pegasus:overview
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pegasus:overview [09/12/2019 18:35] – lipatov | pegasus:overview [02/09/2023 14:36] – lipatov | ||
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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:// | + | Most of them (for example, [[http:// |
+ | [[https:// | ||
or collinear QCD factorization, | or collinear QCD factorization, | ||
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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:// |
- | Les Houches Event file or presented "on the fly" with convenient | + | built-in tool [[pegasus: |
- | built-in tool PEGASUS Plotter. | + | |
+ | The underlying physics in [[https:// | ||
+ | [[https:// | ||
+ | basically the same. However, PEGASUS simplifies setting | ||
+ | the parameters and kinematic constraints (through the menu, with | ||
+ | no programming); | ||
+ | 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 | + | The calculations |
- | When PEGASUS is running, one can select the colliding particles, proton-proton | + | When PEGASUS is running, one can select the colliding particles, proton-proton, proton-antiproton |
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, | * From the list of available processes one can select the necessary process and then (optionally) correct the default kinematical restrictions, | ||
- | * 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 '' | + | * 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 '' |
* The user-defined setup for any process (total center-of-mass energy, selected parton densities, kinematical restrictions, | * The user-defined setup for any process (total center-of-mass energy, selected parton densities, kinematical restrictions, | ||
* 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:// |
- | * The calculation will start by choosing the corresponding option in main menu (// | + | * The calculation will start by choosing the corresponding option in main menu (// |
* If there are several contributing subprocesses, | * If there are several contributing subprocesses, | ||
- | The generated events can be accumulated in Les Houches Event ('' | + | The generated events can be accumulated in Les Houches Event ('' |
===== Implemented TMD gluon densities in a proton ===== | ===== Implemented TMD gluon densities in a proton ===== | ||
^ Set ^ Order of a< | ^ Set ^ Order of a< | ||
+ | | LLM' | ||
| A0 (CCFM) | | A0 (CCFM) | ||
| B0 (CCFM) | | B0 (CCFM) | ||
| JH' | | JH' | ||
| JH' | | JH' | ||
- | | KMR (MMHT'2014) | 1 | 5 | 211 | [[https:// | + | | KLSZ'2020 (KMR) | 1 | 4 | 143 | [[https:// |
- | | KMR (NNPDF3.1) | + | |
- | | KMR (DAS set 1) | 1 | 4 | 143 | [[https:// | + | |
- | | KMR (DAS set 2) | 1 | 4 | 143 | [[https:// | + | |
| PB NLO set 1 | 2 | 4 | 118 | [[https:// | | PB NLO set 1 | 2 | 4 | 118 | [[https:// | ||
| PB NLO set 2 | 2 | 4 | 118 | [[https:// | | PB NLO set 2 | 2 | 4 | 118 | [[https:// | ||
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The A0+, A0-, B0+, B0-, JH' | The A0+, A0-, B0+, B0-, JH' | ||
to estimate the scale uncertainties of the CCFM-based calculations, | to estimate the scale uncertainties of the CCFM-based calculations, | ||
+ | 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:// | ||
===== Strong coupling and masses of particles ===== | ===== Strong coupling and masses of particles ===== | ||
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The Les Houche Event '' | The Les Houche Event '' | ||
- | We mention the basic features of the '' | + | We mention the basic features of the '' |
* 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:// | * Conventional (collinear) parton densities in a proton are numbered according to the [[https:// | ||
- | The produced '' | + | The produced '' |
to be compatible with such Monte Carlo generators as [[http:// | to be compatible with such Monte Carlo generators as [[http:// | ||
===== 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:// | + | 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:// |
+ | |||
+ | ===== References ===== | ||
+ | |||
+ | * A.V. Lipatov, M.A. Malyshev, S.P. Baranov, [[https:// | ||
+ | |||
+ | ===== Acknowledgements ====== | ||
+ | |||
+ | We would like to thank all our colleages and friends, who supported us during work on this program. We thank Victor Savrin and Edward Boos for their encouraging interest and creating comfortable and friendly atmosphere in SINP MSU. Special thanks to Elena Boos. Without her the way of this program to the release would be much longer. | ||
+ | |||
+ | A part of the work was done during author' | ||
+ | |||
+ | 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) and | ||
+ | Gennady Lykasov (JINR, Dubna). We thank Vladimir Lyubushkin (JINR, Dubna) and Alsu Bagdatova (LPI, Moscow), who contributed significantly to the functionality and stability of PEGASUS. | ||
- | ===== PEGASUS Plotter ===== | + | We are especially grateful to Nikolai Zotov, who guided and supervised our first steps in High Energy Physics, |
+ | who encouraged our progress in k< | ||
pegasus/overview.txt · Last modified: 15/04/2024 10:14 by lipatov