Study of the lineshape of the chi(c1) (3872) state

A study of the lineshape of the chi(c1) (3872) state is made using a data sample corresponding to an integrated luminosity of 3 fb(-1) collected in pp collisions at center-of-mass energies of 7 and 8 TeV with the LHCb detector. Candidate chi(c1)(3872) and psi(2S) mesons from b-hadron decays are selected in the J/psi pi(+)pi(-) decay mode. Describing the lineshape with a Breit-Wigner function, the mass splitting between the chi(c1 )(3872) and psi(2S) states, Delta m, and the width of the chi(c1 )(3872) state, Gamma(Bw), are determined to be (Delta m=185.598 +/- 0.067 +/- 0.068 Mev,)(Gamma BW=1.39 +/- 0.24 +/- 0.10 Mev,) where the first uncertainty is statistical and the second systematic. Using a Flatte-inspired model, the mode and full width at half maximum of the lineshape are determined to be (mode=3871.69+0.00+0.05 MeV.)(FWHM=0.22-0.04+0.13+0.07+0.11-0.06-0.13 MeV, ) An investigation of the analytic structure of the Flatte amplitude reveals a pole structure, which is compatible with a quasibound D-0(D) over bar*(0) state but a quasivirtual state is still allowed at the level of 2 standard deviations

Precision measurement of the Xi(++)(cc) mass

A measurement of the \u39ecc++ mass is performed using data collected by the LHCb experiment between 2016 and 2018 in pp collisions at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.6 fb 121. The \u39ecc++ candidates are reconstructed via the decay modes \u39ecc++\u2192\u39bc+K 12\u3c0+\u3c0+ and \u39ecc++\u2192\u39ec+\u3c0+. The result, 3621.55 \ub1 0.23 (stat) \ub1 0.30 (syst) MeV/c2, is the most precise measurement of the \u39ecc++ mass to date. [Figure not available: see fulltext.]

Measurement of vertical bar V-cb vertical bar with B-s(0) -> D-s(()*()-) mu(+)nu(mu) decays

The element |Vcb| of the Cabibbo-Kobayashi-Maskawa matrix is measured using semileptonic Bs0 decays produced in proton-proton collision data collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb-1. Rates of Bs0\u2192Ds-\u3bc+\u3bd\u3bc and Bs0\u2192Ds 17-\u3bc+\u3bd\u3bc decays are analyzed using hadronic form-factor parametrizations derived either by Caprini, Lellouch and Neubert (CLN) or by Boyd, Grinstein and Lebed (BGL). The measured values of |Vcb| are (41.4\ub10.6\ub10.9\ub11.2) 710-3 and (42.3\ub10.8\ub10.9\ub11.2) 710-3 in the CLN and BGL parametrization, respectively. The first uncertainty is statistical, the second systematic, and the third is due to the external inputs used in the measurement. These results are in agreement with those obtained from decays of B+ and B0 mesons. They are the first determinations of |Vcb| at a hadron-collider experiment and the first using Bs0 meson decays

First Observation of Excited Omega(-)(b) States

We report four narrow peaks in the \u39eb0K- mass spectrum obtained using pp collisions at center-of-mass energies of 7, 8, and 13 TeV, corresponding to a total integrated luminosity of 9 fb-1 recorded by the LHCb experiment. Referring to these states by their mass, the mass values are m[\u3c9b(6316)-]=6315.64\ub10.31\ub10.07\ub10.50 MeV, m[\u3c9b(6330)-]=6330.30\ub10.28\ub10.07\ub10.50 MeV, m[\u3c9b(6340)-]=6339.71\ub10.26\ub10.05\ub10.50 MeV, m[\u3c9b(6350)-]=6349.88\ub10.35\ub10.05\ub10.50 MeV, where the uncertainties are statistical, systematic, and the last is due to the knowledge of the \u39eb0 mass. The natural widths of the three lower mass states are consistent with zero, and the 90% confidence-level upper limits are determined to be \u393[\u3c9b(6316)-]<2.8 MeV, \u393[\u3c9b(6330)-]<3.1 MeV and \u393[\u3c9b(6340)-]<1.5 MeV. The natural width of the \u3c9b(6350)- peak is 1.4-0.8+1.0\ub10.1 MeV, which is 2.5\u3c3 from zero and corresponds to an upper limit of 2.8 MeV. The peaks have local significances ranging from 3.6\u3c3 to 7.2\u3c3. After accounting for the look-elsewhere effect, the significances of the \u3c9b(6316)- and \u3c9b(6330)- peaks are reduced to 2.1\u3c3 and 2.6\u3c3, respectively, while the two higher mass peaks exceed 5\u3c3. The observed peaks are consistent with expectations for excited \u3c9b- resonances

Isospin Amplitudes in Lambda(0)(b) -> J/psi Lambda (Sigma(0)) and Xi(0)(b)-> J/psi Xi(0) (Lambda) Decays

Ratios of isospin amplitudes in hadron decays are a useful probe of the interplay between weak and strong interactions and allow searches for physics beyond the standard model. We present the first results on isospin amplitudes in b-baryon decays, using data corresponding to an integrated luminosity of 8.5 fb-1, collected with the LHCb detector in pp collisions at center of mass energies of 7, 8, and 13 TeV. The isospin amplitude ratio |A1(\u39bb0\u2192J/\u3c8\u3c20)/A0(\u39bb0\u2192J/\u3c8\u39b)|, where the subscript on A indicates the final-state isospin, is measured to be less than 1/21.8 at 95% confidence level. The Cabibbo suppressed \u39eb0\u2192J/\u3c8\u39b decay is observed for the first time, allowing for the measurement |A0(\u39eb0\u2192J/\u3c8\u39b)/A1/2(\u39eb0\u2192J/\u3c8\u39e0)|=0.37\ub10.06\ub10.02, where the uncertainties are statistical and systematic, respectively

Observation of structure in the J/ψ-pair mass spectrum

Using proton-proton collision data at centre-of-mass energies of √s = 8 and 13 TeV recorded by the LHCb experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 9 fb1 , the invariant mass spectrum of J/ψ pairs is studied. A narrow structure around 6.9 GeV=c2 matching the lineshape of a resonance and a broad structure just above twice the J/ψ mass are observed. The deviation of the data from nonresonant J/ψ-pair production is above five standard deviations in the mass region between 6:2 and 7:4 GeV=c2, covering predicted masses of states composed of four charm quarks. The mass and natural width of the narrow X6900 structure are measured assuming a Breit-Wigner lineshape

Brazilian Flora 2020: Leveraging the power of a collaborative scientific network

International audienceThe shortage of reliable primary taxonomic data limits the description of biological taxa and the understanding of biodiversity patterns and processes, complicating biogeographical, ecological, and evolutionary studies. This deficit creates a significant taxonomic impediment to biodiversity research and conservation planning. The taxonomic impediment and the biodiversity crisis are widely recognized, highlighting the urgent need for reliable taxonomic data. Over the past decade, numerous countries worldwide have devoted considerable effort to Target 1 of the Global Strategy for Plant Conservation (GSPC), which called for the preparation of a working list of all known plant species by 2010 and an online world Flora by 2020. Brazil is a megadiverse country, home to more of the world's known plant species than any other country. Despite that, Flora Brasiliensis, concluded in 1906, was the last comprehensive treatment of the Brazilian flora. The lack of accurate estimates of the number of species of algae, fungi, and plants occurring in Brazil contributes to the prevailing taxonomic impediment and delays progress towards the GSPC targets. Over the past 12 years, a legion of taxonomists motivated to meet Target 1 of the GSPC, worked together to gather and integrate knowledge on the algal, plant, and fungal diversity of Brazil. Overall, a team of about 980 taxonomists joined efforts in a highly collaborative project that used cybertaxonomy to prepare an updated Flora of Brazil, showing the power of scientific collaboration to reach ambitious goals. This paper presents an overview of the Brazilian Flora 2020 and provides taxonomic and spatial updates on the algae, fungi, and plants found in one of the world's most biodiverse countries. We further identify collection gaps and summarize future goals that extend beyond 2020. Our results show that Brazil is home to 46,975 native species of algae, fungi, and plants, of which 19,669 are endemic to the country. The data compiled to date suggests that the Atlantic Rainforest might be the most diverse Brazilian domain for all plant groups except gymnosperms, which are most diverse in the Amazon. However, scientific knowledge of Brazilian diversity is still unequally distributed, with the Atlantic Rainforest and the Cerrado being the most intensively sampled and studied biomes in the country. In times of “scientific reductionism”, with botanical and mycological sciences suffering pervasive depreciation in recent decades, the first online Flora of Brazil 2020 significantly enhanced the quality and quantity of taxonomic data available for algae, fungi, and plants from Brazil. This project also made all the information freely available online, providing a firm foundation for future research and for the management, conservation, and sustainable use of the Brazilian funga and flora