cern.ch

First observation of a baryonic $B_s^0$ decay

[to restricted-access page]

Abstract

We report the first observation of a baryonic $B_s^0$ decay, $B_s^0 \to p \overline{\Lambda} K^-$, using proton-proton collision data recorded by the LHCb experiment at center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of $3.0\,\mathrm{fb}^{-1}$. The branching fraction is measured to be $ \mathcal{B}(B_s^0 \to p \overline{\Lambda} K^-) + \mathcal{B}(B_s^0 \to \bar{p} \Lambda K^+) = \left[5.46 \pm 0.61 \pm 0.57 \pm 0.50 (\mathcal{B}) \pm 0.32 (f_s/f_d)\right]\times 10^{-6}, $ where the first uncertainty is statistical and the second systematic, the third uncertainty accounts for the experimental uncertainty on the branching fraction of the $B^0 \to p \overline{\Lambda} \pi^-$ decay used for normalization, and the fourth uncertainty relates to the knowledge of the ratio of $b$-quark hadronization probabilities $f_s/f_d$.

Figures and captions

Mass distributions for $b$-hadron candidates for (left) the $ p \overline{\Lambda} \pi ^- $ and (right) the $ p \overline{\Lambda} K ^- $ sample for the combined long and downstream categories. The black points represent the data, the solid blue curve the result of the fit, the red dashed curve the $ B ^0_ s \!\rightarrow p \overline{\Lambda} K ^- $ contribution, the black (magenta) dotted curve the $ B ^0 \!\rightarrow p \overline{\Lambda} \pi ^- $ ( $ B ^0_ s \!\rightarrow p \overline \Sigma {}^0 K ^- $ ) and the green dash-dotted curve the contribution from $ B ^0 \!\rightarrow p \overline \Sigma {}^0 \pi ^- $ decays. The combinatorial background distribution is indicated by the shaded histogram.

Fig1a.pdf [62 KiB]
HiDef png [514 KiB]
Thumbnail [146 KiB]
*.C file
Fig1a.pdf
Fig1b.pdf [79 KiB]
HiDef png [480 KiB]
Thumbnail [136 KiB] *.C file
Fig1b.pdf

Efficiency-corrected and background-subtracted $m( p \overline{\Lambda} )$ invariant mass distributions for (left) $ B ^0 \!\rightarrow p \overline{\Lambda} \pi ^- $ and (right) $ B ^0_ s \!\rightarrow p \overline{\Lambda} K ^- $ candidates. The distributions are normalized to unity.

Fig2a.pdf [32 KiB]
HiDef png [128 KiB]
Thumbnail [54 KiB]
*.C file
Fig2a.pdf
Fig2b.pdf [32 KiB]
HiDef png [124 KiB]
Thumbnail [52 KiB] *.C file
Fig2b.pdf

Animated gif made out of all figures.

PAPER-2017-012.gif
Thumbnail
thumbnail_PAPER-2017-012.gif

Supplementary Material [file]

Supplementary material full pdf

supple[..].pdf [382 KiB]
supplementary.pdf

This ZIP file contains supplemetary material for the publication LHCb-PAPER-2017-012. The files are: README : this README file supplementary.pdf : An overview of the extra figures and tables *.pdf, *.png, *.eps : The figures in various formats

Fig1a.pdf [61 KiB]
HiDef png [260 KiB]
Thumbnail [87 KiB]
*C file
Fig1a.pdf
Fig1b.pdf [61 KiB]
HiDef png [271 KiB]
Thumbnail [83 KiB]
*C file
Fig1b.pdf
Fig1c.pdf [62 KiB]
HiDef png [263 KiB]
Thumbnail [89 KiB]
*C file
Fig1c.pdf
Fig1d.pdf [63 KiB]
HiDef png [279 KiB]
Thumbnail [92 KiB]
*C file
Fig1d.pdf
Fig2a.pdf [62 KiB]
HiDef png [255 KiB]
Thumbnail [88 KiB]
*C file
Fig2a.pdf
Fig2b.pdf [63 KiB]
HiDef png [276 KiB]
Thumbnail [91 KiB]
*C file
Fig2b.pdf
Fig2c.pdf [64 KiB]
HiDef png [265 KiB]
Thumbnail [91 KiB]
*C file
Fig2c.pdf
Fig2d.pdf [64 KiB]
HiDef png [279 KiB]
Thumbnail [93 KiB]
*C file
Fig2d.pdf
Fig3a.pdf [76 KiB]
HiDef png [772 KiB]
Thumbnail [154 KiB]
*C file
Fig3a.pdf
Fig3b.pdf [69 KiB]
HiDef png [690 KiB]
Thumbnail [146 KiB]
*C file
Fig3b.pdf
Fig4a.pdf [35 KiB]
HiDef png [145 KiB]
Thumbnail [61 KiB]
*C file
Fig4a.pdf
Fig4b.pdf [35 KiB]
HiDef png [144 KiB]
Thumbnail [61 KiB]
*C file
Fig4b.pdf
Fig4c.pdf [42 KiB]
HiDef png [149 KiB]
Thumbnail [62 KiB]
*C file
Fig4c.pdf
Fig4d.pdf [41 KiB]
HiDef png [147 KiB]
Thumbnail [64 KiB]
*C file
Fig4d.pdf
Fig4e.pdf [42 KiB]
HiDef png [149 KiB]
Thumbnail [64 KiB]
*C file
Fig4e.pdf
Fig4f.pdf [42 KiB]
HiDef png [143 KiB]
Thumbnail [62 KiB]
*C file
Fig4f.pdf
Fig5a.pdf [39 KiB]
HiDef png [123 KiB]
Thumbnail [48 KiB]
*C file
Fig5a.pdf
Fig5b.pdf [39 KiB]
HiDef png [125 KiB]
Thumbnail [49 KiB]
*C file
Fig5b.pdf
Fig5c.pdf [39 KiB]
HiDef png [114 KiB]
Thumbnail [48 KiB]
*C file
Fig5c.pdf
Fig5d.pdf [39 KiB]
HiDef png [119 KiB]
Thumbnail [49 KiB]
*C file
Fig5d.pdf

Created on 23 February 2019.Citation count from INSPIRE on 23 February 2019.