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Inorganic crystal scintillators play a crucial role in particle detection for various applications in fundamental physics and applied science. The use of such materials as scintillating bolometers, which operate at temperatures as low as 10 mK and detect both heat (phonon) and scintillation signals, significantly extends detectors performance compared to the conventional scintillation counters. In particular, such low-temperature devices offer a high energy resolution in a wide energy interval thanks to a phonon signal detection, while a simultaneous registration of scintillation emitted provides an efficient particle identification tool. This feature is of great importance for a background identification and rejection. Combined with a large variety of elements of interest, which can be embedded in crystal scintillators, scintillating bolometers represent powerful particle detectors for rare-event searches (e.g., rare alpha and beta decays, double-beta decay, dark matter particles, neutrino detection). Here, we review the features and results of low-temperature scintillation detection achieved over a 30-year history of developments of scintillating bolometers and their use in rare-event search experiments.

The rock burst causes a significant threat to the construction of the deep-buried tunnel, and the displacement and fracture evolution characteristics of surrounding rock are investigated during the rock burst. First, the full-time numerical simulation of the rock burst is conducted. Then, the displacement evolution characteristic of the rock is analyzed. Finally, the fracture evolution characteristic of the rock is analyzed. The results indicate that more and more surrounding rock near the left straight-wall segment undergoes fracture and movement with the increase of time, and the rock that heaps up in the tunnel mainly comes from the middle-upper part. With the increase of time, the volume V r of rock moving into the tunnel and the fracture ratio α keep increasing, while the growth trends of V r and α decay. The fracture degree of rock near the left straight-wall segment is the most severe, and the fracture area gradually expands with the increase of time.

In this study, we investigate the application of support vector machines utilizing a radial basis function kernel for predicting nuclear α-decay half-lives. Our approach integrates a comprehensive set of physics-derived features, including characteristics derived from nuclear structure, to systematically evaluate their impact on predictive accuracy. In addition to traditional parameters such as proton and neutron numbers, as well as terms based on the liquid drop model (e.g., volume, surface, Coulomb features), we incorporate decay energies and orbital angular momentum quantum numbers for both parent and daughter nuclei. Our analysis of 2232 nuclear data points demonstrates that the use of the radial basis function kernel yields predictive models with root mean square errors of 0.819 (for set1) and 0.352 (for set2), aligning with results obtained from comparable machine learning methodologies. Furthermore, Shapley additive explanations values highlight the predominant role of parent nuclei in predicting α-decay half-lives within the support vector machines. These results highlight the effectiveness of machine learning in nuclear structure research, opening up new possibilities for predicting the α-decay half-lives of previously unstudied nuclei.

Based on the Santhosh formula (Nucl Phys A 825:159, 2009), considering the blocking effect of unpaired nucleons and the orbital angular momentum taken away by the emitted α particle, we put forward an improved formula to evaluate α decay half-lives for superheavy nuclei. Using this formula, we systematically investigate the α decay half-lives of 141 nuclei ranging from Z = 96 to Z = 118 with the corresponding root-mean-square (rms) deviations being 0.319 , 0.619 and 0.388 for 41 even–even, 78 odd-A and 22 odd–odd nuclei, respectively. In addition, this improved formula is generalized to predict α decay half-lives for 100 nuclei with Z = 117, 118, 119 and 120. For comparison, the predicted results obtained by using phenomenological formulae, semi-microscopic and/or microscopic models are also present. The corresponding predictions consistently indicate that N = 184 may be the next possible neutron magic number.

Quartetting ( $\\alpha $ -like clustering) occurs in low-density matter ( ${\\le }0.03$ fm$^{-3}$ ) which exists, e.g., at the surface of nuclei. It is of interest for the $\\alpha $ preformation to calculate the $\\alpha $ decay of heavy nuclei such as$^{212}$ Po, but also in light nuclei (e.g.,$^{20}$ Ne) which shows strong signatures of quartetting. We analyze the intrinsic structure of the $\\alpha $ -like cluster and the center-of-mass motion of the quartet, in particular the role of Pauli blocking. The Thomas–Fermi model for the (daughter) core nucleus is improved introducing quasiparticle nucleon states. Calculations performed for harmonic oscillator basis states show that the effective potential for the quartet center-of-mass motion remains nearly constant within the core nucleus. The relation to the (Tohsaki–Horiuchi–Schuck–Röpke) THSR approach is discussed.

Synthesizing isotopes located far away from the line of β -stability is the core research topic in nuclear physics. However, it remains a challenge due to their tiny production cross sections and short half-lives. Here, we report on the observation of a very neutron-deficient isotope 210 Pa produced via the fusion-evaporation reaction 175 Lu( 40 Ca, 5n) 210 Pa at a newly constructed China Accelerator Facility for Superheavy Elements. The measured α -particle energy of E α = 8284(15) keV and half-life of T 1 / 2 = 6 . 0 − 1.1 + 1.5 ms of 210 Pa allow us to extend the α -decay systematics and test the predictive power of theoretical models for heavy nuclei near the proton drip line. Based on its unhindered α -decay character, the spin and parity of 210 Pa is proposed to be (3 + ), supported by the large-scale shell model and cranked shell model calculations. This isotope is discovered with substantial statics within  ∼ 3 days using intensive 2 p μ A beam, demonstrating the tremendous capability of the facility for the study of heavy and superheavy nuclei. The study of isotopes away from the beta stability valley is crucial for the understanding of nuclear structure, especially for neutron-deficient heavy nuclei. Here, the authors report the observation of the alpha-decay isotope 210-protactinium (Pa), extending the alpha-decay systematics of underexplored regions of the nuclides chart.

We derive a closed-form optimal dynamic portfolio policy when trading is costly and security returns are predictable by signals with different mean-reversion speeds. The optimal strategy is characterized by two principles: (1) aim in front of the target, and (2) trade partially toward the current aim. Specifically, the optimal updated portfolio is a linear combination of the existing portfolio and an \"aim portfolio,\" which is a weighted average of the current Markowitz portfolio (the moving target) and the expected Markowitz portfolios on all future dates (where the target is moving). Intuitively, predictors with slower mean-reversion (alpha decay) get more weight in the aim portfolio. We implement the optimal strategy for commodity futures and find superior net returns relative to more naive benchmarks.

We study the out-of-equilibrium dynamics induced by quantum quenches in quadratic Hamiltonians featuring both short- and long-range interactions. The spreading of correlations in the presence of algebraic decaying interactions, 1/R , is studied for lattice Bose models in arbitrary dimension D. These models are exactly solvable and provide useful insight in the universal description of more complex systems as well as comparisons to the known universal upper bounds for the spreading of correlations. Using analytical calculations of the dominant terms and full numerical integration of all quasi-particle contributions, we identify three distinct dynamical regimes. For strong decay of interactions, > D + 1 , we find a causal regime, qualitatively similar to what previously found for short-range interactions. This regime is characterized by ballistic (linear cone) spreading of the correlations with a cone velocity equal to twice the maximum group velocity of the quasi-particles. For weak decay of interactions, < D, we find instantaneous activation of correlations at arbitrary distance. This signals the breaking of causality, which can be associated with the divergence of the quasi-particle energy spectrum. Finite-size scaling of the activation time precisely confirms this interpretation. For intermediate decay of interactions, D < < D + 1 , we find a sub-ballistic, algebraic (bent cone) spreading and determine the corresponding exponent as a function of . These outcomes generalize existing results for one-dimensional systems to arbitrary dimension. We precisely relate the three regimes to the first- and second-order divergences of the quasi-particle energy spectrum for any dimension. The long-range transverse Ising model in dimensions D = 1, 2, and 3 in the (quadratic) spin-wave approximation is more specifically studied and we also discuss the shape of the correlation front in dimension higher than one. Our results apply to several condensed-matter systems as well as atomic, molecular, and optical systems, and pave the way to the observation of causality and its breaking in diverse experimental realization.

We study the behaviour of the streamwise velocity variance in turbulent wall-bounded flows using a direct numerical simulation (DNS) database of pipe flow up to friction Reynolds number ${{Re}}_{\\tau } \\approx 12000$. The analysis of the spanwise spectra in the viscous near-wall region strongly hints to the presence of an overlap layer between the inner- and the outer-scaled spectral ranges, featuring a $k_{\\theta }^{-1+\\alpha }$ decay (with $k_{\\theta }$ the wavenumber in the azimuthal direction, and $\\alpha \\approx 0.18$), hence shallower than suggested by the classical formulation of the attached-eddy model. The key implication is that the contribution to the streamwise velocity variance $(\\langle{u}^2\\rangle)$ from the largest scales of motion (superstructures) slowly declines as ${{Re}}_{\\tau }^{-\\alpha }$, and the integrated inner-scaled variance follows a defect power law of the type $\\langle u^2 \\rangle ^+ = A - B \\, {{Re}}_{\\tau }^{-\\alpha }$, with constants $A$ and $B$ depending on $y^+$. The DNS data very well support this behaviour, which implies that strict wall scaling is restored in the infinite-Reynolds-number limit. The extrapolated limit distribution of the streamwise velocity variance features a buffer-layer peak value of $\\langle u^2 \\rangle ^+ \\approx 12.1$, and an additional outer peak with larger magnitude. The analysis of the velocity spectra also suggests a similar behaviour of the dissipation rate of the streamwise velocity variance at the wall, which is expected to attain a limiting value of approximately $0.28$, hence slightly exceeding the value $0.25$ which was assumed in previous analyses (Chen & Sreenivasan, J. Fluid Mech., vol. 908, 2021, R3). We have found evidence suggesting that the reduced near-wall influence of wall-attached eddies is likely linked to the formation of underlying turbulent Stokes layers.

A first search for rare decays of gadolinium isotopes was performed with an ultra-low background high-purity germanium detector at Gran Sasso Underground Laboratory (Italy). A 198 g Gd 2 O 3 powder sample was measured for 63.8 d with a total Gd exposure of 12.6 kg × d. 152 Gd is the most promising isotope for resonant enhanced neutrinoless double electron capture which could significantly increase the decay rate over other neutrinoless double beta decay processes. The half-life for this decay was constrained to > 4.2 × 10 12  year (90% credibility). This limit is still orders of magnitude away from theoretical predictions but it is the first established limit on the transition paving the way for future experiments. In addition, other rare alpha and double beta decay modes were investigated in 152 Gd, 154 Gd, and 160 Gd with half-life limits in the range of 10 17 - 20 year.