Measurement of the branching fraction of the $B^{0}\rightarrow D_{s}^{+}\pi^{-}$ decay

Information

LHCb-PAPER-2020-021
CERN-EP-2020-183
arXiv:2010.11986 [PDF]

(Submitted on 22 Oct 2020)
Eur. Phys. J. C81 (2021) 314
Inspire 1825957

Tools

Abstract

A branching fraction measurement of the $B^{0}\rightarrow D_{s}^{+}\pi^{-}$ decay is presented using proton-proton collision data collected with the LHCb experiment, corresponding to an integrated luminosity of $5.0 $fb$^{-1}$. The branching fraction is found to be ${\mathcal{B}(B^{0}\rightarrow D_{s}^{+}\pi^{-}) = (19.4 \pm 1.8\pm 1.3 \pm 1.2)\times 10^{-6}}$, where the first uncertainty is statistical, the second systematic and the third is due to the uncertainty on the $B^0 \to D^{-}\pi^{+}$, $D_{s}^{+}\rightarrow K^{+}K^{-}\pi^{+}$ and $D^{-}\rightarrow K^{+}\pi^{-}\pi^{-}$ branching fractions. This is the most precise single measurement of this quantity to date. As this decay proceeds through a single amplitude involving a $b \to u$ charged-current transition, the result provides information on non-factorisable strong interaction effects and the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element $V_{ub}$. Additionally, the collision energy dependence of the hadronisation-fraction ratio $f_s/f_d$ is measured through $\bar{B}{}_{s}^{0}\rightarrow D_{s}^{+}\pi^{-}$ and $B^0 \to D^{-}\pi^{+}$ decays.

Figures and captions

Tree diagram of the $ B ^0 \rightarrow D ^+_ s \pi ^- $ decay, in which a $ B ^0$ meson decays through the weak interaction to a $ D ^+_ s $ meson and a charged pion. This diagram represents the only (leading order) process contributing to this decay. Strong interaction between the $ D ^+_ s $ meson and the pion lead to a non-factorisable contribution to the decay amplitude.	Bd2DsP[..].png [19 KiB] HiDef png [109 KiB] Thumbnail [31 KiB] *.C file
The invariant mass distributions of normalisation $ B ^0 \rightarrow D ^- \pi ^+ $ candidates, for (left) Run 1 and (right) Run 2 data samples. Overlaid are the fit projections along with the signal and background contributions.	mass_B[..].pdf [84 KiB] HiDef png [373 KiB] Thumbnail [276 KiB] *.C file
	mass_B[..].pdf [83 KiB] HiDef png [299 KiB] Thumbnail [217 KiB] *.C file
The (top) $ D ^+_ s \pi ^- $ and (bottom) $ K ^+ K ^- \pi ^+ $ invariant mass distributions of signal $ B ^0 \rightarrow D ^+_ s \pi ^- $ candidates, for (left) Run 1 and (right) Run 2 data samples. Overlaid are the fit projections along with the signal and background contributions.	mass_B[..].pdf [71 KiB] HiDef png [464 KiB] Thumbnail [337 KiB] *.C file
	mass_B[..].pdf [72 KiB] HiDef png [400 KiB] Thumbnail [270 KiB] *.C file
	mass_B[..].pdf [74 KiB] HiDef png [446 KiB] Thumbnail [288 KiB] *.C file
	mass_B[..].pdf [75 KiB] HiDef png [422 KiB] Thumbnail [276 KiB] *.C file
Result of the determination of $\|V_{ub}\|\|a_{\text{NF}}\|$. The blue line represents the result of this measurement, the vertical bands are the known exclusive and inclusive measurements of $\|V_{ub}\|$, which are $(3.70\pm 0.16)\times 10^{-3}$ and $(4.49\pm 0.28)\times 10^{-3}$, respectively [38]. The horizontal dashed line at $\|a_{\text{NF}}\|=1.0$ represents exact factorisation. The error bands represent an uncertainty of one standard deviation.	Plot_a[..].png [70 KiB] HiDef png [192 KiB] Thumbnail [86 KiB] *.C file
Visualisation of the $pp$ collision energy dependence of the efficiency-corrected yield ratio of $\overline{ B } {}^0_ s \rightarrow D ^+_ s \pi ^- $ and $ B ^0 \rightarrow D ^- \pi ^+ $ decays, which scales with $f_{s}/f_{d}$. The inner error bars indicate the statistical uncertainty only, whereas the outer indicate the uncorrelated, including statistical, uncertainties. The correlated systematic uncertainty is not shown. The red dotted line represents a linear fit through the three values of $\mathcal{R}$ with uncorrelated, including statistical, uncertainties.	R_Ener[..].pdf [14 KiB] HiDef png [137 KiB] Thumbnail [123 KiB] *.C file
Animated gif made out of all figures.	PAPER-2020-021.gif Thumbnail

Tables and captions

Relative systematic uncertainty $\sigma$ on the $ B ^0 \rightarrow D ^+_ s \pi ^- $ branching fraction measurement.	Table_1.pdf [72 KiB] HiDef png [82 KiB] Thumbnail [38 KiB] tex code
Relative systematic uncertainty $\sigma$ on the ratio of the efficiency-corrected $\overline{ B } {}^0_ s \rightarrow D ^+_ s \pi ^- $ and $ B ^0 \rightarrow D ^- \pi ^+ $ yield ratios. The ratios $\mathcal{R}_{13\text{ Te V} }/\mathcal{R}_{7\text{ Te V} }$ and $\mathcal{R}_{13\text{ Te V} }/\mathcal{R}_{8\text{ Te V} }$ are reported together as the difference of the systematic uncertainty for 7 and 8 $\text{ Te V}$ is negligible.	Table_2.pdf [71 KiB] HiDef png [57 KiB] Thumbnail [26 KiB] tex code
Results of $ B ^0 \rightarrow D ^+_ s \pi ^- $ and $ B ^0 \rightarrow D ^- \pi ^+ $ signal efficiencies and yields, as well as the branching fractions used as input for this measurement [38].	Table_3.pdf [90 KiB] HiDef png [58 KiB] Thumbnail [28 KiB] tex code

Supplementary Material [file]

Supplementary material full pdf	Supple[..].pdf [787 KiB]
This ZIP file contains supplemetary material for the publication LHCb-PAPER-2020-021. The files are: Supplementary.pdf : An overview of the extra figures supplementary.tex : LaTeX document with extra figures .pdf, .png, .eps, .C : The figures in variuous formats	Fig1a-S.pdf [83 KiB] HiDef png [314 KiB] Thumbnail [254 KiB] *C file
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