Missing Mass Method for Short-Lived Particle Reconstruction in the CBM and Star Experiments

Abstract

The search for short-lived particles is an important part of physics research in experiments withrelativistic heavy ions. To find, select and study the properties of such short-lived particles in real timein the CBM experiment (FAIR/GSI, Germany), we have developed a package of algorithms, KFParticle Finder, which contains a search for more than 150 decay channels. The decays of short-livedcharged particles, when one of the daughter particles is neutral and cannot be registered in the detectorsystem, are also of great physics interest. To find and study such decays, we have extended the KFParticle Finder package by implementing the missing mass method, which is based on theconservation of energy and momentum laws.The method was studied in detail on simulated data of the CBM experiment, showing high efficiencywith a large signal-to-background ratio, as well as high significance. As part of the FAIR Phase-0program, the KF Particle Finder package of algorithms has been adapted for online and offlineprocessing in the STAR experiment (BNL, USA).Here we describe and discuss in detail the missing mass method for finding and analyzing short-livedparticles. The features of the application of the method to both simulated data in the CBM experimentand in the STAR experiment as part of real-time express data processing, as well as the results of thereal-time reconstruction of short-lived particle decays in the BES-II environment of the STARexperiment, are given.

Cellular automaton based track finder in the STAR experiment (BNL, USA)

“…This allows the implementation to use more advanced versions of software products as they are developed. So, the KF Particle Finder package, which performs physical analysis of the events, in the HLT is more advanced in relation to the offline version and significantly surpasses it in terms of functionality, including such useful features as the Missing Mass Method [102,103], which makes it possible searching of the short-lived particles which decay into a charged fragment Figure 6.11: Scheme of online data analysis in their express processing on the HLT cluster of the STAR experiment [102]. and a neutron.…”