Phys. Rev. D 93, 112018 (2016); erratum: Phys. Rev. D 94, 079902
(2016) The first study is presented of CP violation with an amplitude analysis of
the Dalitz plot of $B^0 \to D K^+ \pi^-$ decays, ...with $D \to K^+ \pi^-$, $K^+
K^-$ and $\pi^+ \pi^-$. The analysis is based on a data sample corresponding to
$3.0\,{\rm fb}^{-1}$ of $pp$ collisions collected with the LHCb detector. No
significant CP violation effect is seen, and constraints are placed on the
angle $\gamma$ of the unitarity triangle formed from elements of the
Cabibbo-Kobayashi-Maskawa quark mixing matrix. Hadronic parameters associated
with the $B^0 \to D K^*(892)^0$ decay are determined for the first time. These
measurements can be used to improve the sensitivity to $\gamma$ of existing and
future studies of the $B^0 \to D K^*(892)^0$ decay.
Phys. Rev. Lett. 116, 191601 (2016) A search for CP violation in $D^0 \rightarrow K^{-} K^{+} $ and $D^0
\rightarrow \pi^{-} \pi^{+} $ decays is performed using $pp$ collision data,
corresponding to ...an integrated luminosity of $3~fb^{-1}$, collected using the
LHCb detector at centre-of-mass energies of 7 and $8~$TeV. The flavour of the
charm meson is inferred from the charge of the pion in $D^{*+}\rightarrow
D^0\pi^+$ and $D^{*-}\rightarrow \bar{D^0}\pi^{-}$ decays. The difference
between the CP asymmetries in $D^0 \rightarrow K^{-} K^{+} $ and $D^0
\rightarrow \pi^{-} \pi^{+} $ decays, $\Delta A_{CP} \equiv A_{CP}(K^{-} K^{+})
- A_{CP}(\pi^{-} \pi^{+})$, is measured to be $\left( -0.10 \pm 0.08(stat) \pm
0.03(syst) \right) \%$. This is the most precise measurement of a
time-integrated CP asymmetry in the charm sector from a single experiment.
JHEP 1603 (2016) 133 The production of $\psi(2S)$ mesons is studied in dimuon final states using
proton-lead collision data collected by the LHCb detector. The data sample
corresponds to an ...integrated luminosity of $1.6~\mathrm{nb}^{-1}$. The
nucleon-nucleon centre-of-mass energy of the proton-lead collisions is
$\sqrt{s_{NN}}=5~\mathrm{TeV}$. The measurement is performed using $\psi(2S)$
mesons with transverse momentum less than $14~\mathrm{GeV}/c$ and rapidity $y$
in the ranges $1.5<y<4.0$ and $-5.0<y<-2.5$ in the nucleon-nucleon
centre-of-mass system. The forward-backward production ratio and the nuclear
modification factor are determined for $\psi(2S)$ mesons. Using the production
cross-section results of $\psi(2S)$ and $J/\psi$ mesons from $b$-hadron decays,
the $b\bar{b}$ cross-section in pPb collisions at
$\sqrt{s_{NN}}=5~\mathrm{TeV}$ is obtained.
JHEP 02 (2016) 133 A search is performed for $D^{(*)+}_{sJ}$ mesons in the reactions $pp \to
D^{*+} K^0_{\rm S} X$ and $pp \to D^{*0} K^+ X$ using data collected at
centre-of-mass energies of 7 and 8 ...TeV with the LHCb detector. For the $D^{*+}
K^0_{\rm S}$ final state, the decays $D^{*+} \to D^0 \pi^+$ with $D^0 \to K^-
\pi^+$ and $D^0 \to K^- \pi^+ \pi^+ \pi^-$ are used. For $D^{*0} K^+$, the
decay $D^{*0} \to D^0 \pi^0$ with $D^0 \to K^- \pi^+$ is used. A prominent
$D_{s1}(2536)^+$ signal is observed in both $D^{*+} K^0_{\rm S}$ and $D^{*0}
K^+$ final states. The resonances $D^*_{s1}(2700)^+$ and $D^*_{s3}(2860)^+$ are
also observed, yielding information on their properties, including spin-parity
assignments. The decay $D^*_{s2}(2573)^+ \to D^{*+} K^0_{\rm S}$ is observed
for the first time, at a significance of 6.9 $\sigma$, and its branching
fraction relative to the $D^*_{s2}(2573)^+ \to D^+ K^0_{\rm S}$ decay mode is
measured.
JHEP 02 (2016) 104 An angular analysis of the $B^{0}\rightarrow K^{*0}(\rightarrow
K^{+}\pi^{-})\mu^{+}\mu^{-}$ decay is presented. The dataset corresponds to an
integrated luminosity of ...$3.0\,{\mbox{fb}^{-1}}$ of $pp$ collision data
collected at the LHCb experiment. The complete angular information from the
decay is used to determine $C\!P$-averaged observables and $C\!P$ asymmetries,
taking account of possible contamination from decays with the $K^{+}\pi^{-}$
system in an S-wave configuration. The angular observables and their
correlations are reported in bins of $q^2$, the invariant mass squared of the
dimuon system. The observables are determined both from an unbinned maximum
likelihood fit and by using the principal moments of the angular distribution.
In addition, by fitting for $q^2$-dependent decay amplitudes in the region
$1.1<q^{2}<6.0\mathrm{\,Ge\kern -0.1em V}^{2}/c^{4}$, the zero-crossing points
of several angular observables are computed. A global fit is performed to the
complete set of $C\!P$-averaged observables obtained from the maximum
likelihood fit. This fit indicates differences with predictions based on the
Standard Model at the level of 3.4 standard deviations. These differences could
be explained by contributions from physics beyond the Standard Model, or by an
unexpectedly large hadronic effect that is not accounted for in the Standard
Model predictions.
Phys. Rev. D 93, 051101 (2016) The $B^{+}\to D^{+} K^{+} \pi^{-}$ decay is observed in a data sample
corresponding to $3.0\,{\rm fb}^{-1}$ of $pp$ collision data recorded by the
LHCb experiment ...during 2011 and 2012. The signal significance is $8\,\sigma$
and the branching fraction is measured to be ${\cal B}\left(B^{+}\to D^{+}
K^{+} \pi^{-}\right) = (5.31 \pm 0.90 \pm 0.48 \pm 0.35)\times 10^{-6}$, where
the uncertainties are statistical, systematic and due to the normalisation mode
$B^{+}\to D^{-} K^{+} \pi^{+}$, respectively. The Dalitz plot appears to be
dominated by broad structures. Angular distributions are exploited to search
for quasi-two-body contributions from $B^{+}\to D^{*}_{2}(2460)^{0}K^{+}$ and
$B^{+}\to D^{+} K^{*}(892)^{0}$ decays. No significant signals are observed and
upper limits are set on their branching fractions.
JHEP 01 (2016) 155 Measurements are presented of electroweak boson production using data from
$pp$ collisions at a centre-of-mass energy of $\sqrt{s} = 8\mathrm{\,Te\kern
-0.1em V}$. The analysis is ...based on an integrated luminosity of
$2.0\mathrm{\,fb}^{-1}$ recorded with the LHCb detector. The bosons are
identified in the $W\rightarrow\mu\nu$ and $Z\rightarrow\mu^{+}\mu^{-}$ decay
channels. The cross-sections are measured for muons in the pseudorapidity range
$2.0 < \eta < 4.5$, with transverse momenta $p_{\rm T} > 20{\mathrm{\,Ge\kern
-0.1em V\!/}c}$ and, in the case of the $Z$ boson, a dimuon mass within $60 <
M_{\mu^{+}\mu^{-}} < 120{\mathrm{\,Ge\kern -0.1em V\!/}c^{2}}$. The results are
\begin{align*} \sigma_{W^{+}\rightarrow\mu^{+}\nu} &= 1093.6 \pm 2.1 \pm 7.2
\pm 10.9 \pm 12.7{\rm \,pb} \, , \sigma_{W^{-}\rightarrow\mu^{-}\bar{\nu}} &=
\phantom{0}818.4 \pm 1.9 \pm 5.0 \pm \phantom{0}7.0 \pm \phantom{0}9.5{\rm
\,pb} \, , \sigma_{Z\rightarrow\mu^{+}\mu^{-}} &= \phantom{00}95.0 \pm 0.3 \pm
0.7 \pm \phantom{0}1.1 \pm \phantom{0}1.1{\rm \,pb} \, , \end{align*} where the
first uncertainties are statistical, the second are systematic, the third are
due to the knowledge of the LHC beam energy and the fourth are due to the
luminosity determination. The evolution of the $W$ and $Z$ boson cross-sections
with centre-of-mass energy is studied using previously reported measurements
with $1.0\mathrm{\,fb}^{-1}$ of data at $7\mathrm{\,Te\kern -0.1em V}$.
Differential distributions are also presented. Results are in good agreement
with theoretical predictions at next-to-next-to-leading order in perturbative
quantum chromodynamics.
Phys. Lett. B754 (2016) 167 A search for the lepton-flavour violating decay $D^0 \to e^\pm \mu^\mp$ is
made with a dataset corresponding to an integrated luminosity of 3.0 fb$^{-1}$
of proton-proton ...collisions at centre-of-mass energies of $7$ TeV and $8$ TeV,
collected by the LHCb experiment. Candidate $D^0$ mesons are selected using the
decay $D^{*+} \to D^0 \pi^+$ and the $D^0 \to e^\pm \mu^\mp$ branching fraction
is measured using the decay mode $D^0 \to K^-\pi^+$ as a normalisation channel.
No significant excess of $D^0 \to e^\pm \mu^\mp$ candidates over the expected
background is seen, and a limit is set on the branching fraction,
$\mathcal{B}(D^0 \to e^\pm \mu^\mp) < 1.3 \times 10^{-8}$, at 90 % confidence
level. This is an order of magnitude lower than the previous limit and it
further constrains the parameter space in some leptoquark models and in
supersymmetric models with R-parity violation.
JHEP 07 (2016) 052 Associated production of bottomonia and open charm hadrons in $pp$ collisions
at $\sqrt{s}=7$ and $8$TeV is observed using data corresponding to an
integrated luminosity of ...3$fb^{-1}$ accumulated with the LHCb detector. The
observation of five combinations, $\Upsilon(1S)D^0$, $\Upsilon(2S)D^0$,
$\Upsilon(1S)D^+$, $\Upsilon(2S)D^+$ and $\Upsilon(1S)D^+_{s}$, is reported.
Production cross-sections are measured for $\Upsilon(1S)D^0$ and
$\Upsilon(1S)D^+$ pairs in the forward region. The measured cross-sections and
the differential distributions indicate the dominance of double parton
scattering as the main production mechanism. This allows a precise measurement
of the effective cross-section for double parton scattering.
Phys. Rev. Lett. 115, 241801 (2015) Using a $pp$ collision data sample corresponding to an integrated luminosity
of 3.0~fb$^{-1}$, collected by the LHCb detector, we present the first search
for the ...strangeness-changing weak decay $\Xi_b^-\to\Lambda_b^0\pi^-$. No $b$
hadron decay of this type has been seen before. A signal for this decay,
corresponding to a significance of 3.2 standard deviations, is reported. The
relative rate is measured to be
${{f_{\Xi_b^-}}\over{f_{\Lambda_b^0}}}{\cal{B}}(\Xi_b^-\to\Lambda_b^0\pi^-) =
(5.7\pm1.8^{+0.8}_{-0.9})\times10^{-4}$, where $f_{\Xi_b^-}$ and
$f_{\Lambda_b^0}$ are the $b\to\Xi_b^-$ and $b\to\Lambda_b^0$ fragmentation
fractions, and ${\cal{B}}(\Xi_b^-\to\Lambda_b^0\pi^-)$ is the branching
fraction. Assuming $f_{\Xi_b^-}/f_{\Lambda_b^0}$ is bounded between 0.1 and
0.3, the branching fraction ${\cal{B}}(\Xi_b^-\to\Lambda_b^0\pi^-)$ would lie
in the range from $(0.57\pm0.21)\%$ to $(0.19\pm0.07)\%$.
