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The problem of propagation of an electroactive unidirectional wave signal of elastic shear (or plane elastic deformation) in an infinite piezoelectric composite waveguide consisting of periodically repeating two-layer cells is considered. In the sagittal plane of one piezo layer in the cell, antiplane electroactive deformation is possible, and in the adjacent layer, electroactive planar deformation is possible. The layers are in a state of non-acoustic contact. The surfaces of the piezoelectric composite waveguide are free from mechanical influences. One of the waveguide surfaces is electrically open, while the other is electrically closed. The propagation of an electroacoustic wave signal occurs due to the penetration of accompanying electrical oscillations through a non-acoustic contact between the piezoelectric layers. There is a multiple transformation of a three-component electroelastic shear wave into a four-component electroelastic wave of plane deformation and vice versa. A hybrid of electroacoustic waves is formed. In the case of a high-frequency wave signal, a hybrid of surface electroacoustic waves of the Rayleigh and Gulyaev-Bluestein types is formed. The distributions of elastic displacements and electric potential along the thickness of the waveguide are determined. The resulting hybrid has the character of a periodic Floquet-Bloch wave. The zones of allowable frequencies and allowed lengths of the hybrid are determined. Rapidly decaying components of the electroacoustic wave are also found. Դիտարկված է առաձգական սահքի (կամ հարթ առաձգական դեֆորմացիայի) էլեկտրաակտիվ, ուղղորդված ալիքային ազդանշանի տարածման խնդիրը անվերջ երկար պիեզոէլեկտրական բաղադրյալ ալիքատարում, որը բաղկացած է պարբերաբար կրկնվող երկշերտ բջիջներից: Բջջի մեկ շերտի սագիտալ հարթությունում հնարավոր է հակահարթ էլեկտրաակտիվ դեֆորմացիա, իսկ հարակից շերտում՝ էլեկտրաակտիվ հարթ դեֆորմացիա։ Միջնաշերտերը գտնվում են անհպում շփման վիճակում։ Պիեզոէլեկտրական բաղադրյալ ալիքատարի մակերևույթները զերծ են մեխանիկական ազդեցություններից: Ալիքատարի մակերևույթներից մեկը էլեկտրականորեն բաց է, իսկ մյուսը էլեկտրականորեն փակ է: Էլեկտրաակուստիկ ալիքի տարածումը տեղի է ունենում շերտից-շերտ էլեկտրական դաշտի ուղեկցող տատանումների ներթափանցման շնորհիվ՝ պիեզոէլեկտրական շերտերի միջև անհպում շփման միջոցով։ Տեղի է ունենում եռաբաղադրիչ սահքի էլեկտրաառաձգական ալիքի բազմակի փոխակերպում, հարթ դեֆորմացիայի քառաբաղադրիչ էլեկտրաառաձգական ալիքի և հակառակը: Ձևավորվում է էլեկտրաակուստիկ ալիքների հիբրիդ։ Բարձր հաճախականության ալիքային ազդանշանի դեպքում ձևավորվում են Ռելեյի և Գուլյաև-Բլյուստեյնի տիպային մակերևութային էլեկտրաակուստիկ ալիքների հիբրիդ։ Որոշվում են առաձգական սահքիի և էլեկտրական դաշտի բաշխումները ալիքատարի հաստությամբ: Ստացված հիբրիդն ունի Ֆլոկե-Բլոխի պարբերական ալիքի բնույթ։ Որոշվում են հիբրիդների թույլատրելի հաճախականությունների և թույլատրելի երկարությունների գոտիները: Գտնվում են նաև էլեկտրաակուստիկ ալիքի արագ մարող բաղադրիչներ։ Рассмотрена задача о распространении электроактивного однонаправленного волнового сигнала упругого сдвига (или плоской упругой деформации) в бесконечном пьезоэлектрическом композитном волноводе, состоящем из периодически повторяющихся двухслойных ячеек. В сагиттальной плоскости одной прослойки в ячейке, возможна анти плоская электро активная деформация, а в соседней прослойке возможна электроактивное плоскостная деформация. Прослойки находятся в состоянии не акустического контакта. Поверхности пьезоэлектрического композитного волновода свободны от механических воздействий. Одна из поверхностей волновода электрически открыта, а другая электрически замкнута. Распространение сигнала электроакустической волны происходит за счет проникновения сопутствующих колебаний электрического поля, через неакустический контакт между пьезоэлектрическими слоями. Происходит многократное преобразование трехкомпонентной электроупругой сдвиговой волны в четырехкомпонентную электроупругую волну плоской деформации и наоборот. Образуется гибрид электроакустических волн. В случае высокочастотного волнового сигнала формируется гибрид поверхностных электроакустических волн типов Рэлея и Гуляева-Блюстейна. Определены распределения упругих перемещений и электрического потенциала по толщине волновода. Полученный гибрид имеет характер периодической волны Флоке-Блоха. Определены зоны допустимых частот и разрешенных длин гибрида. Обнаружены также быстро затухающие компоненты электроакустической волны.

International audience; Several factors can contribute to the difficulty of aligning the sensors of tracking detectors, including a large number of modules, multiple types of detector technologies, and non-linear strip patterns on the sensors. The latter two of these three factors apply to the CLAS12 CVT, which is a hybrid detector consisting of planar silicon sensors with non-parallel strips, and cylindrical micromegas sensors with longitudinal and arc-shaped strips located within a 5 T superconducting solenoid. To align this detector, we used the Kalman Alignment Algorithm, which accounts for correlations between the alignment parameters without requiring the time-consuming inversion of large matrices. This is the first time that this algorithm has been adapted for use with hybrid technologies, non-parallel strips, and curved sensors. We present the results for the first alignment of the CLAS12 CVT using straight tracks from cosmic rays and from a target with the magnetic field turned off. After running this procedure, we achieved alignment at the level of l. 967 10μm, and the widths of the residual spectra were greatly reduced. These results attest to the flexibility of this algorithm and its applicability to future use in the CLAS12 CVT and other hybrid or curved trackers, such as those proposed for the future Electron-Ion Collider.

The article presents a clinical observation of long-term (18 years) artifi cial ventilation in a patient in a chronic vegetative state.

In the present paper on the basis of the previously developed hypotheses system the applied model of thermoelasticity of micropolar thin beams with a circular axis with constrained rotation is constructed. Energy theorems are proved and the corresponding variational principles are established. To solve boundary-value problems of the applied model of thermoelasticity of micropolar thin beams with a circular axis with constrained rotation ways of construction of analytical solutions are considered as well as a version of the finite element method is developed. On the basis of numerical results and parametric analysis of problems, it is established that the consideration of the micropolar properties of the material, in case of other equal conditions, increases the rigidity of the beams in comparison with the classical case. В работе на основе ранее разработанной системы гипотез построена прикладная модель термоупругости микрополярных тонких стержней с круговой осью со стесненным вращением. Доказаны энергетические теоремы и установлен вариационный принцип типа Лагранжа. Для решения граничных задач прикладной модели термоупругости микрополярных тонких стержней с круговой осью со стесненным вращением, рассматриваются пути построения аналитических решений, а также разрабатывается вариант метода конечных элементов. На основе численных результатов и параметрического анализа задач устанавливается, что учет микрополярных свойств материала при остальных равных условиях повышает жесткость стержней по сравнению с классическим случаем.

Experiments on 23 white male rats (250 g) analyzed the spike activity of individual neurons in the substantia nigra pars compacta (SNc, 242 neurons, n = 11) and substantia nigra pars reticulata (SNr, 289 neurons, n = 12) during high-frequency stimulation of the primary motor cortex (M1)in normal animals and in animals with a rotenone model of Parkinson’s disease (BP). SNc neurons in the model of PD showed a complete absence of depressor effects induced by stimulation, though tetanic potentiation was accompanied by posttetanic potentiation and depression at levels 1.65 and 2.02 times greater than in normal animals. In SNr neurons in normal animals, tetanic potentiation, accompanied by post-tetanic potentiation and depression, was 2.37 times greater than tetanic depression, while in the model of PD the levels of both depressor and excitatory activity induced by stimulation were below normal. Spike activity frequency in SNc and SNr neurons preceding and accompanying stimulation was significantly greater than normal in the model of PD. This is evidence for excitotoxicity accompanying neurodegenerative damage, which is completed by neuron apoptosis and death. In SNr neurons, both depressor and excitatory reactions accompanying stimulation were markedly dominant over those in SNc neurons, which is evidence for more extensive cortical projections to the SNr. Furthermore, SNc neurons demonstrated greater susceptibility to pathological changes due to poststimulus depressor effects than SNr neurons, with formation of more marked excitatory effects, which is evidence of a greater involvement of the SNc in PD. In the model of PD, lacking stimulation-induced depressor effects and more marked excitatory effects in SNc neurons, SNr neurons retained their depressor reactions and relatively decreased excitatory reactions, which is evidence of a lower level of susceptibility of SNr neurons to excitotoxicity, extreme increases in the excitability of surviving neurons compensating for the lack of excitation of dead cells.

According to the World Health Organization, iron deficiency anemia affects more than 30% of the world's population. In the Russian Federation, anemia is diagnosed in 35,6% of pregnant women, and the prevalence rate among children in the first year of life is about 83,8 ‰. In the Stavropol Territory, more than 10 thousand cases of anemia are registered annually, of which half are the first. More than 20% of these cases are diagnosed in children and adolescents. In this regard, there is a steady dynamics in the consumption of a specific nomenclature of antianemic drugs at various levels of the drug supply system: federal, regional and municipal. The purpose of the work was to analyze the availability of antianemic drugs used in the treatment of patients living in the city of Pyatigorsk, Stavropol Territory. In the course of work, we used methods of content analysis, analytical, direct observation, grouping and comparison. The studies were carried out from november 2019 to february 2020 on the basis of 11 pharmacy of various legal forms included in the pharmacy chains «Vita +», «Gorzdrav», and the «Pharmacy Warehouse» located in Pyatigorsk. When studying the pharmaceutical range of antianemic drugs, it was found that at the municipal level it includes 12 trade names of drugs based on Fe2+ and Fe3+ ions. Analysis of the liquidity of the prices of antianemic drugs in the pharmacies of Pyatigorsk and the solvency of the population showed the economic affordability of most of the studied range of drugs for patients. An analysis of the width and depth of the range of antianemic drugs for the treatment of iron deficiency anemia revealed the presence of reserves for increasing the range of products for patients. It is concluded that it is necessary to consolidate the efforts of medical and pharmaceutical workers to expand the range of antianemic drugs used by patients, which will increase the quality of medical care.

B3 1343 + 451 is a distant ( z = 2.534 ) and bright flat-spectrum radio quasar observed in the γ -ray band. The results from the multiwavelength observations of B3 1343 + 451 with Fermi-LAT and Swift are reported. In the γ -ray band, strong flares were observed on 05 December 2011 and on 13 December 2009 when the flux increased up to (8.78 ± 0.83)·10-7 photon cm-2 s-1. The hardest photon index Γ = 1.73 ± 0.24 has been observed on MJD 58089 which is not common for flat-spectrum radio quasars. The analysis of Swift XRT data shows that in 2014 the X-ray flux of the source increased ~2 times as compared to 2009, but in both periods the X-ray emission is characterized by a hard photon index of ΓX-ray = 1.2–1.3. During the γ -ray flares, the shortest flux halving timescale was ~2.34 days, implying the emission had been produced in a very compact region, R ≤ δ ct /(1 + z) = 3.43·1016 cm (when δ = 20 ). The spectral energy distribution of B3 1343 + 451 is modeled during the quiescent and flaring periods assuming a compact emitting region outside the BLR. It is found that the flares can be explained by only changing the bulk Lorentz factor of the emitting region without significant modification of the emitting electron parameters and luminosity of the jet.

KEEN The factors associated with the spread and persistence of African swine fever (ASF) in the Caucasus region remain to be fully identified. It is assumed that large naive populations of domestic free-ranging and wild pigs are critical to disease transmission and maintenance. Nonetheless, 11 years since its epidemic introduction into the region in 2007, ASF virus (ASFV) is still circulating, suggesting that an endemic cycle has been established based on contact between free-ranging domestic pigs and wild pigs, and that native Ornithodoros ticks probably serve as reservoirs for the virus. Therefore, research is required to gather information on the epidemiological status of ASF in the Caucasus region, focusing particularly on understanding modes of ASFV spread and persistence in this new virus environment. The authors established an ASFV survey targeting domestic pigs in the Tavush province of northern Armenia, an area of the country considered to be at high risk of disease incursion/occurrence. All tested samples collected for this survey were negative for ASF. The probability of observing no reactors by antibody enzyme-linked immunosorbent assay in a sample of this size (n = 1,506) from a population with an estimated disease prevalence of 1% is very low (< 0.0001). Therefore, it is possible but very unlikely for ASFV to be present among domestic pigs in the Tavush province region.

The deepest all-sky survey available in the $\gamma$-ray band - the last release of the Fermi-LAT catalogue (4FGL-DR3) based on the data accumulated in 12 years, contains more than 6600 sources. The largest population among the sources is blazar subclass - 3743, $60.1\%$ of which are classified as BL Lacertae objects (BL Lacs) or Flat Spectrum Radio Quasars (FSRQs), while the rest are listed as blazar candidates of uncertain type (BCU) as their firm optical classification is lacking. The goal of this study is to classify BCUs using different machine learning algorithms which are trained on the spectral and temporal properties of already classified BL Lacs and FSRQs. Artificial Neural Networks, \textit{XGBoost} and LightGBM algorithms are employed to construct predictive models for BCU classification. Using 18 input parameters of 2219 BL Lacs and FSRQs, we train (80\% of the sample) and test (20\%) these algorithms and find that LightGBM model, state-of-the-art classification algorithm based on gradient boosting decision trees, provides the highest performance. Based on our best model, we classify 825 BCUs as BL Lac candidates and 405 as FSRQ candidates, however, 190 remain without a clear prediction but the percentage of BCUs in 4FGL is reduced to 5.1\%. The $\gamma$-ray photon index, synchrotron peak frequency, and high energy peak frequency of a large sample are used to investigate the relationship between FSRQs and BL Lacs (LBLs, IBLs, and HBLs)., Comment: Accepted for publication in MNRAS

The ratio of the nucleon F_{2} structure functions, F_{2}^{n}/F_{2}^{p}, is determined by the MARATHON experiment from measurements of deep inelastic scattering of electrons from ^{3}H and ^{3}He nuclei. The experiment was performed in the Hall A Facility of Jefferson Lab using two high-resolution spectrometers for electron detection, and a cryogenic target system which included a low-activity tritium cell. The data analysis used a novel technique exploiting the mirror symmetry of the two nuclei, which essentially eliminates many theoretical uncertainties in the extraction of the ratio. The results, which cover the Bjorken scaling variable range 0.19x0.83, represent a significant improvement compared to previous SLAC and Jefferson Lab measurements for the ratio. They are compared to recent theoretical calculations and empirical determinations of the F_{2}^{n}/F_{2}^{p} ratio.

We present long-term multiwavelength observations of blazar CTA 102 ($z=1.037$). Detailed temporal and spectral analyses of $\gamma$-ray, X-ray and UV/optical data observed by {\it Fermi}-LAT, Swift XRT, NuSTAR and Swift-UVOT over a period of 14 years, between August 2008 and March 2022, was performed. We found strong variability of source emission in all the considered bands, especially in the $\gamma$-ray band it exhibited extreme outbursts when the flux crossed the level of $10^{-5}\:{\rm photon\:cm^{-2}\:s^{-1}}$. Using the Bayesian Blocks algorithm, we split the adaptively binned $\gamma$-ray light curve into 347 intervals of quiescent and flaring episodes and for each period built corresponding multiwavelength spectral energy distributions (SEDs), using the available data. Among the considered SEDs, 117 high-quality (quasi) contemporaneous SEDs which have sufficient multiwavelength data, were modeled using JetSeT framework within a one-zone leptonic synchrotron and inverse Compton emission scenario assuming the emitting region is within the broad-line-region and considering internal and external seed photons for the inverse Compton up-scattering. As a result of modeling, the characteristics of the relativistic electron distribution in the jet as well as jet properties are retrieved and their variation in time is investigated. The applied model can adequately explain the assembled SEDs and the modelling shows that the data in the bright flaring periods can be reproduced for high Doppler boosting and magnetic field. The obtained results are discussed in the context of particle cooling in the emitting region., Comment: Accepted for publication in MNRAS; doi.org/10.1093/mnras/stac2875

When protons and neutrons (nucleons) are bound into atomic nuclei, they are close enough to feel significant attraction, or repulsion, from the strong, short-distance part of the nucleon-nucleon interaction. These strong interactions lead to hard collisions between nucleons, generating pairs of highly energetic nucleons referred to as short-range correlations (SRCs). SRCs are an important but relatively poorly understood part of nuclear structure

The beam spin asymmetry of the exclusive pseudoscalar channel e → p → e ′ p ′ η was measured for the first time in the deep-inelastic regime ( W > 2 GeV / c 2 and Q 2 > 1 GeV 2 / c 2 ) using a longitudinally polarized 5.78 GeV electron beam at Jefferson Lab with the CEBAF Large Acceptance Spectrometer. The data were accumulated in 144 four-dimensional bins of Q 2 , x B , − t and ϕ over a wide kinematic range, where ϕ is the azimuthal angle between the lepton and hadron scattering planes, The measured azimuthal dependence with large amplitudes of the sin ⁡ ϕ moments is a clear indication of a substantial contribution to the polarized cross-section from transversely polarized virtual photons. In the framework of generalized parton distributions (GPDs) this contribution is expressed via longitudinal-transverse interference between chiral-even and chiral-odd GPDs. The experimental results are compared to the existing theoretical models demonstrating the sensitivity to the product of chiral-odd and chiral-even GPDs and provide new constraints to the existing GPD parameterizations.

The observation of beam spin asymmetries in two-pion production in semi-inclusive deep inelastic scattering off an unpolarized proton target is reported for the first time. The data presented here were taken in the fall of 2018 with the CLAS12 spectrometer using a 10.6 GeV longitudinally spin-polarized electron beam delivered by CEBAF at JLab. The measured asymmetries provide the first observation of a signal that can be used to extract the PDF $e(x)$ in a collinear framework and the helicity-dependent two-pion fragmentation function $G_1^\perp$.

We report a measurement of the π- photoproduction beam asymmetry for the reaction γp→π-Δ++ using data from the GlueX experiment in the photon beam energy range 8.2-8.8 GeV. The asymmetry ς is measured as a function of four-momentum transfer t to the Δ++ and compared to phenomenological models. We find that ς varies as a function of t: negative at smaller values and positive at higher values of |t|. The reaction can be described theoretically by t-channel particle exchange requiring pseudoscalar, vector, and tensor intermediaries. In particular, this reaction requires charge exchange, allowing us to probe pion exchange and the significance of higher-order corrections to one-pion exchange at low momentum transfer. Constraining production mechanisms of conventional mesons may aid in the search for and study of unconventional mesons. This is the first measurement of the process at this energy. © 2021 American Physical Society.

Photoproduction cross sections are reported for the reaction $\gamma p\to p\eta$ using energy-tagged photons and the CLAS spectrometer at Jefferson Laboratory. The $\eta$ mesons are detected in their dominant charged decay mode, $\eta\to \pi^+\pi^-\pi^0$, and results on differential cross sections are presented for incident photon energies between 1.2 and 4.7 GeV. These new $\eta$ photoproduction data are consistent with earlier CLAS results but extend the energy range beyond the nucleon resonance region into the Regge regime. The normalized angular distributions are compared with the experimental results from several other experiments, and with predictions of $\eta$ MAID\,2018 and the latest solution of the Bonn-Gatchina coupled-channel analysis. Differential cross sections $d\sigma/dt$ are presented for incident photon energies $E_\gamma > 2.9$ GeV ($W > 2.5$ GeV), and compared with predictions which are based on Regge trajectories exchange in the $t$-channel (Regge models). The data confirm the expected dominance of $\rho$, $\omega$ vector-meson exchange in an analysis by the Joint Physics Analysis Center.

Investigating the reflection and refraction of electroelastic waves at a plane interface without acoustic contact between two piezoelectric half-spaces of different textures, it was found that: (i)As a result of the incidence of a two-component electroelastic shear wave on the interface between the media, the same wave is reflected into the first half-space, and a three-component electroelastic plane strain wave is refracted into the second half-space. In the utmost cases, in layered inhomogeneous waveguide, a wave hybrid of electroacoustic waves is formed. This makes it possible to transmit along the boundary of non-acoustic contact of media a hybrid of electroacoustic surface waves of the Gulyaev-Bluestein type and Rayleigh type localized near this boundary. (ii)As a result of the incidence of a two-component electroelastic plane strain wave on the interface between the media, the same wave is reflected into the first half-space, and a three-component electroelastic shear wave is refracted into the second half-space. This also makes it possible to organize a hybrid of electroacoustic waves of elastic shear and plane deformation of the type of periodic electroelastic Floquet waves in a periodically transversely inhomogeneous piezoelectric composite. The conditions for the possible formation of the hybrid and the characteristics of their propagation in the layered composites of piezoelectrics of the hexagonal symmetry class 6mm and 6 ¯ m2 are discussed.

We have measured beam-spin asymmetries to extract the \ud sin\ud ϕ\ud moment \ud A\ud sin\ud ϕ\ud L\ud U\ud from the hard exclusive \ud →\ud e\ud p\ud →\ud e\ud ′\ud n\ud π\ud +\ud reaction above the resonance region, for the first time with nearly full coverage from forward to backward angles in the center of mass. The \ud A\ud sin\ud ϕ\ud L\ud U\ud moment has been measured up to \ud 6.6\ud \ud \ud GeV\ud 2\ud in \ud −\ud t\ud , covering the kinematic regimes of generalized parton distributions (GPD) and baryon-to-meson transition distribution amplitudes (TDA) at the same time. The experimental results in very forward kinematics demonstrate the sensitivity to chiral-odd and chiral-even GPDs. In very backward kinematics where the TDA framework is applicable, we found \ud A\ud sin\ud ϕ\ud L\ud U\ud to be negative, while a sign change was observed near 90° in the center of mass. The unique results presented in this Letter will provide critical constraints to establish reaction mechanisms that can help to further develop the GPD and TDA frameworks.

We present the first measurement of the exclusive reaction $\gamma p \rightarrow a_2(1320)^0 \, p$ in the photon energy range $3.5$-$5.5$ GeV and four-momentum transfer squared $0.2

The extraction of neutrino mixing parameters from accelerator-based neutrino oscillation experiments relies on proper modeling of neutrino-nucleus scattering processes using neutrino-interaction event generators. Experimental tests of these generators are difficult due to the broad range of neutrino energies produced in accelerator-based beams and the low statistics of current experiments. Here we overcome these difficulties by exploiting the similarity of neutrino and electron interactions with nuclei to test neutrino event generators using high-precision inclusive electron scattering data. To this end, we revised the electron-scattering mode of the GENIE event generator ($e$-GENIE) to include electron-nucleus bremsstrahlung radiation effects and to use, when relevant, the exact same physics models and model parameters, as the standard neutrino-scattering version. We also implemented new models for quasielastic (QE) scattering and meson exchange currents (MEC) based on the theory-inspired SuSAv2 approach. Comparing the new $e$-GENIE predictions with inclusive electron scattering data, we find an overall adequate description of the data in the QE- and MEC-dominated lower energy transfer regime, especially when using the SuSAv2 models. Higher energy transfer-interactions, which are dominated by resonance production, are still not well modeled by $e$-GENIE., 13 pages, 14 figures. Significantly updated following referee comments

High-redshift blazars are among the most powerful objects in the Universe. The spectral and temporal properties of thirty-three distant blazars ($z>2.5$) detected in the high energy $\gamma$-ray band are investigated by analyzing the {\it Fermi}-LAT and {\it Swift} UVOT/ XRT data. The considered sources have soft time averaged $\gamma$-ray spectra ($\Gamma_{\rm \gamma}\geq2.2$) whereas those that have been observed in the X-ray band have hard X-ray spectra ($\Gamma_{\rm X}=1.01-1.86$). The $\gamma$-ray flux of high-redshift blazars ranges from $4.84\times10^{-10}$ to $1.50\times10^{-7}\:{\rm photon\:cm^{-2}\:s^{-1}}$ and the luminosity is within $(0.10-5.54)\times10^{48}\:{\rm erg\:s^{-1}}$ which during the $\gamma$-ray flares increases up to $(0.1-1)\times10^{50}\:{\rm erg\:s^{-1}}$. In the X-ray band, only the emission of PKS 0438-43, B2 0743+25 and TXS 0222+185 is found to vary in different Swift XRT observations whereas in the $\gamma$-ray band, the emission is variable for fourteen sources: the flux of B3 1343+451 and PKS 0537-286 changes in sub-day scales, that of PKS 0347-211 and PKS 0451-28 in day scales, while the$\gamma$-ray variability of the others is in week or month scales. The properties of distant blazar jets are derived by modeling the multiwavelength spectral energy distributions within a one-zone leptonic scenario assuming that the X-ray and $\gamma$-ray emissions are produced from inverse Compton scattering of synchrotron and dusty torus photons. From the fitting, the emission region size is found to be $\leq0.05$ pc and the magnetic field and the Doppler factor are correspondingly within $0.10-1.74$ G and $10.0-27.4$. By modeling the optical-UV excess, we found that the central black hole masses and accretion disk luminosities are within $L_{\rm d}\simeq(1.09-10.94)\times10^{46}\:{\rm erg \: s^{-1}}$ and $(1.69-5.35)\times10^{9}\:M_\odot$, respectively., Comment: Accepted for publication in MNRAS

We report the first measurement of the (e,e^{'}p) three-body breakup reaction cross sections in helium-3 (^{3}He) and tritium (^{3}H) at large momentum transfer [⟨Q^{2}⟩≈1.9 (GeV/c)^{2}] and x_{B}>1 kinematics, where the cross section should be sensitive to quasielastic (QE) scattering from single nucleons. The data cover missing momenta 40≤p_{miss}≤500 MeV/c that, in the QE limit with no rescattering, equals the initial momentum of the probed nucleon. The measured cross sections are compared with state-of-the-art ab initio calculations. Overall good agreement, within ±20%, is observed between data and calculations for the full p_{miss} range for ^{3}H and for 100≤p_{miss}≤350 MeV/c for ^{3}He. Including the effects of rescattering of the outgoing nucleon improves agreement with the data at p_{miss}>250 MeV/c and suggests contributions from charge-exchange (SCX) rescattering. The isoscalar sum of ^{3}He plus ^{3}H, which is largely insensitive to SCX, is described by calculations to within the accuracy of the data over the entire p_{miss} range. This validates current models of the ground state of the three-nucleon system up to very high initial nucleon momenta of 500 MeV/c.

The exclusive electroproduction process ep→e′p′π0 was measured in the range of photon virtualities Q2=0.4–1.0GeV2 and the invariant mass range of the pπ0 system of W=1.1–1.8 GeV. These kinematics are covered in exclusive π0 electroproduction off the proton with nearly complete angular coverage in the pπ0 center-of-mass system and with high statistical accuracy. Nearly 36 000 cross-section points were measured, and the structure functions σT+eσL,σLT, and σTT, were extracted via fitting the ϕπ0 dependence of the cross section. A Legendre polynomial expansion analysis demonstrates the sensitivity of our data to high-lying N* and Δ* resonances with M>1.6 GeV. As part of a broad effort to determine the electrocouplings of the N* and Δ* resonances using both single- and double-pion electroproduction, this dataset is crucial for the reliable extraction of the high-lying resonance electrocouplings from the combined isospin analysis of the Nπ and π+π−p channels.

We report a measurement of a beam–target double-polarisation observable (E) for the γ→n→(p)→K+Σ−(p) reaction. The data were obtained impinging the circularly-polarised energy-tagged photon beam of Hall B at Jefferson Lab on a longitudinally-polarised frozen-spin hydrogen deuteride (HD) nuclear target. The E observable for an effective neutron target was determined for centre-of-mass energies 1.70≤W≤2.30 GeV, with reaction products detected over a wide angular acceptance by the CLAS spectrometer. These new double-polarisation data give unique constraints on the strange decays of excited neutron states. Inclusion of the new data within the Bonn-Gatchina theoretical model results in significant changes for the extracted photocouplings of a number of established nucleon resonances. Possible improvements in the PWA description of the experimental data with additional “missing” resonance states, including the N(2120)3/2− resonance, are also quantified.

International audience; The CEBAF Large Acceptance Spectrometer for operation at 12 GeV beam energy (CLAS12) in Hall B at Jefferson Laboratory is used to study electro-induced nuclear and hadronic reactions. This spectrometer provides efficient detection of charged and neutral particles over a large fraction of the full solid angle. CLAS12 has been part of the energy-doubling project of Jefferson Lab’s Continuous Electron Beam Accelerator Facility, funded by the United States Department of Energy. An international collaboration of 48 institutions contributed to the design and construction of detector hardware, developed the software packages for the simulation of complex event patterns, and commissioned the detector systems. CLAS12 is based on a dual-magnet system with a superconducting torus magnet that provides a largely azimuthal field distribution that covers the forward polar angle range up to 35 ∘ , and a solenoid magnet and detector covering the polar angles from 35° to 125° with full azimuthal coverage. Trajectory reconstruction in the forward direction using drift chambers and in the central direction using a vertex tracker results in momentum resolutions of < 1% and < 3%, respectively. Cherenkov counters, time-of-flight scintillators, and electromagnetic calorimeters provide good particle identification. Fast triggering and high data-acquisition rates allow operation at a luminosity of 1035 cm −2 s −1 . These capabilities are being used in a broad program to study the structure and interactions of nucleons, nuclei, and mesons, using polarized and unpolarized electron beams and targets for beam energies up to 11 GeV. This paper gives a general description of the design, construction, and performance of CLAS12.

We report the first measurement of the (e,e^{'}p) three-body breakup reaction cross sections in helium-3 (^{3}He) and tritium (^{3}H) at large momentum transfer [⟨Q^{2}⟩≈1.9 (GeV/c)^{2}] and x_{B}1 kinematics, where the cross section should be sensitive to quasielastic (QE) scattering from single nucleons. The data cover missing momenta 40≤p_{miss}≤500 MeV/c that, in the QE limit with no rescattering, equals the initial momentum of the probed nucleon. The measured cross sections are compared with state-of-the-art ab initio calculations. Overall good agreement, within ±20%, is observed between data and calculations for the full p_{miss} range for ^{3}H and for 100≤p_{miss}≤350 MeV/c for ^{3}He. Including the effects of rescattering of the outgoing nucleon improves agreement with the data at p_{miss}250 MeV/c and suggests contributions from charge-exchange (SCX) rescattering. The isoscalar sum of ^{3}He plus ^{3}H, which is largely insensitive to SCX, is described by calculations to within the accuracy of the data over the entire p_{miss} range. This validates current models of the ground state of the three-nucleon system up to very high initial nucleon momenta of 500 MeV/c.

We present precision measurements of the target and beam-target spin asymmetries from neutral pion electroproduction in deep-inelastic scattering (DIS) using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. We scattered 6-GeV, longitudinally polarized electrons off longitudinally polarized protons in a cryogenic $^{14}$NH$_3$ target, and extracted double and single target spin asymmetries for $ep\rightarrow e^\prime\pi^0X$ in multidimensional bins in four-momentum transfer ($1.0, Comment: 18 preprint pages, 3 figures

High-momentum configurations of nucleon pairs at short-distance are probed using measurements of the $^{12}$C$(e,e'p)$ and $^{12}$C$(e,e'pN)$ reactions (where $N$ is either $n$ or $p$), at high-$Q^2$ and $x_B>1.1$. The data span a missing-momentum range of 300--1000 MeV/c and are predominantly sensitive to the transition region of the strong nuclear interaction from a Tensor to Scalar interaction. The data are well reproduced by theoretical calculations using the Generalized Contact Formalism with both chiral and phenomenological nucleon-nucleon ($NN$) interaction models. This agreement suggests that the measured high missing-momentum protons up to $1000$ MeV/c predominantly belong to short-ranged correlated (SRC) pairs. The measured $^{12}$C$(e,e'pN)$ / $^{12}$C$(e,e'p)$ and $^{12}$C$(e,e'pp)$ / $^{12}$C$(e,e'pn)$ cross-section ratios are consistent with a decrease in the fraction of proton-neutron SRC pairs and increase in the fraction of proton-proton SRC pairs with increasing missing momentum. This confirms the transition from an isospin-dependent tensor $NN$ interaction at $\sim 400$ MeV/c to an isospin-independent scalar interaction at high-momentum around $\sim 800$ MeV/c as predicted by theoretical calculation., Accepted for publication in Physics Letters B. 7 pages, 3 figures, and online supplementary materials

Photon beam asymmetry Σ measurements for ω photoproduction in the reaction γ → p → ω p are reported for photon energies from 1.152 to 1.876 GeV. Data were taken using a linearly-polarized tagged photon beam, a cryogenic hydrogen target, and the CLAS spectrometer in Hall B at Jefferson Lab. The measurements obtained markedly increase the size of the database for this observable, extend coverage to higher energies, and resolve discrepancies in previously published data. Comparisons of these new results with predictions from a chiral-quark-based model and from a dynamical coupled-channels model indicate the importance of interferences between t-channel meson exchange and s- and u-channel contributions, underscoring sensitivity to the nucleon resonances included in those descriptions. Comparisons with the Bonn–Gatchina partial-wave analysis indicate the Σ data reported here help to fix the magnitudes of the interference terms between the leading amplitudes in that calculation (Pomeron exchange and the resonant portion of the J P = 3 / 2 + partial wave), as well as the resonant portions of the smaller partial waves with J P = 1 / 2 − , 3 / 2 − , and 5 / 2 + .