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Elastic electron–proton scattering (e–p) and the spectroscopy of hydrogen atoms are the two methods traditionally used to determine the proton charge radius, r p . In 2010, a new method using muonic hydrogen atoms 1 found a substantial discrepancy compared with previous results 2 , which became known as the ‘proton radius puzzle’. Despite experimental and theoretical efforts, the puzzle remains unresolved. In fact, there is a discrepancy between the two most recent spectroscopic measurements conducted on ordinary hydrogen 3 , 4 . Here we report on the proton charge radius experiment at Jefferson Laboratory (PRad), a high-precision e–p experiment that was established after the discrepancy was identified. We used a magnetic-spectrometer-free method along with a windowless hydrogen gas target, which overcame several limitations of previous e–p experiments and enabled measurements at very small forward-scattering angles. Our result, r p  = 0.831 ± 0.007 stat  ± 0.012 syst  femtometres, is smaller than the most recent high-precision e–p measurement 5 and 2.7 standard deviations smaller than the average of all e–p experimental results 6 . The smaller r p we have now measured supports the value found by two previous muonic hydrogen experiments 1 , 7 . In addition, our finding agrees with the revised value (announced in 2019) for the Rydberg constant 8 —one of the most accurately evaluated fundamental constants in physics. A magnetic-spectrometer-free method for electron–proton scattering data reveals a proton charge radius 2.7 standard deviations smaller than the currently accepted value from electron–proton scattering, yet consistent with other recent experiments.

The interaction between dopamine and RNA structures holds significant potential for understanding neurotransmitter-driven RNA modulation and biosensor design. Here, we employ all-atom molecular dynamics (MD) simulations to investigate the concentration-dependent binding of dopamine to poly(rA)/poly(rU) complex. We reveal that the dopamine molecules are preferentially trapped by poly(A)/poly(U) complex where the dopamine catechol rings became oriented parallel towards to RNA amine rings, although with the increase of dopamine concentration we track a multi-mode binding of dopamine molecules, i.e., different configurations can be found. The increasing of dopamine concentration leads to the dense packing of poly(A)/poly(U) complex, where more than half of dopamine molecules are strongly bound. We argue that the dopamine shows mainly intercalation mechanism of stabilization of poly(A)–poly(U) complexes governed by the hydrogen bonds network formation. These findings offer new insights relevant to RNA-based biosensors and the interplay between neurotransmitters and nucleic acids.

The internal structure of nucleons (protons and neutrons) remains one of the greatest outstanding problems in modern nuclear physics. By scattering high-energy electrons off a proton we are able to resolve its fundamental constituents and probe their momenta and positions. Here we investigate the dynamics of quarks and gluons inside nucleons using deeply virtual Compton scattering (DVCS)—a highly virtual photon scatters off the proton, which subsequently radiates a photon. DVCS interferes with the Bethe-Heitler (BH) process, where the photon is emitted by the electron rather than the proton. We report herein the full determination of the BH-DVCS interference by exploiting the distinct energy dependences of the DVCS and BH amplitudes. In the regime where the scattering is expected to occur off a single quark, measurements show an intriguing sensitivity to gluons, the carriers of the strong interaction. It remains a challenge to find the structure and the distribution of the constituents of nucleons. Here the authors use a scattering method to get information about the gluons and quarks inside a proton and separate the contribution of Bethe-Heitler from the deeply virtual Compton scattering process.

A sodium dioctyl sulfosuccinate (AOT)/benzyl hexadecyl dimethyl ammonium chloride (BDAC) mixed micelle self-organization and adsorption on gold Au(111) surfaces have been investigated using a molecular dynamics approach. The spherical AOT/BDAC mixed micelle is strongly adsorbed on the gold surface and is disoriented to a cylinder-like shape.

The protons and neutrons in a nucleus can form strongly correlated nucleon pairs. Scattering experiments, in which a proton is knocked out of the nucleus with high-momentum transfer and high missing momentum, show that in carbon-12 the neutron-proton pairs are nearly 20 times as prevalent as proton-proton pairs and, by inference, neutron-neutron pairs. This difference between the types of pairs is due to the nature of the strong force and has implications for understanding cold dense nuclear systems such as neutron stars.

The article presents the results of studies of the characteristics of lead tungstate crystals (PbWO 4 ). Measurements of light transmission and light output from the passage of cosmic muons were carried out. The average light transmittance of crystals in the transverse direction is 62.82, 68.38, and 75.68% at wavelengths λ = 360, 420, and 620 nm, and the light output is ~16 pe/MeV. A prototype of an electromagnetic calorimeter was designed and built from crystals arranged in a 4 × 4 matrix which has been tested by cosmic muons. The results obtained confirm the conclusions of other groups in the Electron-Ion Collider collaboration that the quality of the crystals produced by CRYTUR meets the requirements for an electromagnetic calorimeter, and that they can be the basis for its creation.

The effect of dimethylsulfoxide (DMSO) and diethylsulfoxide (DESO) on binding between quinine sulfate (QS) and DNA was studied by virtue of UV–Vis absorption, steady-state fluorescence spectroscopies, and fluorescence polarization measurements. The binding constant was determined at three different temperatures and the values of standard Gibbs energy change, enthalpy and entropy of binding were determined. The mechanism of binding and the effect of sulfoxides on this process was revealed. The values of binding constant, fluorescence polarization and iodide quenching studies confirmed that the main binding mode in QS-DNA system is groove binding. Addition of sulfoxides does not change the binding mechanism. Moreover, with addition of sulfoxides binding constant increases due to the removal of water molecules from DNA grooves making them more available for QS molecules. To explain the effect of DMSO and DESO on QS-DNA binding the photophysical properties of QS in aqueous solutions of DMSO and DESO were also studied. On the basis of quantum yield of QS in water, DMSO and DESO the types of intermolecular interactions were discussed. The obtained results show that quantum yield of QS in sulfoxides is lower compared with that in water and aqueous solution of 0.1 M H 2 SO 4 . QS forms ground state complexes with both DMSO and DESO that are stronger fluorophores compared with free QS molecules.

For the first time in Armenia, gamma activation analysis of geological samples of obsidian was carried out using beams of bremsstrahlung photons at the linear electron accelerator of the A. Alikhanyan National Scientific Laboratory (AANL). It is shown that the results of the chemical composition of the obsidian sample are comparable with the results of instrumental neutron activation analysis (INAA) of the same sample, carried out at the Curt-Engelhom-Center for Archaeometry (Mannheim, Germany), after irradiation with neutrons in a specialized nuclear reactor TRIGA at the Institute of Nuclear Chemistry of the Mainz University. It is also shown that gamma activation analysis makes it possible to determine the content of a number of elements for which the use of INAA is impossible or difficult.

The detailed study of the effect of dimethylsulfoxide (or diethylsulfoxide) on interaction between methylene blue (MB) and calf thymus DNA was performed at 293.15 K using steady-state fluorescence quenching and fluorescence polarization. The combination of steady-state fluorescence quenching and fluorescence polarization reveal the main binding modes at different concentrations of DNA and the effect of sulfoxides on binding mechanism. For comparison, the other polar solvents such as N, N -dimethyl formamide and acetonitrile were used. From Stern–Volmer equation, the values of binding constant and standard Gibbs free energy change were determined. At low concentrations of DNA with addition of various organic cosolvents, the binding constant of DNA–MB complex decreases indicating that hydrogen bonds are predominant, and thus, the main binding mode is groove binding. At high concentrations of DNA, the binding mechanism changes and intercalation becomes the main binding mode in all solutions. Addition of cosolvents distorts the groove binding and, as a result, weakens the intercalation between MB and base pairs of double-stranded DNA.

JLab E12-19-002 Experiment is planned to measure the Λ-binding energies of 3 Λ H [ J π = 1/2 + or 3/2 + ( T = 0)] and 4 Λ H (1 + ) at JLab Hall C. The expected accuracy for the binding-energy measurement is |Δ B total Λ | ≃ 70 keV. The accurate spectroscopy for these light hypernuclei would shed light on the puzzle of the small binding energy and short lifetime of 3 Λ H, and the chargesymmetry breaking in the ΛN interaction. We aim to perform the experiment in 2025.