Based on data corresponding to an integrated luminosity of 0.37 fb^1 collected by the LHCb experiment in 2011, the following ratios of branching fractions are measured: B(B0 > pi+ pi) / B(B0 > K+pi) = 0.262 +/ 0.009 +/ 0.017, (fs/fd) * B(Bs > K+K) / B(B^0 > K+pi) = 0.316 +/ 0.009 +/ 0.019, (fs/fd) * B(Bs >pi+ K) / B(B0 > K+pi) = 0.074 +/ 0.006 +/ 0.006, (fd/fs) * B(B0 > K+K) / B(Bs > K+K) = 0.018 {+ 0.008  0.007} +/ 0.009, (fs/fd) * B(Bs > pi+pi) / B(B0 > pi+pi) = 0.050 {+ 0.011  0.009} +/ 0.004, B(Lambda_b > p pi) / B(Lambda_b > p K) = 0.86 +/ 0.08 +/ 0.05, where the first uncertainties are statistical and the second systematic. Using the current world average of B(B0 > K+pi) and the ratio of the strange to light neutral B meson production fs/fd measured by LHCb, we obtain: B(B0 > pi+pi) = (5.08 +/ 0.17 +/ 0.37) x 10^6, B(Bs > K+K) = (23.0 +/ 0.7 +/ 2.3) x 10^6, B(Bs > pi+K) = (5.4 +/ 0.4 +/ 0.6) x 10^6, B(B0 > K+K) = (0.11 {+ 0.05  0.04} +/ 0.06) x 10^6, B(Bs > pi+pi) = (0.95 {+ 0.21  0.17} +/ 0.13) x 10^6. The measurements of B(Bs > K+K), B(Bs > pi+ K) and B(B0 > K+K) are the most precise to date. The decay mode Bs > pi+pi is observed for the first time with a significance of more than 5 sigma.
Distributions of (a) $\delta m=m_{K\pi\pi}m_{K\pi}$ for $D^{*+}\rightarrow D^0(K^\pi^+)\pi^+$ candidates and (b) invariant mass of $\Lambda \rightarrow p \pi^$ candidates, used for the PID calibration. The curves are the results of maximum likelihood fits. 
dstar.pdf [153 KiB] HiDef png [174 KiB] Thumbnail [148 KiB] *.C file 

lambda.pdf [152 KiB] HiDef png [156 KiB] Thumbnail [107 KiB] *.C file 

Invariant $\pi^+\pi^$ mass for candidates passing the selection A of Table 1. The result of an unbinned maximum likelihood fit is overlaid. The main contributions to the fit model are also shown. 
mpipi_tot.pdf [246 KiB] HiDef png [424 KiB] Thumbnail [331 KiB] *.C file 

Momentum distributions of (a) pions and (b) kaons from $D^0$ decays in the PID calibration sample (histograms). For comparison, the points represent the inclusive momentum distribution of daughter particles in $H_b \rightarrow h^+h^{\prime}$ decays. The distributions are normalized to the same area. This example corresponds to selection A. 
c_PI.pdf [136 KiB] HiDef png [148 KiB] Thumbnail [129 KiB] *.C file 

c_K.pdf [134 KiB] HiDef png [164 KiB] Thumbnail [129 KiB] *.C file 

Invariant mass spectra corresponding to selection A for the mass hypotheses (a) $K^+\pi^$, (b) $\pi^+\pi^$, (c) $K^+K^$, (d) $pK^$ and (e) $p\pi^$, and to selection B for the mass hypothesis (f) $K^+\pi^$. The results of the unbinned maximum likelihood fits are overlaid. The main components contributing to the fit model are also shown. 
ckpi2_[..].pdf [151 KiB] HiDef png [321 KiB] Thumbnail [217 KiB] *.C file 

cpipi_[..].pdf [187 KiB] HiDef png [325 KiB] Thumbnail [257 KiB] *.C file 

ckk_bd2kpi.pdf [154 KiB] HiDef png [238 KiB] Thumbnail [174 KiB] *.C file 

cpk2_b[..].pdf [144 KiB] HiDef png [260 KiB] Thumbnail [184 KiB] *.C file 

cppi2_[..].pdf [152 KiB] HiDef png [256 KiB] Thumbnail [188 KiB] *.C file 

ckpi2_[..].pdf [155 KiB] HiDef png [294 KiB] Thumbnail [188 KiB] *.C file 

Invariant mass spectra corresponding to selection C for the mass hypotheses (a, b) $K^+K^$ and (c, d) $\pi^+\pi^$. Plots (b) and (d) are the same as (a) and (c) respectively, but magnified to focus on the rare $B^0 \rightarrow K^+ K^$ and $B^0_s \rightarrow \pi^+ \pi^$ signals. The results of the unbinned maximum likelihood fits are overlaid. The main components contributing to the fit model are also shown. 
ckk_rare.pdf [143 KiB] HiDef png [187 KiB] Thumbnail [143 KiB] *.C file 

ckk_zo[..].pdf [206 KiB] HiDef png [333 KiB] Thumbnail [268 KiB] *.C file 

cpipi_rare.pdf [151 KiB] HiDef png [242 KiB] Thumbnail [181 KiB] *.C file 

cpipi_[..].pdf [162 KiB] HiDef png [332 KiB] Thumbnail [237 KiB] *.C file 

Animated gif made out of all figures. 
PAPER2012002.gif Thumbnail 
Summary of criteria adopted in the event selections A, B and C defined in the text. 
Table_1.pdf [56 KiB] HiDef png [96 KiB] Thumbnail [48 KiB] tex code 

Ratios of reconstruction efficiencies of the various channels, as determined from Monte Carlo simulation, corresponding to the three event selections of Table 1. PID efficiencies are not included here. The tight requirement on $t_{\pi\pi}$ used in selection C leads to a sizable difference from unity of the ratios in the last two rows, as the $B_s^0\rightarrow\pi^+\pi^$ and $B_s^0\rightarrow K^+K^$ decays proceed mainly via the short lifetime component of the $B^0_s$ meson. 
Table_2.pdf [53 KiB] HiDef png [89 KiB] Thumbnail [45 KiB] tex code 

PID efficiencies (in %), for the various mass hypotheses, corresponding to the event samples passing the selections A, B and C of Table 1. Different sets of PID requirements are applied in the three cases. 
Table_3.pdf [53 KiB] HiDef png [327 KiB] Thumbnail [171 KiB] tex code 

Ratios of PID efficiencies used to compute the relevant ratios of branching fractions, corresponding to selection A. 
Table_4.pdf [44 KiB] HiDef png [70 KiB] Thumbnail [33 KiB] tex code 

Signal yields determined by the unbinned maximum likelihood fits to the data samples surviving the event selections A, B and C of Table 1 with the associated PID criteria. Only statistical uncertainties are shown. 
Table_5.pdf [53 KiB] HiDef png [150 KiB] Thumbnail [76 KiB] tex code 

Ratios of signal yields needed for the measurement of the relative branching fractions. Only statistical uncertainties are shown. 
Table_6.pdf [74 KiB] HiDef png [153 KiB] Thumbnail [71 KiB] tex code 

Systematic uncertainties on the ratios of signal yields. The total systematic uncertainties are obtained by summing the individual contributions in quadrature. 
Table_7.pdf [69 KiB] HiDef png [83 KiB] Thumbnail [37 KiB] tex code 
Created on 17 August 2019.Citation count from INSPIRE on 20 August 2019.