论文信息 - Improved limit on the branching fraction of the rare decay \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{K} ^0_{\m

Improved limit on the branching fraction of the rare decay \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{K} ^0_{\m

A search for the decay \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{K} ^0_{\mathrm { \scriptscriptstyle S}}} \rightarrow \mu ^+\mu ^-$$\end{document}KS0→μ+μ- is performed, based on a data sample of proton-proton collisions corresponding to an integrated luminosity of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$3\,\text{ fb }^{-1} $$\end{document}3fb-1, collected by the LHCb experiment at centre-of-mass energies of 7 and 8\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathrm {\,TeV}$$\end{document}TeV. The observed yield is consistent with the background-only hypothesis, yielding a limit on the branching fraction of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathcal{B}({{K} ^0_{\mathrm { \scriptscriptstyle S}}} \rightarrow \mu ^+\mu ^-) < 0.8~(1.0) \times 10^{-9}$$\end{document}B(KS0→μ+μ-)<0.8(1.0)×10-9 at \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$90\%~(95\%)$$\end{document}90%(95%) confidence level. This result improves the previous upper limit on the branching fraction by an order of magnitude.

[1] J. Podolanski,et al. III. Analysis of V-events , 1954 .

[2] J. H. Smith,et al. Search for the Decay K S 0 → μ + μ − , 1969 .

[3] T. Skwarnicki. A study of the radiative CASCADE transitions between the Upsilon-Prime and Upsilon resonances , 1986 .

[4] G. Azuelos,et al. Search for the Decay K+ -> pi+ pi0 nu nubar , 2000, hep-ex/0009055.

[5] A. Pich,et al. The longitudinal muon polarization in KL → μ+μ- , 1991 .

[6] G. D’Ambrosio,et al. Radiative nonleptonic kaon decays , 1994 .

[7] Yoav Freund,et al. A decision-theoretic generalization of on-line learning and an application to boosting , 1995, EuroCOLT.

[8] Hayes,et al. Review of Particle Physics. , 1996, Physical review. D, Particles and fields.

[9] John Langford,et al. Beating the hold-out: bounds for K-fold and progressive cross-validation , 1999, COLT '99.

[10] S. Mrenna,et al. Pythia 6.3 physics and manual , 2003, hep-ph/0308153.

[11] D. Lange,et al. The EvtGen particle decay simulation package , 2001 .

[12] G. Punzi. Sensitivity of Searches for New Signals and Its Optimization , 2003, physics/0308063.

[13] Z. Was,et al. PHOTOS Monte Carlo: a precision tool for QED correctionsin Z and W decays , 2005, hep-ph/0506026.

[14] S. Incerti,et al. Geant4 developments and applications , 2006, IEEE Transactions on Nuclear Science.

[15] F. Tegenfeldt,et al. TMVA - Toolkit for multivariate data analysis , 2012 .

[16] Chris P. Barnes,et al. The LHCb detector at the LHC , 2008 .

[17] Peter Skands,et al. A brief introduction to PYTHIA 8.1 , 2007, Comput. Phys. Commun..

[18] P. Harrison,et al. Handling of the generation of primary events in Gauss, the LHCb simulation framework , 2010, IEEE Nuclear Science Symposuim & Medical Imaging Conference.

[19] Wei-Yin Loh,et al. Classification and regression trees , 2011, WIREs Data Mining Knowl. Discov..

[20] S. Miglioranzi,et al. The LHCb Simulation Application, Gauss: Design, Evolution and Experience , 2011 .

[21] R. Oldeman,et al. Performance of the Muon Identification at LHCb , 2013, 1306.0249.

[22] Mark Williams,et al. The LHCb trigger and its performance in 2011 , 2013 .

[23] S. M. Etesami,et al. EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH (CERN) , 2015 .

[24] D. M. Santos,et al. Mass distributions marginalized over per-event errors , 2013, 1312.5000.

[25] Tianqi Chen,et al. XGBoost: A Scalable Tree Boosting System , 2016, KDD.

[26] Li-Yu Daisy Liu,et al. Search for the rare decay of , 2018 .