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Multiplet Recombination and the CFT Distance Conjecture
No full textMotivated by quantum gravity and the CFT Distance Conjecture, we study infinite-distance limits in four-dimensional superconformal field theories with higher-dimensional conformal manifolds and their AdS duals. We focus on partial decoupling limits where a gauge sector becomes weakly coupled while an interacting sector persists. We analyse the structure of towers of states emerging in these limits. The weakly coupled sector contributes, among others, the massless higher-spin tower predicted by the CFT Distance Conjecture exhibiting polynomial degeneracy. The key novelty is the appearance of a protected BPS tower in the interacting sector, characterised by exponential degeneracy and masses at the AdS scale. This structure follows from multiplet recombination in the superconformal algebra: As unprotected long multiplets hit the unitarity bound at weak coupling, they recombine into protected short multiplets. We verify this picture through an explicit one-loop computation in the simplest two-node quiver gauge theory with a two-dimensional conformal manifold
Navigating the Bio‐Inspired Structure‐Function Landscape: Spectroscopy Driven Finding of Hidden Radical Oxidation in Co‐porphyrinic Porous Organic Polymer
No full textThe conventional synthesis of acetophenone via the Friedel-Crafts reaction is a highly waste-intensive process. Consequently, thedevelopment of more sustainable and efficient alternatives is important. In this regard, radical oxidation represents a promising,environmentally benign route for acetophenone production. In this work, we designed a cobalt porphyrin-based metalatedporous organic polymer (Co@POR-POP), a highly active catalytic system, offering a potentially viable and cleaner approach toacetophenone production, utilizing styrene as the starting material. The catalyst exhibits a high surface area (BET = 650 m 2 g−1 )with bimodal pores, and delivers more than 90% yield of acetophenone under ambient conditions with excellent selectivity.Synchrotron-based XAFS spectroscopy study revealed a square-planar Co-N 4 coordination environment with coordinationnumber (CN) ≈4 and Co─N bond distance of ∼1.93 Å, with no evidence of Co–Co scattering, confirming the presence of isolatedactive sites. In situ EPR spectroscopy investigation displayed g⊥ = 2.049 and g∥ = 1.985 with hyperfine couplings A⊥ = 49.8 MHzand A∥ = 46.16 MHz, alongside an organic radical signal at g = 2.003. Spin-trapping with DMPO detected both hydrogen (∙H) andstyrene (∙C) radicals, validating a radical-mediated mechanism. DFT calculations established a thermodynamically favourablepathway with an overall energy drop of −4.5 eV, supported by spin density localization at the Co centre and significant d-π orbitaloverlap facilitating O2 activation. Overall, this work presents a new avenue of exploring novel organic transformation reactionsusing metalated porous organic polymer, opening scope for further investigations in this domain
High-level hadronic tau lepton triggers of the CMS experiment in proton-proton collisions at = 13.6 TeV
No full textThe trigger system of the CMS detector is pivotal in the acquisition of data for physics measurements and searches. Studies of final states characterized by hadronic decays of tau leptons require the reconstruction and the identification of genuine tau leptons against quark- and gluon-initiated jets at the trigger level. This is a difficult task, particularly as improvements to the LHC have resulted in an increased number of interactions per bunch crossing in recent years. To address this challenge, a series of machine-learning algorithms with high identification efficiency and low computational cost have been incorporated into the high-level trigger for hadronically decaying tau leptons. In this paper, these developments and the trigger performance are summarized using data collected by the CMS experiment in proton-proton collisions at = 13.6 TeV in 20222023, corresponding to an integrated luminosity of 62 fb
Luminescence of CsI:Na crystal scintillator under synchrotron radiation excitation
No full textThis work investigates the luminescence properties and energetic structure of emission centers created by NaCsisoelectronic impurities in a well-known CsI:Na scintillation crystal. Using synchrotron radiation excitation at 8K, high-resolution spectroscopic techniques were employed to probe the electronic transitions and luminescentdynamics within the crystal. The study reveals distinct emission bands that can be attributed to both self-trappedexciton (STE) states and excitons bound to NaCs and defect-related centers, with a clear separation between fastand slow decay components. These findings provide deeper insight into how the NaCs impurity alters theemission behaviour of the CsI host, including modifications to energy transfer and relaxation processes
Stress-induced orthorhombic O phase in TiAl alloys
No full textThe orthorhombic O phase precipitation within the D0 phase has attracted increasing attention recently inhigh Nb containing TiAl (high Nb-TiAl) alloys since the precipitation temperature is close to the expected servicetemperature of the alloys. In this study, in-situ synchrotron high energy X-ray diffraction (HEXRD) reveals thatthe O phase precipitates at 550 ◦C while it dissolves into the phase at 750 ◦C during heat treatments. However,under external stress the O phase unexpectedly precipitates from phase at 800 ◦C and even 900 ◦C. The Ophase formation proceeds further in the presence of a critical stress promoted by internal stress accumulation inthe phase, whereas the reverse O → phase transformation takes place when the internal stresses are relaxed.Additionally, it has been revealed that the O phase preferentially precipitates from specifically oriented grainswith one of their directions aligned perpendicular and their 〈0001〉directions rotated by an angle of 120◦ out of the external load axis. This phase orientation facilitates the → O crystal transition during uniaxialcompression. Transmission electron microscopy (TEM) study shows that stress-induced → O transformation isgoverned by small atomic shifts in the lattice. In addition, the selective growth of certain O variants viashuffling along an [110] direction is found to accommodate the external strain component in this direction
FLAG review 2024
No full textWe review lattice results related to pion, kaon, D-meson, B-meson, and nucleon physics with the aim of making them easily accessible to the nuclear and particle physics communities. More specifically, we report on the determination of the light-quark masses, the form factor f+(0) arising in the semileptonic K→π transition at zero momentum transfer, as well as the decay-constant ratio fK/fπ and its consequences for the Cabibbo–Kobayashi–Maskawa (CKM) matrix elements Vus and Vud. We review the determination of the BK parameter of neutral kaon mixing as well as the additional four B parameters that arise in theories of physics beyond the Standard Model. For the heavy-quark sector, we provide results for mc and mb as well as those for the decay constants, form factors, and mixing parameters of charmed and bottom mesons and baryons. These are the heavy-quark quantities most relevant for the determination of CKM matrix elements and the global CKM unitarity-triangle fit. We review the status of lattice determinations of the strong coupling constant αs. We review the determinations of nucleon charges from the matrix elements of both isovector and flavor-diagonal axial, scalar and tensor local quark bilinears, and momentum fraction, helicity moment and the transversity moment from one-link quark bilinears. We also review determinations of scale-setting quantities. Finally, in this review we have added a new section on the general definition of the low-energy limit of the Standard Model
Anisotropic growth of ferberite (FeWO ) on W(110) by high-temperature oxygen-assisted molecular beam epitaxy
No full textWe report on the growth of nanowires of ferberite (FeWO) by high-temperature oxygen-assisted molecular beam epitaxy on W(110). This multifunctional material has promising applications in different fields. The wires extend for several millimeters in length, with widths in the hundreds and heights in the tens of nanometers. We have monitored the growth process by real-time low-energy electron microscopy and characterized the wires in-situ by low-energy electron microscopy and laterally-resolved X-ray absorption and photoelectron spectroscopies. Further analysis was performed ex-situ by atomic force and optical microscopies as well as by Raman spectroscopy. The growth of ferberite on W(110) was possible by dosing iron in a molecular oxygen atmosphere likely due to the formation of highly mobile WO units that can be incorporated into the anisotropic wolframite structure, which in turn is responsible for the highly anisotropic growth. We propose that the same method may be used for the growth of other tungstate or related compounds
Study of decays at Belle and Belle II
No full textWe report a measurement of the branching fraction for the leptonic decay . This work presents the first result using Belle~II data, an updated Belle measurement that supersedes the previous result, and their combination, which yields the most precise search to date. The analysis is based on of collision data collected at a center-of-mass energy of with the Belle and Belle~II detectors at the KEKB and SuperKEKB colliders, respectively. We measure , where the first uncertainty is statistical and the second systematic. The observed significance relative to the background-only hypothesis is 2.4 standard deviations. We set a 90% confidence level upper limit of , obtaining . We present a model-dependent study of weak annihilation decays using the muon momentum spectrum. We observe a signal of 2.4 standard deviations above the background-only hypothesis in regions where the distribution resembles that of decays