Abstract

Evidence for the decays $B^{0}\rightarrow\bar{D}^{0}\phi$ and $B^{0} \rightarrow \bar{D}^{*0}\phi$ is reported with a significance of 3.6$ \sigma$ and 4.3$ \sigma$, respectively. The analysis employs $pp$ collision data at centre-of-mass energies $\sqrt{s}=7$, 8 and 13 TeV collected by the LHCb detector and corresponding to an integrated luminosity of 9 $\rm{fb}^{-1}$. The branching fractions are measured to be $\mathcal{B}(B^{0}\rightarrow\bar{D}^{0}\phi) = (7.7\pm2.1\pm0.7\pm0.7)\times10^{-7}$,$\mathcal{B}(B^{0} \rightarrow \bar{D}^{*0}\phi)=(2.2\pm0.5\pm0.2\pm0.2)\times10^{-6}$. In these results, the first uncertainties are statistical, the second systematic, and the third is related to the branching fraction of the $B^{0}\rightarrow\bar{D}^{0}K^{+}K^{-}$ decay, used for normalisation. By combining the branching fractions of the decays $B^{0}\rightarrow\bar{D}^{(*)0}\phi$ and $B^{0}\rightarrow\bar{D}^{(*)0}\omega$, the $\omega$-$\phi$ mixing angle $\delta$ is constrained to be $\tan^2\delta = (3.6\pm0.7\pm0.4)\times10^{-3}$, where the first uncertainty is statistical and the second systematic. An updated measurement of the branching fractions of the $B^{0}_{s} \rightarrow \bar{D}^{(*)0}\phi$ decays, which can be used to determine the CKM angle $\gamma$, leads to $\mathcal{B}(B^{0}_{s}\rightarrow\bar{D}^{0}\phi)=(2.30\pm0.10 \pm 0.11\pm0.20)\times10^{-5}$,$\mathcal{B}(B^{0}_{s}\rightarrow\bar{D}^{*0}\phi) =(3.17\pm0.16 \pm 0.17 \pm 0.27)\times10^{-5}$.

Figures and captions

Feynman diagram for the decay $ B ^0 \rightarrow{{\overline{ D } {}^{(*)0}} \phi}$.	Fig1.pdf [37 KiB] HiDef png [47 KiB] Thumbnail [21 KiB] *.C file
Distributions of $m_{\overline{ D } {}^0 K ^+ K ^- }$ for the (left) Run 1 and (right) Run 2 data samples. The results of the fits are overlaid.	Fig2a.pdf [47 KiB] HiDef png [350 KiB] Thumbnail [285 KiB] *.C file
	Fig2b.pdf [48 KiB] HiDef png [365 KiB] Thumbnail [303 KiB] *.C file
Distributions of $m_{ K ^+ K ^- }$ for (left) the Run 1 data and (right) the Run 2 data. The results of the fits are overlaid.	Fig3a.pdf [33 KiB] HiDef png [269 KiB] Thumbnail [231 KiB] *.C file
	Fig3b.pdf [34 KiB] HiDef png [269 KiB] Thumbnail [236 KiB] *.C file
Distributions of weighted $m_{D\phi}$ for (left) Run 1 data and (right) Run 2 data. The results of the fits are overlaid.	Fig4a.pdf [41 KiB] HiDef png [373 KiB] Thumbnail [296 KiB] *.C file
	Fig4b.pdf [42 KiB] HiDef png [342 KiB] Thumbnail [276 KiB] *.C file
Animated gif made out of all figures.	PAPER-2023-003.gif Thumbnail

Tables and captions

Results of the simultaneous fit to the $m_{D\phi}$ invariant-mass distribution with $\phi$-sWeighted data. The uncertainties are after corrections using pseudoexperiments (uncertainties before corrections are shown in parentheses).	Table_1.pdf [70 KiB] HiDef png [130 KiB] Thumbnail [67 KiB] tex code
Summary of total efficiencies for the signal modes $ B ^0_ s \rightarrow \overline{ D } {}^0 \phi$, $ B ^0_ s \rightarrow \overline{ D } {}^{*0} \phi$ and the control mode $ B ^0 \rightarrow \overline{ D } {}^0 K ^+ K ^- $. The efficiencies for $ B ^0 \rightarrow {\overline{ D } {}^{(*)0}} \phi$ decays are assumed to be the same as for the $ B ^0_ s \rightarrow {\overline{ D } {}^{(*)0}} \phi$ modes.	Table_2.pdf [70 KiB] HiDef png [79 KiB] Thumbnail [38 KiB] tex code
Summary of systematic uncertainties on the measurements of ratios of branching fractions.	Table_3.pdf [70 KiB] HiDef png [39 KiB] Thumbnail [16 KiB] tex code
Summary of systematic uncertainties on the measurements of the fraction of longitudinal polarisation $f_L$ of the $ B ^0_ s \rightarrow \overline{ D } {}^{*0} \phi$ mode.	Table_4.pdf [72 KiB] HiDef png [80 KiB] Thumbnail [36 KiB] tex code

Created on 02 May 2024.