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Search for a boosted Higgs boson decaying to bottom quark pairs in association with a W or Z boson in proton-proton collisions at = 13 TeV
No full textA search is conducted for standard model Higgs bosons with large transverse momentum () decaying to bottom quark pairs and produced in association with a hadronically decaying W or Z boson at the LHC. The result is based on a dataset of proton-proton collisions at a center-of-mass energy of 13 TeV collected with the CMS detector in 20162018, corresponding to an integrated luminosity of 138 fb. Boosted Higgs, W, and Z boson decays are reconstructed using large-radius jets with 450 GeV and identified with heavy-flavor classifiers based on a graph convolutional neural network. The observed signal strength relative to the standard model expectation is = 0.7 including statistical and systematic uncertainties
Measurement of the (1S), (2S), and (3S) differential cross sections in pp collisions at = 13.6 TeV
No full textThe production cross sections of the (1S), (2S), and (3S) mesons are measured in proton-proton collisions at = 13.6 TeV, using a data sample collected in 2022 by the CMS experiment and corresponding to an integrated luminosity of 37.4 fb. The measurement is performed in the decay channels, differentially as a function of transverse momentum in the 20200 GeV range, in the 0.6 and 0.6 1.2 rapidity intervals
Measurement and effective field theory interpretation of the photon-fusion production cross section of a pair of W bosons in proton-proton collisions at = 13 TeV
No full textThis analysis presents an observation of the photon-fusion production of W boson pairs using the CMS detector at the LHC. The total cross section of the WW production in photon fusion is measured using proton-proton collision data with an integrated luminosity of 138 fb collected with the CMS detector in 20162018 at a center-of-mass energy of = 13 TeV. Events are selected in the final state with one isolated electron and one isolated muon, and no additional tracks associated with the electron-muon production vertex. The total and fiducial production cross sections are 643 fb and 3.96 fb, respectively, in agreement with the standard model predictions of 631 126 fb and 3.87 0.77 fb. This agreement enables stringent constraints to be imposed on anomalous quartic gauge couplings within a dimension-8 effective field theory framework
Exploring real-time monitoring of laser-induced recrystallization using acoustic emissions
No full textThis study explores the use of acoustic emission (AE) signals for in situ characterization of recrystallization during laser processing. With millisecond-scale temporal resolution, AE monitoring can detect critical events during the recrystallization processes, including dislocation reorganization, nucleation, and grain growth. To connect such AE signals to recrystallization events, simultaneous in situ X-ray diffraction measurements were performed to establish a ground truth that could be correlated to collected AE data. From these experiments, a dominant frequency related to recrystallization was identified at ∼ 188 kHz using the current experimental setup. This frequency was isolated by filtering the raw AE data via a combination of power spectrum density distribution analysis, harmonic identification, and empirical mode decomposition. Focusing on the AE data from this frequency, it was possible to identify critical events during recrystallization, including the onset of nucleation as well as the completion of the recrystallization process. These findings represent the first attempt to unveil the acoustic signature of recrystallization, demonstrating the potential for real-time monitoring and control of diffusive microstructural evolutions during rapid processing. They further suggest that AE monitoring can serve as a powerful tool to optimize laser processing and enable precise microstructure control during recrystallization
Global tuning of hadronic interaction models with accelerator-based and astroparticle data
No full textIn high-energy and astroparticle physics, event generators play an essential role, even in the simplest data analyses. As analysis techniques become more sophisticated, e.g. based on deep neural networks, their correct description of the observed event characteristics becomes even more important. Physical processes occurring in hadronic collisions are simulated within a Monte Carlo framework. A major challenge is the modeling of hadron dynamics at low momentum transfer, which includes the initial and final phases of every hadronic collision. QCD-inspired phenomenological models used for these phases cannot guarantee completeness or correctness over the full phase space. These models usually include parameters which must be tuned to suitable experimental data. Until now, event generators have been developed and tuned mainly on the basis of data from high-energy physics experiments at accelerators. The wealth of data available from the latest generation of astroparticle experiments has not yet been fully exploited, and in many cases is not satisfactorily described. Both kinds of data sets are complementary as astroparticle experiments provide sensitivity especially to hadrons produced nearly parallel to the collision axis and cover center-of-mass energies up to several hundred TeV, well beyond those reached at colliders so far. In this report, we provide an overview of state-of-the-art event generators and their tuning, including the most relevant inputs from high-energy accelerator and astroparticle experiments. We present a road map that shows, for the first time, how the unified tuning of event generators with accelerator-based and astroparticle data can be performed
Scaling of thin wire cylindrical compression with material, diameter, and laser energy after 100 fs Joule surface heating
No full textWe present the first systematic experimental validation of return-current-driven cylindrical implosion scaling in micrometer-sized Cu and Al wires irradiated by J-class femtosecond laser pulses. Employing XFEL-based imaging with sub-micrometer spatial and femtosecond temporal resolution, supported by hydrodynamic and particle-in-cell simulations, we reveal how return current density depends precisely on wire diameter, material properties, and incident laser energy. We identify deviations from simple theoretical predictions due to geometrically influenced electron escape dynamics. These results refine and confirm the scaling laws essential for predictive modeling in high-energy-density physics and inertial fusion research
Role of local structural distortions in the variation of martensitic transformation temperature with ratio in NiMnZ (Z = In, Sn or Sb) alloys
No full textNiMnZ (Z = In, Sn or Sb) undergo martensitic transformation with transformation temperature (TM) scaling with the average valence electron per atom ratio. However, the rate of increase of TM depends on the type of Z atom, with the slope of TM vs. e/a curve increasing from Z = In to Z = Sb. Local structural distortions are believed to be the leading cause of martensitic transformation in these alloys. A careful study of the Ni and Mn local structures in several NiMnZ alloys with varying e/a ratio and the same Z atom, with the same e/a ratio but different Z atoms and with the same T but with different Z atoms and different e/a ratio, revealed that the difference between Ni–Mn and Ni–Z nearest neighbor distances decreases as the Z atom changes from In to Sb. This decrease in the local structural distortion accommodates a higher content of Mn until the L2 structure becomes unstable and the alloy undergoes a martensitic transformation
Characterization of the Spin-Frustration in Doubly Ordered Perovskite NaYbZnWO Obtained by High-Pressure Synthesis
No full textWe present the high-pressure synthesis of a novel doubly ordered perovskite NaYbZnWO composed of the rare earth magnetic Yb ions and its comprehensive magnetic characterization. The structure consists of alternating layers of Yb and Na ions along the c-axis, with Yb ions forming slightly distorted two-dimensional (2D) square lattices of kite-shape (Yb)4 units. Low-temperature magnetic susceptibility measurements indicate that the ground state of Yb can be described by an effective J = 1/2 Kramers doublet. Further, specific heat analysis reveals an internal magnetic field of the order of 1.48 K; however, magnetization data do not exhibit magnetic ordering down to 0.4 K. The spin exchanges of NaYbZnWO evaluated by density functional theory (DFT) calculations unveil spin frustration in the compound. These findings suggest that NaYbZnWO is a promising candidate for realizing a magnetically disordered quantum state
Modulating Local Oxygen Coordination to Achieve Highly Reversible Anionic Redox and Negligible Voltage Decay in ‐Type Layered Cathodes for Li‐Ion Batteries
No full textO2-type layered oxides have emerged as promising cathode materials for high-energy lithium-ion batteries, offering a solution to mitigate voltage decay through reversible transition metal (TM) migration between TM and Li layers during cycling. However, achieving a fully reversible oxygen redox remains a significant challenge. Here, this is addressed by introducing Li─O─Li configurations in the layered structure of Li0.85□0.15[Li0.08□0.04Ni0.22Mn0.66]O2 (O2-LLNMO), where □ represents vacancies. This adjustment alters the redox-active oxygen environment and increases the energy gap between the O 2p nonbonding and TM─O antibonding bands. As a result, the contribution of lattice oxygen to capacity is significantly enhanced, improving the reversibility of oxygen redox processes. The O2-LLNMO cathode demonstrates minimal voltage decay (0.13 mV per cycle) and excellent cycling stability, retaining 95.8% of its capacity after 100 cycles. A novel strategy is presented to design high-performance layered oxides with stable anionic redox activity, advancing the development of next-generation lithium-ion batteries