Abstract A reduction mechanism of the theoretically predicted excessive abundance of 7Li via baryons evaporated by primordial black holes is suggested. It is shown that the fraction of 7Li with respect to the number density of baryons can be diminished down to the observed value via the process of 7Li transformation by neutron or proton capture. The created in this process 8Li or 8Be quickly decay into a pair of 4He nuclei.
Astrophysics, Nuclear and particle physics. Atomic energy. Radioactivity
Abstract This paper focuses on a conformal block with rank 3 2 $$ \frac{3}{2} $$ irregular singularity which corresponds to the prepotential of the H 1 $$ {\mathcal{H}}_1 $$ Argyres-Douglas theory in Ω background. We derive this irregular conformal block using the generalized holomorphic anomaly recursion relation. This results in an expression which is a power series in Ω-background parameters ϵ 1,2 and exact in coupling. We have verified that in the small coupling regime our result is consistent with previously known expressions. Furthermore we derive the Deformed Seiberg-Witten curve which provides an alternative tool to explore the above mentioned theory in Nekrasov-Shatashvili limit of Ω-background. We checked that the results are in complete agreement with the holomorphic anomaly approach.
Nuclear and particle physics. Atomic energy. Radioactivity
Akash Kumar Saha, Abhijeet Singh, Priyank Parashari
et al.
Abstract A very pressing question in contemporary physics is the identity of Dark Matter (DM). Primordial Black Holes (PBHs) are one of the most well-motivated DM candidates. Light PBHs have been constrained by either the non-detection of their Hawking radiation itself, or by the non-observation of any measurable effects of this radiation on astrophysical and cosmological observables. We constrain the PBH contribution to the DM density by non-detection of their Hawking radiation’s effect on the intergalactic medium (IGM) temperature evolution. We use the latest deductions of IGM temperature from Lyman- $$\alpha $$ α forest observations. We put constraints on the fraction of DM as PBHs with masses $$5 \times 10^{15}$$ 5 × 10 15 g– $$10^{17}$$ 10 17 g, separately for spinning and non-spinning BHs. We derive constraints by dealing with the heating effects of the astrophysical reionization sources on the IGM in two ways. In one way, we completely neglect this heating due to astrophysical sources, thus giving us weaker constraints, but completely robust to the reionization history of the universe. In the second way, we utilise some modelling of the ionization and temperature history, and use it to derive more stringent constraints. We find that for non-spinning PBHs of mass $$10^{16}$$ 10 16 g, the current measurements can constrain the PBH-density to be $$\lesssim $$ ≲ 0.1% of the total DM. We find that these constraints are competitive, and hence provide a new observable to probe the nature of PBH DM. The systematics affecting Lyman- $$\alpha $$ α forest measurements are different from other constraining observations, and thus this is a complementary probe.
Astrophysics, Nuclear and particle physics. Atomic energy. Radioactivity
The propagation speed of the gravitational wave in scalar–Einstein–Gauss-Bonnet (sEGB) gravity is generally different from that of light. Using differential equation conditions for the speed of gravitational waves to coincide with the light speed in the expanding universe, we constructed a general class of sEGB gravities where this condition is satisfied and realistic inflation occurs. It is demonstrated that the condition that the speed of gravitational wave coincides with that of the light in the Friedmann-Lemaître-Robertson-Walker (FRLW) universe is always different from the condition for gravitational wave speed in the sEGB black hole background. Moreover, it is shown that when gravitational wave speed in sEGB black hole is equal to the speed of light the black hole spacetime geometry is changing too so that formally there is no solution for such sEGB black hole. This may indicate that sEGB black holes hardly can be considered as realistic black holes unless some reasonable scenario to make gravitational wave speed to be equal to that of light is proposed, at least asymptotically.
Nuclear and particle physics. Atomic energy. Radioactivity
Matteo Bruno, Sebastiano Segreto, Giovanni Montani
In this work, we show that it is possible to define a classical system associated with a Generalized Uncertainty Principle (GUP) theory via the implementation of a consistent symplectic structure. This provides a solid framework for the classical Hamiltonian formulation of such theories and the study of the dynamics of physical systems in the corresponding deformed phase space.By further characterizing the functions that govern non-commutativity in the configuration space using the algebra of angular momentum, we determine a general form for the rotation generator in these theories and crucially, we show that, under these conditions, unlike what has been previously found in the literature at the quantum level, this requirement does not lead to the superselection of GUP models at the classical level.Finally, we postulate that a properly defined GUP theory can be correctly interpreted classically if and only if the corresponding quantum commutators satisfy the Jacobi identities, identifying those quantization prescriptions for which this holds true.
Nuclear and particle physics. Atomic energy. Radioactivity
The LHCb collaboration, R. Aaij, A. S. W. Abdelmotteleb
et al.
Abstract A measurement of the CP-violating observables from B ± → D * K ± and B ± → D * π ± decays is presented, where D *(D) is an admixture of D *0 and D ¯ ∗ 0 $$ {\overline{D}}^{\ast 0} $$ (D 0 and D ¯ 0 $$ {\overline{D}}^0 $$ ) states and is reconstructed through the decay chains D * → Dπ 0 /γ and D → K S 0 π + π − / K S 0 K + K − $$ D\to {K}_S^0{\pi}^{+}{\pi}^{-}/{K}_S^0{K}^{+}{K}^{-} $$ . The measurement is performed by analysing the signal yield variation across the D decay phase space and is independent of any amplitude model. The data sample used was collected by the LHCb experiment in proton-proton collisions and corresponds to a total integrated luminosity of 9 fb −1 at centre-of-mass energies of 7, 8 and 13 TeV. The CKM angle γ is determined to be 69 − 14 + 13 ∘ $$ {\left({69}_{-14}^{+13}\right)}^{\circ } $$ using the measured CP-violating observables. The hadronic parameters r B D ∗ K ± , r B D ∗ π ± , δ B D ∗ K ± , δ B D ∗ π ± $$ {r}_B^{D^{\ast }{K}^{\pm }},{r}_B^{D^{\ast }{\pi}^{\pm }},{\delta}_B^{D^{\ast }{K}^{\pm }},{\delta}_B^{D^{\ast }{\pi}^{\pm }} $$ , which are the ratios and strong phase differences between favoured and suppressed B ± decays, are also reported.
Nuclear and particle physics. Atomic energy. Radioactivity
Abstract The dynamics of electrically neutral or charged particles around a magnetized Kerr–Newman black hole immersed in an external electromagnetic field can be described by a dimensionless Hamiltonian system. This Hamiltonian is given an appropriate time transformation, which allows for construction of explicit symplectic integrators. Selecting one of the integrators with good accuracy, long-term stabilized Hamiltonian error behavior and less computational cost, we employ the 0–1 binary test correlation method to distinguish between regular and chaotic dynamics of electrically neutral or charged particles. The correlation method is almost the same as the techniques of Poincaré map and fast Lyapunov indicators in identifying the regular and chaotic two cases. It can well describe the dependence of the transition from regularity to chaos on varying one or two dynamical parameters. From a statistical viewpoint, chaos occurs easily under some circumstances with an increase of the external magnetic field strength and the particle electric charge and energy or a decrease of the black hole spin and the particle angular momentum. A small change of the black hole electric charge does not very sensitively affect the dynamics of neutral particles. With the black hole electric charge increasing, positively charged particles do not easily yield chaotic motions, but negatively charged particles do. On the other hand, the effect of a small change of the black hole magnetic charge on the dynamical transition from order to chaos has no universal rule.
Astrophysics, Nuclear and particle physics. Atomic energy. Radioactivity
Broadband lasers have been proposed as future drivers of inertial confined fusion (ICF) to enhance the laser–target coupling efficiency via the mitigation of various parametric instabilities. The physical mechanisms involved have been explored recently, but are not yet fully understood. Here, stimulated Raman scattering (SRS) as one of the key parametric instabilities is investigated theoretically and numerically for a broadband laser propagating in homogeneous plasma in multidimensional geometry. The linear SRS growth rate is derived as a function of scattering angles for two monochromatic laser beams with a fixed frequency difference δω. If δω/ω0 ∼ 1%, with ω0 the laser frequency, these two laser beams may be decoupled in stimulating backward SRS while remaining coupled for sideward SRS at the laser intensities typical for ICF. Consequently, side-scattering may dominate over backward SRS for two-color laser light. This finding of SRS transition from backward to sideward SRS is then generalized for a broadband laser with a few-percent bandwidth. Particle-in-cell simulations demonstrate that with increasing laser bandwidth, the sideward SRS gradually becomes dominant over the backward SRS. Since sideward SRS is very efficient in producing harmful hot electrons, attention needs to be paid on this effect if ultra-broadband lasers are considered as next-generation ICF drivers.
Nuclear and particle physics. Atomic energy. Radioactivity
We first derive the boundary theory from the U(1) Chern-Simons theory. The boundary action on an n-sheet manifold appears from its back-reaction of the Wilson line. The reason is that the U(1) Chern-Simons theory can provide an exact effective action when introducing the Wilson line. The Wilson line in the pure AdS3 Einstein gravity is equivalent to entanglement entropy in the boundary theory up to classical gravity. The U(1) Chern-Simons theory deviates by a self-interaction term from the gauge formulation on the boundary. We also compare the Hayward term in the SL(2) Chern-Simons formulation to the Wilson line approach. Introducing two wedges can reproduce the entanglement entropy for a single interval at the classical level. We propose quantum generalization by combining the bulk and Hayward terms. The quantum correction of the partition function vanishes. In the end, we calculate the entanglement entropy for a single interval. The pure AdS3 Einstein gravity theory shows a shift of central charge by 26 at the one-loop level. The U(1) Chern-Simons theory does not show a shift from the quantum effect. The result is the same in the weak gravitational constant limit. The non-vanishing quantum correction shows that the Hayward term is incorrect.
Nuclear and particle physics. Atomic energy. Radioactivity
Abstract In this paper, we use the latest observations of quasars covering the redshift range of $$0.04<z<5.1$$ 0.04 < z < 5.1 to investigate a series of Chaplygin gas models as candidates for unified dark matter and dark energy. Based on different combinations of available standard candle and standard ruler data, we put constraints on the generalized Chaplygin gas (GCG), modified Chaplygin gas (MCG), new generalized Chaplygin gas (NGCG) and viscous generalized Chaplygin gas (VGCG) models. Moreover, we apply Jensen–Shannon divergence (JSD), statefinder diagnostics, and the deviance information criterion (DIC) to distinguish these CG models, based on the statistical results derived from Markov chain Monte Carlo method. The results show that (1) The standard ruler data could provide more stringent constraints on the cosmological parameters of different CG models considered in this analysis. Interestingly, the matter density parameter $$\varOmega _{m}$$ Ω m and Hubble constant $$H_{0}$$ H 0 derived from the available data are well consistent with those from the Planck 2018 results; (2) Based on the statistical criteria JSD, our findings demonstrate the well consistency between Chaplygin gas and the concordance $$\varLambda $$ Λ CDM model. However, in the framework of statefinder diagnostics, the GCG and NGCG models cannot be distinguished from $$\varLambda $$ Λ CDM, while MCG and VGCG models show significant deviation from $$\varLambda $$ Λ CDM in the present epoch; (3) According to the the statistical criteria DIC, we show that the MCG and VGCG models have substantial observational support from high-redshift quasars, whereas the GCG and NGCG models miss out on the less observational support category but can not be ruled out.
Astrophysics, Nuclear and particle physics. Atomic energy. Radioactivity
Mehedi Masud, Poonam Mehta, Christoph A. Ternes
et al.
Abstract We formulate an alternative approach based on unitarity triangles to describe neutrino oscillations in presence of non-standard interactions (NSI). Using perturbation theory, we derive the expression for the oscillation probability in case of NSI and cast it in terms of the three independent parameters of the leptonic unitarity triangle (LUT). The form invariance of the probability expression (even in presence of new physics scenario as long as the mixing matrix is unitary) facilitates a neat geometric view of neutrino oscillations in terms of LUT. We examine the regime of validity of perturbative expansions in the NSI case and make comparisons with approximate expressions existing in literature. We uncover some interesting dependencies on NSI terms while studying the evolution of LUT parameters and the Jarlskog invariant. Interestingly, the geometric approach based on LUT allows us to express the oscillation probabilities for a given pair of neutrino flavours in terms of only three (and not four) degrees of freedom which are related to the geometric properties (sides and angles) of the triangle. Moreover, the LUT parameters are invariant under rephasing transformations and independent of the parameterization adopted.
Nuclear and particle physics. Atomic energy. Radioactivity
Abstract The impact of nonlinear effects in the diffractive observables that will be measured in future electron-ion collisions is investigated. We present, for the first time, the predictions for the diffractive structure function and reduced cross sections derived using the solution to the Balitsky–Kovchegov equation with the collinearly-improved kernel and including the impact-parameter dependence. We demonstrate that the contribution of the diffractive events is enhanced in nuclear collisions and that the study of the ratio between the nuclear and proton predictions will be useful to discriminate among different models of the dipole-target scattering amplitude and, consequently, will allow us to constrain the description of QCD dynamics in parton densities.
Astrophysics, Nuclear and particle physics. Atomic energy. Radioactivity
Abstract In the presence of non-standard neutrino interactions (NSI), a degeneracy exists in neutrino oscillation data, which involves the flipping of the octant of the mixing angle θ 12 and the type of the neutrino mass ordering. In this article, we revisit the status of this degeneracy in the light of recent data on coherent elastic neutrino-nucleus scattering (CEνNS) from the COHERENT experiment. For general relative couplings to up and down quarks, the degeneracy is disfavoured at the 2σ level by the latest data but remains at a higher confidence level. We investigate the requirements of future CEνNS measurements to resolve the degeneracy with high significance. We find that a measurement involving both, electron and muon neutrino flavours and a target with a neutron-to-proton ratio close to 1 is required. For example, an experiment with a silicon target at the European Spallation Source can resolve the degeneracy at more than 4σ for arbitrary relative couplings to up and down quarks.
Nuclear and particle physics. Atomic energy. Radioactivity
Quantum theory is awash in multidimensional integrals that contain exponentials in the integration variables, their inverses, and inverse polynomials of those variables. The present paper introduces a means to reduce pairs of such integrals to one dimension when the integrand contains powers multiplied by an arbitrary function of <inline-formula><math display="inline"><semantics><mrow><mi>x</mi><mi>y</mi><mo>/</mo><mo>(</mo><mi>x</mi><mo>+</mo><mi>y</mi><mo>)</mo></mrow></semantics></math></inline-formula> multiplying various combinations of exponentials. In some cases these exponentials arise directly from transition-amplitudes involving products of plane waves, hydrogenic wave functions, and Yukawa and/or Coulomb potentials. In other cases these exponentials arise from Gaussian transforms of such functions.
Nuclear and particle physics. Atomic energy. Radioactivity
Nuclear–nuclear collisions at energies attainable at the large accelerators RHIC and the LHC are an ideal environment to study nuclear matter under extreme conditions of high temperature and energy density. One of the most important probes of such nuclear matter is the study of production of jets. In this article, several jet shape observables in Au+Au collisions at the center of mass energy per nucleon–nucleon pair of <inline-formula> <math display="inline"> <semantics> <msqrt> <msub> <mi>s</mi> <mrow> <mi>N</mi> <mi>N</mi> </mrow> </msub> </msqrt> </semantics> </math> </inline-formula> = 200 GeV simulated in the Monte Carlo generator JEWEL are presented. Jets were reconstructed using the anti-<inline-formula> <math display="inline"> <semantics> <msub> <mi>k</mi> <mi>T</mi> </msub> </semantics> </math> </inline-formula> algorithm and their shapes were studied as a function of the jet-resolution parameter <i>R</i>, transverse momentum <inline-formula> <math display="inline"> <semantics> <msub> <mi>p</mi> <mi>T</mi> </msub> </semantics> </math> </inline-formula> and collision centrality.
Juan Herrero-García, Emiliano Molinaro, Michael A. Schmidt
Abstract The strong direct detection limits could be pointing to dark matter – nucleus scattering at loop level. We study in detail the prototype example of an electroweak singlet (Dirac or Majorana) dark matter fermion coupled to an extended dark sector, which is composed of a new fermion and a new scalar. Given the strong limits on colored particles from direct and indirect searches we assume that the fields of the new dark sector are color singlets. We outline the possible simplified models, including the well-motivated cases in which the extra scalar or fermion is a Standard Model particle, as well as the possible connection to neutrino masses. We compute the contributions to direct detection from the photon, the Z and the Higgs penguins for arbitrary quantum numbers of the dark sector. Furthermore, we derive compact expressions in certain limits, i.e., when all new particles are heavier than the dark matter mass and when the fermion running in the loop is light, like a Standard Model lepton. We study in detail the predicted direct detection rate and how current and future direct detection limits constrain the model parameters. In case dark matter couples directly to Standard Model leptons we find an interesting interplay between lepton flavor violation, direct detection and the observed relic abundance.
Astrophysics, Nuclear and particle physics. Atomic energy. Radioactivity