Abstract

Since 2015, with the restart of the LHC for its second run of data taking, the LHCb experiment has been empowered with a dedicated computing model to select and analyse calibration samples to measure the performance of the particle identification (PID) detectors and algorithms. The novel technique was developed within the framework of the innovative trigger model of the LHCb experiment, which relies on online event reconstruction for most of the datasets, reserving offline reconstruction to special physics cases. The strategy to select and process the calibration samples, which includes a dedicated data-processing scheme combining online and offline reconstruction, is discussed. The use of the calibration samples to measure the detector PID performance, and the efficiency of PID requirements across a large range of decay channels, is described. Applications of the calibration samples in data-quality monitoring and validation procedures are also detailed.

Figures and captions

On the left, mass distributions of the decaying particles with the results of the fit superimposed; signal contributions are shown by the red dashed curves, and the total fit functions including background contributions are shown by the blue solid curves. On the right, the background-subtracted distributions of the calibration samples for electrons, muons, pions, kaons and protons as a function of the track pseudorapidity, $\eta$, and momentum $p$ are shown. The colour scale units are arbitrary.	c_Jpsi[..].pdf [121 KiB] HiDef png [201 KiB] Thumbnail [143 KiB]
	Coverage_E.pdf [173 KiB] HiDef png [1 MiB] Thumbnail [415 KiB]
	c_Jpsi_c1.pdf [154 KiB] HiDef png [170 KiB] Thumbnail [133 KiB]
	Covera[..].pdf [294 KiB] HiDef png [1 MiB] Thumbnail [614 KiB]
	c_KS0LL_c1.pdf [136 KiB] HiDef png [158 KiB] Thumbnail [119 KiB]
	Covera[..].pdf [298 KiB] HiDef png [1 MiB] Thumbnail [633 KiB]
	c_DstX_c1.pdf [132 KiB] HiDef png [168 KiB] Thumbnail [128 KiB]
	c_DstY_c1.pdf [132 KiB] HiDef png [187 KiB] Thumbnail [144 KiB]
	Coverage_K.pdf [305 KiB] HiDef png [2 MiB] Thumbnail [645 KiB]
	c_Lam0[..].pdf [133 KiB] HiDef png [140 KiB] Thumbnail [108 KiB]
	Coverage_P.pdf [254 KiB] HiDef png [1 MiB] Thumbnail [518 KiB]
Schematic representation of the PID resampling and variable transformation techniques.	PIDGen.pdf [26 KiB] HiDef png [145 KiB] Thumbnail [116 KiB]
Schematic representation of the computing model for the PID calibration samples.	comput[..].pdf [51 KiB] HiDef png [873 KiB] Thumbnail [466 KiB]
Animated gif made out of all figures.	DP-2018-001.gif Thumbnail

Tables and captions

Input variables of the ANNPID classifiers for the various subsystems of the LHCb detector.	Table_1.pdf [44 KiB] HiDef png [189 KiB] Thumbnail [76 KiB] tex code
Overview of decay modes that are used to select calibration samples. The high momentum samples are primarily selected, while the low momentum samples are included to maximise the kinematic coverage as much as possible.”	Table_2.pdf [68 KiB] HiDef png [41 KiB] Thumbnail [19 KiB] tex code

Created on 18 October 2023.