621 research outputs found

    Multidifferential study of identified charged hadron distributions in ZZ-tagged jets in proton-proton collisions at s=\sqrt{s}=13 TeV

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    Jet fragmentation functions are measured for the first time in proton-proton collisions for charged pions, kaons, and protons within jets recoiling against a ZZ boson. The charged-hadron distributions are studied longitudinally and transversely to the jet direction for jets with transverse momentum 20 <pT<100< p_{\textrm{T}} < 100 GeV and in the pseudorapidity range 2.5<η<42.5 < \eta < 4. The data sample was collected with the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 1.64 fb1^{-1}. Triple differential distributions as a function of the hadron longitudinal momentum fraction, hadron transverse momentum, and jet transverse momentum are also measured for the first time. This helps constrain transverse-momentum-dependent fragmentation functions. Differences in the shapes and magnitudes of the measured distributions for the different hadron species provide insights into the hadronization process for jets predominantly initiated by light quarks.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-013.html (LHCb public pages

    Study of the BΛc+ΛˉcKB^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} decay

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    The decay BΛc+ΛˉcKB^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} is studied in proton-proton collisions at a center-of-mass energy of s=13\sqrt{s}=13 TeV using data corresponding to an integrated luminosity of 5 fb1\mathrm{fb}^{-1} collected by the LHCb experiment. In the Λc+K\Lambda_{c}^+ K^{-} system, the Ξc(2930)0\Xi_{c}(2930)^{0} state observed at the BaBar and Belle experiments is resolved into two narrower states, Ξc(2923)0\Xi_{c}(2923)^{0} and Ξc(2939)0\Xi_{c}(2939)^{0}, whose masses and widths are measured to be m(Ξc(2923)0)=2924.5±0.4±1.1MeV,m(Ξc(2939)0)=2938.5±0.9±2.3MeV,Γ(Ξc(2923)0)=0004.8±0.9±1.5MeV,Γ(Ξc(2939)0)=0011.0±1.9±7.5MeV, m(\Xi_{c}(2923)^{0}) = 2924.5 \pm 0.4 \pm 1.1 \,\mathrm{MeV}, \\ m(\Xi_{c}(2939)^{0}) = 2938.5 \pm 0.9 \pm 2.3 \,\mathrm{MeV}, \\ \Gamma(\Xi_{c}(2923)^{0}) = \phantom{000}4.8 \pm 0.9 \pm 1.5 \,\mathrm{MeV},\\ \Gamma(\Xi_{c}(2939)^{0}) = \phantom{00}11.0 \pm 1.9 \pm 7.5 \,\mathrm{MeV}, where the first uncertainties are statistical and the second systematic. The results are consistent with a previous LHCb measurement using a prompt Λc+K\Lambda_{c}^{+} K^{-} sample. Evidence of a new Ξc(2880)0\Xi_{c}(2880)^{0} state is found with a local significance of 3.8σ3.8\,\sigma, whose mass and width are measured to be 2881.8±3.1±8.5MeV2881.8 \pm 3.1 \pm 8.5\,\mathrm{MeV} and 12.4±5.3±5.8MeV12.4 \pm 5.3 \pm 5.8 \,\mathrm{MeV}, respectively. In addition, evidence of a new decay mode Ξc(2790)0Λc+K\Xi_{c}(2790)^{0} \to \Lambda_{c}^{+} K^{-} is found with a significance of 3.7σ3.7\,\sigma. The relative branching fraction of BΛc+ΛˉcKB^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} with respect to the BD+DKB^{-} \to D^{+} D^{-} K^{-} decay is measured to be 2.36±0.11±0.22±0.252.36 \pm 0.11 \pm 0.22 \pm 0.25, where the first uncertainty is statistical, the second systematic and the third originates from the branching fractions of charm hadron decays.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-028.html (LHCb public pages

    Measurement of the ratios of branching fractions R(D)\mathcal{R}(D^{*}) and R(D0)\mathcal{R}(D^{0})

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    The ratios of branching fractions R(D)B(BˉDτνˉτ)/B(BˉDμνˉμ)\mathcal{R}(D^{*})\equiv\mathcal{B}(\bar{B}\to D^{*}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(\bar{B}\to D^{*}\mu^{-}\bar{\nu}_{\mu}) and R(D0)B(BD0τνˉτ)/B(BD0μνˉμ)\mathcal{R}(D^{0})\equiv\mathcal{B}(B^{-}\to D^{0}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(B^{-}\to D^{0}\mu^{-}\bar{\nu}_{\mu}) are measured, assuming isospin symmetry, using a sample of proton-proton collision data corresponding to 3.0 fb1{ }^{-1} of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode τμντνˉμ\tau^{-}\to\mu^{-}\nu_{\tau}\bar{\nu}_{\mu}. The measured values are R(D)=0.281±0.018±0.024\mathcal{R}(D^{*})=0.281\pm0.018\pm0.024 and R(D0)=0.441±0.060±0.066\mathcal{R}(D^{0})=0.441\pm0.060\pm0.066, where the first uncertainty is statistical and the second is systematic. The correlation between these measurements is ρ=0.43\rho=-0.43. Results are consistent with the current average of these quantities and are at a combined 1.9 standard deviations from the predictions based on lepton flavor universality in the Standard Model.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-039.html (LHCb public pages

    NYMPHA per i materiali lapidei - NYMPHA for marbles (Progetto NYMPHA per la protezione dei materiali lapidei nei Beni Culturali)

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    Vivere nell’era del cambiamento climatico ha portato la ricerca a porre maggiore attenzione alla salvaguardia dell’ambiente, intraprendendo attraverso lo sviluppo tecnologico azioni consapevoli e sostenibili volte a migliorare le prospettive ambientali future. Il progetto NYMPHA si inserisce in questo contesto, cercando di rispondere alla necessità di fornire un prodotto per il restauro e la conservazione dei Beni Culturali che sia non dannoso per uomo e ambiente, totalmente caratterizzato dal punto di vista chimico e compatibile con le superfici antiche polimateriche. Il prodotto¹, un estratto di polisaccaridi di microalghe, è innovativo per la sua origine e ha potenzialità antimicotiche, antibatteriche e di miglioramento strutturale. Ad oggi i polisaccaridi, ottenuti seguendo quattro protocolli di estrazione, sono stati applicati su provini inorganici (marmo bianco); successivamente è stata effettuata una caratterizzazione delle superfici lapidee per valutare l’efficacia del trattamento. Ringraziamenti: questo lavoro è stato supportato dal POR-FESR Progetti Gruppi di Ricerca Lazio Innova NYMPHA Project A0375-2020-36489. 1- Masi, A., Medeghini, L., Masi, A., Sadori, L., Leonelli, F., Favero, G., &amp; Antonacci, A. (2021). Natural polysaccharides from microalgae for the protection of cultural heritage. SMART ELAB, 16, 24. https://doi.org/10.30441/smartelab.v16i.12

    Nympha – test su carta Nympha – tests on paper

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    Il progetto "Natural polYsaccharides from Microalgae for the Protection of cultural HeritAge"- NYMPHA si pone come obiettivo quello di fornire un prodotto di origine naturale (polisaccaride estratto da microalghe) non dannoso per l’uomo e compatibile con i materiali antichi e di studiarne l’applicabilità e l’efficacia per il consolidamento/protezione di manufatti cartacei. Il prodotto è stato applicato su campioni di carta Whatman e su provini di pellicola pittorica a tempera magra su carta. Lo scopo del lavoro è di valutare la compatibilità dell’estratto polisaccaridico sia su carta caratterizzata da un’elevata purezza strutturale che su strati pittorici. Le misure colorimetriche hanno mostrato la non interferenza cromatica del materiale e il prodotto ha evidenziato un discreto effetto consolidante sulle pellicole pittoriche decoese. Le proprietà dell’estratto NYMPHA sono state confrontate con quelli di altri consolidanti per pellicole pittoriche, tra cui il Funori, consolidante a base polisaccaridica, estratto da alghe, in uso nel campo dei beni culturali. L’estratto NYMPHA è stato caratterizzato tramite SEM-EDS e FTIR e la sua composizione confrontata con quella del Funori e del Jun Funori. I risultati ottenuti evidenziano una differenza nella composizione chimica dei due prodotti. Sono in fase di esecuzione ulteriori test atti a valutare il potere consolidante dell’estratto NYMPHA sia su supporti cartacei degradati che su pellicole pittoriche decoese.The “Natural polYsaccharides from Microalgae for the Protection of cultural HeritAge" - NYMPHA project aims: i) to provide a natural origin product (polysaccharide extracted from microalgae) not harmful to man and compatible with ancient materials; ii) to study the applicability and effectiveness for the consolidation/protection on paper products. The extract was applied on Whatman paper samples and on painted samples with tempera on paper. The purpose of the work was to assess the compatibility of the polysaccharide extract both on paper characterized by a high structural purity and on pictorial decohese layers. Colorimetric measurements showed no chromatic variation and a discrete cohesion on the painted layers. The NYMPHA extract have been compared with those of other consolidants for painting films, e.g. Funori, a consolidating material extracted from algae, in use in the field of cultural heritage. The polysaccharide extract was characterized by SEM-EDS and FTIR and its composition was compared with that of Funori and Jun Funori. The results show a difference in the chemical composition of the two products. Future studies will evaluate the consolidating power of NYMPHA extract both on degraded paper supports and on decohese pictorial films

    ON-Tech: from Roman mortars to green innovative solutions

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    ON-Tech project is based on the idea to produce modern and green restoration mortars according to the recipe of ancient mortars from the Trajan Aqueduct (Rome, II century AD), which showed high durability and resistance thanks to a synergic combination of raw materials, grain size and production technology. The main objective is to realize eco-friendly restoration mortars, not harmful to humans and compatible with ancient materials, with high performance and minimum CO2 production to make them more effective and sustainable, to preserve cultural heritage for future generations. First, a preliminary characterization of three typologies of Pozzolan materials from the surrounding of Bracciano Lake has been provided by means of optical microscopy (OM), X-ray powder diffraction (XRPD), Fourier-transform infrared spectroscopy (FTIR) and Scanning Electron Microscopy (SEM-EDS). The results showed differences in the matrix, leucite crystals (presence, dimension, typology), amount of phenocrystals (clinopyroxenes and feldspars) and porosity. After the preliminary investigations, the pozzolan materials compatible with ancient samples were chosen for the new formulations, which have been then analyzed from the mineralogical point of view by FTIR and XRPD and non-destructive tests (usb analysis, peeling tests, Karsten tube, sponge test) in order to assess physical and mechanical characteristics and durability of the new products
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