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

Jet fragmentation functions are measured for the first time in proton-proton collisions for charged pions, kaons, and protons within jets recoiling against a $Z$ boson. The charged-hadron distributions are studied longitudinally and transversely to the jet direction for jets with transverse momentum 20 $< p_{\textrm{T}} < 100$ GeV and in the pseudorapidity range $2.5 < \eta < 4$. 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 fb$^{-1}$. 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 B−→Λc+Λˉc−K−B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} decay

The decay $B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-}$ is studied in proton-proton collisions at a center-of-mass energy of $\sqrt{s}=13$ TeV using data corresponding to an integrated luminosity of 5 $\mathrm{fb}^{-1}$ collected by the LHCb experiment. In the $\Lambda_{c}^+ K^{-}$ system, the $\Xi_{c}(2930)^{0}$ state observed at the BaBar and Belle experiments is resolved into two narrower states, $\Xi_{c}(2923)^{0}$ and $\Xi_{c}(2939)^{0}$, whose masses and widths are measured to be $$m(\Xi_{c}(2923)^{0}) = 2924.5 \pm 0.4 \pm 1.1 \,\mathrm{MeV}, \\ m(\Xi_{c}(2939)^{0}) = 2938.5 \pm 0.9 \pm 2.3 \,\mathrm{MeV}, \\ \Gamma(\Xi_{c}(2923)^{0}) = \phantom{000}4.8 \pm 0.9 \pm 1.5 \,\mathrm{MeV},\\ \Gamma(\Xi_{c}(2939)^{0}) = \phantom{00}11.0 \pm 1.9 \pm 7.5 \,\mathrm{MeV},$$ where the first uncertainties are statistical and the second systematic. The results are consistent with a previous LHCb measurement using a prompt $\Lambda_{c}^{+} K^{-}$ sample. Evidence of a new $\Xi_{c}(2880)^{0}$ state is found with a local significance of $3.8\,\sigma$, whose mass and width are measured to be $2881.8 \pm 3.1 \pm 8.5\,\mathrm{MeV}$ and $12.4 \pm 5.3 \pm 5.8 \,\mathrm{MeV}$, respectively. In addition, evidence of a new decay mode $\Xi_{c}(2790)^{0} \to \Lambda_{c}^{+} K^{-}$ is found with a significance of $3.7\,\sigma$. The relative branching fraction of $B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-}$ with respect to the $B^{-} \to D^{+} D^{-} K^{-}$ decay is measured to be $2.36 \pm 0.11 \pm 0.22 \pm 0.25$, 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})

The ratios of branching fractions $\mathcal{R}(D^{*})\equiv\mathcal{B}(\bar{B}\to D^{*}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(\bar{B}\to D^{*}\mu^{-}\bar{\nu}_{\mu})$ and $\mathcal{R}(D^{0})\equiv\mathcal{B}(B^{-}\to D^{0}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(B^{-}\to D^{0}\mu^{-}\bar{\nu}_{\mu})$ are measured, assuming isospin symmetry, using a sample of proton-proton collision data corresponding to 3.0 fb${ }^{-1}$ of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode $\tau^{-}\to\mu^{-}\nu_{\tau}\bar{\nu}_{\mu}$. The measured values are $\mathcal{R}(D^{*})=0.281\pm0.018\pm0.024$ and $\mathcal{R}(D^{0})=0.441\pm0.060\pm0.066$, where the first uncertainty is statistical and the second is systematic. The correlation between these measurements is $\rho=-0.43$. 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

Study of nanometric thin pyrolytic carbon films for explosive electron emission cathode in high-voltage planar diode

We report on an experimental study of explosive electron emission properties of cathode made by nanometric thin pyrolytic carbon (PyC) films (2–150 nm) deposited on Cu substrate via methane-based chemical vapor deposition. High current density at level of 300 A/cm2 in 5 · 10− 5 Pa vacuum has been observed together with very stable explosive emission from the planar cathode. The Raman spectroscopy investigation proves that the PyC films remain the same after seven shots. According to the optical image analysis of the cathode before and after one and seven shots, we conclude that the most unusual and interesting feature of using the PyC films/Cu cathode for explosive emission is that the PyC layer on the top of the copper target prevents its evaporation and oxidation, which leads to higher emission stability compared to conventional graphitic/Cu cathodes, and therefore results in longer working life

Study of nanometric thin pyrolytic carbon films for explosive electron emission cathode in high-voltage planar diode

We report on an experimental study of explosive electron emission properties of cathode made by nanometric thin pyrolytic carbon (PyC) films (2–150 nm) deposited on Cu substrate via methane-based chemical vapor deposition. High current density at level of 300 A/cm2 in 5 · 10− 5 Pa vacuum has been observed together with very stable explosive emission from the planar cathode. The Raman spectroscopy investigation proves that the PyC films remain the same after seven shots. According to the optical image analysis of the cathode before and after one and seven shots, we conclude that the most unusual and interesting feature of using the PyC films/Cu cathode for explosive emission is that the PyC layer on the top of the copper target prevents its evaporation and oxidation, which leads to higher emission stability compared to conventional graphitic/Cu cathodes, and therefore results in longer working life

The Institutional Foundations of the Digital Economy in the 21st Century/ Elena G. Popkova, Artem Krivtsov, Aleksei V. Bogoviz.

In English.The development of the Digital Economy has been a landmark breakthrough for economic systems in the 21st century, as it opens up opportunities for the full-scale implementation of new digital technologies and the optimization of economic activities. While the conceptual essence and specific features of the digital economy are described in detail in the existing literature, the practical foundations of its formation are poorly studied. In this book, the digital economy is studied from the perspective of neo-institutional economic theory. This allows for the tracking of the process of formation (institutionalization) of the digital economy, determining the basic institutions that are necessary for its formation and that exist in modern economic practice, and analyzing scenarios for the future development of the digital economy in the 21st century.Frontmatter -- Contents -- Digital Economy in the 21 Century: An Introduction to the Institutional Approach -- Part I: The Scientific Concept of the Digital Economy in the 21st Century -- 1 Digital Economy as a Modern Type of Economic System -- 2 “Digitalization”- Overcoming Institutional Barriers -- 3 Development of the Information Technologies Sector in Latvia under Globalization -- 4 The Principles of Functioning and Priorities of Development of the Digital Economy -- 5 Classification of Breakthrough Digital Technologies and the Perspectives of Their Application in Economy -- Part II: The Process of Digital Economy Institutionalization in the 21st Century -- 6 The Essence and Logic of the Process of Sectorial Markets' Digital Transformation -- 7 The Current Tendencies of Economy Digitalization in Developed and Developing Countries -- 8 The Main Stages of the Digital Modernization of Economy -- 9 Implementation of Cluster Initiatives in the Digital Sphere as a Tool of Digital Entrepreneurship's Institutionalization -- 10 Institutions of Support for Digital Entrepreneurship: Special Economic Zones, Innovative Networks and Technological Parks -- Part III: Meso-Level Institutions of the Digital Economy in the 21st Century -- 11 Digitalization of Regional Economy: Problems and Perspectives -- 12 The Institutional Model of the Digital Economy Creation in a Modern Region -- 13 Managing a Modern Region Based on Digital Technologies -- Part IV: Macro-Level Institutions of the Digital Economy in the 21st Century -- 14 State Institutional Regulation of Economy Digital Modernization -- 15 The Role of Financial Institutions in Supporting the Digital Economy -- 16 Digital Economy of the 21st Century: A View from the Positions of Developed and Developing Countries -- Part V: The Global Institutions of the Digital Economy in the 21st Century -- 17 International Trade in the Digital Sphere: Barriers and Prospects for Development -- 18 The Existing and Perspective International Institutions for Supporting Digital Transformation of Economy -- 19 The Scientific and Methodological Approach to Provision and Evaluation of the Digital Economy's Global Competitiveness -- 20 The Strategy of Optimal Development of the Digital Economy: A View from the Positions of Game Theory -- 21 The Institutional Model of Well-Balanced and Sustainable Digital Economy -- 22 The Institutional Mechanism of Managing the Digital Economy's Development -- Part VI: Case Studies of Institutions of the Digital Economy in the 21st Century -- 23 Problems and Prospects of Economic Cooperation Between Russia and Mexico -- 24 Innovative Critical Success Factors for Public - Private Partnerships (PPP) in Infrastructure Projects of Developing Countries. A Case of Zambia -- 25 Prediction Mechanism of the Territorial Socio-Economic Processes in Formation of the Information Systems -- 26 Specific Economic Security Regulations in the Context of Pathological Crises of Digital Transformation of Agricultural Organizations -- Conclusion: Institutional Perspectives of the Digital Economy's Development in the 21st Century -- List of Figures -- List of Tables -- Index.1 online resource (XI, 258 p.)