Search for the doubly charmed baryon $it{Omega}_{cc}^{+}$

A search for the doubly charmed baryon $it{Omega}_{cc}^{+}$ with the decay mode $it{Omega}_{cc}^{+}toit{Xi}_c^{+}K^{-}pi^{+}$ is performed using proton-proton collision data at a centre-of-mass energy of 13$mathrm{,Tekern -0.1em V}$ collected by the LHCb experiment from 2016 to 2018, corresponding to an integrated luminosity of $5.4,mathrm{fb}^{-1}$. No significant signal is observed within the invariant mass range of 3.6 to 4.0$mathrm{,Gekern -0.1em V}/c^2$. Upper limits are set on the ratio $R$ of the production cross-section times the total branching fraction of the $it{Omega}_{cc}^{+}toit{Xi}_c^{+}K^{-}pi^{+}$ decay with respect to the $it{Xi}_{cc}^{++}toit{Lambda}_c^{+}K^{-}pi^{+}pi^{+}$ decay. Upper limits at 95% credibility level for $R$ in the range $0.005$ to $0.11$ are obtained for different hypotheses on the $it{Omega}_{cc}^{+}$ mass and lifetime in the rapidity range from 2.0 to 4.5 and transverse momentum range from 4 to 15$mathrm{,Gekern -0.1em V}/c$.

Light isovector resonances in $pi^- p to pi^-pi^-pi^+ p$ at 190 GeV/${it c}$

We have performed the most comprehensive resonance-model fit of $pi^-pi^-pi^+$ states using the results of our previously published partial-wave analysis (PWA) of a large data set of diffractive-dissociation events from the reaction $pi^- + p to pi^-pi^-pi^+ + p_text{recoil}$ with a 190 GeV/$c$ pion beam. The PWA results, which were obtained in 100 bins of three-pion mass, $0.5 < m_{3pi} < 2.5$ GeV/$c^2$, and simultaneously in 11 bins of the reduced four-momentum transfer squared, $0.1 < t < 1.0$ $($GeV$/c)^2$, are subjected to a resonance-model fit using Breit-Wigner amplitudes to simultaneously describe a subset of 14 selected waves using 11 isovector light-meson states with $J^{PC} = 0^{-+}$, $1^{++}$, $2^{++}$, $2^{-+}$, $4^{++}$, and spin-exotic $1^{-+}$ quantum numbers. The model contains the well-known resonances $pi(1800)$, $a_1(1260)$, $a_2(1320)$, $pi_2(1670)$, $pi_2(1880)$, and $a_4(2040)$. In addition, it includes the disputed $pi_1(1600)$, the excited states $a_1(1640)$, $a_2(1700)$, and $pi_2(2005)$, as well as the resonancelike $a_1(1420)$. We measure the resonance parameters mass and width of these objects by combining the information from the PWA results obtained in the 11 $t$ bins. We extract the relative branching fractions of the $rho(770) pi$ and $f_2(1270) pi$ decays of $a_2(1320)$ and $a_4(2040)$, where the former one is measured for the first time. In a novel approach, we extract the $t$ dependence of the intensity of the resonances and of their phases. The $t$ dependence of the intensities of most resonances differs distinctly from the $t$ dependence of the nonresonant components. For the first time, we determine the $t$ dependence of the phases of the production amplitudes and confirm that the production mechanism of the Pomeron exchange is common to all resonances.

A search for $it{Xi}^{++}_{cc} rightarrow D^{+} p K^{-} pi^{+}$ decays

A search for the $it{Xi}^{++}_{cc}$ baryon through the $it{Xi}^{++}_{cc} rightarrow D^{+} p K^{-} pi^{+}$ decay is performed with a data sample corresponding to an integrated luminosity of 1.7 $mathrm{fb}^{-1}$ recorded by the LHCb experiment in $pp$ collisions at a centre-of-mass energy of 13 TeV. No significant signal is observed in the mass range from the kinematic threshold of the decay to 3800 $mathrm{MeV}/c^{2}$. An upper limit is set on the ratio of branching fractions $mathcal{R} = frac{mathcal{B}(it{Xi}^{++}_{cc} rightarrow D^{+} p K^{-} pi^{+})}{mathcal{B}(it{Xi}^{++}_{cc} rightarrow Lambda^{+}_{c} K^{-} pi^{+}pi^{+})}$ with $mathcal{R} < 1.7 hspace{2pt} (2.1) times 10^{-2}$ at the 90% (95%) confidence level at the known mass of the $it{Xi}^{++}_{cc}$ state.

Building up spacetime with quantum entanglement II: It from BC-bit

In this note, we describe how collections of arbitrary numbers of BC-bits, distinct non-interacting quantum systems each consisting of a holographic boundary conformal field theory (BCFT), can be placed in multipartite entangled states in order to encode single connected bulk spacetimes that approximate geometries dual to holographic CFT states. The BC-bit version of a holographic CFT state corresponds to a geometry that can be made arbitrarily similar to the associated CFT-state geometry within a causal diamond region defined by points that are spacelike separated from the boundary time slice at which the state is defined. These holographic multi BC-bit states can be well-represented by tensor networks in which the individual tensors are associated with states of small numbers of BC-bits.