• Energy Research

AbstractUsing 34.7 pb−1 of data collected with the LHCb detector, the inclusive production of the X(3872) meson in pp collisions at $\sqrt{s}=7\mbox{~TeV}$ is observed for the first time. Candidates are selected in the X(3872)→J/ψπ+π− decay mode, and used to measure "Equation missing" where σ(pp→X(3872)+anything) is the inclusive production cross section of X(3872) mesons with rapidity in the range 2.5–4.5 and transverse momentum in the range 5–20 GeV/c. In addition the masses of both the X(3872) and ψ(2S) mesons, reconstructed in the J/ψπ+π− final state, are measured to be $$m_{X(3872)} = 3871.95 \pm0.48 \ (\mathrm{stat}) \pm0.12 \ (\mathrm {syst})\ \mathrm{MeV}/c^2 $$ and $$m_{\psi(2S)} = 3686.12\pm0.06 \ (\mathrm{stat}) \pm0.10 \ (\mathrm {syst})\ \mathrm{MeV}/c^2. $$

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

The branching fractions of the decay $B^{+} \to p \bar p K^{+}$ for different intermediate states are measured using data, corresponding to an integrated luminosity of $1.0 fb^{-1}$, collected by the LHCb experiment. The total branching fraction, its charmless component $(M_{p\bar p} <2.85 {GeV/}c^{2})$ and the branching fractions via the resonant $c\bar c$ states $��_{c}(1S)$ and $��(2S)$ relative to the decay via a $J/��$ intermediate state are {align*} \frac{{\mathcal B}(B^{+} \to p \bar p K^{+})_{total}}{{\mathcal B}(B^{+} \to J/��K^{+} \to p \bar p K^{+})}=& \, 4.91 \pm 0.19 \, {(\rm stat)} \pm 0.14 \, {(\rm syst)}, \frac{{\mathcal B}(B^{+} \to p \bar p K^{+})_{M_{p\bar p} <2.85 {GeV/}c^{2}}}{{\mathcal B}(B^{+} \to J/��K^{+} \to p \bar p K^{+})}=& \, 2.02 \pm 0.10 \, {(\rm stat)}\pm 0.08 \, {(\rm syst)}, \frac{{\mathcal B} (B^{+} \to ��_{c}(1S) K^{+} \to p \bar p K^{+})}{{\mathcal B}(B^{+} \to J/��K^{+} \to p \bar p K^{+})} = & \, 0.578 \pm 0.035 \, {(\rm stat)} \pm 0.027 \, {(\rm syst)}, \frac{{\mathcal B} (B^{+} \to ��(2S) K^{+} \to p \bar p K^{+})}{{\mathcal B}(B^{+} \to J/��K^{+} \to p \bar p K^{+})}=& \, 0.080 \pm 0.012 \, {(\rm stat)} \pm 0.009 \, {(\rm syst)}. {align*} Upper limits on the $B^{+}$ branching fractions into the $��_{c}(2S)$ meson and into the charmonium-like states X(3872) and X(3915) are also obtained. 14 pages, 5 figures