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Revisiting the distance to the nearest UHECR source: Effects of extra-galactic magnetic fields
No full textWe update the constraints on the location of the nearest ultrahigh energy cosmic ray (UHECR) source. By analyzing recent data from the Pierre Auger Observatory using state-of-the-art CR propagation models, we reaffirm the need of local sources with a distance less than 25–100 Mpc, depending on mass composition. A new fast semianalytical method for the propagation of UHECR in environments with turbulent magnetic fields is developed. The onset of an enhancement and a low-energy magnetic horizon of cosmic rays from sources located within a particular distance range is demonstrated. We investigate the distance to the nearest source, taking into account these magnetic field effects. The results obtained highlight the robustness of our constrained distances to the nearest source
Resonant backreaction in axion inflation
No full textAxion inflation entails a coupling of the inflaton field to gauge fields through the Chern-Simons term. This results in a strong gauge field production during inflation, which backreacts on the inflaton equation of motion. We show that this strongly non-linear system generically experiences a resonant enhancement of the gauge field production, resulting in oscillatory features in the inflaton velocity as well as in the gauge field spectrum. The gauge fields source a strongly enhanced scalar power spectrum at small scales, exceeding previous estimates. For appropriate parameter choices, the collapse of these over-dense regions can lead to a large population of (light) primordial black holes with remarkable phenomenological consequences
Observation of electroweak production of W with two jets in proton-proton collisions at 13 TeV
No full textA first observation is presented for the electroweak production of a W boson, a photon, and two jets in proton-proton collisions. The W boson decays are selected by requiring one identified electron or muon and an imbalance in transverse momentum. The two jets are required to have a high dijet mass and a large separation in pseudorapidity. The measurement is based on data collected with the CMS detector at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb. The observed (expected) significance for this process is 4.9 (4.6) standard deviations. After combining with previously reported CMS results at 8 TeV, the observed (expected) significance is 5.3 (4.8) standard deviations. The cross section for the electroweak Wjj production in a restricted fiducial region is measured as 20.4 4.5 fb and the total cross section for W production in association with 2 jets in the same fiducial region is 108 16 fb. All results are in good agreement with recent theoretical predictions. Constraints are placed on anomalous quartic gauge couplings in terms of dimension-8 effective field theory operators
Measurements of production cross sections of WZ and same-sign WW boson pairs in association with two jets in proton-proton collisions at 13 TeV
No full textMeasurements of production cross sections of WZ and same-sign WW boson pairs in association with two jets in proton-proton collisions at s=13TeV at the LHC are reported. The data sample corresponds to an integrated luminosity of 137 fb , collected with the CMS detector during 2016–2018. The measurements are performed in the leptonic decay modes W±Z → ℓ±νℓ′±ℓ′ and W±W± → ℓ±νℓ′±ν, where ℓ,ℓ′ = e,μ. Differential fiducial cross sections as functions of the invariant masses of the jet and charged lepton pairs, as well as of the leading-lepton transverse momentum, are measured for W±W± production and are consistent with the standard model predictions. The dependence of differential cross sections on the invariant mass of the jet pair is also measured for WZ production. An observation of electroweak production of WZ boson pairs is reported with an observed (expected) significance of 6.8 (5.3) standard deviations. Constraints are obtained on the structure of quartic vector boson interactions in the framework of effective field theory
Molecular Mechanisms of the Interactions of N-(2-Hydroxypropyl)methacrylamide Copolymers Designed for Cancer Therapy with Blood Plasma Proteins
No full textThe binding of plasma proteins to a drug carrier alters the circulation of nanoparticles (NPs) in the bloodstream, and, as a consequence, the anticancer efficiency of the entire nanoparticle drug delivery system. We investigate the possible interaction and the interaction mechanism of a polymeric drug delivery system based on N-(2-hydroxypropyl)methacrylamide (HPMA) copolymers (pHPMA) with the most abundant proteins in human blood plasma—namely, human serum albumin (HSA), immunoglobulin G (IgG), fibrinogen (Fbg), and apolipoprotein (Apo) E4 and A1—using a combination of small-angle X-ray scattering (SAXS), analytical ultracentrifugation (AUC), and nuclear magnetic resonance (NMR). Through rigorous investigation, we present evidence of weak interactions between proteins and polymeric nanomedicine. Such interactions do not result in the formation of the protein corona and do not affect the efficiency of the drug delivery
Matching the heavy-quark fields in QCD and HQET at four loops
No full textThe QCD/HQET matching coefficient for the heavy-quark field is calculated up to four loops. It must be finite; this requirement produces analytical results for some terms in the four-loop on-shell heavy-quark field renormalization constant which were previously only known numerically. The effect of a non-zero lighter-flavor mass is calculated up to three loops. A class of on-shell integrals with two masses is analyzed in detail. By specifying our result to QED, we obtain the relation between the electron field and the Bloch--Nordsieck field with four-loop accuracy
Nucleation and Growth of PbBrF Crystals at the Liquid Mercury–Electrolyte Interface Studied by Operando X-ray Scattering
No full textDetailed in operando studies of electrochemically induced PbBrF deposition at the liquid mercury/liquid electrolyte interface are presented. The nucleation and growth were monitored using time-resolved X-ray diffraction and reflectivity combined with electrochemical measurements, revealing a complex potential-dependent behavior. PbBrF deposition commences at potentials above −0.7 V with the rapid formation of an ultrathin adlayer of one unit cell thickness, on top of which (001)-oriented three-dimensional crystallites are formed. Two potential regimes are identified. At low overpotentials, slow growth of a low surface density film of large crystals is observed. At high overpotentials, crossover to a potential-independent morphology occurs, consisting of a compact PbBrF deposit with a saturation thickness of 25 nm, which forms within a few minutes. This potential behavior can be rationalized by the increasing supersaturation near the interface, caused by the potential-dependent Pb deamalgamation, which changes from a slow reaction-controlled process to a fast transport-controlled process in this range of overpotentials. In addition, growth on the liquid substrate is found to involve complex micromechanical effects, such as crystal reorientation and film breakup during dissolution
Effect of silver nanoparticle doping on the physicochemical properties of a room temperature ferroelectric liquid crystal mixture
No full textWe have investigated the effect of doping of a small amount of silver nanoparticles (AgNPs) on the physicochemical properties of a room temperature ferroelectric liquid crystal mixture. Polarizing optical microscopy, differential scanning calorimetry, synchrotron X-ray diffraction, dielectric and electro-optic studies showed that the inclusion of AgNPs greatly influences the phase transition temperatures, structural, dielectric, and electro-optic properties. Doping slightly decreases the SmC*-SmA* and SmA*-Iso transition temperatures signifying decreased ordering which is also reflected in reduced tilt angles. The Goldstone mode dielectric increment of the nanocomposite increases twofold but the critical frequency decreases slightly. Spontaneous polarization of the mixture also increases significantly in the presence of AgNPs whereas the conductivity decreases indicating trapping of ions by the nanoparticles. Goldstone mode rotational viscosity decreases and as a result of which the switching time also decreases by 88 μs making the nano doped mixture more suitable for practical applications
Ferroelectric phase transitions in multi-domain epitaxial thin films
No full textA high-temperature phase transition in strained ferroelectric KNaNbO thin films epitaxially grown on orthorhombic (110) NdScO substrates is identified and investigated by in situ x-ray diffraction and piezoresponse force microscopy. At room temperature, the thin films exhibit a highly anisotropic misfit strain, inducing the occurrence of monoclinic aa/M phases and manifesting itself in the formation of a highly regular, herringbone-like domain arrangement. With increasing temperature, a ferroelectric-to-ferroelectric phase transition to an orthorhombic a/a phase with exclusive lateral electrical polarization takes place. Within a wide temperature range from 180 °C to about 260 °C, a coexistence of the monoclinic aa/M room temperature phases and the orthorhombic a/a high temperature phase is observed. Finally, at higher temperatures only the orthorhombic a/a phase, which is arranged in a regular stripe domain pattern, is present. Corresponding simulations of the scattered x-ray intensity patterns show that the orthorhombic unit cells undergo a small in-plane rotation. This leads to four different in-plane orientations of the orthorhombic unit cells and four corresponding variants of superdomains