JHEP 10 (2018) 167 Measurements are reported of the central exclusive production of \jpsi and
\psitwos mesons in $pp$ collisions at a centre-of-mass energy of 13 TeV.
Backgrounds are significantly ...reduced compared to previous measurements made at
lower energies through the use of new forward shower counters. The products of
the cross-sections and the branching fractions for the decays to dimuons, where
both muons are within the pseudorapidity range $2.0<\eta<4.5$, are measured to
be $$
\begin{array}{rcl} \sigma_{J/\psi\rightarrow\mu^+\mu^-}&=&435 \pm 18 \pm 17
\pm 16 {\rm \ pb},\\ \sigma_{\psi(2S)\rightarrow\mu^+\mu^-}&=&11.1 \pm 1.1 \pm
0.3 \pm 0.4 {\rm \ pb}.\\ \end{array} $$ The first uncertainties are
statistical, the second are systematic, and the third are due to the luminosity
determination. The cross-sections are also measured differentially for meson
rapidities between 2.0 and 4.5. Good agreement is observed with theoretical
predictions. Photoproduction cross-sections are derived and compared to
previous experiments, and a deviation from a pure power-law extrapolation of
lower energy data is observed.
JHEP 11(2018)048 A measurement of the time-integrated $CP$ asymmetry in $D^0\rightarrow K^0_S
K^0_S$ decays is reported. The data correspond to an integrated luminosity of
about $2$ fb$^{-1}$ ...collected in 2015-2016 by the LHCb collaboration in $pp$
collisions at a centre-of-mass energy of $13$ TeV. The $D^0$ candidate is
required to originate from a $D^{\ast +} \rightarrow D^0 \pi^+$ decay, allowing
the determination of the flavour of the $D^0$ meson using the pion charge. The
$D^0 \rightarrow K^{+}K^{-}$ decay, which has a well measured $CP$ asymmetry,
is used as a calibration channel. The $CP$ asymmetry for $D^0\rightarrow K^0_S
K^0_S$ is measured to be \begin{equation*} \mathcal{A}^{CP}(D^0\rightarrow
K^0_S K^0_S) = (4.3\pm 3.4\pm 1.0)\%, \end{equation*} where the first
uncertainty is statistical and the second is systematic. This result is
combined with the previous LHCb measurement at lower centre-of-mass energies to
obtain \begin{equation*} \mathcal{A}^{CP}(D^0\rightarrow K^0_S K^0_S) = (2.3\pm
2.8\pm 0.9)\%. \end{equation*}
JHEP 08 (2018) 008 The inclusive $D_s^{\pm}$ production asymmetry is measured in $pp$ collisions
collected by the LHCb experiment at centre-of-mass energies of $\sqrt{s} =7$
and 8 TeV. Promptly ...produced $D_s^{\pm}$ mesons are used, which decay as
$D_s^{\pm}\to\phi\pi^{\pm}$, with $\phi\to K^+K^-$. The measurement is
performed in bins of transverse momentum, $p_{\rm T}$, and rapidity, $y$,
covering the range $2.5<p_{\rm T}<25.0$ GeV$/c$ and $2.0<y<4.5$. No kinematic
dependence is observed. Evidence of nonzero $D_s^{\pm}$ production asymmetry is
found with a significance of 3.3 standard deviations.
JHEP 08 (2018) 147 A search is performed for a spin-0 boson, $\phi$, produced in proton-proton
collisions at centre-of-mass energies of 7 and 8 TeV, using prompt
$\phi\rightarrow\mu^+\mu^-$ decays ...and a data sample corresponding to an
integrated luminosity of approximately 3.0 ${\rm fb}^{-1}$ collected with the
LHCb detector. No evidence is found for a signal in the mass range from 5.5 to
15 GeV. Upper limits are placed on the product of the production cross-section
and the branching fraction into the dimuon final state. The limits are
comparable to the best existing over most of the mass region considered and are
the first to be set near the $\Upsilon$ resonances.
Phys. Rev. Lett. 121, 072002 (2018) From samples of $pp$ collision data collected by the LHCb experiment at
$\sqrt{s}=7$, $8$ and $13$ TeV corresponding to integrated luminosities of 1.0,
2.0 and 1.5 ...fb$^{-1}$, respectively, a peak in both the $\Lambda_b^0K^-$ and
$\Xi_b^0\pi^-$ invariant mass spectra is observed. In the quark model, radially
and orbitally excited $\Xi_b^-$ resonances with quark content $bds$ are
expected. Referring to this peak as $\Xi_b(6227)^-$, the mass and natural width
are measured to be $m_{\Xi_{b}(6227)^-}=6226.9\pm2.0\pm0.3\pm0.2$ MeV/$c^2$ and
$\Gamma_{\Xi_b(6227)^-}=18.1\pm5.4\pm1.8$ MeV/$c^2$, where the first
uncertainty is statistical, the second is systematic, and the third, on
$m_{\Xi_b(6227)^-}$, is due to the knowledge of the $\Lambda_b^0$ baryon mass.
Relative production rates of the ${\Xi_b(6227)^-\to\Lambda_b^0K^-}$ and
${\Xi_b(6227)^-\to\Xi_b^0\pi^-}$ decays are also reported.
Phys. Rev. D 98, 032004 (2018) The time-dependent $C\!P$ asymmetries in $B^0\to\pi^+\pi^-$ and $B_s^0\to
K^+\!K^-$ decays are measured using a data sample of $pp$ collisions
corresponding to an ...integrated luminosity of 3.0 fb$^{-1}$, collected with the
LHCb detector at centre-of-mass energies of 7 and 8 TeV. The same data sample
is used to measure the time-integrated $C\!P$ asymmetries in $B^0\to K^+\pi^-$
and $B_s^0\to\pi^+ K^-$ decays. The results are $C_{\pi^+\pi^-} = -0.34 \pm
0.06 \pm 0.01$, $S_{\pi^+\pi^-} = -0.63 \pm 0.05 \pm 0.01$, $C_{K^+\!K^-} =
0.20 \pm 0.06 \pm 0.02$, $S_{K^+\!K^-} = 0.18 \pm 0.06 \pm 0.02$,
$C_{K^+\!K^-}^{\Delta\Gamma} = -0.79 \pm 0.07 \pm 0.10$, $A_{C\!P}^{B^0} =
-0.084 \pm 0.004 \pm 0.003$, and $A_{C\!P}^{B_s^0} = 0.213 \pm 0.015 \pm
0.007$, where the first uncertainties are statistical and the second
systematic. Evidence for $C\!P$ violation is found in the $B_s^0\to K^+\!K^-$
decay for the first time.
JHEP 08 (2018) 039 A search for $C$P and $P$ violation using triple-product asymmetries is
performed with $\Lambda^{0}_{b}\to pK^{-}\pi^{+}\pi^{-}$, $\Lambda^{0}_{b}\to
pK^{-}K^{+}K^{-}$ and ...$\Xi^{0}_{b}\to pK^{-}K^{-}\pi^{+}$ decays. The data
sample corresponds to integrated luminosities of 1.0fb$^{-1}$ and 2.0fb$^{-1}$,
recorded with the LHCb detector at centre-of-mass energies of 7TeV and 8TeV,
respectively. The $CP$- and $P$-violating asymmetries are measured both
integrating over all phase space and in specific phase-space regions. No
significant deviation from $CP$ or $P$ symmetry is found. The first observation
of $\Lambda^{0}_{b}\to pK^{-}\chi_{c0}(1P)(\to\pi^{+}\pi^{-}, K^{+}K^{-})$
decay is also reported.
JHEP 06 (2018) 084 A measurement of the $CP$ asymmetries $S_{f}$ and $S_{\bar{f}}$ in $B^0\to
D^{\mp}\pi^{\pm}$ decays is reported. The decays are reconstructed in a dataset
collected with the LHCb ...experiment in proton-proton collisions at
centre-of-mass energies of 7 and 8 TeV and corresponding to an integrated
luminosity of $3.0 \rm{ fb}^{-1}$. The $CP$ asymmetries are measured to be
$S_{f} = 0.058 \pm 0.020 (\rm{stat}) \pm 0.011(\rm{syst})$ and $S_{\bar{f}} =
0.038\pm 0.020 (\text{stat})\pm 0.007 (\text{syst})$. These results are in
agreement with, and more precise than, previous determinations. They are used
to constrain $|\sin\left(2\beta+\gamma\right)|$ and $\gamma$ to intervals that
are consistent with the current world-average values.
Phys. Lett. B 784 (2018) 101-111 The decay $\Lambda_b^0 \to \Lambda_c^+ p \overline{p} \pi^-$ is observed
using $pp$ collision data collected with the LHCb detector at centre-of-mass
energies of ...$\sqrt{s}=$ 7 and 8 TeV, corresponding to an integrated luminosity
of 3 $fb^{-1}$. The ratio of branching fractions between $\Lambda_b^0 \to
\Lambda_c^+ p \overline{p} \pi^-$ and $\Lambda_b^0 \to \Lambda_c^+ \pi^-$
decays is measured to be \begin{equation*}
\frac{\mathcal{B}(\Lambda_b^0 \to \Lambda_c^+ p
\overline{p}\pi^-)}{\mathcal{B}(\Lambda_b^0 \to \Lambda_c^+ \pi^-)} = 0.0540
\pm 0.0023 \pm 0.0032. \end{equation*} Two resonant structures are observed in
the $ \Lambda_c^+ \pi^-$ mass spectrum of the ${\Lambda_b^0 \to \Lambda_c^+
p\overline{p} \pi^-}$ decays, corresponding to the $\Sigma_c(2455)^0$ and
$\Sigma_c^{*}(2520)^0$ states. The ratios of branching fractions with respect
to the decay $\Lambda_b^0 \to \Lambda_c^+ p \overline{p} \pi^-$ are
\begin{align*}
\frac{\mathcal{B}(\Lambda_b^0 \to \Sigma_c^0
p\overline{p})\times\mathcal{B}(\Sigma_c^0\to \Lambda_c^+
\pi^-)}{\mathcal{B}(\Lambda_b^0 \to \Lambda_c^+ p \overline{p}\pi^-)} =
0.089\pm0.015\pm0.006,
\frac{\mathcal{B}(\Lambda_b^0 \to \Sigma_c^{*0}
p\overline{p})\times\mathcal{B}(\Sigma_c^{*0}\to \Lambda_c^+
\pi^-)}{\mathcal{B}(\Lambda_b^0 \to \Lambda_c^+ p \overline{p}\pi^-)} =
0.119\pm0.020\pm0.014. \end{align*} In all of the above results, the first
uncertainty is statistical and the second is systematic. The phase space is
also examined for the presence of dibaryon resonances. No evidence for such
resonances is found.
JHEP 07(2018)134 The production cross-sections of $\Upsilon(1S)$, $\Upsilon(2S)$ and
$\Upsilon(3S)$ mesons in proton-proton collisions at $\sqrt{s}$= 13 TeV are
measured with a data sample ...corresponding to an integrated luminosity of $277
\pm 11$ $\rm pb^{-1}$ recorded by the LHCb experiment in 2015. The $\Upsilon$
mesons are reconstructed in the decay mode $\Upsilon\to\mu^{+}\mu^{-}$. The
differential production cross-sections times the dimuon branching fractions are
measured as a function of the $\Upsilon$ transverse momentum, $p_{\rm T}$, and
rapidity, $y$, over the range $0 < p_{\rm T}< 30$ GeV/c and $2.0 < y < 4.5$.
The ratios of the cross-sections with respect to the LHCb measurement at
$\sqrt{s}$= 8 TeV are also determined. The measurements are compared with
theoretical predictions based on NRQCD.