Explore the vast range of titles available.

Direct detection experiments obtain 90% upper limits on the elastic scattering cross sections of dark matter with nucleons assuming point-like interactions and standard astrophysical and cosmological parameters. In this paper we provide a recasting of the limits from XENON1T, PICO-60, CRESST-III and DarkSide-50 and include them in micrOMEGAs. The code can then be used to directly impose constraints from these experiments on generic dark matter models under different assumptions about the DM velocity distribution or on the nucleus form factors. Moreover, new limits on the elastic scattering cross sections can be obtained in the presence of a light t-channel mediator or of millicharged particles.

Ultra-intense MeV photon and neutron beams are indispensable tools in many research fields such as nuclear, atomic and material science as well as in medical and biophysical applications. For applications in laboratory nuclear astrophysics, neutron fluxes in excess of 10 21 n/(cm 2 s) are required. Such ultra-high fluxes are unattainable with existing conventional reactor- and accelerator-based facilities. Currently discussed concepts for generating high-flux neutron beams are based on ultra-high power multi-petawatt lasers operating around 10 23 W/cm 2 intensities. Here, we present an efficient concept for generating γ and neutron beams based on enhanced production of direct laser-accelerated electrons in relativistic laser interactions with a long-scale near critical density plasma at 10 19 W/cm 2 intensity. Experimental insights in the laser-driven generation of ultra-intense, well-directed multi-MeV beams of photons more than 10 12 ph/sr and an ultra-high intense neutron source with greater than 6 × 10 10 neutrons per shot are presented. More than 1.4% laser-to-gamma conversion efficiency above 10 MeV and 0.05% laser-to-neutron conversion efficiency were recorded, already at moderate relativistic laser intensities and ps pulse duration. This approach promises a strong boost of the diagnostic potential of existing kJ PW laser systems used for Inertial Confinement Fusion (ICF) research. Laser-plasma interaction can provide alternative platform over conventional method for particle and photon beam generation. Here the authors demonstrate generation of gamma ray and neutron beams from intense laser interaction with near critical density plasma.

A Higgs Factory is considered the highest priority next collider project by the high-energy physics community. Very advanced designs based on radio-frequency cavities exist, and variations on this approach are still being developed. Recently, an option based on electron-bunch driven plasma wakefield acceleration has also been proposed. In this article, we discuss a further option based on proton-driven plasma wakefield acceleration. This option has significant potential advantages due to the high energy of the plasma wakefield driver, simplifying the plasma acceleration stage. Its success will depend on further developments in producing compact high-energy proton bunches at a high rate, which would also make possible a broad range of synergistic particle-physics research.

A bstract We propose simple freeze-in models where the observed dark matter abundance is explained via the decay of an electrically charged and/or coloured parent particle into Feebly Interacting Massive Particles (FIMP). The parent particle is long-lived and yields a wide variety of LHC signatures depending on its lifetime and quantum numbers. We assess the current constraints and future high luminosity reach of these scenarios at the LHC from searches for heavy stable charged particles, disappearing tracks, displaced vertices and displaced leptons. We show that the LHC constitutes a powerful probe of freeze-in dark matter and can further provide interesting insights on the validity of vanilla baryogenesis and leptogenesis scenarios.

Intense laser-plasma ion sources are characterized by an unsurpassed acceleration gradient and exceptional beam emittance. They are promising candidates for next-generation accelerators towards a broad range of potential applications. However, the laser-accelerated ion beams available currently have limitations in energy spread and peak energy. Here, we propose and demonstrate an all-optical single laser scheme to generate proton beams with low spread at about 1% level and hundred MeV energy by irradiating the edge of a microtape with a readily available femtosecond petawatt laser. Three-dimensional particle-in-cell simulations show that when the electron beam extracted from both sides of the tape is injected into vacuum, a longitudinal bunching and transverse focusing field is self-established because of its huge charge (about 100 nC) and small divergence. Protons are accelerated and bunched simultaneously, leading to a monoenergetic high-energy proton beam. The proposed scheme opens a new route for the development of future compact ion sources.

Reaching gigagauss magnetic fields opens new horizons both in atomic and plasma physics. At these magnetic field strengths, the electron cyclotron energy ℏω c becomes comparable to the atomic binding energy (the Rydberg), and the cyclotron frequency ω c approaches the plasma frequency at solid state densities that significantly modifies optical properties of the target. The generation of such strong quasistatic magnetic fields in laboratory remains a challenge. Using supercomputer simulations, we demonstrate how it can be achieved all-optically by irradiating a micro-channel target by a circularly polarized relativistic femtosecond laser. The laser pulse drives a strong electron vortex along the channel wall, inducing a megagauss longitudinal magnetic field in the channel by the Inverse Faraday Effect. This seed field is then amplified up to a gigagauss level and maintained on a sub-picosecond time scale by the synergistic effect of hydrodynamic flows and dynamos. Our scheme sets a possible platform for producing long living extreme magnetic fields in laboratories using readily available lasers. The concept might also be relevant for applications such as magneto-inertial fusion.

It is shown that by using a certain set of variables, the motion equations of a charged particle in a plane electromagnetic wave with account of radiation reaction can be solved in quadratures. An explicit solution is presented for special cases, such as constant crossed fields, linearly and circularly polarized monochromatic plane waves. Multiple features of the solution are explored, such as average increase of the energy and longitudinal momentum, violation of the Lawson-Woodward theorem, and finiteness of the total radiated energy.

The vast majority of QED results are obtained in relatively weak fields and so in the framework of perturbation theory. However, forthcoming laser facilities providing extremely high fields can be used to enter not-yet-studied regimes. Here, a scheme is proposed that might be used to reach a supercritical regime of radiation reaction or even the fully non-perturbative regime of quantum electrodynamics. The scheme considers the collision of a 100 GeV-class electron beam with a counterpropagating ultraintense electromagnetic pulse. To reach these supercritical regimes, it is unavoidable to use a pulse with ultrashort duration. Using two-dimensional particle-in-cell simulations, it is therefore shown how one can convert a next-generation optical laser to an ultraintense ( I  ≈ 2.9 × 10 24 Wcm −2 ) attosecond (duration ≈ 150 as) pulse. It is shown that if the perturbation theory persists in extreme fields, the spectrum of secondary particles can be found semi-analytically. In contrast, a comparison with experimental data may allow differentiating the contribution of high-order radiative corrections if the perturbation theory breaks.

Stripping heavy atoms in solid matter of most of their electrons requires the extreme conditions that exist in astrophysical plasmas, but are difficult to create in the laboratory1–3. Here we demonstrate solid-density gold plasmas with atoms stripped of up to 72 electrons (N-like Au72+) over large target depths. This record ionization is achieved by irradiating solid foils and near-solid-density nanowire arrays with highly relativistic (3 × 1021 W cm−2) second-harmonic femtosecond laser pulses of <10 J energy focused into a 1.6 µm spot. The short wavelength and high intensity enable the interaction to occur at a relativistic critical density4,5 of 1023 cm−3. Solid targets reach a higher average charge in 1- to 2-µm-thick layers, while the less dense nanowire plasmas are heated to much larger depths (>8 µm) by energetic electrons generated near the nanowire tips. Larger laser spots could result in solid Au plasmas ionized up to He-like.Gold atoms were stripped of up to 72 electrons by irradiating gold foils and nanowire arrays with a relativistic 400 nm laser pulse. This work will open the door to the study of the atomic physics of highly charged atoms in very-high-density plasmas.

We demonstrate a new type of non-Hermitian phase transition in open systems far from thermal equilibrium, which can have place in the absence of an exceptional point. This transition takes place in coupled systems interacting with reservoirs at different temperatures. We show that the spectrum of energy flow through the system caused by the temperature gradient is determined by the φ 4 -potential. Meanwhile, the frequency of the maximum in the spectrum plays the role of the order parameter. The phase transition manifests itself in the frequency splitting of the spectrum of energy flow at a critical point, the value of which is determined by the relaxation rates and the coupling strength. Near the critical point, fluctuations of the order parameter diverge according to a power law with the critical exponent that depends only on the ratio of reservoirs temperatures. The phase transition at the critical point has the non-equilibrium nature and leads to the change in the energy flow between the reservoirs. Our results pave the way to manipulate the heat energy transfer in the coupled out-of-equilibrium systems.