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arXiv · 2007.15537

YAM2: Yet another library for the $M_2$ variables using sequential quadratic programming

Chan Beom Park
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Abstract

The $M_2$ variables are devised to extend $M_{T2}$ by promoting transverse masses to Lorentz-invariant ones and making explicit use of on-shell mass relations. Unlike simple kinematic variables such as the invariant mass of visible particles, where the variable definitions directly provide how to calculate them, the calculation of the $M_2$ variables is undertaken by employing numerical algorithms. Essentially, the calculation of $M_2$ corresponds to solving a constrained minimization problem in mathematical optimization, and various numerical methods exist for the task. We find that the sequential quadratic programming method performs very well for the calculation of $M_2$, and its numerical performance is even better than the method implemented in the existing software package for $M_2$. As a consequence of our study, we have developed and released yet another software library, YAM2, for calculating the $M_2$ variables using several numerical algorithms.

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Chan Beom Park. 2020-07-30. YAM2: Yet another library for the $M_2$ variables using sequential quadratic programming. https://doi.org/10.1016/j.cpc.2021.107967

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