In this paper, we summarize the existing methods of solving the evolution equation of the leading-twist
In this work, the characteristics of
Weakly bound states often occur in nuclear physics. To precisely understand their properties, the coupling to the continuum should be worked out explicitly. As the first step, we use a simple nuclear model in the continuum and on a lattice to investigate the influence of a third particle on a loosely bound state of a particle and a heavy core. Our approach is consistent with the Lüscher formalism.
We revisit the hyperon weak radiative decays in the framework of the non-relativistic constituent quark model. This study confirms the nonlocal feature of the hyperon weak radiative transition operators, which are dominated by the pole terms, and an overall self-consistent description of the available experimental data for the Cabibbo-favored hyperon weak radiative decays is presented. It provides a natural mechanism for evading the Hara theorem, where sizeable parity-violating contributions can come from the intermediate orbital excitations. Cancellations between pole terms also explain the significant SU(3) flavor symmetry breaking manifested by the experimental data. We also discuss several interesting selection rules arising from either the electromagnetic or the weak interaction vertices. These features suggest nontrivial relations among various hyperon decays.
We construct a new global optical model potential to describe the elastic scattering of 12C. The experimental data of elastic-scattering angular distributions and total reaction cross sections for targets from 24Mg to 209Bi are considered below 200 MeV within the framework of the optical model. The results calculated using the derived global optical potential are then compared with the existing experimental data. The reliability of the global optical potential is further tested by predicting the elastic scattering data out of the mass and energy ranges, within which the global potential parameters are determined, and reasonable results are also obtained.
We study the emission of fragments in central collisions of light and heavily charged systems of 40Ar+45Sc and 84Kr+197Au, respectively, using the Quantum Molecular Dynamics (QMD) model as the primary model. The fragments are identified using an energy based clusterization algorithm, i.e., the Simulated Annealing Clusterization Algorithm (SACA). The charge distributions of intermediate mass fragments [3≤
We use a geometric model for hadron polarization in heavy ion collisions with an emphasis on the rapidity dependence. The model is based on the model of Brodsky, Gunion, and Kuhn, as well as the Bjorken scaling model. We make predictions regarding the rapidity dependence of global
Hawking-Page phase transitions between the thermal anti-de Sitter vacuum and charged black holes surrounded by quintessence are studied in the extended phase space. The quintessence field, with the state parameter
The Circular Electron Positron Collider (CEPC), proposed as a future Higgs boson factory, will operate at a center-of-mass energy of 240 GeV and will accumulate 5.6 ab−1 of integrated luminosity in 7 years. In this study, we estimate the upper limit of BR(
The 12C+12C fusion reaction plays a crucial role in stellar evolution and explosions. Its main open reaction channels include
We report the dark matter search results obtained using the full 132 ton·day exposure of the PandaX-II experiment, including all data from March 2016 to August 2018. No significant excess of events is identified above the expected background. Upper limits are set on the spin-independent dark matter-nucleon interactions. The lowest 90% confidence level exclusion on the spin-independent cross section is 2.2 × 10−46 cm2 at a WIMP mass of 30 GeV/c2.
The cross sections for the 94Zr(n,d*)93m+gY, 96Zr(n,γ)97Z, 96Zr(n,2n)95Zr, 90Zr(n,α)87mSr, 94Zr(n,α)91Sr,90Zr(n,p)90mY, 92Zr(n,p)92Y, and 94Zr(n,p)94Y reactions have been measured in the neutron energy range of 13.5-14.8 MeV by means of the activation technique. The neutrons were produced via the D-T reaction. A high-purity germanium detector with high energy resolution was used to measure the induced γ activities. In combination with the nuclear reaction theoretical models, the excitation curves of the above-mentioned eight nuclear reactions within the incident neutron energy range from the threshold to 20 MeV were obtained by adopting the nuclear theoretical model program system Talys-1.9. The resulting experimental cross sections were analyzed and compared with the experimental data from published studies. Calculations were performed using Talys-1.9 and are in agreement with our experimental results, previous experimental values, as well as results of the theoretical excitation curves at the corresponding energies. The theoretical excitation curves generally match the experimental data well.
Scrupulous theoretical study of 8Be nucleus states, both clustered and non-clustered, is performed over a wide range of excitation energies. The quantities that characterize the degree of the alpha-clustering of these states, i.e., spectroscopic factors, cluster form factors, and alpha-decay widths, are computed in the framework of the developed accurate ab initio approach. Other basic properties of the 8Be spectrum, including the binding and excitation energies and the mean values of the isospin, are calculated simultaneously. In the majority of instances, the results of the computation turn out to be in good agreement with the spectroscopic data. A number of predictions are made, and corresponding verification experiments are proposed. Prospects of the developed approach for nuclear spectroscopy are demonstrated.
The transonic phenomenon of black hole accretion and the existence of the photon sphere characterize strong gravitational fields near a black hole horizon. Here, we study the spherical accretion flow onto general parametrized spherically symmetric black hole spacetimes. We analyze the accretion process for various perfect fluids, such as the isothermal fluids of ultra-stiff, ultra-relativistic, and sub-relativistic types, and the polytropic fluid. The influences of additional parameters, beyond the Schwarzschild black hole in the framework of general parameterized spherically symmetric black holes, on the flow behavior of the above-mentioned test fluids are studied in detail. In addition, by studying the accretion of the ideal photon gas, we further discuss the correspondence between the sonic radius of the accreting photon gas and the photon sphere for general parameterized spherically symmetric black holes. Possible extensions of our analysis are also discussed.
We investigated the tendency in the variations of CFT2 when a rotating AdS3 black hole changes because of the fluxes transferred by the scattering of a massive scalar field according to the anti-de Sitter (AdS)/conformal field theory (CFT) correspondence. The conserved quantities of the black hole are definitely constrained by the extremal condition. Moreover, the laws of thermodynamics provide a direction for the changes in the conserved quantities. Therefore, the black hole cannot be extremal under the scattering; this is naturally preferred. According to the relationship between the rotating AdS3 black hole and dual CFT2, we find that such changes in the black hole constrain the variations in the eigenstates of dual CFT2. Furthermore, the tendency in the variations is closely related to the laws of thermodynamics.
According to a corrected dispersion relation proposed in the study on the string theory and quantum gravity theory, the Rarita-Schwinger equation was precisely modified, which resulted in the Rarita-Schwinger-Hamilton-Jacobi equation. Using this equation, the characteristics of arbitrary spin fermion quantum tunneling radiation from non-stationary Kerr-de Sitter black holes were determined. A number of accurately corrected physical quantities, such as surface gravity, chemical potential, tunneling probability, and Hawking temperature, which describe the properties of black holes, were derived. This research has enriched the research methods and enabled increased precision in black hole physics research.
The valence-quark distribution function of the pion has been of interest for decades; particularly, the profile it should adopt when
Vector boson scattering at the Large Hadron Collider (LHC) is sensitive to anomalous quartic gauge couplings (aQGCs). In this study, we investigate the aQGC contribution to
Global symmetry can guarantee the stability of dark matter particles (DMps). However, the nonminimal coupling between dark matter (DM) and gravity can break the global symmetry of DMps, which in turn leads to their decay. Under the framework of nonminimal coupling between scalar singlet dark matter (ssDM) and gravity, it is worth exploring the extent to which the symmetry of ssDM is broken. It is suggested that the total number of decay products of ssDM cannot exceed current observational constraints. Along these lines, the data obtained with satellites such as Fermi-LAT and AMS-02 suggest that the scale of ssDM global symmetry breaking can be limited. Because the mass of many promising DM candidates is likely to be in the GeV-TeV range, we determine reasonable parameters for the ssDM lifetime within this range. We find that when the mass of ssDM is around the electroweak scale (246 GeV), the corresponding 3
Half-lives of α decay for Z≥ 84 nuclei are calculated based on the WKB theory applied for a phenomenological potential barrier composed of a centrifugal contribution and a screened electrostatic interaction represented by a Hulthen potential. For favored decays, the model has a single adjustable parameter associated with the screening of the electrostatic potential. The description of half lives for unfavored decays requires an additional hindrance term. A good agreement with experimental data is obtained in all considered cases. The evolution of the screening parameter for each nucleus revealed its dependence on shell filling. The model is also used for theoretical predictions on a few nuclei with uncertain or incomplete decay information.
We calculate the spinor helicity amplitudes of anomalous
In this work, we propose the possible assignment of the newly observed
It is believed that there are more fundamental gauge symmetries beyond those described by the Standard Model of particle physics. The scales of these new gauge symmetries are usually too high to be reachable by particle colliders. Considering that the phase transition (PT) relating to the spontaneous breaking of new gauge symmetries to the electroweak symmetry might be strongly first order, we propose considering the stochastic gravitational waves (GW) arising from this phase transition as an indirect way of detecting these new fundamental gauge symmetries. As an illustration, we explore the possibility of detecting the stochastic GW generated from the PT of
To solve the cosmological constant fine tuning problem, we investigate an
Using bare Argonne V4' (AV4'), V6' (AV6'), and V8' (AV8') nucleon–nucleon (
The momentum-space subtraction (MOM) scheme is one of the most frequently used renormalization schemes in perturbative QCD (pQCD) theory. In this paper, we discuss in detail the gauge dependence of the pQCD predictions obtained under the MOM scheme. Conventionally, a renormalization scale ambiguity exists for the fixed-order pQCD predictions; this assigns an arbitrary range and error for the fixed-order pQCD prediction and makes the discussions on the issue of the gauge dependence much more involved. The principle of maximum conformality (PMC) adopts the renormalization group equation to determine the magnitude of the coupling constant; hence, it determines the effective momentum flow of the process, which is independent of the choice of renormalization scale. Thus, no renormalization scale ambiguity exists in PMC predictions. To focus our attention on the MOM scheme's gauge dependence, we first apply the PMC to deal with the pQCD series. As an explicit example, we adopt the Higgs boson decay width
In this study, the mathematical expression formulated by Bohr for the moment of inertia of even-even nuclei based on the hydrodynamical model is modified. The modification pertains to the kinetic energy of the surface oscillations, including the second and third terms of the R-expansion as well as the first term, which had already been modified by Bohr. Therefore, this work can be considered a continuation and support of Bohr's hydrodynamic model. The procedure yields a Bohr formula to be multiplied by a factor that depends on the deformation parameter. Bohr's (modified) formula is examined by applying it on axially symmetric even-even nuclei with atomic masses ranging between 150 and 190 as well as on some triaxial symmetry nuclei. In this paper, the modification of Bohr's formula is discussed, including information about the stability of this modification and the second and third terms of the R-expansion in Bohr's formula. The results of the calculation are compared with the experimental data and Bohr's results recorded earlier. The results obtained are in good agreement with experimental data, with a ratio of approximately 0.7, and are better than those of the unmodified ones.
In this article, we study the first radial excited states of the scalar, axialvector, vector, and tensor diquark-antidiquark-type
Recently, the non-trivial solutions for 4-dimensional black holes of Einstein-Gauss-Bonnet gravity had been discovered. In this paper, considering a charged particle entering into a 4-dimensional Gauss-Bonnet-Maxwell black hole, we calculate the black hole thermodynamic properties using the Hamilton-Jacobi equation. In the normal phase space, the cosmological constant and Gauss-Bonnet parameter are fixed, the black hole satisfies the first and second laws of thermodynamics, and the weak cosmic censorship conjecture (WCCC) is valid. On the other hand, in the case of extended phase space, the cosmological constant and Gauss-Bonnet parameter are treated as thermodynamic variables. The black hole also satisfies the first law of thermodynamics. However, the increase or decrease in the black hole's entropy depends on some specific conditions. Finally, we observe that the WCCC is violated for the near-extremal black holes in the extended phase space.
Recent progress regarding multiple chiral doublet bands (
Fragment production in spallation reactions yields key infrastructure data for various applications. Based on the empirical SPACS parameterizations, a Bayesian-neural-network (BNN) approach is established to predict the fragment cross sections in proton-induced spallation reactions. A systematic investigation has been performed for the measured proton-induced spallation reactions of systems ranging from intermediate to heavy nuclei systems and incident energies ranging from 168 MeV/u to 1500 MeV/u. By learning the residuals between the experimental measurements and SPACS predictions, it is found that the BNN-predicted results are in good agreement with the measured results. The established method is suggested to benefit the related research on nuclear astrophysics, nuclear radioactive beam sources, accelerator driven systems, proton therapy, etc.
Well-motivated electroweak dark matter is often hosted by an extended electroweak sector that also contains new lepton pairs with masses near the weak scale. In this study, we explore such electroweak dark matter by combining dark matter direct detection experiments and high-luminosity LHC probes of new lepton pairs. Using Z- and W-associated electroweak processes with two or three lepton final states, we show that depending on the overall coupling constant, dark matter masses of up to
Motivated by the large rates of
The atomic mass table presents zones where the structure of the states changes rapidly as a function of the neutron or proton number. Among them, notable examples are the A ≈ 100 Zr region, the Pb region around the neutron midshell (N = 104), and the N ≈ 90 rare-earth region. The observed phenomena can be understood in terms of either shape coexistence or quantum phase transitions. The objective of this study is to find an observable that can distinguish between both shape coexistence and quantum phase transitions. As an observable to be analyzed, we selected the two-neutron transfer intensity between the 0+ states in the parent and daughter nuclei. The framework used for this study is the Interacting Boson Model (IBM), including its version with configuration mixing (IBM-CM). To generate wave functions of isotope chains of interest needed for calculating transfer intensities, previous systematic studies using IBM and IBM-CM were used without changing the parameters. The results of two-neutron transfer intensities are presented for Zr, Hg, and Pt isotopic chains using IBM-CM. Moreover, for Zr, Pt, and Sm isotopic chains, the results are presented using IBM with only a single configuration, i.e., without using configuration mixing. For Zr, the two-neutron transfer intensities between the ground states provide a clear observable, indicating that normal and intruder configurations coexist in the low-lying spectrum and cross at A = 98 → 100. This can help clarify whether shape coexistence induces a given quantum phase transition. For Pt, in which shape coexistence is present and the regular and intruder configurations cross for the ground state, there is almost no impact on the value of the two-neutron transfer intensity. Similar is the situation with Hg, where the ground state always has a regular nature. For the Sm isotope chain, which is one of the quantum phase transition paradigms, the value of the two-neutron transfer intensity is affected strongly.
We study light rays in the static and spherically symmetric gravitational field of the null aether theory (NAT). To this end, we employ the Gauss-Bonnet theorem to compute the deflection angle formed by a NAT black hole in the weak limit approximation. Using the optical metrics of the NAT black hole, we first obtain the Gaussian curvature and then calculate the leading terms of the deflection angle. Our calculations indicate how gravitational lensing is affected by the NAT field. We also illustrate that the bending of light stems from global and topological effects.
The sensitivity of the direct detection of dark matter (DM) approaches the so-called neutrino floor, below which it is difficult to disentangle the DM candidate from the neutrino background. In this work, we consider the scenario that no DM signals are reported in various DM direct detection experiments and explore whether collider searches could probe DM below the neutrino floor. We adopt several simplified models in which the DM candidate couples to electroweak gauge bosons or leptons in the standard model only through high-dimensional operators. After including the RGE running effect, we investigate the constraints of direct detection, indirect detection, and collider searches. The collider search can probe light DM below the neutrino floor. Particularly, for the effective interaction of
A numerical study has indicated that there exists a relation between the quasinormal modes and the Davies point for a black hole. In this paper, we analytically study this relation for charged Reissner-Nordström black holes in asymptotically flat and de Sitter (dS) spacetimes in the eikonal limit, under which the quasinormal modes can be obtained from the null geodesics using the angular velocity
We study the inclusive production of strange vector
We present a universal interpretation of a class of conformal extended standard models that include Higgs portal interactions as realized in low-energy effective theories. The scale generation mechanism in this class (scalegenesis) arises along the (nearly) conformal/flat direction for breaking scale symmetry, where the electroweak symmetry-breaking structure arises similarly as in the standard model. A dynamical origin for the Higgs portal coupling can provide the discriminator for the low-energy “universality class,” to be probed in forthcoming collider experiments.
In this study,
We investigate an
By adopting the adiabatic assumption in the cooling process, we discuss a novel mechanism of
The cross sections at 5 energy points of the 58Ni(n, α)55Fe reaction were measured in the 4.50 MeV ≤ En ≤ 5.50 MeV region while those for the 60Ni(n, α)57Fe and 61Ni(n, α)58Fe reactions were measured at En = 5.00 and 5.50 MeV using the 4.5 MV Van de Graaff accelerator at Peking University. A gridded twin ionization chamber (GIC) was used as the detector, and enriched 58Ni, 60Ni, and 61Ni foil samples were prepared and mounted at the sample changer of the GIC. Three highly enriched 238U3O8 samples inside the GIC were used to determine the relative and absolute neutron fluxes. The neutron energy spectra were obtained through unfolding the pulse height spectra measured by the EJ-309 liquid scintillator. The interference from the low-energy neutrons and impurities in the samples has been corrected. The present data of the 60Ni(n, α)57Fe reaction are the first measurement results below 6.0 MeV, and those of the 61Ni(n, α)58Fe reactions are the first measurement results in the MeV region. The present results have been compared with existing measurements, evaluations, and TALYS-1.9 calculations.
A flavor-dependent kernel is constructed based on the rainbow-ladder truncation of the Dyson-Schwinger and Bethe-Salpeter equation approach of quantum chromodynamics. The quark-antiquark interaction is composed of a flavor-dependent infrared part and a flavor-independent ultraviolet part. Our model gives a successful and unified description of the light, heavy, and heavy-light ground pseudoscalar and vector mesons. For the first time, our model shows that the infrared-enhanced quark-antiquark interaction is stronger and wider for lighter quarks.
Within an advanced Langevin-hydrodynamics framework coupled to a hybrid fragmentation-coalescence hadronization model, we study heavy flavor quenching and flow in relativistic heavy-ion collisions. We investigate how the initial heavy quark spectrum, the in-medium energy loss and hadronization mechanisms of heavy quarks, the evolution profile of the pre-equilibrium stage, the medium flow, and the temperature dependence of heavy quark diffusion coefficients influence the suppression and elliptic flow of heavy mesons at the RHIC and the LHC. Our results show that the different modeling of initial conditions, pre-equilibrium evolution, and in-medium interactions can individually yield uncertainties of approximately 10-40% in D meson suppression and flow at a low transverse momentum. We also find that proper combinations of collisional versus radiative energy loss, coalescence versus fragmentation in hadronization, and the inclusion of medium flow are the most important factors for describing the suppression and elliptic flow of heavy mesons.
We investigate whether the new horizon first law still holds in
Given the insufficient cross-sectional data regarding the 14-MeV-neutron experiment of molybdenum, the vital fusion reactor structural material, and the significant heterogeneities among the reported values, this study examined the (n,2n), (n,α), (n,p), (n,d), and (n,t) reaction cross sections in molybdenum isotopes based on the neutrons produced via a T(d,n)4He reaction carried out in the Pd-300 Neutron Generator at the China Academy of Engineering Physics (CAEP). A high-resolution gamma-ray spectrometer, which was equipped with a coaxial high-purity germanium detector, was used to measure the product nuclear gamma activities. In addition, 27Al(n,α)24Na and 93Nb(n,2n)92mNb reactions were utilized as the neutron fluence standards. The experimental 92Mo(n,2n)91Mo, 94Mo(n,2n)93mMo, 100Mo(n,2n)99Mo, 98Mo(n,α)95Zr, 100Mo(n,α)97Zr, 92Mo(n,p)92mNb, 96Mo(n,p)96Nb, 97Mo(n,p)97Nb, 98Mo(n,p)98mNb, 92Mo(n,d)91mNb, and 92Mo(n,t)90Nb reaction cross sections were acquired within the 13–15 MeV neutron energy range. Thereafter, we compared and analyzed these obtained cross sections based on the existing IAEA-EXFOR database-derived experimental data, together with evaluation results corresponding to ENDF/B-VIII.0, JEFF-3.3, BROND-3.1, and CENDL-3.1 and the theoretical outcomes acquired through TALYS-1.95 and EMPIRE-3.2.3 (nuclear-reaction modeling tools).
We investigate mesonic condensation in isospin matter under rotation. Using the two-flavor NJL effective model in the presence of global rotation, we demonstrate two important effects of rotation on its phase structure: a rotational suppression of the scalar-channel condensates, in particular, the pion condensation region; and a rotational enhancement of the rho condensation region with vector-channel condensate. A new phase diagram for isospin matter under rotation is mapped out on the
Proton-induced scattering of 238U nuclei, with spheroidal deformations at beam energies above 100 MeV, is simulated using an improved quantum molecular dynamics model. The angular distribution of the deflected protons is highly sensitive to the orientation of the symmetrical long axis of the target nuclei with respect to the beam direction. As a result, in reverse kinematic reactions, an orientation dichroism effect is predicted, implying that the absorption rate of the 238U beam by a proton target discerns between the parallel and perpendicular orientations of the deformed 238U nuclei.
We systematically construct all the tetraquark currents/operators of
We argue that the difference in the yield ratio
Ultraperipheral collisions (UPCs) of protons and nuclei are important for the study of the photoproduction of vector mesons and exotic states. The photoproduction of vector mesons in the pentaquark resonance channel in p-
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