Retrieving Comparative Arguments using Ensemble Methods and Neural Information Retrieval

In this paper, we present a submission to the Touche lab's Task 2 on Argument Retrieval for Comparative Questions. Our team Katana supplies several approaches based on decision tree ensembles algorithms to rank comparative documents in accordance with their relevance and argumentative support. We use PyTerrier library to apply ensembles models to a ranking problem, considering statistical text features and features based on comparative structures. We also employ large contextualized language modelling techniques, such as BERT, to solve the proposed ranking task. To merge this technique with ranking modelling, we leverage neural ranking library OpenNIR. Our systems substantially outperforming the proposed baseline and scored first in relevance and second in quality according to the official metrics of the competition (for measure NDCG@5 score). Presented models could help to improve the performance of processing comparative queries in information retrieval and dialogue systems

Particle-identification techniques and performance at LHCb in Run 2

One of the most challenging data analysis tasks of modern High Energy Physics experiments is the identification of particles. In this proceedings we review the new approaches used for particle identification at the LHCb experiment. Machine-Learning based techniques are used to identify the species of charged and neutral particles using several observables obtained by the LHCb sub-detectors. We show the performances of various solutions based on Neural Network and Boosted Decision Tree models

MEKER: Memory Efficient Knowledge Embedding Representation for Link Prediction and Question Answering

Knowledge Graphs (KGs) are symbolically structured storages of facts. The KG embedding contains concise data used in NLP tasks requiring implicit information about the real world. Furthermore, the size of KGs that may be useful in actual NLP assignments is enormous, and creating embedding over it has memory cost issues. We represent KG as a 3rd-order binary tensor and move beyond the standard CP decomposition by using a data-specific generalized version of it. The generalization of the standard CP-ALS algorithm allows obtaining optimization gradients without a backpropagation mechanism. It reduces the memory needed in training while providing computational benefits. We propose a MEKER, a memory-efficient KG embedding model, which yields SOTA-comparable performance on link prediction tasks and KG-based Question Answering

Observation of a new Ξb−\Xi_b^- resonance

International audienceFrom samples of pp collision data collected by the LHCb experiment at 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 Λb0K- and Ξb0π- invariant mass spectra is observed. In the quark model, radially and orbitally excited Ξb- resonances with quark content bds are expected. Referring to this peak as Ξb(6227)-, the mass and natural width are measured to be mΞb(6227)-=6226.9±2.0±0.3±0.2  MeV/c2 and ΓΞb(6227)-=18.1±5.4±1.8  MeV/c2, where the first uncertainty is statistical, the second is systematic, and the third, on mΞb(6227)-, is due to the knowledge of the Λb0 baryon mass. Relative production rates of the Ξb(6227)-→Λb0K- and Ξb(6227)-→Ξb0π- decays are also reported

Observation of the decay Bs0→D‾0K+K−B_s^0 \to \overline{D}^0 K^+ K^-

International audienceThe first observation of the Bs0→D¯0K+K- decay is reported, together with the most precise branching fraction measurement of the mode B0→D¯0K+K-. The results are obtained from an analysis of pp collision data corresponding to an integrated luminosity of 3.0  fb-1. The data were collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV. The branching fraction of the B0→D¯0K+K- decay is measured relative to that of the decay B0→D¯0π+π- to be B(B0→D¯0K+K-)B(B0→D¯0π+π-)=(6.9±0.4±0.3)%, where the first uncertainty is statistical and the second is systematic. The measured branching fraction of the Bs0→D¯0K+K- decay mode relative to that of the corresponding B0 decay is B(Bs0→D¯0K+K-)B(B0→D¯0K+K-)=(93.0±8.9±6.9)%. Using the known branching fraction of B0→D¯0π+π-, the values of B(B0→D¯0K+K-)=(6.1±0.4±0.3±0.3)×10-5 and B(Bs0→D¯0K+K-)=(5.7±0.5±0.4±0.5)×10-5 are obtained, where the third uncertainties arise from the branching fraction of the decay modes B0→D¯0π+π- and B0→D¯0K+K-, respectively

Observation of Bs0→D‾∗0ϕB_s^0 \to \overline{D}^{*0} \phi and search for B0→D‾0ϕB^0 \to \overline{D}^0 \phi decays

International audienceThe first observation of the Bs0→D¯*0ϕ decay is reported, with a significance of more than seven standard deviations, from an analysis of pp collision data corresponding to an integrated luminosity of 3  fb-1, collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV. The branching fraction is measured relative to that of the topologically similar decay B0→D¯0π+π- and is found to be B(Bs0→D¯*0ϕ)=(3.7±0.5±0.3±0.2)×10-5, where the first uncertainty is statistical, the second systematic, and the third from the branching fraction of the B0→D¯0π+π- decay. The fraction of longitudinal polarization in this decay is measured to be fL=(73±15±4)%. The most precise determination of the branching fraction for the Bs0→D¯0ϕ decay is also obtained, B(Bs0→D¯0ϕ)=(3.0±0.3±0.2±0.2)×10-5. An upper limit, B(B0→D¯0ϕ)<2.0 (2.3)×10-6 at 90% (95%) confidence level is set. A constraint on the ω-ϕ mixing angle δ is set at |δ|<5.2° (5.5°) at 90% (95%) confidence level

Observation of Bs0→Dˉ∗0ϕB_s^0 \to \bar{D}^{*0} \phi and search for B0→Dˉ0ϕB^0 \to \bar{D}^0 \phi decays

The first observation of the $B^0_s → \bar{D}^{*0}ϕ$ decay is reported, with a significance of more than seven standard deviations, from an analysis of pp collision data corresponding to an integrated luminosity of 3  fb$^{−1}$, collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV. The branching fraction is measured relative to that of the topologically similar decay $B^0 → \bar{D}^0 π^+ π^−$ and is found to be $\mathcal{B}(B^0_s → \bar{D}^{*0}ϕ)=(3.7±0.5±0.3±0.2) × 10^{−5}$, where the first uncertainty is statistical, the second systematic, and the third from the branching fraction of the $B^0 → \bar{D}^0 π^+ π^−$ decay. The fraction of longitudinal polarization in this decay is measured to be $f_L = (73±15±4)\%$. The most precise determination of the branching fraction for the $B^0_s → \bar{D}^{0}ϕ$ decay is also obtained, $\mathcal{B}(B^0_s → \bar{D}^0 ϕ)=(3.0±0.3±0.2±0.2) × 10^{−5}$. An upper limit,$\mathcal{B}(B^0 → \bar{D}^0 ϕ) < 2.0 (2.3) × 10^{−6}$ at 90% (95%) confidence level is set. A constraint on the $ω−ϕ$ mixing angle $δ$ is set at $|δ| < 5.2°$ (5.5°) at 90% (95%) confidence level