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Corrigendum: Time-resolved soft X-ray methods on solids with the MUSIX endstation . Recent upgrades for geometric flexibility (2025 J. Phys.: Conf. Ser. 3010 012174)
No full textAbstractPlease see Article PDF for corrigendum text
Ultrafast Terahertz Field Control of the Emergent Magnetic and Electronic Interactions at Oxide Interfaces
No full textUltrafast electric-field control of emergent electronic and magnetic states at oxide interfaces offers exciting prospects for the development of the next generation of energy-efficient devices. Here, it is demonstrated that the electronic structure and emergent ferromagnetic interfacial state in epitaxial LaNiO3/CaMnO3 superlattices can be effectively controlled using intense, single-cycle THz electric-field pulses. A suite of advanced X-ray spectroscopic techniques is employed to measure a detailed magneto-optical profile and the thickness of the ferromagnetic interfacial layer. Then, a combination of time-resolved and temperature-dependent optical measurements is used to disentangle several correlated electronic and magnetic processes driven by ultrafast, high-field THz pulses. Sub-picosecond non-equilibrium Joule heating of the electronic system is observed, ultrafast demagnetization of the ferromagnetic interfacial layer, and slower dynamics indicative of a change in the magnetic state of the superlattice due to the transfer of spin-angular momentum to the lattice. These findings suggest a promising avenue for the efficient control of 2D ferromagnetic states at oxide interfaces using ultrafast electric-field pulses
Search for charged Higgs bosons decaying into top and bottom quarks in lepton+jets final states in proton-proton collisions at = 13 TeV
No full textA search is presented for charged Higgs bosons (H) in proton-proton (pp) collision events via the pp (b)H processes, with H decaying into top (t) and bottom (b) quarks. The search targets final states with one lepton, missing transverse momentum, and two or more b jets. The analysis is based on data collected at a center-of-mass energy of 13 TeV with the CMS detector at the LHC, corresponding to an integrated luminosity of 138 fb. We search for charged Higgs bosons in the 200 GeV to 1 TeV mass range. The results are interpreted within the generalized two-Higgs-doublet model (g2HDM). This model predicts additional Yukawa couplings of the Higgs bosons to the top quark , the top and charm quark , and the top and up quark . This search focuses on the real components of and , which are probed up to values of unity. An excess is observed with respect to the standard model expectation with a local significance of 2.4 standard deviations for a signal with an H boson mass () of 600 GeV. Limits are derived on the product of the cross section (pp (b)H) and branching fraction (H tb, t b), where = e, . The values of 0.150.5 are excluded at 95% confidence level, depending on the and assumptions. The results represent the first search for charged Higgs bosons within the g2HDM framework and complement the existing results on additional neutral Higgs bosons
Final-state polarization of lepto-produced hyperons
No full textHyperon polarization in high-energy reactions has been an intriguing and puzzling topic in QCD for 50 years, starting with the surprising observation of large transverse hyperon polarization produced in collision of unpolarized hadrons. Hyperons are especially interesting in this regard as their weak decay provides access to their polarization via an asymmetric decay distribution, something that can be analyzed relatively easily. The HERMES experiment at DESY, utilizing the 27.6 GeV electron or positron beam of HERA impinging on pure nuclear gas targets was dedicated to the study of mainly the spin structure of the proton but also other spin effects. Transverse polarization of Lambda hyperons in the scattering of unpolarized leptons by unpolarised nuclei has been observed and spin correlations between the polarized leptons and final-state Lambda hyperons in deep- inelastic scattering have been studied, results of which will be presented in this contribution
The Gamma-Ray Luminosity Function of Flat-spectrum Radio Quasars
No full textWe have utilized the largest sample of gamma-ray-selected Fermi flat-spectrum radio quasars (FSRQs) ever used (519 sources) to construct the luminosity function and its evolution through cosmic history. In addition to spanning large redshift (0 < z ≲ 4) and luminosity ranges (2.9 × 10 erg s–7.3 × 10 erg s), this sample also has a robust calculation of the detection efficiency associated with its observation, making its selection effects and biases well understood. We confirm that the local luminosity function is best explained by a double power law. The evolution of the luminosity function of FSRQs follows a luminosity-dependent density evolution. FSRQs experience positive evolution, with their space density growing with increasing redshift up to a maximum redshift, after which the numbers decrease. This peak in redshift occurs at larger redshifts for higher-luminosity sources and at lower redshifts for lower-luminosity sources. We find an unexpected similarity between the luminosity function of FSRQs and that of BL Lacertae objects (BL Lacs) at intermediate luminosity. This could be a sign of a strong genetic link between the two blazar subclasses or of BL Lac samples being contaminated by large amounts of FSRQs with their jets nearly perfectly aligned with our line of sight
Local lattice distortions drive the transition of BaIrO into a ferromagnetic insulator state
No full textUsing variable temperature total and resonant x-ray scattering at the K edge of Ir species, we study the “bad metal” to insulator transition in BaIrO, a canonical third transition series oxide. The usage of advanced experimental techniques and large-scale computer modeling helps us show that, contrary to the widely accepted view, charge disproportionation leading to the formation of Ir-trimers with a different number of 5d valence electrons already exists at room temperature. The charge disbalance between the trimers does not evolve much with decreasing temperature while local lattice distortions do, suggesting that the latter and not the former make a key contribution to the emergence of the enigmatic ferromagnetic insulator state of BaIrO. The conclusion is supported by DFT calculations based on unmodified experimental structure data. Our work calls for a reconsideration of the role of lattice distortions in determining the electronic properties of third transition series oxides. It also charts a path to assessing these properties on a realistic and not assumed crystal structure basis
Ultrafast Pulsed Laser Annealing of Pd100-xSix Thin Films
No full textExcitation of materials by ultrashort laser pulses is characterized initially by a strong non-equilibrium between the electronic and lattice degrees of freedom. This is followed by a rapid transfer of the electronic excess energy to the lattice, which leads to heating within a few picoseconds. In thin films deposited on a substrate, the subsequent nanosecond-scale quenching is driven by rapid heat diffusion into the substrate. This non-equilibrium heating–cooling cycle with ultrahigh heating and cooling rates enables access to metastable states that are difficult to reach with conventional techniques. In this work, we report on a comprehensive characterization of structural changes driven by ultrashort pulsed laser annealing in thin Pd100-xSix films (x = 0, 3, 5, 10, 17%). The combined use of microscopy and X-ray diffraction for post-mortem analysis provides new insights into the composition-dependent crystallization behavior. By analyzing optical images from a series of laser irradiations at varying pulse energies (fluence scan), a two-dimensional fluence map was reconstructed for an arbitrary pulse energy. This enabled a direct correlation between deposited energy density, surface morphology, and structural changes derived from the micro-X-ray diffraction measurements analyzed using the Rietveld method. Above a fluence threshold of 25 mJ/cm2, all samples exhibit significant structural modifications — changes of the surface morphology, an increase of the lattice parameters, reduction of strain, grain growth, and reduced amorphous contributions. These observations are consistent with a scenario in which the sample undergoes ultrafast melting, followed by rapid cooling and recrystallization, thereby relaxing towards a lower energy state. Notably, only the face-centered cubic phase of crystalline Pd was observed across all samples and irradiation conditions, in contrast to the equilibrium phase diagram including the Pd–Si compounds. This confirms that ultrafast laser treatment produces metastable states, previously unreported in Pd–Si alloys
Search for resonant leptoquark production via lepton-jet signatures in collisions at TeV and TeV with the ATLAS detector
No full textThis paper presents a search for physics beyond the Standard Model targeting a heavy resonance visible in the invariant mass of the lepton-jet system. The analysis focuses on final states with a high-energy lepton and jet, and is optimised for the resonant production of leptoquarks-a novel production mode mediated by the lepton content of the proton originating from quantum fluctuations. Four distinct and orthogonal final states are considered: +light jet, +light jet, +-jet, and +-jet, constituting the first search at the Large Hadron Collider for resonantly produced leptoquarks with couplings to electrons and muons. Events with an additional same-flavour lepton, as expected from higher-order diagrams in the signal process, are also included in each channel. The search uses proton-proton collision data from the full Run 2, corresponding to an integrated luminosity of 140 fb at a centre-of-mass energy of TeV, and from a part of Run 3 (2022-2023), corresponding to 55 fb at TeV. No significant excess over Standard Model predictions is observed. The results are interpreted as exclusion limits on scalar leptoquark () production, substantially improving upon previous ATLAS constraints from leptoquark pair production for large coupling values. The excluded mass ranges depend on the coupling strength, reaching up to 3.4 TeV for quark-lepton couplings , and up to 4.3 TeV, 3.1 TeV, and 2.8 TeV for , , and couplings set to 3.5, respectively
