public Types
enum	PythiaObject { HADRON = 0, MBIAS = 1, SASD = 2, SIGPP = 3, SIGPN = 4, SIGNP = 5, SIGNN = 6, ALL = 7 }
	Enumerate the different internal Pythia objects. More...

Public Types inherited from PhysicsBase
enum	Status { INCOMPLETE = -1, COMPLETE = 0, CONSTRUCTOR_FAILED, INIT_FAILED, LHEF_END, LOWENERGY_FAILED, PROCESSLEVEL_FAILED, PROCESSLEVEL_USERVETO, MERGING_FAILED, PARTONLEVEL_FAILED, PARTONLEVEL_USERVETO, HADRONLEVEL_FAILED, CHECK_FAILED, OTHER_UNPHYSICAL, HEAVYION_FAILED, HADRONLEVEL_USERVETO }
	Enumerate the different status codes the event generation can have.

Public Member Functions
	Angantyr (Pythia &mainPythiaIn)
	Angantyr is the main HeavyIons model in Pythia. More...

virtual	~Angantyr ()

virtual bool	init () override
	Initialize Angantyr. More...

virtual bool	next () override
	Produce a collision involving heavy ions. More...

bool	setUserHooksPtr (PythiaObject sel, UserHooksPtr userHooksPtrIn)
	Set UserHooks for specific (or ALL) internal Pythia objects. More...

bool	setKinematics (double eCMIn) override
	Set beam kinematics.

bool	setKinematics (double eAIn, double eBIn) override

bool	setKinematics (double, double, double, double, double, double) override

bool	setKinematics (Vec4, Vec4) override

bool	setKinematics ()
	Set beam kinematics.

bool	setBeamIDs (int idAIn, int idBIn=0) override
	Set beam IDs. More...

void	unifyFrames ()
	Make sure the correct information is available irrespective of frame type.

void	banner () const
	Print the Angantyr banner.

const SubCollisionSet &	subCollisions () const
	Subcollisions for the current event.

const SubCollisionModel &	subCollisionModel () const
	Get the underlying subcollision model.

const ImpactParameterGenerator	impactParameterGenerator () const
	Get the underlying impact parameter generator.

const Nucleus &	projectile () const
	Projectile nucleus configuration for the current event.

const Nucleus &	target () const
	Target nucleus configuration for the current event.

const NucleusModel &	projectileModel () const
	The underlying projectile nucleus model.

const NucleusModel &	targetModel () const
	The underlying target nucleus model.

const SigmaTotal	sigmaNN () const
	Hadronic cross sections used by the subcollision model.

Public Member Functions inherited from HeavyIons
	HeavyIons (Pythia &mainPythiaIn)

virtual	~HeavyIons ()
	Destructor.

bool	setHIUserHooksPtr (HIUserHooksPtr userHooksPtrIn)
	Possibility to pass in pointer for special heavy ion user hooks.

virtual void	stat ()
	Print out statistics. More...

Public Member Functions inherited from PhysicsBase
void	initInfoPtr (Info &infoPtrIn)
	This function is called from above for physics objects used in a run. More...

virtual	~PhysicsBase ()
	Empty virtual destructor.

bool	flag (string key) const
	Shorthand to read settings values.

int	mode (string key) const

double	parm (string key) const

string	word (string key) const

vector< bool >	fvec (string key) const

vector< int >	mvec (string key) const

vector< double >	pvec (string key) const

vector< string >	wvec (string key) const

Static Public Member Functions
static bool	getTransforms (Vec4 p1, Vec4 p2, const Vec4 &p1p, pair< RotBstMatrix, RotBstMatrix > &R12)

static double	mT2 (const Vec4 &p)

static double	mT (const Vec4 &p)

Static Public Member Functions inherited from HeavyIons
static void	addSpecialSettings (Settings &settings)
	The abstract HeavyIons class. More...

static bool	isHeavyIon (Settings &settings)
	Check the settings and return false of there are no heavy ion beams. More...

Protected Member Functions
virtual void	onInitInfoPtr () override

void	setBeamKinematics (int idA, int idB)
	Figure out what beams the user want. More...

bool	init (PythiaObject sel, string name, int n=0)

EventInfo	mkEventInfo (Pythia &, Info &, const SubCollision *coll=0)
	Setup an EventInfo object from a Pythia instance. More...

EventInfo	getSignal (const SubCollision &coll)
	Generate events from the internal Pythia oblects;. More...

EventInfo	getND ()

EventInfo	getND (const SubCollision &coll)

EventInfo	getEl (const SubCollision &coll)

EventInfo	getSDP (const SubCollision &coll)

EventInfo	getSDT (const SubCollision &coll)

EventInfo	getDD (const SubCollision &coll)

EventInfo	getCD (const SubCollision &coll)

EventInfo	getSDabsP (const SubCollision &coll)

EventInfo	getSDabsT (const SubCollision &coll)

EventInfo	getMBIAS (const SubCollision *coll, int procid)

EventInfo	getSASD (const SubCollision *coll, int procid)

bool	genAbs (SubCollisionSet &subCollsIn, list< EventInfo > &subEventsIn)

void	addSASD (const SubCollisionSet &subCollsIn)
	Add secondary absorptive sub-collisions to the primary ones. More...

bool	addDD (const SubCollisionSet &subCollsIn, list< EventInfo > &subEventsIn)
	Add primary double diffraction sub-collisions. More...

bool	addSD (const SubCollisionSet &subCollsIn, list< EventInfo > &subEventsIn)
	Add primary single diffraction sub-collisions. More...

void	addSDsecond (const SubCollisionSet &subCollsIn)

bool	addCD (const SubCollisionSet &subCollsIn, list< EventInfo > &subEventsIn)
	Add all primary central diffraction sub-colliions. More...

void	addCDsecond (const SubCollisionSet &subCollsIn)

bool	addEL (const SubCollisionSet &subCollsIn, list< EventInfo > &subEventsIn)
	Add all primary elastic sub-colliions. More...

void	addELsecond (const SubCollisionSet &subCollsIn)
	Add all secondary elastic sub-colliions to primary ones. More...

bool	buildEvent (list< EventInfo > &subEventsIn)
	Take all sub-events and merge them together. More...

bool	setupFullCollision (EventInfo &ei, const SubCollision &coll, Nucleon::Status projStatus, Nucleon::Status targStatus)
	Prepare a primary sub-collision.

bool	isRemnant (const EventInfo &ei, int i, int past=1) const

bool	fixIsoSpin (EventInfo &ei)

EventInfo &	shiftEvent (EventInfo &ei)

bool	nextSASD (int proc)
	Generate a single diffractive. More...

bool	addNucleonExcitation (EventInfo &orig, EventInfo &add, bool colConnect=false)
	Add a secondary sub-collision to a primary one. More...

vector< int >	findRecoilers (const Event &e, bool tside, int beam, int end, const Vec4 &pdiff, const Vec4 &pbeam)

void	addSubEvent (Event &evnt, Event &sub)
	Add a sub-event to the final event record. More...

bool	addNucleusRemnants ()

Protected Member Functions inherited from HeavyIons
void	updateInfo ()
	Update the Info object in the main Pythia object. More...

void	clearProcessLevel (Pythia &pyt)

Protected Member Functions inherited from PhysicsBase
	PhysicsBase ()
	Default constructor.

virtual void	onBeginEvent ()
	This function is called in the very beginning of each Pythia::next call.

virtual void	onEndEvent (Status)

virtual void	onStat ()
	This function is called from the Pythia::stat() call.

void	registerSubObject (PhysicsBase &pb)
	Register a sub object that should have its information in sync with this.

Static Protected Member Functions
static int	getBeam (Event &ev, int i)
	Trace a particle back to one of the beams in an event.

static void	addJunctions (Event &evnt, Event &sub, int coloff)

Static Protected Member Functions inherited from HeavyIons
static void	setupSpecials (Settings &settings, string match)
	Duplicate setting on the form match: to settings on the form HImatch:

static void	setupSpecials (Pythia &p, string match)

Additional Inherited Members
Public Attributes inherited from HeavyIons
HIInfo	hiInfo

Protected Attributes inherited from HeavyIons
int	idProj
	Save current beam configuration.

int	idTarg

Pythia *	mainPythiaPtr

SigmaTotal	sigTotNN

HIUserHooksPtr	HIHooksPtr

vector< Pythia * >	pythia

vector< string >	pythiaNames
	The names associated with the secondary pythia objects.

vector< Info * >	info

Protected Attributes inherited from PhysicsBase
Info *	infoPtr = {}

Settings *	settingsPtr = {}
	Pointer to the settings database.

ParticleData *	particleDataPtr = {}
	Pointer to the particle data table.

Logger *	loggerPtr = {}
	Pointer to logger.

HadronWidths *	hadronWidthsPtr = {}
	Pointer to the hadron widths data table.

Rndm *	rndmPtr = {}
	Pointer to the random number generator.

CoupSM *	coupSMPtr = {}
	Pointers to SM and SUSY couplings.

CoupSUSY *	coupSUSYPtr = {}

BeamSetup *	beamSetupPtr = {}

BeamParticle *	beamAPtr = {}

BeamParticle *	beamBPtr = {}

BeamParticle *	beamPomAPtr = {}

BeamParticle *	beamPomBPtr = {}

BeamParticle *	beamGamAPtr = {}

BeamParticle *	beamGamBPtr = {}

BeamParticle *	beamVMDAPtr = {}

BeamParticle *	beamVMDBPtr = {}

PartonSystems *	partonSystemsPtr = {}
	Pointer to information on subcollision parton locations.

SigmaTotal *	sigmaTotPtr = {}
	Pointers to the total/elastic/diffractive cross sections.

SigmaCombined *	sigmaCmbPtr = {}

set< PhysicsBase * >	subObjects

UserHooksPtr	userHooksPtr

Detailed Description

The default HeavyIon model in Pythia.

Member Enumeration Documentation

enum PythiaObject

Enumerate the different internal Pythia objects.

Enumerator
MBIAS	For hadronization only.
SASD	Minimum Bias processed.
SIGPP	Single diffractive as one side of non-diffractive.
SIGPN	Optional object for signal processes (pp).
SIGNP	Optional object for signal processes (pn).
SIGNN	Optional object for signal processes (np).
ALL	Optional object for signal processes (nn).

Constructor & Destructor Documentation

Angantyr ( Pythia & mainPythiaIn )

Angantyr is the main HeavyIons model in Pythia.

The constructor needs a reference to the main Pythia object to which it will belong. A Angantyr object cannot belong to more than one main Pythia object.

Constructor.

~Angantyr ( )

virtual

Destructor deleting model objects that are not provided from the outside (via HIUserHooks).

Member Function Documentation

bool addCD	(	const SubCollisionSet &	subCollsIn,
		list< EventInfo > &	subEventsIn
	)

protected

Add all primary central diffraction sub-colliions.

Collect full central diffraction collisions.

void addCDsecond ( const SubCollisionSet & subCollsIn )

protected

Add all secondary central diffraction sub-colliions to primary ones.

Collect secondary central diffractive sub-collisions.

bool addDD	(	const SubCollisionSet &	subCollsIn,
		list< EventInfo > &	subEventsIn
	)

protected

Add primary double diffraction sub-collisions.

Collect full double diffraction collisions.

bool addEL	(	const SubCollisionSet &	subCollsIn,
		list< EventInfo > &	subEventsIn
	)

protected

Add all primary elastic sub-colliions.

Collect full elastic collisions.

void addELsecond ( const SubCollisionSet & subCollsIn )

protected

Add all secondary elastic sub-colliions to primary ones.

Collect secondary elastic sub-collisions.

void addJunctions	(	Event &	evnt,
		Event &	sub,
		int	coloff
	)

staticprotected

Read out junctions one by one.

Add colour offsets to all three legs.

Append junction to summed event.

bool addNucleonExcitation	(	EventInfo &	orig,
		EventInfo &	add,
		bool	colConnect = `false`
	)

protected

Add a secondary sub-collision to a primary one.

Add a diffractive event to an exsisting one. Optionally connect the colours of the added event to the original.

First get the projectile system to take recoil and their momentum.

Find the transform to the recoilers and the diffractive combined cms.

Transform the recoilers.

Copy the event and transform and offset the particles appropriately.

Special handling of central diffraction.

Add energy to zeroth line and calculate new invariant mass.

Add offset to nonzero mother, daughter and colour indices.

Append particle to summed event.

bool addNucleusRemnants ( )

protected

Add a nucleus remnant to the given event. Possibly introducing a new particle type.

Construct nucleus remnants fron all non-interacting nucleons and add them to the main event.

void addSASD ( const SubCollisionSet & subCollsIn )

protected

Add secondary absorptive sub-collisions to the primary ones.

Collect absorptively wounded nucleons in secondary sub-collisions.

bool addSD	(	const SubCollisionSet &	subCollsIn,
		list< EventInfo > &	subEventsIn
	)

protected

Add primary single diffraction sub-collisions.

Collect full single diffraction collisions.

void addSDsecond ( const SubCollisionSet & subCollsIn )

protected

Add all secondary single diffractive sub-collisions to primary ones.

Collect secondary single diffractive sub-collisions.

void addSubEvent	(	Event &	evnt,
		Event &	sub
	)

protected

Add a sub-event to the final event record.

Add sub-events together taking special care with the status of the incoming nucleons, and also handle the junctions correctly.

Add offset to nonzero mother, daughter and colour indices.

Append particle to summed event.

bool buildEvent ( list< EventInfo > & subEventsIn )

protected

Take all sub-events and merge them together.

Start with the signal event(s)

Then all the others

Finally add all nucleon remnants.

vector< int > findRecoilers	(	const Event &	e,
		bool	tside,
		int	beam,
		int	end,
		const Vec4 &	pdiff,
		const Vec4 &	pbeam
	)

protected

Find the recoilers in the current event to conserve energy and momentum in addNucleonExcitation.

Find recoilers in a primary sub-collisions to conserve energy and momentum when adding a secondary one. Not actually used yet.

cout << "--- find recoilers ----" << endl; cout << setw(10) << setprecision(4) << log(pdiff.pPos()) << setw(10) << pdiff.rap() << " diffractive system" << pdiff;

cout << setw(10) << setprecision(4) << it->first*dir << " failed " << (pz2 < 0.0? -sqrt(-pz2): sqrt(pz2)) << endl;

cout << setw(10) << setprecision(4) << it->first*dir << " accept " << sqrt(pz2) << " (" << sqrt(S) << ")" << test;

cout << "--- found recoilers ---" << endl;

*** THINK! *** Is this the best way?

bool fixIsoSpin ( EventInfo & ei )

protected

Minimum-bias sub-collisions are always generated as p-p events, and it is assumed to be safe to be assumed that they are iso-spin invariant so we can just modify the quark content in the remnants to get p-n, n-p, and n-n collisions.

Check if isospin needs fixing.

Try to find corresponding remnants that change flavour

Try to find any final state quark that we modify, preferably far in the beam direction.

bool genAbs	(	SubCollisionSet &	subCollsIn,
		list< EventInfo > &	subEventsIn
	)

protected

Generate primary absorptive (non-diffractive) nucleon-nucleon sub-collisions.

The fully absorptive

The partly absorptive

The non-diffractive and signal events

Select the primary absorptive sub collisions.

Count how many potential absorpitve collisions there are for each iso-spin combination.

*** THINK *** Is it ok to always pair the hardest events with the *** most central sub-collisions, or will this introduce a strange *** bias?

EventInfo getSignal ( const SubCollision & coll )

protected

Generate events from the internal Pythia oblects;.

Generate events and return EventInfo objects for different process types.

bool getTransforms	(	Vec4	prec,
		Vec4	pdiff,
		const Vec4 &	pbeam,
		pair< RotBstMatrix, RotBstMatrix > &	R12
	)

static

Helper function to construct two transformations that would give the vectors p1 and p2 the total four momentum of p1p + p2p.

Calculate boosts to shuffle momenta when adding secondary sub-collisions.

bool init ( )

overridevirtual

Initialize Angantyr.

Initialise Angantyr. Called from within Pythia::init().

Read settings.

Fix settings to be used for subobjects.

Create Pythia subobjects.

Allow for user to override with a custom HIUserHooks.

Initialize kinematics and cross sections.

Set up nucleus geometry.

Set up subcollision model.

Set up impact parameter generator.

Initialize subobject for minimum bias processes.

Initialize subobject for secondary absorptive processes.

Initialize subobject for hadronization.

Initialize subobjects for signal processes.

Implements HeavyIons.

bool init	(	PythiaObject	sel,
		string	name,
		int	n = `0`
	)

protected

Initiaize a specific Pythia object and optionally run a number of events to get a handle of the cross section.

Initialize a specific Pythia object and optionally run a number of events to get a handle of the cross section.

EventInfo mkEventInfo	(	Pythia &	pyt,
		Info &	infoIn,
		const SubCollision *	coll = `0`
	)

protected

Setup an EventInfo object from a Pythia instance.

Create an EventInfo object connected to a SubCollision from the last event generated by the given PythiaObject.

bool next ( )

overridevirtual

Produce a collision involving heavy ions.

The main method called from Pythia::next().

Generate impact parameter, nuclei, and sub-collisions.

Collect absorptively wounded nucleons in secondary sub-collisions.

Collect full double diffraction collisions.

Collect full single diffraction collisions.

Collect secondary single diffractive sub-collisions.

Collect full central diffraction collisions.

Collect secondary central diffractive sub-collisions.

Collect full elastic collisions.

Collect secondary elastic sub-collisions.

Finally bunch all events together.

Finally we hadronise everything, if requested.

Implements HeavyIons.

bool nextSASD ( int procid )

protected

Generate a single diffractive.

Special function to generate secondary absorptive events as single diffraction. Called from Angantyr::next() and used for debugging and tuning purposes.

virtual void onInitInfoPtr ( )

inlineoverrideprotectedvirtual

If an object needs to set up infoPtr for sub objects, override this and call registerSubObject for each object in question.

Reimplemented from PhysicsBase.

bool setBeamIDs	(	int	idAIn,
		int	idBIn = `0`
	)

overridevirtual

Set beam IDs.

Switch to new beam particle identities.

Reimplemented from HeavyIons.

void setBeamKinematics	(	int	idA,
		int	idB
	)

protected

Figure out what beams the user want.

Figure out what beams the user wants.

We will use the MBIAS BeamSetup object to figure out what is happening. Whatever we do here will be overridden when we do the proper init().

bool setUserHooksPtr	(	PythiaObject	sel,
		UserHooksPtr	userHooksPtrIn
	)

Set UserHooks for specific (or ALL) internal Pythia objects.

Add a HIUserHooks object to customise the Angantyr model.

EventInfo & shiftEvent ( EventInfo & ei )

protected

Shift an event in impact parameter from the nucleon-nucleon sub-collision to the overall nucleus-nucleus frame. It is assumed that all partonic vertices are given in units of femtometers.

The documentation for this class was generated from the following files:

include/Pythia8/HeavyIons.h
src/HeavyIons.cc

Public Types

Public Member Functions

Static Public Member Functions

Protected Member Functions

Static Protected Member Functions

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation