cern.ch

Search for lepton-flavour-violating decays of Higgs-like bosons

[to restricted-access page]

Information

Tools

Abstract

A search is presented for a Higgs-like boson with mass in the range 45 to 195 GeV/$c^2$ decaying into a muon and a tau lepton. The dataset consists of proton-proton interactions at a centre-of-mass energy of 8 TeV, collected by the LHCb experiment, corresponding to an integrated luminosity of 2 fb$^{-1}$. The tau leptons are reconstructed in both leptonic and hadronic decay channels. An upper limit on the production cross-section multiplied by the branching fraction at 95 confidence level is set and ranges from 22 pb for a boson mass of 45 GeV/$c^2$ to 4 pb for a mass of 195 GeV/$c^2$.

Figures and captions

Invariant-mass distributions for the $\mu ^\pm\tau^\mp$ candidates for the four decay channels (from top to bottom: $\mu \tau_e$ , $\mu \tau_{h{\mu \tau_\mu }}$ {mumu }) and the three selections (from left to right: L-selection, C-selection, H-selection). The distribution of candidates observed (black points) is compared with backgrounds (filled colour, stacked), and with signal hypothesis (cyan). The signal is normalised to $\sqrt{N}$, with $N$ the total number of candidates in the corresponding data histogram.

 fig1a.pdf [23 KiB]
HiDef png [420 KiB]
Thumbnail [293 KiB]
*.C file
fig1a.pdf
fig1b.pdf [22 KiB]
HiDef png [412 KiB]
Thumbnail [280 KiB]
*.C file
fig1b.pdf
fig1c.pdf [20 KiB]
HiDef png [266 KiB]
Thumbnail [207 KiB]
*.C file
fig1c.pdf
fig1d.pdf [24 KiB]
HiDef png [410 KiB]
Thumbnail [299 KiB]
*.C file
fig1d.pdf
fig1e.pdf [23 KiB]
HiDef png [391 KiB]
Thumbnail [279 KiB]
*.C file
fig1e.pdf
fig1f.pdf [22 KiB]
HiDef png [281 KiB]
Thumbnail [234 KiB]
*.C file
fig1f.pdf
fig1g.pdf [23 KiB]
HiDef png [397 KiB]
Thumbnail [289 KiB]
*.C file
fig1g.pdf
fig1h.pdf [23 KiB]
HiDef png [385 KiB]
Thumbnail [286 KiB]
*.C file
fig1h.pdf
fig1i.pdf [21 KiB]
HiDef png [272 KiB]
Thumbnail [219 KiB]
*.C file
fig1i.pdf
fig1j.pdf [24 KiB]
HiDef png [424 KiB]
Thumbnail [286 KiB]
*.C file
fig1j.pdf
fig1k.pdf [24 KiB]
HiDef png [445 KiB]
Thumbnail [298 KiB]
*.C file
fig1k.pdf
fig1l.pdf [22 KiB]
HiDef png [318 KiB]
Thumbnail [234 KiB]
*.C file
fig1l.pdf

Cross-section times branching fraction 95% CL limits for the $ H \rightarrow \mu ^\pm \tau ^\mp $ decay as a function of $ m_H$ , from the simultaneous fit. The observed limits from individual channels are also shown.

 fig2.pdf [17 KiB]
HiDef png [286 KiB]
Thumbnail [202 KiB]
*.C file
fig2.pdf

Animated gif made out of all figures.

 PAPER-2018-030.gif
Thumbnail
thumbnail_PAPER-2018-030.gif

Tables and captions

Requirements for each decay channel and selection set.

 Table_1.pdf [83 KiB]
HiDef png [122 KiB]
Thumbnail [59 KiB]
tex code 		Table_1.pdf

Expected number of background candidates from each component, total background with uncertainty, and number of observed candidates with statistical uncertainty, from each decay channel and selection set.

 [Error creating the table]

Relative systematic uncertainties (in %) on the normalisation factors in the cross-section calculation. When the uncertainty depends on $ m_H$ a range is indicated.

 Table_3.pdf [54 KiB]
HiDef png [57 KiB]
Thumbnail [25 KiB]
tex code 		Table_3.pdf

Created on 27 April 2024.