Starting from a user's process card in XML format which defines the process information as follows:
- Decay chains with particle elements at nodes and leaves,
- Objective mass function of the (sub) decay chain,
- Invisible particles whose momenta are to be optimized for the objective function,
- Kinematic constraint functions,
- Assignment of independent PT-conserving chains (for multiple decay chains from independent events),
the interpreter of OPTIMASS generates a process job directory which includes the main function (C++) for loading events and running OPTIMASS(es) for a selective set of user-defined processes all together.
Currently OPTIMASS's constrained minimization of the mass function with respect to the invisible momenta subject to the kinematic constraints, is implemented by the Augmented Lagrange Method, utilizing the libraries of ROOT with MINUIT2 for a series of unconstrained minimizations required.
Installation (ver 2.0+)
Download and instructions on installation can be found in the Github repository:
Generating User's Process Directory and Running
After installation, one can
- check the list of available process cards (.xml format),
- edit and add one's own process cards,
- generate a job directory to calculate OptiMasses in a single main function for a set of designated (multiple) processes one may want to analyze,
- revise the main function e.g. for feeding your events, and run in the job directory.
Command-line scripts supporting such operations can also be found at:
References
- W.S. Cho et al., OPTIMASS : A Package for the Minimization of Kinematic Mass Functions with Constraints, JHEP 1601(2016) 026, arXiv:1508.00589 [hep-ph].
- W.S. Cho et al., On-shell constrained M2 variables with applications to mass measurements and topology disambiguation, JHEP 08 (2014) 070, arXiv:1401.1449.
- C.B. Park, YAM2: Yet another library for the M2 variables using sequential quadratic programming, Comput. Phys. Commun. 264 (2021) 107967, arXiv:2007.15537.
- C. Lester et al., MT2/Stransverse Mass/Oxbridge Kinetic Library.
- J. Nocedal and S. Wright, Numerical Optimization, Springer, 2006.
Authors
- (v2) Kayoung Ban, Won Sang Cho, Sung Hak Lim
- (v1) Won Sang Cho, James S. Gainer, Doojin Kim, Sung Hak Lim, Konstantin Matchev, Filip Moortgat, Luc Pape, Myeonghun Park