Neutrinos are elementary particles that interact only very weakly with matter. Neutrino experiments are, therefore, usually big, with masses in the multi-tonne range. The thresholdless interaction of coherent elastic scattering of neutrinos on atomic nuclei leads to greatly enhanced interaction rates, which allows for much smaller detectors. The study of this process gives insights into physics beyond the Standard Model of particle physics. The CONUS+ experiment1 was designed to first detect elastic neutrino–nucleus scattering in the fully coherent regime with low-energy neutrinos produced in nuclear reactors. For this purpose, semiconductor detectors based on high-purity germanium crystals with extremely low-energy thresholds were developed2. Here we report the first observation of a neutrino signal with a statistical significance of 3.7σ from the CONUS+ experiment, operated at the nuclear power plant in Leibstadt, Switzerland. In 119 days of reactor operation (395 ± 106) neutrinos were measured compared with a predicted number from calculations assuming Standard Model physics of (347 ± 59) events. With increased precision, there is potential for fundamental discoveries in the future. The CONUS+ results in combination with other measurements of this interaction channel might therefore mark a starting point for a new era in neutrino physics. Direct observation of coherent elastic neutrino–nucleus scattering is reported using the data from the CONUS+ experiment in which the antineutrinos with energy less than 10 MeV are produced in a nuclear reactor.
The difference in the proton and neutron separation energies ($\Delta S$) of the weakly bound $^{15}$C ground state is -19.86 MeV, an extreme value. Data from intermediate-energy heavy-ion induced (HI-induced) knockout reactions on nuclei spanning $-20\lesssim\Delta S\lesssim+20$ MeV, suggest that the degree to which single-particle strength is quenched, $R\mathrm{_{s}}$, has a negative correlation with $\Delta S$, decreasing from unity around $-20$~MeV to around 0.2 at $+20$~MeV. For the $^{15}$C ground state ($R_s=0.96(4)$ in HI-induced knockout), contrasting results have recently been obtained via the neutron-adding transfer reaction, which reveal a value of $R_s=0.64(15)$, similar to the value observed at modest $\Delta S$ and more extreme values of $\Delta S$ with reaction probes other than HI knockout. In order to explore the any potential differences between $adding$ and $removing$ processes in transfer reactions at extreme $\Delta S$, single-neutron removal transfer reactions on $^{15}$C were performed at 7.1MeV/u in inverse kinematics. The removal of a valence neutron in 2$s_{1/2}$ orbit using both ($p$,$d$) and ($d$,$t$) reactions shows consistent quenching factors and agrees with those from the neutron-adding reaction. The present results, which can be compared with neutron knockout reaction, suggest that correlations, represented by the quenching factor, show limited dependence on neutron-proton asymmetry under the most extreme asymmetry conditions so far achieved in transfer reactions.
Asalkhon Alimova, Farruh Atamurotov, Ahmadjon Abdujabbarov
et al.
Abstract The motion of spinning particles around a quantum-corrected black hole is examined in this paper. We investigate the dynamics of spinning test particles by using the Mathisson–Papapetrou–Dixon equations, the Tulczyjew spin-supplementary condition, and restricting the motion to the equatorial plane. We determine the innermost stable circular orbit (ISCO), effective potential, and effective force and examine how these depend on the black hole’s $$\alpha $$ α parameter and the particle’s s spin. However, we also take into account a superluminal bound on the motion of the spinning particle since its kinematical four-velocity and dynamical four-momentum are not always parallel. We also show how the parameter $$\alpha $$ α affects the maximum value of the spin parameter s. We determine the critical angular momentum of the particle for which a collision is possible by investigating collisions of spinning particles close to the horizon of a black hole. Finally, we compute the particle’s center-of-mass energy $$\mathcal {E}_{cm}$$ E cm and analyze how the spin of the colliding particles affects it.
Astrophysics, Nuclear and particle physics. Atomic energy. Radioactivity
Abstract We explore the mathematical relationship between the holographic Wilsonian renormalization group (HWRG) and stochastic quantization(SQ) motivated by the similarity of the monotonicity in RG flow with Langevin dynamics of non-equilibrium thermodynamics. We look at scalar field theory in AdS space with its generic mass, self-interaction, and marginal boundary deformation in the momentum space. Identifying the stochastic time t with radial coordinate r in AdS, we establish maps between the fictitious time evolution of stochastic multi-point correlation function and the radial evolution of multi-trace deformation, which respectively, express the relaxation process of Langevin dynamics and holographic RG flow. We show that the multi-trace deformations in the HWRG are successfully captured by the Langevin dynamics of SQ.
Astrophysics, Nuclear and particle physics. Atomic energy. Radioactivity
The flow and heat transfer characteristics of helically-coiled tubes are crucial for the design of spiral tube steam generators. In this paper, the flow and heat transfer characteristics of a vertical helically-coiled tube with an inner diameter of 8.8 mm and a helical diameter of 568 mm were experimentally investigated in a wide pressure range: 0.2-14.1 MPa. The mass flow rate is 49-1 902 kg/(m2·s). The heat flux of the experimental section is 14.5-580 kW/m2. In this experiment, the flow rate of the main loop is adjusted by the valve opening, the system pressure is adjusted by the high-pressure nitrogen cylinder, the metering pump and the pressure relief valve, the inlet fluid parameters of the experimental section is adjusted by the input power of the preheater and the direct-current (DC) voltage loaded in the preheating section, and the heating heat flux is adjusted by the DC voltage loaded in the experimental section. Finally, the friction coefficients of single-phase and two-phase, as well as heat transfer coefficients of single-phase, subcooled boiling, saturated boiling and dry out under different working conditions were obtained. Comparison and analysis of the experimental results with the empirical relational formulas of recent years revealed that the empirical formulas of Akagawa’s, Hart’s, and Ito’s predicted the single-phase friction coefficients with high accuracy within ±5%. The secondary flow increases the critical Reynolds number, which is about 10 000 in this experiment. In the range of straight tube laminar flow (Re＜2 300), the influence of secondary flow is greater. When the Reynolds number increases, the energy dissipation of secondary flow to the turbulent region is much smaller than that of laminar flow region. The current empirical formula has at least 10%-20% deviation in predicting the two-phase friction coefficient and the heat transfer coefficient in different regions. The relative average deviation between the friction coefficient of the two phases and the calculation formulas of Chen, Guo, Ferraris and M-N is about ±20%, and the prediction accuracy difference between the empirical formulas of spiral tube and straight tube is not obvious. The heat transfer coefficient of single-phase water section has the smallest relative average deviation from Guo et al. empirical formula, which is 18.2%. The relative average deviation between the heat transfer coefficient of the subcooled boiling zone and Hardik’s empirical formula is the smallest, which is −21.1%. The heat transfer coefficient of saturated boiling region has the smallest relative average deviation from the modified Chen’s formula, which is 7.5%. The relative average deviation of heat transfer coefficient of dry zone from Gao’s empirical formula is the least, which is 17.9%. The results of the analysis can provide a reference for the design of helically-coiled tube steam generators.
Considering the elastic scattering of two charged particles, we present two methods for numerically solving the generalized Coulomb-corrected BERW formula with high accuracy across the entire energy spectrum. We illustrate these methods using p-alpha scattering, employing a phenomenological p-alpha short-range interaction. Our results reproduce the phase shifts computed with the Numerov method for all l=0 and l=1 channels. We also provide full access to the Python script used to obtain these results, which can be readily applied to a wide range of core-fragment scattering problems in nuclear and atomic physics.
Mustapha Eddah, Henning Markötter, Björn Mieller
et al.
In synchrotron X-ray radiography, achieving high image resolution and an optimal signal-to-noise ratio (SNR) is crucial for the subsequent accurate image analysis. Traditional methods often struggle to balance these two parameters, especially in situ applications where rapid data acquisition is essential to capture specific dynamic processes. For quantitative image data analysis, using monochromatic X-rays is essential. A double multilayer monochromator (DMM) is successfully used for this aim at the BAMline, BESSY II (Helmholtz Zentrum Berlin, Germany). However, such DMMs are prone to producing an unstable horizontal stripe pattern. Such an unstable pattern renders proper signal normalization difficult and thereby causes a reduction of the SNR. We introduce a novel approach to enhance SNR while preserving resolution: dynamic tilting of the DMM. By adjusting the orientation of the DMM during the acquisition of radiographic projections, we optimize the X-ray imaging quality, thereby enhancing the SNR. The corresponding shift of the projection during this movement is corrected in post-processing. The latter correction allows a good resolution to be preserved. This dynamic tilting technique enables the homogenization of the beam profile and thereby effectively reduces noise while maintaining high resolution. We demonstrate that data captured using this proposed technique can be seamlessly integrated into the existing radiographic data workflow, as it does not need hardware modifications to classical X-ray imaging beamline setups. This facilitates further image analysis and processing using established methods.
Nuclear and particle physics. Atomic energy. Radioactivity, Crystallography
Abstract We examine the effective theory of critical dynamics near superfluid phase transitions in the framework of the Keldysh-Schwinger formalism. We focus on the sector capturing the dynamics of the complex order parameter and the conserved current corresponding to the broken global symmetry. After constructing the theory up to quadratic order in the a-fields, we compare the resulting stochastic system with Model F as well as with holography. We highlight the role of a time independent gauge symmetry of the effective theory also known as “chemical shift”. Finally, we consider the limiting behaviour at energies much lower than the gap of the amplitude mode by integrating out the high energy degrees of freedom to reproduce the effective theory of superfluids.
Nuclear and particle physics. Atomic energy. Radioactivity
: The atomic structure forms the cornerstone of modern science, bridging disciplines from chemistry and physics to material science and quantum computing. This review traces the historical evolution of atomic theories, from ancient philosophical conjectures to the development of quantum mechanical models. Key contributions by pioneering scientists, such as Dalton, Rutherford, Bohr, and Schrödinger, are revisited to highlight their impact on contemporary understanding. The paper explores experimental breakthroughs, including spectroscopy and advanced imaging techniques, that have refined our knowledge of atomic arrangements and interactions. Applications of atomic structure in diverse fields, such as material science and nuclear energy, are discussed, alongside challenges in modeling subatomic particles and forces. Finally, the review outlines emerging directions in atomic structure research, emphasizing the potential of artificial intelligence and nanotechnology in unlocking new scientific frontiers.
Abstract In this paper, we generalize the Nguyen–Spradlin–Volovich–Wen (NSVW) tree formula from the MHV sector to any helicity sector. We find a close connection between the Permutohedron and the KLT relation, and construct a non-trivial mapping between them, linking the amplitudes in the gauge and gravity theories. The gravity amplitude can also be mapped from a determinant followed from the matrix-tree theorem. Besides, we use the binary tree graphs to manifest its Lie structure. In our tree formula, there is an evident Hopf algebra of the permutation group behind the gravity amplitudes. Using the tree formula, we can directly re-derive the soft/collinear limit of the amplitudes.
Astrophysics, Nuclear and particle physics. Atomic energy. Radioactivity
In this white paper, we outline some of the scientific opportunities and challenges related to detection and reconstruction of low-energy (less than 100 MeV) signatures in liquid argon time-projection chamber (LArTPC) detectors. Key takeaways are summarized as follows. 1) LArTPCs have unique sensitivity to a range of physics and astrophysics signatures via detection of event features at and below the few tens of MeV range. 2) Low-energy signatures are an integral part of GeV-scale accelerator neutrino interaction final states, and their reconstruction can enhance the oscillation physics sensitivities of LArTPC experiments. 3) BSM signals from accelerator and natural sources also generate diverse signatures in the low-energy range, and reconstruction of these signatures can increase the breadth of BSM scenarios accessible in LArTPC-based searches. 4) Neutrino interaction cross sections and other nuclear physics processes in argon relevant to sub-hundred-MeV LArTPC signatures are poorly understood. Improved theory and experimental measurements are needed. Pion decay-at-rest sources and charged particle and neutron test beams are ideal facilities for experimentally improving this understanding. 5) There are specific calibration needs in the low-energy range, as well as specific needs for control and understanding of radiological and cosmogenic backgrounds. 6) Novel ideas for future LArTPC technology that enhance low-energy capabilities should be explored. These include novel charge enhancement and readout systems, enhanced photon detection, low radioactivity argon, and xenon doping. 7) Low-energy signatures, whether steady-state or part of a supernova burst or larger GeV-scale event topology, have specific triggering, DAQ and reconstruction requirements that must be addressed outside the scope of conventional GeV-scale data collection and analysis pathways.
Anomaly detection algorithms have been proved to be useful in the search of new physics beyond the Standard Model. However, a prerequisite for using an anomaly detection algorithm is that the signal to be sought is indeed anomalous. This does not always hold true, for example when interference between new physics and the Standard Model becomes important. In this case, the search of new physics is no longer an anomaly detection. To overcome this difficulty, we propose a nested anomaly detection algorithm, which appears to be useful in the study of neutral triple gauge couplings at the CEPC, the ILC and the FCC-ee. Our approach inherits the advantages of the anomaly detection algorithm been nested, while at the same time, it is no longer an anomaly detection algorithm. As a complement to anomaly detection algorithms, it can achieve better results on problems that are no longer anomaly detection.
Nuclear and particle physics. Atomic energy. Radioactivity