cern.ch

Observation of the semileptonic decay $B^{+}\to p\overline{p}\mu^{+}\nu_{\mu}$

[to restricted-access page]

Information

Tools

Abstract

The Cabibbo-suppressed semileptonic decay $B^{+}\to p\overline{p}\mu^{+}\nu_{\mu}$ is observed for the first time using a sample of $pp$ collisions corresponding to an integrated luminosity of 1.0, 2.0 and 1.7fb$^{-1}$ at centre-of-mass energies of 7, 8 and 13TeV, respectively. The differential branching fraction is measured as a function of the $p\overline{p}$ invariant mass using the decay mode $B^{+}\to J/\psi K^{+}$ for normalisation. The total branching fraction is measured to be \begin{align*} \mathcal{B}(B^{+}\to p\overline{p}\mu^{+}\nu_{\mu}) = (5.27 ^{+0.23}_{-0.24} \pm 0.21 \pm 0.15)\times 10^{-6}, \end{align*} where the first uncertainty is statistical, the second systematic and the third is from the uncertainty on the branching fraction of the normalisation channel.

Figures and captions

Result of training (a) the charged-isolation BDT and (b) the part-reco BDT. The chosen selection on the classifier outputs are indicated by the dashed red line. For some candidates there are no additional tracks near the $B$-decay vertex; these candidates are accepted and do not appear in the charged-isolation BDT output. The background samples shown here have the $\overline{ \Lambda} {}^-_ c $ and $\overline{ D } {}^0 $ hadrons decaying via $\overline{ \Lambda} {}^-_ c \rightarrow \overline p K ^+ \pi ^- $ and $\overline{ D } {}^0 \rightarrow \mu ^+ X$. The part-reco BDT is trained on a mixture of background modes with only one shown here for illustration.

Fig1a.pdf [18 KiB]
HiDef png [268 KiB]
Thumbnail [217 KiB]
*.C file
Fig1a.pdf
Fig1b.pdf [19 KiB]
HiDef png [270 KiB]
Thumbnail [212 KiB]
*.C file
Fig1b.pdf

Distribution of $m( { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} K ^+ )$ with the fit result shown for the 2016 data set.

Fig2.pdf [26 KiB]
HiDef png [242 KiB]
Thumbnail [231 KiB]
*.C file
Fig2.pdf

Distributions of $ m_{\mathrm{corr}}$ {} in each $ m( p \overline p )$ {} bin with the fit results shown.

Fig3a.pdf [12 KiB]
HiDef png [79 KiB]
Thumbnail [67 KiB]
*.C file
Fig3a.pdf
Fig3b.pdf [96 KiB]
HiDef png [342 KiB]
Thumbnail [300 KiB]
*.C file
Fig3b.pdf
Fig3c.pdf [96 KiB]
HiDef png [347 KiB]
Thumbnail [322 KiB]
*.C file
Fig3c.pdf
Fig3d.pdf [99 KiB]
HiDef png [377 KiB]
Thumbnail [330 KiB]
*.C file
Fig3d.pdf
Fig3e.pdf [96 KiB]
HiDef png [340 KiB]
Thumbnail [286 KiB]
*.C file
Fig3e.pdf
Fig3f.pdf [95 KiB]
HiDef png [339 KiB]
Thumbnail [278 KiB]
*.C file
Fig3f.pdf

Differential branching fraction as a function of the $ p \overline p $ {} invariant mass. The $\eta _ c \rightarrow p \overline p $, $ { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} \rightarrow p \overline p $ and $\psi {(2S)} \rightarrow p \overline p $ vetoes are indicated by the (left) red, (middle) blue and (right) pink bands, respectively. The red dashed line represents the prediction of the pQCD model normalised to the observed branching fraction [8].

Fig4.pdf [16 KiB]
HiDef png [189 KiB]
Thumbnail [177 KiB]
*.C file
Fig4.pdf

Animated gif made out of all figures.

PAPER-2019-034.gif
Thumbnail
thumbnail_PAPER-2019-034.gif

Tables and captions

Relative efficiencies for Run 1 and 2016 and the weighted combination of both.

Table_1.pdf [62 KiB]
HiDef png [77 KiB]
Thumbnail [39 KiB]
tex code
Table_1.pdf

Summary of the systematic uncertainties on the differential branching fractions. The contributions pertaining to the efficiency estimate are first, those for the yield extraction are below. The particle identification and tracking efficiency uncertainties are assumed to be 100% correlated between Run 1 and 2016. The total correlations of the uncertainties between the bins are shown in Table 4.

Table_2.pdf [44 KiB]
HiDef png [147 KiB]
Thumbnail [68 KiB]
tex code
Table_2.pdf

Number of observed $ B ^+ \rightarrow p \overline p \mu ^+ \nu _\mu $ {} candidates and differential branching fraction in each bin of $ m( p \overline p )$ {} . The uncertainties on the signal yields are statistical only. For the differential branching fractions the first uncertainties are statistical, the second systematic and the third from the uncertainties on the branching fractions of the normalisation channel.

Table_3.pdf [69 KiB]
HiDef png [40 KiB]
Thumbnail [25 KiB]
tex code
Table_3.pdf

Correlations in the uncertainties between bins of $ m( p \overline p )$ {} .

Table_4.pdf [52 KiB]
HiDef png [40 KiB]
Thumbnail [19 KiB]
tex code
Table_4.pdf

Covariance matrix for bins of $ m( p \overline p )$ {} .

Table_5.pdf [60 KiB]
HiDef png [44 KiB]
Thumbnail [21 KiB]
tex code
Table_5.pdf

Supplementary Material [file]

Supplementary material full pdf

supple[..].pdf [101 KiB]
supplementary.pdf

This ZIP file contains supplemetary material for the publication LHCb-PAPER-2019-034. The files are: supplementary.tex : The latex source of the supplementary material supplementary.pdf : An overview of the extra figures *.pdf, *.C, *.png, *.eps : The figures in variuous formats

Fig1a.pdf [26 KiB]
HiDef png [246 KiB]
Thumbnail [237 KiB]
*C file
Fig1a.pdf
Fig1b.pdf [26 KiB]
HiDef png [248 KiB]
Thumbnail [235 KiB]
*C file
Fig1b.pdf

Created on 27 February 2021.