siscone::Csplit_merge_ptcomparison Class Reference

comparison of jets for split–merge ordering More...

#include <split_merge.h>

Public Member Functions
	Csplit_merge_ptcomparison ()
	default ctor More...
std::string	SM_scale_name () const
	return the name corresponding to the SM scale variable More...
bool	operator() (const Cjet &jet1, const Cjet &jet2) const
	comparison between 2 jets More...
void	get_difference (const Cjet &j1, const Cjet &j2, Cmomentum *v, double *pt_tilde) const
	get the difference between 2 jets, calculated such that rounding errors will not affect the result even if the two jets have almost the same content (so that the difference is below the rounding errors) More...

Public Attributes
std::vector< Cmomentum > *	particles
	pointer to the list of particles More...
std::vector< double > *	pt
	pointer to the pt of the particles More...
Esplit_merge_scale	split_merge_scale
	the following parameter controls the variable we're using for the split-merge process i.e. More...

Detailed Description

comparison of jets for split–merge ordering

a class that allows us to carry out comparisons of pt of jets, using information from exact particle contents where necessary.

Definition at line 116 of file split_merge.h.

Constructor & Destructor Documentation

Csplit_merge_ptcomparison()

siscone::Csplit_merge_ptcomparison::Csplit_merge_ptcomparison ( )

inline

default ctor

Definition at line 119 of file split_merge.h.

Member Function Documentation

get_difference()

void siscone::Csplit_merge_ptcomparison::get_difference	(	const Cjet &	j1,
		const Cjet &	j2,
		Cmomentum *	v,
		double *	pt_tilde
	)		const

get the difference between 2 jets, calculated such that rounding errors will not affect the result even if the two jets have almost the same content (so that the difference is below the rounding errors)

Parameters

j1	first jet
j2	second jet
v	jet1-jet2
pt_tilde	jet1-jet2 pt_tilde

Definition at line 179 of file split_merge.cpp.

References siscone::Cjet::contents, and siscone::Cjet::n.

Referenced by operator()().

operator()()

bool siscone::Csplit_merge_ptcomparison::operator()	(	const Cjet &	jet1,
		const Cjet &	jet2
	)		const

comparison between 2 jets

Definition at line 94 of file split_merge.cpp.

References siscone::Cmomentum::E, EPSILON_SPLITMERGE, get_difference(), siscone::Cmomentum::perp2(), siscone::Cjet::pt_tilde, siscone::Cmomentum::px, siscone::Cmomentum::py, siscone::Cmomentum::pz, siscone::Cmomentum::ref, SM_scale_name(), siscone::Cjet::sm_var2, split_merge_scale, and siscone::Cjet::v.

SM_scale_name()

std::string siscone::Csplit_merge_ptcomparison::SM_scale_name ( ) const

inline

return the name corresponding to the SM scale variable

Definition at line 123 of file split_merge.h.

References split_merge_scale.

Referenced by operator()().

Member Data Documentation

particles

std::vector<Cmomentum>* siscone::Csplit_merge_ptcomparison::particles

pointer to the list of particles

Definition at line 126 of file split_merge.h.

Referenced by siscone::Csplit_merge::Csplit_merge(), and siscone::Csplit_merge::init_particles().

pt

std::vector<double>* siscone::Csplit_merge_ptcomparison::pt

pointer to the pt of the particles

Definition at line 127 of file split_merge.h.

Referenced by siscone::Csplit_merge::Csplit_merge(), and siscone::Csplit_merge::init_particles().

split_merge_scale

Esplit_merge_scale siscone::Csplit_merge_ptcomparison::split_merge_scale

the following parameter controls the variable we're using for the split-merge process i.e.

the variable we use for

1. ordering jet candidates;
2. computing the overlap fraction of two candidates. The default value uses pttile (p-scheme pt). Other alternatives are pt, mt=sqrt(pt^2+m^2)=sqrt(E^2-pz^2) or Et. NOTE: Modifying the default choice can have nasty effects:

using pt leads to some IR unsafety when we have two jets, e.g. back-to-back, with the same pt. In that case, their ordering in pt is random and can be affected by the addition of a soft particle. Hence, we highly recommand to keep this to the default value i.e. to use pt only for the purpose of investigating the IR issue

• using Et is safe but does not respect boost invariance
• using mt solves the IR unsafety issues with the pt variable for QCD jets but the IR unsafety remains for nack-to-back jets of unstable narrow-width particles (e.g. Higgs). Therefore, keeping the default value is strongly advised.

Definition at line 163 of file split_merge.h.

Referenced by siscone::Csiscone::compute_jets(), siscone::Csiscone::compute_jets_progressive_removal(), operator()(), siscone::Csiscone::recompute_jets(), and SM_scale_name().

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

• siscone/split_merge.h
• siscone/split_merge.cpp