7022 - DFGT01
    *************

1. code I.D.  : original code DFGT by C. Dionisi, S.Giagu, K.Fujii,
                T.Tsukamoto

                Interfaced by A.Colaleo, M.Maggi, March 97.
                contact people: A.Colaleo, M.Maggi and B. Bloch

2. write-up   :
    DFGT (ref. 3.1,3.2) is a chargino production and decay generator which 
 takes into account the amplitude due to the spin matching of the produced 
 and final state particles.
  The DFGT generator is developed in the minimal super-gravity scenario:
 the masses and the interaction of SUSY particles are described by m0, M2, 
 mu, tanb, A (ref.3.3).
  The user must supplies the SUSY parameters at the GUT scale, and all
 other SUSY mass parameters are calculated at the EW scale by the generator.
 By default the unification of gaugino masses term is assumed, which means
 Rscale=1 in the formula:

        M1=5/3 M2 tan^2(theta_W)*Rscale.
   In DFGT01 it is possible, changing the Rscale variable, to relax the GUT
 condition.
 In DFGT the LSP is always the lightest neutralino. Only the lightest chargino
 is produced and it decays only in neutralino fermions anti-fermions.
 The decay proceeds through a double two-body decay when kinematically allowed.

    The Monte Carlo integration and event generation is made by the 
 BASES/SPRING package v5.1, which is suited for the integration and generation
 of a very singular function.
 BASES/SPRING package (ref.3.4,3.5) performs stratified sampling of the 
 function in up 50 dimension.It works by dividing up the integration space 
 into a series of hypercubes. In each hypercube sample points of a definite 
 number are taken and the integral and variance are evaluated: summing up 
 results of all hypercubes gives the estimate of integral (this process is 
 called iteration).
  The execution of BASES consists of the grid optimization and the integration
 steps. After each iteration of the grid optimization step the grid is adjusted
 in order to make the dimension of hypercube narrower at the parts with larger 
 function value. In the integration step, the maximum value of the function in 
 each hypercube is calculated as well as the estimate of the integral.
   In the next program SPRING, the point in the hypercube with the maximum 
 value of the function is selected: at every iteration a point in the hypercube
 is  examined whether it is accepted or not. When this point is not accepted 
 another point is tested in the same hypercube. If the grid is not enough 
 optimized an event could be not generated (mis-generation) and a message is 
 printed. With an optimized grid, an high efficiency in generating a set of the
 independent variables is achieved (event generation). The behaviour of the 
 grid optimization and integration steps is controlled by the card.
   DFGT uses the BASES/SPRING package to sum over the helicity and phase space,
 to calculate the width and the cross section.

    The helicity amplitudes including decays into final state particles are 
 calculated at tree level by using the HELAS package (ref.3.4): a set of 
 subroutines to evaluate the Feynman diagrams allowing the calculation of the 
 matrix element.
    Initial state radiation,calculated at O(alpha**2), is included in the 
 structure function formalism (ref 3.6).
    The hadronization is then done via JETSET 7.4.

    The generator does not include R-parity violating chargino production or
R-parity violating decays. The final state radiation is not implemented.

3. references :
 3.1 A.Colaleo,M.Maggi, Aleph note ALEPH 97-022, MCARLO 97-001
     http://alephwww.cern.chhttp://cern.ch/aleph/alpub/note/note97/27/notadfn.ps
     " The KINGAL interface of the chargino Monte Carlo generator
       DFGT VERSION 1.0"
 3.2 C.Dionisi, S.Giagu, K.Fujii,T.Tsukamoto, Physics at LEP2, CERN 96-01
     Vol.2.337
 3.3 A.Bartl, H.Fraas, W.Majerotto, Z.Phys.C30(1986)411;
     Z.Phys.C34(1987)411; Z.Phys.C41(1988)475; Nucl.Phys.B278(1986)1.
 3.4 H.Murayama, I. Watanabe and K. Hagirawara, KEK Preprint 91-11 (1992).
 3.5 S.Kawabata, Comput. Phys. Commun. 41 (1986) 127.
 3.6 J.Fujimoto, M.Igarashi, N.Nakazawa, Y. Shimizu, and K. Tobimatsu,
       Radiative Corrections to e+ e- Reactions in
       Electroweak Theory,Progress of Theoretical Physics,
       Supplement No. 100 (1990).

4. data cards :
 Values of parameters and scwitches are given through data cards :

* BEAM   Beam energy in Gev
* IPRINT print out flag for PART bank
* IHISTO 0=delete/1=keep the working histograms
*      BEAM  IPRINT  IHISTO
GENE    86.0    10     0

* Weinberg angle, alpha,  alphas, ISR
PASM    0.2320  0.0078120  0.120   1

* RUSR: basic supersymmetry parameters
*      m0         mu      M2       tanBeta   A      Rscale
RUSR   1000.0    -0.1    0.1     1.01       0.0      1.0

* Control for integration steps of BASES
*
*   NCALW : NUMBER OF SAMPLE POINTS PER ITERATION TO CALCULATE THE WIDTH
*   NCALX : NUMBER OF SAMPLE POINTS PER ITERATION TO CALCULATE THE CROSS
*            SECTION
*   ITM1W : CONTROLS NUMBER OF ITERATIONS FOR GRID OPTIMIZATIONS STEP
*           INCREASE THESE TWO NUMBERS TO IMPROVE ACCURACY FOR WIDTH
*           CALCULATION STEP
*   ITM1X : CONTROLS NUMBER OF ITERATIONS FOR GRID OPTIMIZATIONS STEP
*           INCREASE THESE TWO NUMBERS TO IMPROVE ACCURACY FOR CROSS
*           SECTION CALCULATION STEP
*
*   ITM2W : CONTROLS NUMBER OF ITERATIONS FOR  WIDTH CALC. STEP
*   ITM2X : CONTROLS NUMBER OF ITERATIONS FOR  CROSS SECTION CALC. STEP
*   ACC1  : ACCURACY REQUIRED IN STEP 1 ( STOPS IF ACHIEVED ) FOR BOTH
*            WIDTH AND CROSS SECTION CALC.
*           EXPRESSED IN UNIT OF PERCENT
*   ACC2  : ACCURACY REQUIRED IN STEP 2 ( STOPS IF ACHIEVED ) FOR BOTH
*            WIDTH AND CROSS SECTION CALC.
*           EXPRESSED IN UNIT OF PERCENT
*
*  Increase ITMn(W/X), and NCAL(W/X), and decrease ACCn. to have
*  high precision results. Increase ACCn and decrease NCAL(W,X) and ITMn(W/X)
*  to produce rough but quick results
*
*    NCALW NCALX ITM1W ITM1X ITM2W ITM2X ACC1  ACC2
GBAS 20000 80000   8     5    10    5    0.2   0.01

*
*  Select final states
*  0 == all topology
*  1 == lepton + lepton      (lepton indicates electron or muon)
*  2 == lepton + tau or tau + tau
*  3 == lepton + quarks
*  4 == tau + quarks
*  5 == quarks + quarks
*
GCHC    0

5. header informations :

 5.1 run header
   The Parameter bank 'KPAR' contains  12 values corresponding to:
     1  : topology selection
     2  : centre-of-mass energy
     3  : initial state radiation
     4-8: m0,mu,M2,tanBeta,A
     9  : Rscale value
   10-12: smearing of the vertex position (in cm)

 5.2 event header
 Process identifier IDPR = final topology selected
     1  : lepton - lepton
     2  : quark  - lepton
     3  : quark  - quark
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