**************************** * * * Update notes * * * * PYQUEN version 1.5 * * * **************************** (Last updated 19 December 2007 / 24 November 2019) PYQUEN version 1.5 is a direct continuation of previous versions. It should be used with the latest PYTHIA (PYTHIA6.401 and later versions). ----------------------------------------------------------------------------- PYQUEN1.5.4: 24 Nov 2019 1. Several technical adjustments for Fortran 2018 standard have been done. PYQUEN1.5.3: 23 Mar 2019 1. The two new parameters (minimum and maximum values of impact parameter bmin and bmax) have been introduced to the subroutine PYQUEN. 2. Bug fix in subroutine PYQUEN: in some rare cases status codes of initial hard partons were not updated properly. PYQUEN1.5.2: 13 Mar 2019 1. Several technical improvements have been done over the code to achieve better compatibility with the modern software build systems. 2. The subroutine PYQVER to print out PYQUEN versioning is introduced. PYQUEN1.5.1: 6 May 2010 1. Bug fix in subroutine PLEVNT: when the value of current medium temperature during parton rescatterings becomes close to the critical temperature, additional restriction on such values may need. The mistake did not have dramatic consequences, since it could appear only in the regime where rescatterings are almost halted and energy loss is about zero. However in some very rare cases this bug led to infinite loop in subroutine PLJETR. PYQUEN1.5 : 19 December 2007 1. The treatment of hadronization of in-medium emitted gluons in frames of PYTHIA string fragmentation scheme is improved by additional re-ordering of colour connections of such gluons along the string. The appearance of small rapidity asymmetry of hadroproduction coming from PYQUEN-rearranged strings is avoided by such a way. 2. The previous sharp rapidity dependence of initial energy density in nuclear overlapping zone is replaced by the smooth (Gaussian-like) distribution. The input parameter T0 has now meaning of the effective initial temperature in central Pb-Pb collisions at mid-rapidity (y=0). PYQUEN1.4 : 27 October 2007 1. Wood-Saxon nucleon distribution is implemented in PYQUEN nuclear geometry instead of hard sphere approximation (new function PRHOAA). Tabulation of impact parameter dependence of nuclear thickness function is performed in PYQUEN subroutine (arrays PBAB and PTAB). The spatial jet production vertex is calculated using the tabulated nuclear thickness function. If ifb=1, the tabulation of impact parameter dependence of nuclear overlap function is also performed in PYQUEN subroutine (arrays PBAB and PTAAB) to calculate distribution of jets over impact parameter of AA collisions. Maximum allowed value of impact parameter is three times of the nuclear radius. 2. The radial profile of energy density (temperature) is introduced in the parton rescattering model. The transverse energy density in each point inside the nuclear overlapping zone is proportional to the impact-parameter dependent product of two nuclear thickness functions in this point. Thus the input parameter T0 has now meaning of the effective (i.e. averaged over the nuclear overlapping zone) initial temperature in central Pb-Pb collisions. PYQUEN1.3 : 3 October 2007 1. Bug fix in subroutine PLINIT: it was non-correct calculation of the medium lifetime at very high initial temperatures (T0~2 GeV). 2. Rotations of full event system in subroutines PLEVNT and PLJETR for every parton rescattering are canceled, only rotations for current rescattered parton being hold. 3. New internal parameter in common block PARIMP was introduced, 'noquen'. It provides the possibility to generate the spatial jet production vertex in PYTHIA without subsequent medium-induced rescattering. PYQUEN1.2 : 18 June 2007 1. PYQUEN1.2 can be used for different beam energies (input parameter 'energy' specifies the c.m.s. energy per nucleon pair). 2. Initial parameters of quark-gluon plasma and some energy loss settings can be varied now by user using new common block PYQPAR: COMMON /pyqpar/ T0,tau0,nf,ienglu,ianglu T0 - initial QGP temperature for central Pb+Pb collisions (allowed range is 0.2 GeV < T0 < 2 GeV, default value is T0=1 GeV); tau0 - proper time of QGP formation (allowed range is 0.01 < tau0 < 10 fm/c, default value is tau0=0.1 fm/c); nf - number of active quark flavours in QGP (nf=0, 1, 2 or 3, default value is nf=0); ienglu - flag to fix type of medium-induced partonic energy loss (ienglu=0 - radiative and collisional loss, ienglu=1 - radiative loss only, ienglu=2 - collisional loss only, default value is ienglu=0); ianglu - flag to fix type of angular distribution of emitted gluons (ianglu=0 - small-angular, ianglu=1 - wide-angular, ianglu=2 - collinear, default value is ianglu-0). 3. Bug fix in PLEVNT: at very forward rapidities some angular asymmetry of partonic energy loss was possible. PYQUEN1.1 : 26 April 2006 1. New tolerance parameter paru(14) is used to adjust fragmentation of strings containing in-medium emitted gluons in PYTHIA_6401 routine PYSTRF. 2. Minimum transverse momentum, 200 MeV, is requested for in-medium emitted gluon to be included in event list and strings. 3. Cut off on maximum absolute pseudorapidity of hard parton to be rescattered in a medium is reduced to 3.5 (instead of 5. in previous version). 4. Showering partons produced by the initial state radiation in PYTHIA are not allowed to be rescattered in a medium. 5. Treatment of the option "vacuum showering after in-medium partonic energy loss" is improved. 6. Bug fix in PYQUEN subroutine PLJETR: when hard parton loses almost its energy, restriction on values of collisional and radiative loss may need. 7. Setting parameter mstp(111)=0 in main user routine is recommended to switch off hadronization before calling pyquen instead of mstj(1)=0. -----------------------------------------------------------------------------