JHEP 06 (2017) 108 A search for $C\!P$ violation in the decay $\Lambda^0_b \to p K^- \mu^+
\mu^-$ is presented. This decay is mediated by flavour-changing neutral-current
transitions in the Standard ...Model and is potentially sensitive to new sources
of $C\!P$ violation. The study is based on a data sample of proton-proton
collisions recorded with the LHCb experiment, corresponding to an integrated
luminosity of $3$ $\mathrm{fb}^{-1}$. The $\Lambda^0_b \to p K^- \mu^+ \mu^-$
decay is observed for the first time, and two observables that are sensitive to
different manifestations of $C\!P$ violation are measured,
$\Delta\mathcal{A}_{C\!P} \equiv \mathcal{A}_{C\!P}(\Lambda^0_b \to p K^- \mu^+
\mu^-)-\mathcal{A}_{C\!P}(\Lambda^0_b\to pK^- J/\psi)$ and
$a_{C\!P}^{\widehat{T}-odd}$, where the latter is based on asymmetries in the
angle between the $\mu^+\mu^-$ and $p K^-$ decay planes. These are measured to
be $\Delta\mathcal{A}_{C\!P} = (-3.5 \pm 5.0(stat) \pm 0.2(syst))\times
10^{-2}$, $a_{C\!P}^{\widehat{T}-odd} = (1.2 \pm 5.0(stat) \pm 0.7(syst))\times
10^{-2}$, and no evidence for $C\!P$ violation is found.
JHEP 1707 (2017) 021 A study of $B^{0}_{s} \to \eta_{c} \phi$ and $B^{0}_{s} \to \eta_{c}
\pi^{+}\pi^{-}$ decays is performed using $pp$ collision data corresponding to
an integrated luminosity of ...3.0$\,\rm fb^{-1}$, collected with the LHCb
detector in Run~1 of the LHC. The observation of the decay $B^{0}_{s} \to
\eta_{c} \phi$ is reported, where the $\eta_{c}$ meson is reconstructed in the
$p\bar p$, $K^+K^-\pi^+\pi^-$, $\pi^+\pi^-\pi^+\pi^-$ and $K^+K^-K^+K^-$ decay
modes and the $\phi(1020)$ in the $K^+ K^-$ decay mode. The decay $B^{0}_{s}
\to J/\psi \phi$ is used as a normalisation channel. Evidence is also reported
for the decay $B^{0}_{s} \to \eta_{c} \pi^{+}\pi^{-}$, where the $\eta_{c}$
meson is reconstructed in the $p\bar p$ decay mode, using the decay $B^{0}_{s}
\to J/\psi \pi^+ \pi^-$ as a normalisation channel. The measured branching
fractions are \begin{eqnarray*} {\mathcal B (B^{0}_{s} \to \eta_{c} \phi)} &=&
\left(5.01 \pm 0.53 \pm 0.27 \pm 0.63 \right) \times 10^{-4} \,, \nonumber
\\ {\mathcal B (B^{0}_{s} \to \eta_{c} \pi^+ \pi^-)} &=& \left(1.76 \pm 0.59
\pm 0.12 \pm 0.29 \right) \times 10^{-4} \,, \end{eqnarray*} where in each case
the first uncertainty is statistical, the second systematic and the third
uncertainty is due to the limited knowledge of the external branching
fractions.
J. High Energ. Phys. (2017) 2017: 30 An amplitude analysis of the decay $\Lambda_b^0\to D^0 p \pi^-$ is performed
in the part of the phase space containing resonances in the $D^0 p$ channel.
The ...study is based on a data sample corresponding to an integrated luminosity
of 3.0 fb$^{-1}$ of $pp$ collisions recorded by the LHCb experiment. The
spectrum of excited $\Lambda_c^+$ states that decay into $D^0 p$ is studied.
The masses, widths and quantum numbers of the $\Lambda_c(2880)^+$ and
$\Lambda_c(2940)^+$ resonances are measured. The constraints on the spin and
parity for the $\Lambda_c(2940)^+$ state are obtained for the first time. A
near-threshold enhancement in the $D^0 p$ amplitude is investigated and found
to be consistent with a new resonance, denoted the $\Lambda_c(2860)^+$, of spin
$3/2$ and positive parity.
Phys. Lett. B 772 (2017) 265-273 The observation of the decay $\varXi^{-}_{b}\to J/\psi\varLambda K^{-}$ is
reported, using a data sample corresponding to an integrated luminosity of
...$3~\mathrm{fb}^{-1}$, collected by the LHCb detector in $pp$ collisions at
centre-of-mass energies of $7$ and $8~\mathrm{TeV}$. The production rate of
$\varXi_{b}^{-}$ baryons detected in the decay $\varXi_{b}^{-}\to
J/\psi\varLambda K^{-}$ is measured relative to that of $\varLambda_{b}^{0}$
baryons using the decay $\varLambda_{b}^{0}\to J/\psi \varLambda$. Integrated
over the $b$-baryon transverse momentum $p_{\rm T}<25~\mathrm{GeV/}c $ and
rapidity $2.0<y<4.5$, the measured ratio is \begin{equation*}
\frac{f_{\varXi_{b}^{-}}}{f_{\varLambda_{b}^{0}}}\frac{\mathcal{B}(\varXi_{b}^{-}\to
J/\psi\varLambda K^{-})}{\mathcal{B}(\varLambda_{b}^{0}\to J/\psi
\varLambda)}=(4.19\pm 0.29~(\mathrm{stat})\pm0.15~(\mathrm{syst}))\times
10^{-2}, \end{equation*}where $f_{\varXi_{b}^{-}}$ and $f_{\varLambda_{b}^{0}}$
are the fragmentation fractions of $b\to\varXi_{b}^{-}$ and
$b\to\varLambda_{b}^{0}$ transitions, and $\mathcal{B}$ represents the
branching fraction of the corresponding $b$-baryon decay. The mass difference
between $\varXi_{b}^{-}$ and $\varLambda_{b}^{0}$ baryons is measured to be
\begin{equation*}
M(\varXi_{b}^{-})-M(\varLambda_{b}^{0})=177.08\pm0.47~(\mathrm{stat})\pm0.16~(\mathrm{syst}
)~\mathrm{MeV/}c^{2}. \end{equation*}
Phys. Rev. Lett. 118, 111803 (2017) Using proton-proton collision data corresponding to an integrated luminosity
of 3.0 fb$^{-1}$, recorded by the LHCb detector at centre-of-mass energies of 7
and 8 ...TeV, the $B_{c}^{+} \rightarrow D^{0} K^{+}$ decay is observed with a
statistical significance of 5.1 standard deviations.
By normalising to $B^{+} \rightarrow \bar{D}^{0} \pi^{+}$ decays, a
measurement of the branching fraction multiplied by the production rates for
$B_{c}^{+}$ relative to $B^{+}$ mesons in the LHCb acceptance is obtained, $$
R_{D^{0} K} = \frac{f_{c}}{f_{u}}\times\mathcal{B}(B_{c}^{+} \rightarrow D^{0}
K^{+}) = (9.3\,^{+2.8}_{-2.5} \pm 0.6) \times 10^{-7}\,, $$ where the first
uncertainty is statistical and the second is systematic. This decay is expected
to proceed predominantly through weak annihilation and penguin amplitudes, and
is the first $B_{c}^{+}$ decay of this nature to be observed.
JHEP 05 (2017) 158 A search for the charmless $B^{0}_{s} \to \eta^{\prime}\phi$ decay is
performed using $pp$ collision data collected by the LHCb experiment at
centre-of-mass energies of $7$ and $8$ ...TeV, corresponding to an integrated
luminosity of 3 fb$^{-1}$. No signal is observed and upper limits on the
$B^{0}_{s} \to \eta^{\prime}\phi$ branching fraction are set to $0.82\times
10^{-6}$ at $90\%$ and $1.01\times 10^{-6}$ at $95\%$ confidence level.
J. High Energ. Phys. (2017) 2017: 1; erratum: J. High Energ. Phys.
(2017) 2017: 68 The production cross-section of $J/\psi$ pairs is measured using a data
sample of $pp$ collisions collected by the ...LHCb experiment at a centre-of-mass
energy of $\sqrt{s} = 13 \,{\mathrm{TeV}}$, corresponding to an integrated
luminosity of $279 \pm 11 \,{\mathrm{pb^{-1}}}$. The measurement is performed
for $J/\psi$ mesons with a transverse momentum of less than $10
\,{\mathrm{GeV}}/c$ in the rapidity range $2.0<y<4.5$. The production
cross-section is measured to be $15.2 \pm 1.0 \pm 0.9 \,{\mathrm{nb}}$. The
first uncertainty is statistical, and the second is systematic. The
differential cross-sections as functions of several kinematic variables of the
$J/\psi$ pair are measured and compared to theoretical predictions.
Phys. Rev. D 95, 071101 (2017) A search for a long-lived scalar particle $\chi$ is performed, looking for
the decay ${B^+ \to K^+ \chi}$ with ${\chi \to \mu^+\mu^-}$ in $pp$ collision
data ...corresponding to an integrated luminosity of $3\, {\rm fb}^{-1}$,
collected by the LHCb experiment at centre-of-mass energies of $\sqrt{s}=7$ and
8$\,$TeV. This new scalar particle, predicted by Hidden Sector models, is
assumed to have a narrow width. The signal would manifest itself as an excess
in the dimuon invariant mass distribution over the Standard Model background.
No significant excess is observed in the accessible ranges of mass ${250 <
m(\chi) < 4700\,\rm MeV/c^2}$ and lifetime ${0.1 < \tau(\chi) < 1000\,\rm ps}$.
Upper limits on the branching fraction $\mathcal{B}(B^+ \to K^+ \chi
(\mu^+\mu^-))$ at 95% confidence level are set as a function of $m(\chi)$ and
$\tau(\chi)$, varying between $2\times10^{-10}$ and $10^{-7}$. These are the
most stringent limits to date. The limits are interpreted in the context of a
model with a light inflaton particle.
Phys. Rev. D 95, 032005 (2017) A search for the decays $B_c^+ \to J/\psi D^{(*)0} K^+$ and $B_c^+ \to J/\psi
D^{(*)+} K^{*0}$ is performed with data collected at the LHCb experiment
corresponding to ...an integrated luminosity of 3 fb$^{-1}$. The decays $B_c^+ \to
J/\psi D^0 K^+$ and $B_c^+ \to J/\psi D^{*0} K^+$ are observed for the first
time, while first evidence is reported for the $B_c^+ \to J/\psi D^{*+} K^{*0}$
and $B_c^+ \to J/\psi D^+ K^{*0}$ decays. The branching fractions of these
decays are determined relative to the $B_c^+ \to J/\psi \pi^+$ decay. The
$B_c^+$ mass is measured, using the $J/\psi D^0 K^+$ final state, to be
$6274.28 \pm 1.40 (stat) \pm 0.32 (syst)$ MeV/$c^2$. This is the most precise
single measurement of the $B_c^+$ mass to date.
Eur. Phys. J. C (2017) 77: 161 A measurement of the phase difference between the short- and long-distance
contributions to the $B^{+}\to K^{+}\mu^{+}\mu^{-}$ decay is performed by
analysing the ...dimuon mass distribution. The analysis is based on $pp$ collision
data corresponding to an integrated luminosity of 3 $\rm fb^{-1}$ collected by
the LHCb experiment in 2011 and 2012. The long-distance contribution to the
$B^{+}\to K^{+}\mu^{+}\mu^{-}$ decay is modelled as a sum of relativistic
Breit--Wigner amplitudes representing different vector meson resonances
decaying to muon pairs, each with their own magnitude and phase. The measured
phases of the $J/\psi$ and $\psi(2S)$ resonances are such that the interference
with the short-distance component in dimuon mass regions far from their pole
masses is small. In addition, constraints are placed on the Wilson
coefficients, $\mathcal{C}_{9}$ and $\mathcal{C}_{10}$, and the branching
fraction of the short-distance component is measured.
