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The Fermi surface plays an important role in controlling the electronic, transport and thermodynamic properties of materials. As the Fermi surface consists of closed contours in the momentum space for well-defined energy bands, disconnected sections known as Fermi arcs can be signatures of unusual electronic states, such as a pseudogap1. Another way to obtain Fermi arcs is to break either the time-reversal symmetry2or the inversion symmetry3of a three-dimensional Dirac semimetal, which results in formation of pairs of Weyl nodes that have opposite chirality4, and their projections are connected by Fermi arcs at the bulk boundary3,5–12. Here, we present experimental evidence that pairs of hole- and electron-like Fermi arcs emerge below the Neel temperature (TN) in the antiferromagnetic state of cubic NdBi due to a new magnetic splitting effect. The observed magnetic splitting is unusual, as it creates bands of opposing curvature, which change with temperature and follow the antiferromagnetic order parameter. This is different from previous theoretically considered13,14and experimentally reported cases15,16of magnetic splitting, such as traditional Zeeman and Rashba, in which the curvature of the bands is preserved. Therefore, our findings demonstrate a type of magnetic band splitting in the presence of a long-range antiferromagnetic order that is not readily explained by existing theoretical ideas.

We report on the low-energy electronic structure of tantalum ditelluride (1T′-TaTe2), one of the charge density wave (CDW) materials from the group V transition metal dichalcogenides using angle-resolved photoemission spectroscopy and density functional theory (DFT). We find that the Fermi surface topology of TaTe2is quite complicated compared to its isovalent compounds such as TaS2, TaSe2, and isostructural compound NbTe2. Most importantly, we discover that the surface electronic structure of 1T′-TaTe2has more resemblance to the 2H-TaTe2, while the bulk electronic structure has more resemblance to the hypothetical 1T-TaTe2. These experimental observations are thoroughly compared with our DFT calculations performed on 1T-, 2H-, and 2H(monolayer)/1T-TaTe2. We further notice that the Fermi surface topology is temperature independent up to 180 K, confirming that the 2Hphase on the surface is stable up to 180 K and the CDW order is not due to the Fermi surface nesting.

In order to increase the efficiency of dedicated frequency channels, i.e. to increase the specific data transfer rate, multipositional quadrature phase shift keying (QPSK, aka 4-PSK) should be used. The problems with QPSK signal demodulation is a rotation of the signal constellation plane by an angle multiple of 90° and a slow response of the carrier oscillation recovery scheme. The study considers the existing methods for eliminating the phase ambiguity of the recovered carrier frequency in typical QPSK modems, and identifies the shortcoming of a low-speed response oscillation recovery circuit. The authors propose a QPSK demodulator circuit with a fast adjustment of the reference oscillator, which is due to the fact that no loop filter is used in the feedback and that a digital calculator of the required phase shift is used. An algorithm for the frame synchronization restoration with the simultaneous elimination of the phase ambiguity multiple of 90° was also developed using synthesized binary sequences with an ideal non-periodic autocorrelation function (NACF) at even shifts that do not have the rotary symmetry property. The phase ambiguity elimination algorithm proposed in the article can be used as an alternative to standard modems with differential coding.

Systemic Lupus Erythematosus (SLE) is an autoimmune disease with diverse manifestations, from mild and sporadic to severe and life-threatening. SLE heterogeneity arises from various factors, including genetic, epigenetic, and immune niche-related features (Kaul et al., 2016; Jenks et al., 2018). However, the exact interactions and hierarchy between these features remain unclear. Recent studies have found somatic mutations in genes typically mutated in B-cell lymphomas, in subsets of B-cells that are associated with SLE pathogenesis (Piotrowski et al., 2015; Pullabhatla et al., 2018; Singh et al., 2020; Brown et al., 2022). These mutations may support B-cell clonal bursts, but direct information from clinical specimens on the impact of these mutations on B-cell lineages and their influence on SLE progression or malignant transformation is missing.

In this paper, we present a new open source environment called PiktoMir (http://www.piktomir.ru/) that allows children to program a virtual robot behavior by using few pictograms. The goal of our research was to investigate the feasibility of using PiktoMir in teaching elements of programming to preschoolers. The obtained results allow us to assume that PiktoMir provides a working example of a natural textless environment that gradually introduces important programming concepts (such as subroutine, loop) without banging kids over heads.

We report a precise measurement of the D±smeson lifetime. The data were taken by the SELEX experiment (E781) spectrometer using 600 GeV/cΣ−, π−and pbeams. The measurement has been done using 918 reconstructed D±s. The lifetime of the D±sis measured to be 472.5±17.2±6.6 fs, using K∗(892)0K±and φπ±decay modes. The lifetime ratio of Ds±to D0is 1.145±0.049.

The Σ−mean squared charge radius has been measured in the space-like Q2range 0.035–0.105 GeV2/c2by elastic scattering of a Σ− beam off atomic electrons. The measurement was performed with the SELEX (E781) spectrometer using the Fermilab hyperon beam at a mean energy of 610 GeV/c.

Coherent π+π−π−production in the interactions of a beam of 600GeVπ−mesons with C, Cu and Pb nuclei has been studied with the SELEX facility (Experiment E781 at Fermilab). The a2(1320) meson signal has been detected in the Coulomb (low q2) region. The Primakoff formalism used to extract radiative decay width of this meson yields Γ=284±25±25keV, which is the most precise measurement to date.

In this paper the behavior of the instantaneous energy of a harmonic oscillator is investigated in the case when at a certain angle to the vector of the phase velocity of the oscillator, random disturbances of the “white and shot noises” types are acting.

In the experiments at the SPHINX facility in 70 GeV proton beam of the IHEP accelerator the coherent diffractive production reactions on carbon nucleip+C? [?(1385)0K++C andp+C?[S0K+]+C were investigated. The evidences for new baryon states were obtained in the study of hyperon-kaon effective mass spectra in these two reactions:X (2050) with massM=(2052±6) MeV and width G=(35-35+22) MeV inM[?(1385)0K+] andX(2000) withM=1999±6 MeV and G=91±17 MeV inM[S0K+]. The unusual features of these massive states (small enough decay widths, anomalously large branching ratios for decays with strange particles emission) make them very serious candidates for cryptoexotic pentaquark baryons with hidden strangeness.

Conclusions 1.Diamond grinding of fine-grained compact ceramic materials increase their strength considerably.2.The parameters of diamond grinding do not have a substantial effect on the strength of the material.3.An effect of the parameters of the regimes of diamond grinding and of the grain size of the diamond wheel on the resistance of the material to thermal loading was not found at all levels of this loading but only at those below the critical values for the given material.

The reactions of baryon diffractive productionp+N?(pK+K-)+N, p+N?(p?)+N, p+N?[?(1520)K+]+N p+N?[S(1385)oK+]+N in the 70 GeV proton beam were studied. Very sensitive upper limits for the production cross sections of heavy narrow cryptoexotic baryon resonances with hidden strangeness were obtained.

In the experiments at the SPHINX facility in the 70 GeV proton beam of the IHEP accelerator the diffractive production reactionsp+N→[Σ(1385)0K+] +N andp+N→[Σ(1385)0K+]+N+ (neutral particles) were studied. In the effective mass spectra of the [Σ(1385)0K+] system in these processes there were no signals from the anomalously narrow baryon stateNϕ (1960) which had been observed earlier in the measurement at the BIS-2 setup.

A formula that connects the eigenvalues of the energy operator of a system of interacting fields with the S matrix generated by the operator of the interaction energy is derived.

An attempt is made to construct a unified theory of the weak, strong, and electro-magnetic interactions, based on a generalization of the Weinberg-Salam theory [1]. The groups of gauge transformations leaving the Lagrangian of the bispinor field invariant are discussed. It is shown that in order to preserve this invariance in transition from global to local transformations it is necessary to introduce seven gauge compensation fields.

This study will attempt to construct a unified theory of weak, strong, electromagnetic, and gravitational interactions, based on a generalization of Weinberg-Salam theory [1] and a theory proposed previously by the present author [2, 3].

The helical twisting powers, temperature dependences of pitch and temperature/frequency dependences of the dielectric constants of low-temperature mixtures of smectic C liquid crystalline salicylidenanilines doped with non-mesogenic optically active compounds were measured.

In the present work, within the framework of gauge-field theory, a model is constructed implying the existence of several generations of nucleons. The masses of nucleons of higher generations are calculated; according to the hadron model previously proposed, these nucleons are responsible for the formation of hadrons with “charm” and “beauty.”

Two problems are examined in this work from a unified viewpoint on the basis of the model of hadrons previously proposed by the author: a theoretical formula is obtained for the Cabibbo angle and the mechanism of CP-parity non-conversation is explained.

On the basis of the finite element method (FEM) the authors devised an effective apparatus of numerical investigation of processes of failure of axisymmetric complexly shaped bodies under plane strain, induced by propagation of initial cracks in them. This apparatus was worked out on the basis of the use of special finite elements approximating the existence of a crack from the condition that the stresses normal and tangential to its path are equal to zero. The article suggests new modifications of the method of separate calculation of stress intensity factors and of an algorithm for solving problems of linear fracture mechanics when the path of crack propagation is not known. The reliability of the results obtained with the application of the new method and realizing its complex of programs was confirmed by the solution of control problems. An illustration of the possibilities of the method and of the complex is the calculation of the load bearing capacity of a permanent joint of a cylindrical glass shell with a metallic end cap.

Conclusions 1.The shape of the thermal damage resistance diagrams depends mainly upon the behavioral characteristics of the materials under load and are characterized by the degree of brittleness ?.2.After thermal shock impairment of samples from material which in the original state is brittle (?=1) nonelastic strain is observed and the degree of brittleness becomes less than unity. Along with this, the fracture properties change as well as the resistance to subsequent mechanical and thermal loads.

Searches for the decay of short-lived particles require real time, high-resolution tracking in active targets, which in the case of neutrino physics should be of large volume. The possibility of achieving this by using glass capillaries filled with organic liquid scintillator is being investigated in the framework of the CHORUS experiment at CERN. In this paper, after outlining the application foreseen, advances in the tracking technique are discussed and results from tests are reported. An active target of dimensions 180 × 2 × 2 cm3has been assembled from capillaries with 20 μm diameter pores. The readout scheme currently in operation allows the reading of ∼ 5 × 105channels using a single chain of image intensifiers having a resolution of σ∼ 20 μm. Following the development of new liquid scintillators and purification methods an attenuation length of ∼3 m has been obtained. This translates into a hit density of 3.5 per mm for a minimum-ionizing particle that crosses the active target at a distance of 1 m from the readout end.

In this paper an attempt is made to build a foundation for statistical physics from the position of quantum mechanics of many particles in the occupation number representation. This approach allowed us to develop a variational method for solving stationary and non-stationary problems.

An attempt is made in this paper to construct a scalar theory of gravitation which is based on the main postulates of the general theory of relativity (GTR), i.e., on the principle of the equivalence of inertial and gravitational mass and on the principle of general covariance of the theory.

An atomic theory is constructed in the centrally symmetric field approximation. A lithium atom is calculated as an example.

We attempt to jusify the quark model of hadrons, assuming that quarks are weakly interacting quasiparticles with no physical existence outside of hadrons.

It is shown that the presence of the additional symmetry discussed in [1] induces additional gauge fields, which can be held responsible for strong interactions of nucleons. In the spontaneous breaking of the symmetry of a vacuum the particles corresponding to these fields acquire masses. The latter are estimated. It is noted that in a special case the given theory goes over to the Weinberg-Salam theory describing weak and electromagnetic interactions of leptons.