[u/mrichter/AliRoot.git] / TEvtGen / EvtGenBase / EvtDalitzResPdf.hh

/*******************************************************************************
 * Project: BaBar detector at the SLAC PEP-II B-factory
 * Package: EvtGenBase
 *    File: $Id: EvtDalitzResPdf.hh,v 1.2 2003/06/20 17:20:04 dvoretsk Exp $
 *  Author: Alexei Dvoretskii, dvoretsk@slac.stanford.edu, 2001-2002
 *
 * Copyright (C) 2002 Caltech
 *******************************************************************************/

/*
 * Pole compensating function for terms that exibit a resonant structure
 * in one dimension only. 
 * 
 * f =  1    g*m0
 *     --  ------------------
 *     pi  (q-q0)^2 + g^2m0^2
 *
 * m is the mass of the resonance, g is its width. The approximation works well for a narrow
 * resonance. It is also readily integrable over the Dalitz plot coordinate to produce
 * 
 * Int = 1/pi atan((q-q0)/(g*m0))
 */

#ifndef EVT_DALITZ_RES_PDF_HH
#define EVT_DALITZ_RES_PDF_HH

#include "EvtGenBase/EvtPdf.hh"
#include "EvtGenBase/EvtDalitzPoint.hh"
#include "EvtGenBase/EvtCyclic3.hh"

class EvtDalitzResPdf : public EvtPdf<EvtDalitzPoint> {

public:

  EvtDalitzResPdf(const EvtDalitzPlot& dp,double m0, double g0, EvtCyclic3::Pair pairRes);
  EvtDalitzResPdf(const EvtDalitzResPdf& other);
  virtual ~EvtDalitzResPdf();
  
  
  EvtPdf<EvtDalitzPoint>* clone() const { return new EvtDalitzResPdf(*this); }
  
  virtual EvtValError compute_integral(int N) const;
  virtual EvtDalitzPoint randomPoint();
  double pdfMaxValue() const;

protected:

  virtual double pdf(const EvtDalitzPoint&) const; 

private:

  EvtDalitzPlot _dp;
  double _m0;                  // mass
  double _g0;                  // width
  EvtCyclic3::Pair _pair;      // resonant pair
};

#endif
Commit	Line	Data
da0e9ce3	1	/*******************************************************************************
	2	* Project: BaBar detector at the SLAC PEP-II B-factory
	3	* Package: EvtGenBase
	4	* File: $Id: EvtDalitzResPdf.hh,v 1.2 2003/06/20 17:20:04 dvoretsk Exp $
	5	* Author: Alexei Dvoretskii, dvoretsk@slac.stanford.edu, 2001-2002
	6	*
	7	* Copyright (C) 2002 Caltech
	8	*******************************************************************************/
	9
	10	/*
	11	* Pole compensating function for terms that exibit a resonant structure
	12	* in one dimension only.
	13	*
	14	* f = 1 g*m0
	15	* -- ------------------
	16	* pi (q-q0)^2 + g^2m0^2
	17	*
	18	* m is the mass of the resonance, g is its width. The approximation works well for a narrow
	19	* resonance. It is also readily integrable over the Dalitz plot coordinate to produce
	20	*
	21	* Int = 1/pi atan((q-q0)/(g*m0))
	22	*/
	23
	24	#ifndef EVT_DALITZ_RES_PDF_HH
	25	#define EVT_DALITZ_RES_PDF_HH
	26
	27	#include "EvtGenBase/EvtPdf.hh"
	28	#include "EvtGenBase/EvtDalitzPoint.hh"
	29	#include "EvtGenBase/EvtCyclic3.hh"
	30
	31	class EvtDalitzResPdf : public EvtPdf<EvtDalitzPoint> {
	32
	33	public:
	34
	35	EvtDalitzResPdf(const EvtDalitzPlot& dp,double m0, double g0, EvtCyclic3::Pair pairRes);
	36	EvtDalitzResPdf(const EvtDalitzResPdf& other);
	37	virtual ~EvtDalitzResPdf();
	38
	39
	40	EvtPdf<EvtDalitzPoint>* clone() const { return new EvtDalitzResPdf(*this); }
	41
	42	virtual EvtValError compute_integral(int N) const;
	43	virtual EvtDalitzPoint randomPoint();
	44	double pdfMaxValue() const;
	45
	46	protected:
	47
	48	virtual double pdf(const EvtDalitzPoint&) const;
	49
	50	private:
	51
	52	EvtDalitzPlot _dp;
	53	double _m0; // mass
	54	double _g0; // width
	55	EvtCyclic3::Pair _pair; // resonant pair
	56	};
	57
	58	#endif
	59