AROMA updates

Updates from version 2.2.4 to 2.2.5

• Potential numerical problem in parton cascade fixed. The problem occured in some cases when events with no emissions generated from the cascade where falsely rejected due to problems with numerical precisions. At Compass energies this may have resulted in distortions mainly of the y-distribution depending on the cuts used.

Updates from version 2.2.3 to 2.2.4

• Included possibility to choose the renormalisation and factorisation scales. Important: the COMMON BLOCK /HFDATA/ has been modified into

  COMMON /HFDATA/ PARHFL(20),CUTHFL(8),LSTHFL(20)

  The new parameters are:

  LSTHFL(10):    (D=2) Choice of renormalisation scale (MTQ is the transverse mass
                  of the quark and MTQB is the transverse mass of the anti-quark)
             =1:  Q2
             =2:  Q2+MTQ**2+MTQB**2
             =3:  SHAT
             =4:  (MTQ+MTQB)**2
             =5:  MTQ**2+MTQB**2
             =6:  PARHFL(8)*Q2+PARHFL(9)*MTQ**2+PARHFL(10)*MTQB**2+PARHFL(11)*SHAT
  
  LSTHFL(11):    (D=2) Choice of factorisation scale (MTQ is the transverse mass
                  of the quark and MTQB is the transverse mass of the anti-quark)
             =1:  Q2
             =2:  Q2+MTQ**2+MTQB**2
             =3:  SHAT
             =4:  (MTQ+MTQB)**2
             =5:  MTQ**2+MTQB**2
             =6:  PARHFL(12)*Q2+PARHFL(13)*MTQ**2+PARHFL(14)*MTQB**2+PARHFL(15)*SHAT
  
  PARHFL(8):      (D=1.) Choice of renormalisation scale, see LSTHFL(10) for details
  PARHFL(9):      (D=1.) Choice of renormalisation scale, see LSTHFL(10) for details
  PARHFL(10):     (D=1.) Choice of renormalisation scale, see LSTHFL(10) for details
  PARHFL(11):     (D=0.) Choice of renormalisation scale, see LSTHFL(10) for details
  PARHFL(12):     (D=1.) Choice of factorisation scale, see LSTHFL(11) for details
  PARHFL(13):     (D=1.) Choice of factorisation scale, see LSTHFL(11) for details
  PARHFL(14):     (D=1.) Choice of factorisation scale, see LSTHFL(11) for details
  PARHFL(15):     (D=0.) Choice of factorisation scale, see LSTHFL(11) for details
  

Updates from version 2.2.1 to 2.2.3

• The Generalised Area Law for Hadronic String Reinteractions, J. Rathsman, Physics Letters B 452 (1999) 364, can be included by using the latest version of the LEPTO routine LSCI with LST(34)=3. For more details see the LEPTO homepage.
• A new model for quarkonium production, presented in Quarkonium production at the Tevatron through Soft Color Interactions
, Phys. Rev. D 56 (1997) 7317, can be included by using the latest version of the LEPTO routine LSMALL. For more details see the LEPTO homepage.
• Removed an old COMMON block LGRID which is not used. (Thanks to Naomi Makins)
• Replaced random number generator used by DIVONNE by RLU from JETSET. (Thanks to Gunther Grindhammer)

Updates from version 2.1 to 2.2.1

• Changed the parameters for the integration and partitioning of the differential cross-section by DIVONNE. This makes the numerical uncertainty in the cross-section smaller.
• Changes similar to the ones made in LEPTO 6.5. (See LEPTO manual for more details.)
  • Soft Colour Interactions can be included with LST(34)
  • The new routine for small mass systems including a diquark is used (LSMALL)
  • A possibility to reduce the constituent masses of the partons in the proton remnant has been introduced, PARL(20).
  • Please note that the new seaquark treatment in LEPTO has not been included in AROMA.