J. High Energ. Phys. 05 (2018) 160 The $CP$ asymmetry in $B^-\to D_s^-D^0$ and $B^-\to D^-D^0$ decays is
measured using LHCb data corresponding to an integrated luminosity of 3.0
fb$^{-1}$, collected ...in $pp$ collisions at centre-of-mass energies of 7 and 8
TeV. The results are $A^{CP}(B^-\to D_s^-D^0)=(-0.4\pm 0.5\pm 0.5)\%$ and
$A^{CP}(B^-\to D^-D^0)=( 2.3\pm 2.7\pm 0.4)\%$, where the first uncertainties
are statistical and the second systematic. This is the first measurement of
$A^{CP}(B^-\to D_s^-D^0)$ and the most precise determination of $A^{CP}(B^-\to
D^-D^0)$. Neither result shows evidence of $CP$ violation.
JHEP 06 (2018) 100 The cross-section for inelastic proton-proton collisions at a centre-of-mass
energy of 13\,TeV is measured with the LHCb detector. The fiducial
cross-section for inelastic ...interactions producing at least one prompt
long-lived charged particle with momentum $p>2$\,GeV/$c$ in the pseudorapidity
range $2<\eta<5$ is determined to be $\sigma_{\rm acc}= 62.2 \pm 0.2 \pm
2.5$\,mb. The first uncertainty is the intrinsic systematic uncertainty of the
measurement, the second is due to the uncertainty on the integrated luminosity.
The statistical uncertainty is negligible. Extrapolation to full phase space
yields the total inelastic proton-proton cross-section $\sigma_{\rm inel}= 75.4
\pm 3.0 \pm 4.5$\,mb, where the first uncertainty is experimental and the
second due to the extrapolation. An updated value of the inelastic
cross-section at a centre-of-mass energy of 7\,TeV is also reported.
J. High Energ. Phys. (2018) 2018: 174 Forward top quark pair production is studied in $pp$ collisions in the $\mu
eb$ final state using a data sample corresponding to an integrated luminosity
of 1.93 ...fb$^{-1}$ collected with the LHCb experiment at a centre-of-mass energy
of 13 TeV. The cross-section is measured in a fiducial region where both
leptons have a transverse momentum greater than 20 GeV and a pseudorapidity
between 2.0 and 4.5. The quadrature sum of the azimuthal separation and the
difference in pseudorapidities, denoted $\Delta R$, between the two leptons
must be larger than 0.1. The $b$-jet axis is required to be separated from both
leptons by a $\Delta R$ of 0.5, and to have a transverse momentum in excess of
20 GeV and a pseudorapidity between 2.2 and 4.2. The cross-section is measured
to be $$\sigma_{t\bar{t}}=
126\pm19\,(\mathrm{stat})\pm16\,(\mathrm{syst})\pm5\,(\mathrm{lumi})\,\,\mathrm{
fb}$$ where the first uncertainty is statistical, the second is systematic, and
the third is due to the luminosity determination. The measurement is compatible
with the Standard Model prediction.
Phys. Rev. Lett. 120, 261801 (2018) The time-integrated Dalitz plot of the three-body hadronic charmless decay
${{\overline{B}}^0 \to K_{\mathrm{\scriptscriptstyle S}}^0 \pi^+ \pi^-}$ is
studied ...using a $pp$ collision data sample recorded with the LHCb detector,
corresponding to an integrated luminosity of $3.0\;\mathrm{fb}^{-1}$. The decay
amplitude is described with an isobar model. Relative contributions of the
isobar amplitudes to the ${\overline{B}^0 \to K_{\mathrm{\scriptscriptstyle
S}}^0 \pi^+ \pi^-}$ decay branching fraction and CP asymmetries of the
flavour-specific amplitudes are measured. The CP asymmetry between the
conjugate ${\overline{B}^0 \to K^{*}(892)^{-}\pi^+}$ and ${\overline{B}^0 \to
K^{*}(892)^{+}\pi^-}$ decay rates is determined to be $-0.308 \pm 0.062$.
Eur. Phys. J. C 78 (2018) 443 Amplitude models are constructed to describe the resonance structure of
${D^{0}\to K^{-}\pi^{+}\pi^{+}\pi^{-}}$ and ${D^{0} \to
K^{+}\pi^{-}\pi^{-}\pi^{+}}$ decays using ...$pp$ collision data collected at
centre-of-mass energies of 7 and 8 TeV with the LHCb experiment, corresponding
to an integrated luminosity of $3.0\mathrm{fb}^{-1}$. The largest contributions
to both decay amplitudes are found to come from axial resonances, with decay
modes $D^{0} \to a_1(1260)^{+} K^{-}$ and $D^{0} \to K_1(1270/1400)^{+}
\pi^{-}$ being prominent in ${D^{0}\to K^{-}\pi^{+}\pi^{+}\pi^{-}}$ and
$D^{0}\to K^{+}\pi^{-}\pi^{-}\pi^{+}$, respectively. Precise measurements of
the lineshape parameters and couplings of the $a_1(1260)^{+}$, $K_1(1270)^{-}$
and $K(1460)^{-}$ resonances are made, and a quasi model-independent study of
the $K(1460)^{-}$ resonance is performed. The coherence factor of the decays is
calculated from the amplitude models to be $R_{K3\pi} = 0.459\pm
0.010\,(\mathrm{stat}) \pm 0.012\,(\mathrm{syst}) \pm 0.020\,(\mathrm{model})$,
which is consistent with direct measurements. These models will be useful in
future measurements of the unitary-triangle angle $\gamma$ and studies of charm
mixing and $C\!P$ violation.
JHEP 03 (2018) 140 A flavour-tagged decay-time-dependent amplitude analysis of
$B_s^0\to(K^+\pi^-)(K^-\pi^+)$ decays is presented in the $K^{\pm}\pi^{\mp}$
mass range from 750 to 1600 MeV$/c^2$. The ...analysis uses $pp$ collision data
collected with the LHCb detector at centre-of-mass energies of $7$ and $8$ TeV,
corresponding to an integrated luminosity of $3.0$ fb$^{-1}$. Several
quasi-two-body decay modes are considered, corresponding to $K^{\pm}\pi^{\mp}$
combinations with spin 0, 1 and 2, which are dominated by the $K_0^*(800)^0$
and $K_0^*(1430)^0$, the $K^*(892)^0$ and the $K_2^*(1430)^0$ resonances,
respectively. The longitudinal polarisation fraction for the $B_s^0\to
K^*(892)^0\overline{K}^*(892)^0$ decay is measured as $f_L=0.208 \pm 0.032 \pm
0.046$, where the first uncertainty is statistical and the second is
systematic. The first measurement of the mixing-induced $CP$-violating phase,
$\phi_s^{d\overline{d}}$, in $b\to d\overline{d}s$ transitions is performed,
yielding a value of $\phi_s^{d\overline{d}}=-0.10$ $\pm$ $0.13$ (stat) $\pm$
$0.14$ (syst) rad.
Phys. Rev. Lett. 120, 221803 (2018) A search for the rare decay $\Sigma^+ \to p \mu^+ \mu^-$ is performed using
$pp$ collision data recorded by the LHCb experiment at centre-of-mass energies
...$\sqrt{s} = 7$ and $8$ TeV, corresponding to an integrated luminosity of $3
fb^{-1}$. An excess of events is observed with respect to the background
expectation, with a signal significance of 4.1 standard deviations. No
significant structure is observed in the dimuon invariant mass distribution, in
contrast with a previous result from the HyperCP experiment. The measured
$\Sigma^+ \to p \mu^+ \mu^-$ branching fraction is
$(2.2\,^{+\,1.8}_{-\,1.3})\times 10^{-8}$, where statistical and systematic
uncertainties are included, which is consistent with the Standard Model
prediction.
Phys. Rev. D 97, 091101 (2018) A search for the flavor-changing neutral-current decay $\Lambda_{c}^{+} \to
p\mu^+\mu^-$ is reported using a data set corresponding to an integrated
luminosity of ...$3.0\rm fb^{-1}$ collected by the LHCb collaboration. No
significant signal is observed outside of the dimuon mass regions around the
$\phi$ and $\omega$ resonances and an upper limit is placed on the branching
fraction of $\mathcal{B} (\Lambda_{c}^{+} \to p\mu^+\mu^-) < 7.7~(9.6)\times
10^{-8}~{\rm at}~90\%~(95\%)$ confidence level. A significant signal is
observed in the $\omega$ dimuon mass region for the first time.
JHEP 03 (2018) 059 We report the measurements of the $CP$-violating parameters in $B_s^0 \to
D_s^{\mp} K^{\pm}$ decays observed in $pp$ collisions, using a data set
corresponding to an integrated ...luminosity of $3.0\,\text{fb}^{-1}$ recorded
with the LHCb detector. We measure $C_f = 0.73 \pm 0.14 \pm 0.05$, $A^{\Delta
\Gamma}_f = 0.39 \pm 0.28 \pm 0.15$, $A^{\Delta \Gamma}_{\overline{f}} = 0.31
\pm 0.28 \pm 0.15$, $S_f = -0.52 \pm 0.20 \pm 0.07$, $S_{\overline{f}} = -0.49
\pm 0.20 \pm 0.07$, where the uncertainties are statistical and systematic,
respectively. These parameters are used together with the world-average value
of the $B_s^0$ mixing phase, $-2\beta_s$, to obtain a measurement of the CKM
angle $\gamma$ from $B_s^0 \to D_s^{\mp} K^{\pm}$ decays, yielding $\gamma =
(128\,_{-22}^{+17})^\circ$ modulo $180^\circ$, where the uncertainty contains
both statistical and systematic contributions. This corresponds to
$3.8\,\sigma$ evidence for $CP$ violation in the interference between decay and
decay after mixing.
JHEP 03 (2018) 182 The difference between the $CP$ asymmetries in the decays $\varLambda_{c}^{+}
\to pK^{-}K^{+}$ and $\varLambda_{c}^{+} \to p\pi^{-}\pi^{+}$ is presented.
Proton-proton collision ...data taken at centre-of-mass energies of $7$ and
$8\,\mathrm{TeV}$ collected by the LHCb detector in 2011 and 2012 are used,
corresponding to an integrated luminosity of $3\,\mathrm{fb}^{-1}$. The
$\varLambda_{c}^{+}$ candidates are reconstructed as part of the
$\varLambda_{b}^{0} \to \varLambda_{c}^{+}\mu^{-}X$ decay chain. In order to
maximize the cancellation of production and detection asymmetries in the
difference, the final-state kinematic distributions of the two samples are
aligned by applying phase-space-dependent weights to the $\varLambda_{c}^{+}
\to p\pi^{-}\pi^{+}$ sample. This alters the definition of the integrated $CP$
asymmetry to $A_{CP}^{\text{wgt}}(p\pi^{-}\pi^{+})$. Both samples are corrected
for reconstruction and selection efficiencies across the five-dimensional
$\varLambda_{c}^{+}$ decay phase space. The difference in $CP$ asymmetries is
found to be \begin{align*}
\Delta{A^{\text{wgt}}_{CP}} &= A_{CP}(pK^{-}K^{+}) -
A_{CP}^{\text{wgt}}(p\pi^{-}\pi^{+})\\
&= (0.30 \pm 0.91 \pm 0.61)\,\%, \end{align*} where the first uncertainty is
statistical and the second is systematic.
