Polarimetry in Λc⁺ → p K⁻ π⁺

Contents

Polarimetry in Λc⁺ → p K⁻ π⁺#

10.1007/JHEP07(2023)228 10.48550/arXiv.2301.07010 10.5281/zenodo.7544989

\(\Lambda^+_\mathrm{c}\) polarimetry using the dominant hadronic mode

The polarimeter vector field for multibody decays of a spin-half baryon is introduced as a generalisation of the baryon asymmetry parameters. Using a recent amplitude analysis of the \(\Lambda^+_\mathrm{c} \to p K^- \pi^+\) decay performed at the LHCb experiment, we compute the distribution of the kinematic-dependent polarimeter vector for this process in the space of Mandelstam variables to express the polarised decay rate in a model-agnostic form. The obtained representation can facilitate polarisation measurements of the \(\Lambda^+_\mathrm{c}\) baryon and eases inclusion of the \(\Lambda^+_\mathrm{c} \to p K^- \pi^+\) decay mode in hadronic amplitude analyses.

Symbolic expressions

Compute the amplitude model over large data samples with symbolic expressions.

JSON grids

Reuse the computed polarimeter field in any amplitude analysis involving \(\Lambda_\mathrm{c}^+\).

Inspect interactively

Investigate how parameters in the amplitude model affect the polarimeter field.

Compute polarization

Learn how to determine the polarization vector using the polarimeter field.

Download this website as a single PDF file

This website shows all analysis results that led to the publication of LHCb-PAPER-2022-044. More information on this publication can be found on the following pages:

Behind SSO login (LHCb members only)

Python package#

PyPI package Supported Python versions

Each of the pages contain code examples for how to reproduce the results with the Python package hosted at github.com/ComPWA/polarimetry. However, to quickly get import the model in another package, it is possible to install the package from PyPI:

pip install polarimetry-lc2pkpi

Each of the models can then simply be imported as

import polarimetry

model = polarimetry.published_model("Default amplitude model")
model.intensity.cleanup()
\[\displaystyle \sum_{\lambda_{0}=-1/2}^{1/2} \sum_{\lambda_{1}=-1/2}^{1/2}{\left|{\sum_{\lambda_0^{\prime}=-1/2}^{1/2} \sum_{\lambda_1^{\prime}=-1/2}^{1/2}{A^{1}_{\lambda_0^{\prime}, \lambda_1^{\prime}, 0, 0} d^{\frac{1}{2}}_{\lambda_1^{\prime},\lambda_{1}}\left(\zeta^1_{1(1)}\right) d^{\frac{1}{2}}_{\lambda_{0},\lambda_0^{\prime}}\left(\zeta^0_{1(1)}\right) + A^{2}_{\lambda_0^{\prime}, \lambda_1^{\prime}, 0, 0} d^{\frac{1}{2}}_{\lambda_1^{\prime},\lambda_{1}}\left(\zeta^1_{2(1)}\right) d^{\frac{1}{2}}_{\lambda_{0},\lambda_0^{\prime}}\left(\zeta^0_{2(1)}\right) + A^{3}_{\lambda_0^{\prime}, \lambda_1^{\prime}, 0, 0} d^{\frac{1}{2}}_{\lambda_1^{\prime},\lambda_{1}}\left(\zeta^1_{3(1)}\right) d^{\frac{1}{2}}_{\lambda_{0},\lambda_0^{\prime}}\left(\zeta^0_{3(1)}\right)}}\right|^{2}}\]

For more examples of how to use the codebase, see the following pages.

Tip

Several cross-checks with Julia can be found here.

Tip

Figures for the paper can be downloaded here:

Figure 2:

total-polarimetry-field-watermark.svg

Figure 3a:

polarimetry-field-L1520-unaligned-watermark.svg

Figure 3b:

polarimetry-field-L1520-aligned-watermark.svg

Figure 4:

polarimetry-field-norm-uncertainties-watermark.png

All other exported figures can be found here.

Notebook execution times

Document

Modified

Method

Run Time (s)

Status

amplitude-model

2024-05-04 17:42

cache

32.54

appendix/alignment

2024-05-04 17:43

cache

83.92

appendix/angles

2024-05-04 17:43

cache

2.49

appendix/benchmark

2024-05-04 17:46

cache

172.88

appendix/dynamics

2024-05-04 17:46

cache

2.14

appendix/homomorphism

2024-05-04 17:46

cache

2.72

appendix/ls-model

2024-05-04 17:51

cache

306.09

appendix/model-serialization

2024-05-04 17:52

cache

48.74

appendix/phase-space

2024-05-04 17:53

cache

18.16

appendix/serialization

2024-05-04 17:54

cache

66.33

appendix/widget

2024-05-04 18:04

cache

598.73

cross-check

2024-05-04 18:05

cache

113.35

index

2024-05-04 18:06

cache

2.21

intensity

2024-05-04 18:09

cache

227.11

polarimetry

2024-05-04 18:13

cache

225.94

resonance-polarimetry

2024-05-04 19:02

cache

2962.4

uncertainties

2024-05-04 19:28

cache

1514.85

zz.polarization-fit

2024-05-04 19:31

cache

219.55