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Pd-Based Bimetallic Nanocrystal Catalysts for the Direct Synthesis of
No full textThe direct hydrogen peroxide (H 2 O 2 ) synthesis from H 2 and O 2 is a strongly desired reaction for green processes and a promising alternative to the commercialized anthraquinone process. The design of efficient catalysts with high activity and H 2 O 2 selectivity is highly desirable and yet challenging. Metal dopants enhance the performance of the active phase by increasing reaction rates, stability, and/or selectivity. Identifying efficient dopants mostly relies on catalysts prepared with the random and non‐uniform deposition of active and promoter phases. To study the promotional effects of metal doping on palladium catalysts, we employ colloidal, bimetallic nanocrystals (NCs) to produce catalysts where the active and doping metals are co‐localized to a fine extent. In the absence of any acid and halide promotors, PdSn and PdGa NCs (PdSn/s‐TiO 2 , PdGa/s‐TiO 2 ) were highly efficient and clearly outperformed the monometallic palladium catalyst (Pd/s‐TiO 2 ), while in the presence of acid promotor the overall H 2 O 2 productivity was also further enhanced for the Ni‐, Ga‐, In‐, and Sn‐doped catalysts with respect to Pd/s‐TiO 2
The geometry of SUSY enhancement
No full textWe provide a precise geometric picture that demystifies the phenomenon of supersymmetry enhancement along certain RG flows of four-dimensional field theories, recently discovered by Maruyoshi and Song. It applies to theories of arbitrary rank and it is based on a hyperkähler-structure restoration on the moduli space of solutions of (twisted) Hitchin systems, which underly the class- construction we use as an engineering tool. Along the way, we formulate a necessary algebraic condition for supersymmetry enhancement, and, when enhancement occurs, we are able to derive the Seiberg-Witten geometry and all conformal dimensions of Coulomb-branch operators for the infrared theory, without using a-maximization
First search for the in decays at Belle
No full textThe first dedicated search for the is carried out using the decays , , , and with . No significant signal is found. For the mass range between and , the branching-fraction upper limits are determined to be , , , and at 90% C. L. The analysis is based on the 711 data sample collected on the resonance by the Belle detector, which operated at the KEKB asymmetric-energy collider
Fermi Large Area Telescope Fourth Source Catalog
No full textWe present the fourth Fermi Large Area Telescope catalog (4FGL) of γ-ray sources. Based on the first eight years of science data from the Fermi Gamma-ray Space Telescope mission in the energy range from 50 MeV to 1 TeV, it is the deepest yet in this energy range. Relative to the 3FGL catalog, the 4FGL catalog has twice as much exposure as well as a number of analysis improvements, including an updated model for the Galactic diffuse γ-ray emission, and two sets of light curves (one-year and two-month intervals). The 4FGL catalog includes 5064 sources above 4σ significance, for which we provide localization and spectral properties. Seventy-five sources are modeled explicitly as spatially extended, and overall, 358 sources are considered as identified based on angular extent, periodicity, or correlated variability observed at other wavelengths. For 1336 sources, we have not found plausible counterparts at other wavelengths. More than 3130 of the identified or associated sources are active galaxies of the blazar class, and 239 are pulsars
Approximate four-loop QCD corrections to the Higgs-boson production cross section
No full textWe study the soft and collinear (SV) contributions to inclusive Higgs-boson production in gluon-gluon fusion at four loops. Using recent progress for the quark and gluon form factors and Mellin moments of splitting functions, we are able to complete the soft-gluon enhanced contributions exactly in the limit of a large number of colours, and to a sufficiently accurate numerical accuracy for QCD. The four-loop SV contributions increase the QCD cross section at 14 TeV by 2.7% and 0.2% for the standard choices mu_R=m_H and mu_R=m_H/2 of the renormalization scale, and reduce the scale uncertainty to below +-3%. As by-products, we derive the complete delta(1-x) term for the gluon-gluon splitting function at four loops and its purely Abelian contributions at five loops, and provide a numerical result for the single pole of the four-loop gluon form factor in dimensional regularization. Finally we present the closely related fourth-order coefficients D_4 for the soft-gluon exponentiation of Higgs-boson and Drell-Yan lepton-pair production
The effect of heat treatment on the precipitation hardening in FeNiCoAlTa single crystals
No full textThe main goal of this work was to examine the effect of aging process on the precipitation behavior including phase morphology, chemical composition and degree of coherence in Fe–28Ni–17Co-11.5Al-2.5Ta single crystals. The nano-sized and coherent γ′ precipitates were used for strengthening process. The particles were investigated with transmission and scanning electron microscopies along with high energy X-ray diffraction. The single crystalline material of [100] (001) orientation was subjected to three different heat treatments: slowly cooled, quenched and then annealed with various aging conditions. Aging at 973 K for short times results in coherent 2-6 nm-sized γ′ precipitates and fully reversible superelastic strains while annealing at 973 K for 5 h and longer times leads to the precipitation of larger γ’ particles formed together with β phase which significantly reduces the transformed martensite volume fraction
Ferromagnetic Kitaev interaction and the origin of large magnetic anisotropy in -RuCl
No full text-RuCl is drawing much attention as a promising candidate for the Kitaev quantum spin liquid1,2,3,4,5,6,7,8. However, despite intensive research efforts, controversy remains about the form of the basic interactions governing the physics of this material. Even the sign of the Kitaev interaction (the bond-dependent anisotropic interaction responsible for Kitaev physics) is still under debate, with conflicting results from theoretical and experimental studies5,6,9,10,11,12,13,14,15. The significance of the symmetric off-diagonal exchange interaction (referred to as the term) is another contentious question16,17,18. Here, we present resonant elastic X-ray scattering data that provide unambiguous experimental constraints to the two leading terms in the magnetic interaction Hamiltonian. We show that the Kitaev interaction (K) is ferromagnetic, and that the term is antiferromagnetic and comparable in size to the Kitaev interaction. Our findings also provide a natural explanation for the large anisotropy of the magnetic susceptibility in -RuCl as arising from the large term. We therefore provide a crucial foundation for understanding the interactions underpinning the exotic magnetic behaviours observed in -RuCl
Measurement of quark- and gluon-like jet fractions using jet charge in PbPb and pp collisions at 5.02 TeV
No full textThe momentum-weighted sum of the electric charges of particles inside a jet, known as jet charge, is sensitive to the electric charge of the particle initiating the parton shower. This paper presents jet charge distributions in 5.02 TeV lead-lead (PbPb) and proton-proton (pp) collisions recorded with the CMS detector at the LHC. These data correspond to integrated luminosities of 404 b and 27.4 pb for PbPb and pp collisions, respectively. Leveraging the sensitivity of the jet charge to fundamental differences in the electric charges of quarks and gluons, the jet charge distributions from simulated events are used as templates to extract the quark- and gluon-like jet fractions from data. The modification of these jet fractions is examined by comparing pp and PbPb data as a function of the overlap of the colliding Pb nuclei (centrality). This measurement tests the color charge dependence of jet energy loss due to interactions with the quark-gluon plasma. No significant modification between different centrality classes and with respect to pp results is observed in the extracted fractions of quark- and gluon-like jet fractions
A New Precision Process at FCC-hh: the diphoton leptonic Wh channel
No full textThe increase in luminosity and center of mass energy at the FCC-hh will open up new clean channels where BSM contributions are enhanced at high energy. In this paper we study one such channel, . We estimate the sensitivity to the , , and SMEFT operators. We find that this channel will be competitive with fully leptonic production in setting bounds on . We also find that the double differential distribution in the and the leptonic azimuthal angle can be exploited to enhance the sensitivity to . However, the bounds on and we obtain in our analysis, though complementary and more direct, are not competitive with those coming from other measurements such as EDMs and inclusive Higgs measurements