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pegasus:overview [09/12/2019 19:15] lipatovpegasus:overview [12/09/2023 13:00] (current) lipatov
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 ====== Overview ====== ====== Overview ======
  
-Here we give some information and explanations about the important features of PEGASUS.+Here we give some information and explanations about the important features of PEGASUS.
  
 ===== Physical problem and solution ===== ===== Physical problem and solution =====
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 The multi-purpose Monte-Carlo event generators are commonly used tools for  The multi-purpose Monte-Carlo event generators are commonly used tools for 
 theoretical description of the collider measurements. theoretical description of the collider measurements.
-Most of them (for example, [[http://home.thep.lu.se/Pythia|PYTHIA 8.2]], [[https://mcfm.fnal.gov|MCFM 9.0]] and other) use conventional,+Most of them (for example, [[http://home.thep.lu.se/Pythia|PYTHIA 8.2]],  
 +[[https://mcfm.fnal.gov|MCFM 9.0]] and other) use conventional,
 or collinear QCD factorization, which is based on the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi resummation. or collinear QCD factorization, which is based on the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi resummation.
  
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 extremely user friendly interface, which allows one  extremely user friendly interface, which allows one 
 to easily implement various kinematical cuts into the calculations. to easily implement various kinematical cuts into the calculations.
-Generated events (weighted or unweighted) can be stored in the  +Generated events (weighted or unweighted) can be stored in the [[https://arxiv.org/abs/hep-ph/0609017|Les Houches Event]] file or presented "on the fly" with convenient
-Les Houches Event file or presented "on the fly" with convenient+
 built-in tool [[pegasus:plotter|PEGASUS Plotter]]. built-in tool [[pegasus:plotter|PEGASUS Plotter]].
 +
 +The underlying physics in [[https://cascade.hepforge.org|CASCADE]], 
 +[[https://bitbucket.org/hameren/katie/src/master|KATIE]] and PEGASUS is
 +basically the same. However, PEGASUS simplifies setting
 +the parameters and kinematic constraints (through the menu, with
 +no programming); it can switch between the collinear and TMD modes;
 +it provides a choice between weighted and unweighted events;
 +and it operates with a graphics interface, which is detached in the
 +console version (if a long-time calculation is needed). These features
 +make PEGASUS more flexible and better adjustable to the user's needs.
  
 ===== Calculation steps ===== ===== Calculation steps =====
  
-The calcualtions using PEGASUS include a few general steps common for all of the processes. +The calculations using PEGASUS include a few general steps common for all of the processes. 
-When PEGASUS is running, one can select the colliding particles, proton-proton or proton-antiproton, +When PEGASUS is running, one can select the colliding particles, proton-protonproton-antiproton or electron-proton
 and set their center-of-mass energy. The default setting corresponds to the LHC Run II setup. and set their center-of-mass energy. The default setting corresponds to the LHC Run II setup.
 Then one can select factorization scheme (TMD or collinear one) for each of the colliding particles, choose corresponding parton density function and set the parameters, important  Then one can select factorization scheme (TMD or collinear one) for each of the colliding particles, choose corresponding parton density function and set the parameters, important 
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   * From the list of available processes one can select the necessary process and then (optionally) correct the default kinematical restrictions, flux definition, list of requested observables and corresponding binnings etc. This can be done by double clicking on the requested process or via main menu (using //Edit -> Task// option).   * From the list of available processes one can select the necessary process and then (optionally) correct the default kinematical restrictions, flux definition, list of requested observables and corresponding binnings etc. This can be done by double clicking on the requested process or via main menu (using //Edit -> Task// option).
-  * For each of the observables one can manually edit the default binning according to own wishes. As another option, the binning can be uploaded immediately from the data file. Several commonly used formats (such as ''.yoda'', ''.yaml'', ''.csv'' or plain data format, compatible with [[http://www.gnuplot.info|Gnuplot]] tool) as provided by [[https://www.hepdata.net|HepData]] repository are supported.+  * For each of the observables one can manually edit the default binning according to own wishes. As another option, the binning can be uploaded immediately from the data file. Several commonly used formats (such as ''.yoda'', ''.yaml'', ''.csv'' or plain data format, compatible with [[http://www.gnuplot.info|Gnuplot]] tool) as provided by [[https://www.hepdata.net|HEPData]] repository are supported.
   * The user-defined setup for any process (total center-of-mass energy, selected parton densities, kinematical restrictions, binnings etc) can be saved to a configuration file in some internal format (''*.pegasus''). This can be done via the main menu (using //File -> Save// or //File -> Save As// options) or via the popup menu available on right mouse button click or via appropriate button in the button panel. Of course, the configuration file can be loaded and a user-defined setup can be used in further applications. This can be done via main menu (with //File -> Open// option) or via popup menu or via //Open// button on the button panel.    * The user-defined setup for any process (total center-of-mass energy, selected parton densities, kinematical restrictions, binnings etc) can be saved to a configuration file in some internal format (''*.pegasus''). This can be done via the main menu (using //File -> Save// or //File -> Save As// options) or via the popup menu available on right mouse button click or via appropriate button in the button panel. Of course, the configuration file can be loaded and a user-defined setup can be used in further applications. This can be done via main menu (with //File -> Open// option) or via popup menu or via //Open// button on the button panel. 
   * Weighted or unweighted events can be generated. This option is available via main menu //Edit -> Settings -> Generated events// or via popup menu.   * Weighted or unweighted events can be generated. This option is available via main menu //Edit -> Settings -> Generated events// or via popup menu.
-  * If one needs to generate the Les Houches Event file, one has to mark corresponding option before the calculation starts. Note that this option affects the speed of the calculations.+  * If one needs to generate the [[https://arxiv.org/abs/hep-ph/0609017|Les Houches Event]] file, one has to mark corresponding option before the calculation starts. Note that this option affects the speed of the calculations.
   * The calculation will start by choosing the corresponding option in main menu (//Calculation -> Start//), popup menu or pressing //Start// button on the button panel. The numerical results for requested observables will be immediately presented "on the fly" with built-in tool [[pegasus:plotter|PEGASUS Plotter]]. The calculations can be paused or even stopped (using main menu options //Calculation -> Pause//, //Calculation -> Stop//, corresponding buttons on the button panel or options in popup menu).   * The calculation will start by choosing the corresponding option in main menu (//Calculation -> Start//), popup menu or pressing //Start// button on the button panel. The numerical results for requested observables will be immediately presented "on the fly" with built-in tool [[pegasus:plotter|PEGASUS Plotter]]. The calculations can be paused or even stopped (using main menu options //Calculation -> Pause//, //Calculation -> Stop//, corresponding buttons on the button panel or options in popup menu).
   * If there are several contributing subprocesses, there is a possibility to immediately jump to the next one (via //Calculation -> Next// option in main menu or appropriate button on button panel or popup menu) during the calculations.   * If there are several contributing subprocesses, there is a possibility to immediately jump to the next one (via //Calculation -> Next// option in main menu or appropriate button on button panel or popup menu) during the calculations.
  
-The generated events can be accumulated in Les Houches Event (''*.lhe'') file and/or presented in [[pegasus:plotter|PEGASUS Plotter]]. Using the latter, one can save the results in a some internal format (''*.pplot'') or as a simple plain data (compatible, for example, with [[http://www.gnuplot.info|Gnuplot]] package) or export them to an image (''*.pdf'', ''*.png'', ''*.jpg'' or ''*.bmp'').+The generated events can be accumulated in Les Houches Event (''*.lhe'') file and/or presented in [[pegasus:plotter|PEGASUS Plotter]]. Using the latter, one can save the results in a some internal format (''*.pplot'') or as a simple plain data (compatible, for example, with [[http://www.gnuplot.info|Gnuplot]] package) or export them to an image (''*.pdf'', ''*.png'', ''*.jpg'' or ''*.bmp'').
  
 ===== Implemented TMD gluon densities in a proton ===== ===== Implemented TMD gluon densities in a proton =====
  
 ^ Set      ^  Order of a<sub>s</sub>      ^  N<sub>f</sub>  ^  QCD scale [MeV]  ^  Reference  ^ ^ Set      ^  Order of a<sub>s</sub>      ^  N<sub>f</sub>  ^  QCD scale [MeV]  ^  Reference  ^
 +| LLM'2022 (CCFM)  |  2  |  4  |  200  |  [[https://arxiv.org/abs/2211.03727|A.V. Lipatov, G.I. Lykasov, M.A. Malyshev]]  |
 | A0 (CCFM)  |  1  |  4  |  250  |  [[https://arxiv.org/abs/hep-ph/0411287|H. Jung]]  | | A0 (CCFM)  |  1  |  4  |  250  |  [[https://arxiv.org/abs/hep-ph/0411287|H. Jung]]  |
 | B0 (CCFM)  |  1  |  4  |  250  |  [[https://arxiv.org/abs/hep-ph/0411287|H. Jung]]  | | B0 (CCFM)  |  1  |  4  |  250  |  [[https://arxiv.org/abs/hep-ph/0411287|H. Jung]]  |
 | JH'2013 set 1 (CCFM)  |  2  |  4  |  200  |  [[https://arxiv.org/abs/1312.7875|F. Hautmann, H. Jung]]  | | JH'2013 set 1 (CCFM)  |  2  |  4  |  200  |  [[https://arxiv.org/abs/1312.7875|F. Hautmann, H. Jung]]  |
 | JH'2013 set 2 (CCFM)  |  2  |  4  |  200  |  [[https://arxiv.org/abs/1312.7875|F. Hautmann, H. Jung]]  | | JH'2013 set 2 (CCFM)  |  2  |  4  |  200  |  [[https://arxiv.org/abs/1312.7875|F. Hautmann, H. Jung]]  |
-KMR (MMHT'2014)  |  1  |  5  |  211  |  [[https://arxiv.org/abs/hep-ph/9911379|M.A. Kimber, A.D. Martin, M.G. Ryskin]] \\ [[https://arxiv.org/abs/hep-ph/0306169|G. Watt, A.D. Martin, M.G. Ryskin]]   | +KLSZ'2020 (KMR)  |  1  |  4  |  143  |  [[https://arxiv.org/abs/1911.01445|A.V. Kotikov, A.V. Lipatov, B.G. Shaikhatdenov, P. Zhang]]   | 
-| KMR (NNPDF3.1)  |  1  |  5  |  167  |  [[https://arxiv.org/abs/hep-ph/9911379|M.A. Kimber, A.D. Martin, M.G. Ryskin]] \\ [[https://arxiv.org/abs/hep-ph/0306169|G. Watt, A.D. Martin, M.G. Ryskin]]   | +| PB NLO set 1  |  2  |  4  |  118  |  [[https://arxiv.org/abs/1804.11152|F. Hautmann, H. Jung, A. Lelek, V. Radescu, R. Zlebcik]]   | 
-KMR (DAS set 1)  |  1  |  4  |  143  |  [[https://arxiv.org/abs/1911.01445|A.V. Kotikov, A.V. Lipatov, B.G. Shaikhatdenov, P. Zhang]]   | +| PB NLO set 2  |  2  |  4  |  118  |  [[https://arxiv.org/abs/1804.11152|F. Hautmann, H. Jung, A. Lelek, V. Radescu, R. Zlebcik]]   |
-| KMR (DAS set 2)  |  1  |  4  |  143  |  [[https://arxiv.org/abs/1911.01445|A.V. Kotikov, A.V. Lipatov, B.G. Shaikhatdenov, P. Zhang]]   | +
-| PB NLO set 1  |  2  |  4  |  118  |  [[https://arxiv.org/abs/1704.01757|F. Hautmann, H. Jung, A. Lelek, V. Radescu, R. Zlebcik]]   | +
-| PB NLO set 2  |  2  |  4  |  118  |  [[https://arxiv.org/abs/1704.01757|F. Hautmann, H. Jung, A. Lelek, V. Radescu, R. Zlebcik]]   |+
  
 The A0+, A0-, B0+, B0-, JH'2013 set 1(2)+ and JH'2013 set 1(2)- distributions, needed The A0+, A0-, B0+, B0-, JH'2013 set 1(2)+ and JH'2013 set 1(2)- distributions, needed
 to estimate the scale uncertainties of the CCFM-based calculations, are not shown in the Table. to estimate the scale uncertainties of the CCFM-based calculations, are not shown in the Table.
 +In principle, any other TMD gluon density in a proton could be used: 
 +one just have to upload it from the separate data file prepared in the standard [[https://arxiv.org/abs/1407.5935|uPDFevolv]] routine format.
  
 ===== Strong coupling and masses of particles ===== ===== Strong coupling and masses of particles =====
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 The Les Houche Event ''*.lhe'' file, generated by the PEGASUS, consists of two main blocks: the first one contains the information about the number of the recorded events, the PDFs used, the colliding hadrons and their energies. Also the total cross section is shown. The second block represents a list of events, including the data on the interacting partons, their 4-momenta and color structure of the event.  The Les Houche Event ''*.lhe'' file, generated by the PEGASUS, consists of two main blocks: the first one contains the information about the number of the recorded events, the PDFs used, the colliding hadrons and their energies. Also the total cross section is shown. The second block represents a list of events, including the data on the interacting partons, their 4-momenta and color structure of the event. 
-We mention the basic features of the ''*.lhe'' file, generated by the PEGASUS:+We mention the basic features of the ''*.lhe'' file, generated by PEGASUS:
  
   * The generated events could be weighted or unweighted. In first case, the sum of all the weights is the total cross section of the subprocess.   * The generated events could be weighted or unweighted. In first case, the sum of all the weights is the total cross section of the subprocess.
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   * Conventional (collinear) parton densities in a proton are numbered according to the [[https://lhapdf.hepforge.org|LHAPDF]] scheme, while TMD parton distributions are numbered according to the [[https://tmdlib.hepforge.org|TMDLib]] package.   * Conventional (collinear) parton densities in a proton are numbered according to the [[https://lhapdf.hepforge.org|LHAPDF]] scheme, while TMD parton distributions are numbered according to the [[https://tmdlib.hepforge.org|TMDLib]] package.
  
-The produced ''*.lhe'' file can then be processed with an external program to introduce some peculiar event selection, to include parton showers, to hadronize the final particles, etc. It is found+The produced ''*.lhe'' file can then be processed with an external program to introduce some peculiar event selection, [[pegasus:showering| to include parton showers, to hadronize the final particles]], etc. It is found
 to be compatible with such Monte Carlo generators as [[http://home.thep.lu.se/Pythia|PYTHIA 8.2]] and [[https://cascade.hepforge.org|CASCADE]]. to be compatible with such Monte Carlo generators as [[http://home.thep.lu.se/Pythia|PYTHIA 8.2]] and [[https://cascade.hepforge.org|CASCADE]].
  
 ===== Random number generator ===== ===== Random number generator =====
  
-Since all the internal variables in PEGASUS are declared as double precision ones, double precision random numbers have to be generated in the Monte-Carlo simulations. The random number generator [[http://luscher.web.cern.ch/luscher/ranlux|RanLux]] is well suited for these purposes. It has a long period, solid theoretical foundations and is commonly used in computational physics. This random number generator is implemented into the PEGASUS.+Since all the internal variables in PEGASUS are declared as double precision ones, double precision random numbers have to be generated in the Monte-Carlo simulations. The random number generator [[http://luscher.web.cern.ch/luscher/ranlux|RanLux]] is well suited for these purposes. It has a long period, solid theoretical foundations and is commonly used in computational physics. This random number generator is implemented into PEGASUS.
  
 ===== References ===== ===== References =====
  
-  * A.V. Lipatov, M.A. Malyshev, S.P. Baranov, in preparation.+  * A.V. Lipatov, M.A. Malyshev, S.P. Baranov, [[https://doi.org/10.1140/epjc/s10052-020-7898-6|Eur. Phys. J. C 80, 330 (2020) ]]
  
 ===== Acknowledgements ====== ===== Acknowledgements ======
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 We are also grateful to Maria Mikova, Natalia Ovechkina and Anastasia Zotova for their support and help for the design of the program. We are also grateful to Maria Mikova, Natalia Ovechkina and Anastasia Zotova for their support and help for the design of the program.
 +
 +Contributions to the physics in PEGASUS were provided by Anatoly Kotikov (JINR, Dubna),  
 +Gennady Lykasov (JINR, Dubna) and Nizami Abdulov. We thank Vladimir Lyubushkin (JINR, Dubna) and Alsu Bagdatova (LPI, Moscow), who contributed significantly to the functionality and stability of PEGASUS.
  
 We are especially grateful to Nikolai Zotov, who guided and supervised our first steps in High Energy Physics,  We are especially grateful to Nikolai Zotov, who guided and supervised our first steps in High Energy Physics, 
 who encouraged our progress in k<sub>t</sub>-factorization and whose enthusiasm consolidated our group. Nikolai Zotov passed away on January 2016. Our work is dedicated to his memory. who encouraged our progress in k<sub>t</sub>-factorization and whose enthusiasm consolidated our group. Nikolai Zotov passed away on January 2016. Our work is dedicated to his memory.
  
pegasus/overview.1575908129.txt.gz · Last modified: 09/12/2019 19:15 by lipatov