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We present a novel method to construct particle accelerators targeting light atoms and nuclei using high-power femtosecond laser pulses. Initially, we confine light atoms within the laser pulse envelope due to longitudinal polarization forces, allowing them to acquire kinetic energies of several GeV. Subsequently, an external electric field separates the nuclei at the cathode, concentrating helium nuclei in a small area. The kinetic energy of the 1.88 GeV impacts, exceeding the alpha particle binding energy (28 MeV) by two orders of magnitude, induces powerful gamma radiation and neutron emission from decay processes. This experiment marks a demonstration of a laser-induced decay method for helium nuclei for the first time. Moreover, helium isotopes or deuterium nuclei trapped on the cathode show significantly reduced Coulomb repulsion, enabling subsequent nuclear fusion reactions and substantial nuclear energy release., Comment: Presented at Conference on Advanced Topics in Photonics, CATP 2024, 15-17 July, Sofia Bulgaria. Submitted to Optics Express at 27 June, 2024

BM@N (Baryonic Matter at Nuclotron) is the first experiment operating and taking data at the Nuclotron/NICA ion-accelerating complex.The aim of the BM@N experiment is to study interactions of relativistic heavy-ion beams with fixed targets. We present a technical description of the BM@N spectrometer including all its subsystems., Comment: 34 pages, 47 figures, 6 tables

First physics results of the BM@N experiment at the Nuclotron/NICA complex are presented on {\pi}+ and K+ meson production in interactions of an argon beam with fixed targets of C, Al, Cu, Sn and Pb at 3.2 AGeV. Transverse momentum distributions, rapidity spectra and multiplicities of $\pi^+$ and $K^+$ mesons are measured. The results are compared with predictions of theoretical models and with other measurements at lower energies., Comment: 29 pages, 20 figures

The aim of this work is to find analytical expressions of the radiation force and potential densities arising from a laser pulse propagating in a dielectric media. In the femtosecond region the force becomes strong enough to confine neutral particles into the pulse envelope and translate them with the group velocity in gases. Additionally, if the trapped particles are with high density, the probability of collision with the free atoms and molecules in air become significant. The collision energies are in the range of 12 - 24 GeV and high enough to ionize the neutral atoms. Thus, a new type of collision ionization can be observed, when powerful femtosecond pulses propagate in gaseous media., Comment: 10 pages,2 figures. arXiv admin note: text overlap with arXiv:2004.13716

From superconductors to atomic nuclei, strongly-interacting many-body systems are ubiquitous in nature. Measuring the microscopic structure of such systems is a formidable challenge, often met by particle knockout scattering experiments. While such measurements are fundamental for mapping the structure of atomic nuclei, their interpretation is often challenged by quantum mechanical initial- and final-state interactions (ISI/FSI) of the incoming and scattered particles. Here we overcome this fundamental limitation by measuring the quasi-free scattering of 48 GeV/c 12C ions from hydrogen. The distribution of single protons is studied by detecting two protons at large angles in coincidence with an intact 11B nucleus. The 11B detection is shown to select the transparent part of the reaction and exclude the otherwise large ISI/FSI that would break the 11B apart. By further detecting residual 10B and 10Be nuclei, we also identified short-range correlated (SRC) nucleon-nucleon pairs, and provide direct experimental evidence for the separation of the pair wave-function from that of the residual many-body nuclear system. All measured reactions are well described by theoretical calculations that do not contain ISI/FSI distortions. Our results thus showcase a new ability to study the short-distance structure of short-lived radioactive atomic nuclei at the forthcoming FAIR and FRIB facilities. These studies will be pivotal for developing a ground-breaking microscopic understanding of the structure and properties of nuclei far from stability and the formation of visible matter in the universe., Comment: Accepted for publication in Nature Physics. 28 pages, 19 figures, and 1 table including main text, Methods, and Supplementary materials

The absence of ionization and observation of white continuum in the initial moment of filamentation of powerful femtosecond laser pulses, propagating in silica glasses, as well as the filamentation without plasma channels observed in the experiments in air, forced us to look for other nonlinear mechanisms of description the above mentioned effects. For this reason we present in this paper new parametric conversion mechanism for asymmetric spectrum broadening of femtosecond laser pulses towards the higher frequencies in isotropic media. This mechanism includes cascade generation with THz spectral shift for solids and GHz spectral delay for gases. The process works simultaneously with the four-photon parametric wave mixing. The proposed theoretical model gives very good coincidence with the experimental data. In addition we demonstrate that the nonlinear model describes the process of reduction of the number of filaments trough two mechanisms of nonlinear interaction: attraction due to cross-phase modulation and energy exchange due to four-photon parametric wave mixing., Comment: 15 pages, 7 figures

The well-known (1+1D) nonlinear Schr\"odinger equation (NSE) governs the propagation of narrow-band pulses in optical fibers and others one-dimensional structures. For exploration the evolution of broad-band optical pulses (femtosecond and attosecond) it is necessary to use the more general nonlinear amplitude equation (GNAE) which differs from NSE with two additional non-paraxial terms. That is way, it is important to make clear the difference between the solutions of these two equations. We found a new analytical soliton solution of GNAE and compare it with the well-known NSE one. It is shown that for the fundamental soliton the main difference between the two solutions is in their phases. It appears that, this changes significantly the evolution of optical pulses in multisoliton regime of propagation and admits a behavior different from that of the higher-order NSE solitons., Comment: 5 pages, 4 figures

We investigate two types of nonlinear interaction between collinear femtosecond laser pulses with power slightly above the critical for self-focusing $P_{cr}$. In the first case we study energy exchange between filaments. The model describes this process through degenerate four-photon parametric mixing (FPPM) scheme and requests initial phase difference between the waves. When there are no initial phase difference between the pulses, the FPPM process does not work. In this case it is obtained the second type of interaction as merging between two, three or four filaments in a single filament with higher power. It is found that in the second case the interflow between the filaments has potential of interaction due to cross-phase modulation (CPM)., Comment: 9 pages, 4 figures. arXiv admin note: text overlap with arXiv:1404.3578

We have investigated the nonlinear amplitude vector equation governing the evolution of optical pulses in optical and UV region. We are normalizing this equation for the cases of different and equal transverse and longitudinal size of optical pulses, of week and strong dispersion. This gives us the possibility to reduce the amplitude equation to different nonlinear evolution equations in the partial cases. For some of these nonlinear equations exact vortex solutions are found. Conditions for experimental observations of these vortices are determined., Comment: 28 pages, 9 figures, Latex

Using the method of separation of variables, we developed a vector nonparaxial theory for the nonlinear wave equations in strong field approximation. We found that exact localized vortex soliton solution exists for the nonlinear 3D+1 vector wave equation and for 3D+1 vector nonlinear Schr\"{o}dinger equation. This method is applicable for angular functions, which satisfy additional conditions. It is shown that exact vortex solitary wave exists only for solution with eigenvalue of momentum L=1, Comment: 5 pages, no figure, pdf