Matchbox/Cuts/PairRapidityCut.h

0001 // -*- C++ -*-
0002 //
0003 // PairRapidityCut.h is a part of Herwig - A multi-purpose Monte Carlo event generator
0004 // Copyright (C) 2002-2019 The Herwig Collaboration
0005 //
0006 // Herwig is licenced under version 3 of the GPL, see COPYING for details.
0007 // Please respect the MCnet academic guidelines, see GUIDELINES for details.
0008 //
0009 #ifndef Herwig_PairRapidityCut_H
0010 #define Herwig_PairRapidityCut_H
0011 //
0012 // This is the declaration of the PairRapidityCut class.
0013 //
0014
0015 #include "ThePEG/Cuts/TwoCutBase.h"
0016 #include "ThePEG/PDT/MatcherBase.h"
0017
0018 namespace Herwig {
0019
0020 using namespace ThePEG;
0021
0022 /**
0023  * \ingroup Matchbox
0024  * \author Christian Reuschle
0025  *
0026  * \brief This class implements a cut on the rapidity of a pair of particles
0027  *
0028  * @see \ref PairRapidityCutInterfaces "The interfaces"
0029  * defined for PairRapidityCut.
0030  */
0031 class PairRapidityCut: public TwoCutBase {
0032
0033 public:
0034
0035   /**
0036    * The default constructor.
0037    */
0038   PairRapidityCut();
0039
0040 public:
0041
0042   /** @name Overridden virtual functions defined in the base class. */
0043   //@{
0044   /**
0045    * Return true if a pair of particles with type \a pitype and \a
0046    * pjtype and momenta \a pi and \a pj respectively passes the
0047    * cuts. \a inci and \a inj indicates if the corresponding particles
0048    * are incoming.
0049    */
0050   virtual bool passCuts(tcCutsPtr parent, tcPDPtr pitype, tcPDPtr pjtype,
0051             LorentzMomentum pi, LorentzMomentum pj,
0052             bool inci = false, bool incj = false) const;
0053
0054   /**
0055    * Return the minimum allowed squared invariant mass of two outgoing
0056    * partons of type \a pi and \a pj.
0057    */
0058   virtual Energy2 minSij(tcPDPtr , tcPDPtr ) const { return ZERO; }
0059
0060   /**
0061    * Return the minimum allowed value of the negative of the squared
0062    * invariant mass of an incoming parton of type \a pi and an
0063    * outgoing parton of type \a po.
0064    */
0065   virtual Energy2 minTij(tcPDPtr , tcPDPtr ) const { return ZERO; }
0066
0067   /**
0068    * Return the minimum allowed value of \f$\Delta
0069    * R_{ij}=\sqrt{\Delta\eta_{ij}^2+\Delta\phi_{ij}^2}\f$ of two
0070    * outgoing partons of type \a pi and \a pj.
0071    */
0072   virtual double minDeltaR(tcPDPtr , tcPDPtr ) const { return ZERO; }
0073
0074   /**
0075    * Return the minimum allowed value of the longitudinally invariant
0076    * \f$k_\perp\f$-algorithms distance measure. This is defined as
0077    * \f$\min(p_{\perp i}, p_{\perp
0078    * j})\sqrt{\Delta\eta_{ij}^2+\Delta\phi_{ij}^2}\f$ for two outgoing
0079    * partons, or simply \f$p_{\perp i}\f$ or \f$p_{\perp j}\f$ for a
0080    * single outgoing parton. Returns 0 if both partons are incoming. A
0081    * null pointer indicates an incoming parton, hence the type of the
0082    * incoming parton is irrelevant.
0083    */
0084   virtual Energy minKTClus(tcPDPtr , tcPDPtr ) const { return ZERO; }
0085
0086   /**
0087    * Return the minimum allowed value of the Durham
0088    * \f$k_\perp\f$-algorithms distance measure. This is defined as
0089    * \f$2\min(E_j^2, E_j^2)(1-\cos\theta_{ij})/\hat{s}\f$ for two
0090    * outgoing partons.
0091    */
0092   virtual double minDurham(tcPDPtr , tcPDPtr ) const { return ZERO; }
0093
0094   //@}
0095
0096   /**
0097    * Describe the currently active cuts in the log file.
0098    */
0099   virtual void describe() const;
0100
0101 public:
0102
0103 //   /**
0104 //    * Return the minimal allowed rapidity
0105 //    */
0106 //   double minRapidity() const { return theMinRapidity; }
0107 //
0108 //   /**
0109 //    * Return the maximal allowed rapidity
0110 //    */
0111 //   double maxRapidity() const { return theMaxRapidity; }
0112
0113   /**
0114    * Return the rapidity ranges.
0115    */
0116   const vector<pair<double,double> >& yRanges() const { return theYRanges; }
0117
0118   /**
0119    * Return whether cut acts on same-flavour fermions only
0120    */
0121   bool sameFlavourOnly() const { return theSameFlavourOnly; }
0122
0123   /**
0124    * Return whether cut acts on opposite-sign fermions only
0125    */
0126   bool oppositeSignOnly() const { return theOppositeSignOnly; }
0127
0128   /**
0129    * Return the matchers for a pair of particles to cut on.
0130    * Only a pair of particles, matching these objects, will be affected.
0131    */
0132   Ptr<MatcherBase>::tptr firstMatcher() const { return theFirstMatcher; }
0133   Ptr<MatcherBase>::tptr secondMatcher() const { return theSecondMatcher; }
0134
0135 protected:
0136
0137    /**
0138    * Return the family of the given PDG id number.
0139    */
0140   int family(long id) const;
0141
0142 public:
0143
0144   /** @name Functions used by the persistent I/O system. */
0145   //@{
0146   /**
0147    * Function used to write out object persistently.
0148    * @param os the persistent output stream written to.
0149    */
0150   void persistentOutput(PersistentOStream & os) const;
0151
0152   /**
0153    * Function used to read in object persistently.
0154    * @param is the persistent input stream read from.
0155    * @param version the version number of the object when written.
0156    */
0157   void persistentInput(PersistentIStream & is, int version);
0158   //@}
0159
0160   /**
0161    * The standard Init function used to initialize the interfaces.
0162    * Called exactly once for each class by the class description system
0163    * before the main function starts or
0164    * when this class is dynamically loaded.
0165    */
0166   static void Init();
0167
0168 protected:
0169
0170   /** @name Clone Methods. */
0171   //@{
0172   /**
0173    * Make a simple clone of this object.
0174    * @return a pointer to the new object.
0175    */
0176   virtual IBPtr clone() const;
0177
0178   /** Make a clone of this object, possibly modifying the cloned object
0179    * to make it sane.
0180    * @return a pointer to the new object.
0181    */
0182   virtual IBPtr fullclone() const;
0183   //@}
0184
0185 private:
0186
0187   /**
0188    * Command to insert a rapidity range
0189    */
0190   string doYRange(string);
0191
0192   /**
0193    * The rapidity ranges.
0194    */
0195   vector<pair<double,double> > theYRanges;
0196
0197   /**
0198    * Whether to use pseudo rapidity instead of rapidity
0199    */
0200   bool thePseudo;
0201
0202   /**
0203    * Whether the cut is active on same-flavour fermions only
0204    * (ignored for pairs not consisting of two fermions)
0205    */
0206   bool theSameFlavourOnly;
0207
0208   /**
0209    * Whether the cut is active on opposite-sign fermions only
0210    * (ignored for pairs not consisting of two fermions)
0211    */
0212   bool theOppositeSignOnly;
0213
0214   /**
0215    * Matchers for a pair of particles to cut on. Only a pair
0216    * of particles, matching these objects, will be affected.
0217    */
0218   Ptr<MatcherBase>::ptr theFirstMatcher;
0219   Ptr<MatcherBase>::ptr theSecondMatcher;
0220
0221 private:
0222
0223   /**
0224    * The assignment operator is private and must never be called.
0225    * In fact, it should not even be implemented.
0226    */
0227   PairRapidityCut & operator=(const PairRapidityCut &) = delete;
0228
0229 };
0230
0231 }
0232
0233 #endif /* Herwig_PairRapidityCut_H */
0234