Coding violation fixes
[u/mrichter/AliRoot.git] / THydjet / hydjet1_1 / hydjet.txt
CommitLineData
cb220f83 1
2 -------------------------------------------------------------
3 HYDJET, fast MC code to simulate flow effects, jet production
4 and jet quenching in heavy ion AA collisions at the LHC
5 -------------------------------------------------------------
6 This code is merging HYDRO (flow effects), PYTHIA6.4 (hard jet
7 production) and PYQUEN (jet quenching)
8 --------------------------------------------------------------
9
10 Igor Lokhtin, SINP MSU, Moscow, RU
11 e-mail: Igor.Lokhtin@cern.ch
12
13 Reference for HYDJET:
14 I.P. Lokhtin, A.M. Snigirev,
15 Eur. Phys. J. C 46 (2006) 211.
16
17 References for HYDRO:
18 N.A.Kruglov, I.P.Lokhtin, L.I.Sarycheva, A.M.Snigirev,
19 Z. Phys. C 76 (1997) 99;
20 I.P.Lokhtin, L.I.Sarycheva, A.M.Snigirev,
21 Phys. Lett. B 537 (2002) 261;
22 I.P.Lokhtin, A.M.Snigirev, Preprint SINP MSU 2004-14/753, hep-ph/0312204.
23
24 References for PYQUEN:
25 I.P.Lokhtin, A.M.Snigirev, Eur.Phys.J. C16 (2000) 527;
26 I.P.Lokhtin, A.M.Snigirev, Preprint SINP MSU 2004-13/752, hep-ph/0406038.
27
28 References for PYTHIA:
29 T.Sjostrand et al., Comput.Phys.Commun. 135 (2001) 238;
30 T.Sjostrand, S. Mrena and P. Skands, hep-ph/0603175.
31
32 Reference for JETSET event format:
33 T.Sjostrand, Comput.Phys.Commun. 82 (1994) 74.
34
35 --------------------------------------------------------------
36 Web-page:
37 http://cern.ch/lokhtin/hydro
38 --------------------------------------------------------------
39
40 Description of routine
41
42CALL hydro(A,ifb,bmin,bmax,bfix,nh) - generates one event
43
44input parameters to fix event configuration :
45(set in main user routine before hydro call)
46
47 A - beam and target nucleus atomic weight
48 ifb - flag of type of centrality generation
49 =0 impact parameter is fixed (bfix)
50 >0 or <0 impact parameter is generated with standard Glauber geometry
51 between minimum (bmin) and maximum (bmax) values
52 bmin - minimum impact parameter in units of nucleus radius RA
53 (i.e. minimum value in [fm] will be bmin*RA),
54 valid only if ifb not equal to zero
55 bmax - maximum impact parameter in units of nucleus radius RA
56 (i.e. maximum value in [fm] will be bmax*RA),
57 valid only if ifb not equal to zero
58 bfix - fixed impact parameter in units of nucleus radius RA
59 (i.e. fixed value in [fm] will be bfix*RA),
60 valid only if ifb=0
61 nh - mean soft hadron multiplicity in central Pb-Pb collisions
62 (multiplicity for other centralities and atomic numbers
63 will be calculated automatically).
64
65 --------------------------------------------------------------
66
67Parameters in COMMON BLOCKS which can be varied by user:
68
69COMMON /hyflow/ ytfl,ylfl,fpart
70ytfl - maximum transverse collective rapidity, controls slope of low-pt spectra
71(allowed range is 0.01<ytfl<3.0, default value is ytfl=1.).
72ylfl - maximum longitudinal collective rapidity, controls width of eta-spectra
73(allowed range is 0.01<ylfl<7.0, default value is ylfl=5.).
74fpart - fraction of soft multiplicity proportional to the number of nucleon
75participants; then (1.-fpart) will be the fraction of soft multiplicity
76proportional to the number of nucleon-nucleon binary sub-collisions
77(allowed range is 0.01<fpart<1.0, default value is fpart=1.).
78
79COMMON /hyjpar/ nhsel,ptmin,njet
80nhsel - flag to include jet production in hydro event:
81nhsel=0 - jet production off (pure HYDRO event);
82nhsel=1 - jet production on, jet quenching off (HYDRO+njet*PYTHIA events);
83nhsel=2 - jet production & jet quenching on (HYDRO+njet*PYQUEN events);
84nhsel=3 - jet production on, jet quenching off, HYDRO off (njet*PYTHIA events);
85nhsel=4 - jet production & jet quenching on, HYDRO off (njet*PYQUEN events);
86(default value is nhsel = 0).
87ptmin - minimal pt of parton-parton scattering in PYTHIA event, parameter
88ckin(3) in PYTHIA common block /pysubs/ should be set equal to ptmin
89(allowed range is 5 GeV < ptmin < 500 GeV, default value ptmin=10 GeV).
90
91 --------------------------------------------------------------
92
93Output event parameters in COMMON BLOCKS:
94
95COMMON /hyjpar/ nhsel,ptmin,njet
96njet - number of hard parton-parton scatterings with pt>ptmin in event.
97
98common /hyfpar/ bgen,nbcol,npart,npyt,nhyd
99bgen - generated value of impact parameter in units of nucleus radius RA
100(i.e the value in [fm] will be bgen*RA).
101nbcol - mean number of nucleon-nucleon binary sub-collisions at given 'bgen'.
102npart - mean number of nucleon participants at given 'bgen'.
103npyt - multiplicity of hard PYTHIA/PYQUEN-induced particles in event
104 (including full parton story).
105nhyd - multiplicity of soft HYDRO-induced hadrons in event.
106
107 --------------------------------------------------------------
108
109Output particle information
110
111COMMON /lujets/ n,k(150000,5),p(150000,5),v(150000,5)
112n - total event multiplicity
113k(i,1-5) - particle codes
114p(i,1-5) - particle four-momentum and mass
115v(i,1-5) - particle vertex, production time and lifetime
116
117NOTE! First 'npyt' lines in event list correspond to PYTHIA/PYQUEN-induced
118 particles, last 'nhyd' lines -- HYDRO-induced hadrons.
119
120COMMON /hyjets/ nl,kl(150000,5),pl(150000,5),vl(150000,5)
121contains list of parton history of event in the same format as /lujets/
122
123 --------------------------------------------------------------
124
125NOTE! Main users routine should be compiled with object files obtained by:
126 - jetset_73.f with extended array size in common block /lujets/;
127 - pythia6.401.f (or later versions);
128 - pyquen1_1.f;
129 - hydjet1_1.f.
130
131NOTE! Since variables (A-H, O-Z) are described as IMPLICIT DOUBLE PRECISION
132in 'pythia' and 'pyquen', the corresponding 'pythia' and 'pyquen' variables and
133parameters used in main users routine should be described also as 'double
134precision'. However variables and parameters from JETSET and HYDRO including
135output event information are supposed to be REAL.
136
137NOTE! Since pyquen deals with partonic pythia event, the fragmentation in
138 subroutine 'hyhard' is switched off before pyquen call using parameter
139 mstp(111) from pythia common block pypars:
140 ...
141 mstp(111)=0 ! fragmentation off
142c mstj(41)=0 ! vacuum showering off
143 call pyevnt ! 'normal' single pythia event
144 ...
145 call pyquen(A,ifb,bfix) ! 'quenched' single pythia event
146 ...
147 call pyexec ! fragmentation done
148 ...
149 in the case if Pythia final state radiation is switching off (if one set
150 mstj(41)=0 in 'hyhard'), the Pyquen option "vacuum showering after
151 in-medium partonic energy loss" is foreseen.
152
153NOTE! In order to adjust string fragmentation with additional gluons in Pythia,
154 the parameter paru(14)=1.d0 have to be specified in main users routine.
155
156 -------------------------------------------------------------------------
157
158 Physics validity of the model
159
1601. Internal parameters of the routine were optimized as an estimation
161for LHC heavy ion beam energies. The result for other beam energy ranges,
162obtained without additional internal parameters adjusting, is not expected
163to be reasonable.
1642. Hydro-type approximation for heavy ion collisions is expected to be
165applicable for central and semi-central collisions. The result obtained for
166very peripheral collisions (b~2*RA) can be not adequate.
1673. We do not expect correct event description for very forward rapidities
168(|y|>3), where other mechanisms of particle production among hydro-flow and
169jets can be important.