We consider the structure and physical properties of specific classes of neutron, quark, and Bose-Einstein condensate stars in the conformally invariant Weyl geometric gravity theory. The basic theory is derived from the simplest conformally invariant action, constructed, in Weyl geometry, from the square of the Weyl scalar, the strength of the Weyl vector, and a matter term, respectively. The action is linearized in the Weyl scalar by introducing an auxiliary scalar field. To keep the theory conformally invariant the trace condition is imposed on the matter energy-momentum tensor. The field equations are derived by varying the action with respect to the metric tensor, Weyl vector field and scalar field. By adopting a static spherically symmetric interior geometry, we obtain the field equations, describing the structure and properties of stellar objects in Weyl geometric gravity. The solutions of the field equations are obtained numerically, for different equations of state of the neutron and quark matter. More specifically, constant density stellar models, and models described by the stiff fluid, radiation fluid, quark bag model, and Bose-Einstein condensate equations of state are explicitly constructed numerically in both general relativity and Weyl geometric gravity, thus allowing an in depth comparison between the predictions of these two gravitational theories. As a general result it turns out that for all the considered equations of state, Weyl geometric gravity stars are more massive than their general relativistic counterparts. As a possible astrophysical application of the obtained results we suggest that the recently observed neutron stars, with masses in the range of $2M_{\odot }$ and $3M_{\odot }$, respectively, could be in fact conformally invariant Weyl geometric neutron or quark stars.

We study spherical charged black holes in the presence of a cosmological constant with corrections motivated by the theory of loop quantum gravity. The effective theory is constructed at the Hamiltonian level by introducing certain correction terms under the condition that the modified constraints form a closed algebra. The corresponding metric tensor is then carefully constructed ensuring that the covariance of the theory is respected, that is, in such a way that different gauge choices on phase space simply correspond to different charts of the same spacetime solution. The resulting geometry is characterized by four parameters: the three usual ones that appear in the general relativistic limit (describing the mass, the charge, and the cosmological constant), as well as a polymerization parameter, which encodes the quantum-gravity corrections. Contrary to general relativity, where this family of solutions is generically singular, in this effective model the presence of the singularity depends on the values of the parameters. The specific ranges of values that define the family of singularity-free spacetimes are explicitly found, and their global structure is analyzed. In particular, the mass and the cosmological constant need to be nonnegative to provide a nonsingular geometry, while there can only be a bounded, relatively small, amount of charge. These conditions are suited for any known spherical astrophysical black hole in the de Sitter cosmological background, and thus this model provides a globally regular description for them.

We present a systematic study of fast neutrino-flavor conversion (FFC) with both small-scale and large-scale numerical simulations in spherical symmetry. We find that FFCs can, in general, reach a quasisteady state, and these features in the nonlinear phase are not characterized by the growth rate of FFC instability but rather angular structures of the electron neutrino lepton number (ELN) and the heavy one. Our result suggests that neutrinos can almost reach a flavor equipartition even in cases with low growth rate of instability (e.g., shallow ELN crossing) and narrow angular regions (in momentum space) where flavor conversions occur vigorously. This shows that ELN and heavy-neutrino lepton number angular distributions cannot provide a sufficient information to determine total amount of flavor conversion in neutrinos and antineutrinos of all flavors. Based on the results of our numerical simulations, we provide a new approximate scheme of FFC that is designed so that one can easily incorporate effects of FFCs in existing classical neutrino transport codes for the study of core-collapse supernova and binary neutron star merger. The scheme has an ability to capture key features of quasisteady state of FFCs without solving quantum kinetic neutrino transport, which will serve to facilitate access to FFCs for core-collapse supernova and binary neutron star merger theorists.

Motivated by the significant experimental progress in probing semileptonic decays $D\to P_1{P}_2{\ell }^{+}{\nu }_{\ell }$ $(\ell =\mu ,e)$, we analyze the branching ratios of the $D\to P_1{P}_2{\ell }^{+}{\nu }_{\ell }$ decays with the nonresonant, the light scalar meson resonant, and the vector meson resonant contributions in this work. We obtain the hadronic amplitude relations between different decay modes by the SU(3) flavor analysis, and then predict relevant branching ratios of the $D\to P_1{P}_2{\ell }^{+}{\nu }_{\ell }$ decays by the present experimental data with $2\sigma$ errors. Most of our predicted branching ratios are consistent with present experimental data within $2\sigma$ error bars, and others are consistent with the data within $3\sigma$ error bars. We find that the branching ratios of the nonresonant decays $D^0\to {\pi }^{-}{\overline{K}}^0{\ell }^{+}{\nu }_{\ell },{\pi }^0{K}^{-}{\ell }^{+}{\nu }_{\ell },D^{+}\to {\pi }^{+}{K}^{-}{\ell }^{+}{\nu }_{\ell },{\pi }^0{\overline{K}}^0{\ell }^{+}{\nu }_{\ell },{\pi }^{+}{\pi }^{-}{\ell }^{+}{\nu }_{\ell },{\pi }^0{\pi }^0{\ell }^{+}{\nu }_{\ell }$, and $D_s^{+}\to K^{+}{K}^{-}{\ell }^{+}{\nu }_{\ell },K^0{\overline{K}}^0{\ell }^{+}{\nu }_{\ell }$ are on the order of $\mathcal{O}({10}^{-3}–{10}^{-4})$. The vector meson resonant contributions are dominant in the $D^0\to {\pi }^{-}{\overline{K}}^0{\ell }^{+}{\nu }_{\ell },{\pi }^0{K}^{-}{\ell }^{+}{\nu }_{\ell },{\pi }^0{\pi }^{-}{\ell }^{+}{\nu }_{\ell },D^{+}\to {\pi }^{+}{K}^{-}{\ell }^{+}{\nu }_{\ell },{\pi }^0{\overline{K}}^0{\ell }^{+}{\nu }_{\ell },{\pi }^{+}{\pi }^{-}{\ell }^{+}{\nu }_{\ell }$, and $D_s^{+}\to K^{+}{K}^{-}{\ell }^{+}{\nu }_{\ell },K^0{\overline{K}}^0{\ell }^{+}{\nu }_{\ell },K^{+}{\pi }^{-}{\ell }^{+}{\nu }_{\ell },K^0{\pi }^0{\ell }^{+}{\nu }_{\ell }$ decays. The nonresonant, the vector meson resonant, and the scalar resonant contributions are all important in the $D^0\to \eta {\pi }^{-}{\ell }^{+}{\nu }_{\ell }$ decays. The $D^0\to K^{-}{K}^0{\ell }^{+}{\nu }_{\ell },{\eta }^{\prime }{\pi }^{-}{\ell }^{+}{\nu }_{\ell }$ and $D^{+}\to {\overline{K}}^0{K}^0{\ell }^{+}{\nu }_{\ell },{\pi }^0{\pi }^0{\ell }^{+}{\nu }_{\ell },\eta {\pi }^0{\ell }^{+}{\nu }_{\ell },{\eta }^{\prime }{\pi }^0{\ell }^{+}{\nu }_{\ell }$ decays only receive both the nonresonant and the scalar resonant contributions, and both contributions are important in their branching ratios. According to our predictions, many decay modes could be observed in the experiments like BESIII, LHCb, and Belle II, and some decay modes might be measured in these experiments in the near future.

A weakly coupled and light dark photon coupling to lepton charges $L_{\mu }-L_{\tau }$ is an intriguing dark matter candidate whose coherent oscillations alter the dispersion relations of leptons. We study how this effect modifies the dynamics of neutrino flavor conversions, focusing on long baseline and solar oscillations. We analyze data from the T2K, SNO, and Super-Kamiokande experiments in order to obtain world-leading limits on the dark photon gauge coupling for masses below $\sim {10}^{-11}\mathrm{eV}$. Degeneracies between shifts in the neutrino mass-squared differences and mixing angles and the new physics effect significantly relax the current constraints on the neutrino vacuum oscillation parameters.

We investigate the possibility of explanation for the muon anomalous magnetic moment $g_{\mu }-2$ in a left-right model with an inverse seesaw mechanism. We emphasize that the observed deviation from the Standard Model predictions can be accommodated in a large part of the parameter space of this class of models, where loops with massive neutrinos and charged Higgs boson as well as the weak $W$ boson contribute significantly to $g_{\mu }-2$. Stringent constraints due to lepton flavor violation $\mu \to e\gamma$, $\mu \text{−}e$ conversion and the electron anomalous magnetic moment $g_e-2$ are considered, and the results are compatible.

The first order transition between the confining and the center symmetry breaking phases of the SU(3) Yang-Mills theory is marked by discontinuities in various thermodynamics functions, such as the energy density or the value of the Polyakov loop. We investigate the nonanalytical behavior of the topological susceptibility and its higher cumulant around the transition temperature and make the connection to the curvature of the phase diagram in the $T-\theta$ plane and to the latent heat.

A framework for quantum simulations of real-time weak decays of hadrons and nuclei in a two-flavor lattice theory in one spatial dimension is presented. A single generation of the Standard Model is found to require 16 qubits per spatial lattice site after mapping to spin operators via the Jordan-Wigner transformation. Both quantum chromodynamics and flavor-changing weak interactions are included in the dynamics, the latter through four-Fermi effective operators. Quantum circuits that implement time evolution in this lattice theory are developed and run on Quantinuum’s H1-1 20-qubit trapped ion system to simulate the $\beta$-decay of a single baryon on one lattice site. These simulations include the initial state preparation and are performed for both one and two Trotter time steps. The potential intrinsic error-correction properties of this type of lattice theory are discussed, and the leading lattice Hamiltonian required to simulate $0\nu \beta \beta$-decay of nuclei induced by a neutrino Majorana mass term is provided.

Tools necessary for quantum simulations of $1+1$ dimensional quantum chromodynamics are developed. When formulated in axial gauge and with two flavors of quarks, this system requires 12 qubits per spatial site with the gauge fields included via nonlocal interactions. Classical computations and $D$-wave’s quantum annealer advantage are used to determine the hadronic spectrum, enabling a decomposition of the masses and a study of quark entanglement. Color “edge” states confined within a screening length of the end of the lattice are found. IBM’s seven-qubit quantum computers, ibmq_jakarta and ibm_perth, are used to compute dynamics from the trivial vacuum in one-flavor QCD with one spatial site. More generally, the Hamiltonian and quantum circuits for time evolution of $1+1$ dimensional $SU(N_c)$ gauge theory with $N_f$ flavors of quarks are developed, and the resource requirements for large-scale quantum simulations are estimated.

The penguin-dominated two-body weak decay of ${\mathrm{\Lambda }}_b\to \mathrm{\Lambda }\varphi$ is studied based on the perturbative QCD approach. In addition to the penguin emission diagrams, the penguin exchange and $W$ exchange ones are also accounted for. It is found that the penguin exchange contribution is in fact important and comparable to the penguin emission one, while the $W$ exchange contribution is highly Cabibbo-Kobayashi-Maskawa (CKM) suppressed. The predicted branching ratio, $\mathcal{B}({\mathrm{\Lambda }}_b\to \mathrm{\Lambda }\varphi )={6.9}_{-2.0-1.6}^{+1.9+1.8}\times {10}^{-6}$, is larger than the previous theoretical estimates but in comparison with the data from Particle Data Group at the level of 1 standard deviation. We also explore some pertinent decay asymmetry parameters that characterize the angular decay distributions. The inclusion of the $W$ exchange contribution provides the nonzero weak phase difference, consequently, allowing us to estimate the direct $CP$ violation and true triple product asymmetries in the concerned process. The numerical results demonstrate that the direct $CP$ violation is at the level of a few percent, and the true triple product asymmetries are also predicted to be tiny, of order ${10}^{-2}–{10}^{-4}$. The observed small $CP$-violating observables have shown no significant deviations from zero. Our predictions will be subject to stringent tests with precise data from LHCb in the future.

We quantify the degree of fine-tuning required to achieve an observationally viable period of inflation in the strongly dissipative regime of warm inflation. The “fine-tuning” parameter $\lambda$ is taken to be the ratio of the change in the height of the potential $\mathrm{\Delta }V$ to the change in the scalar field $(\mathrm{\Delta }\varphi {)}^4$, i.e., the width of the potential, and therefore measures the requisite degree of flatness in the potential. The best motivated warm inflationary scenarios involve a dissipation rate of the kind $\mathrm{\Gamma }\propto T^c$ with $c\ge 0$, and for all such cases, the bounds on $\lambda$ are tighter than those for standard cold inflation by at least 3 orders of magnitude. In other words, these models require an even flatter potential than standard inflation. On the other hand for the case of warm inflation with $c<0$, we find that in a strongly dissipative regime the bound on $\lambda$ can significantly weaken with respect to cold inflation. Thus, if a warm inflation model can be constructed in a strongly dissipative, negatively temperature-dependent regime, it accommodates steeper potentials otherwise ruled out in standard inflation.

The accumulation of gluons inside nucleons, i.e., the gluon condensation, may lead to a characteristic broken power-law gamma-ray spectrum in high-energy nucleon collisions. Here we show that the observed spectra of at least 25 sources in the second Fermi Large Area Telescope Catalog of Gamma-ray Pulsars can be well fitted by such a broken power-law function that has only four free parameters. It strongly indicates that the gamma-ray emission from these pulsars is of hadronic origin, but with gluon condensation inside hadrons. It is well known that the quark-gluon distribution in a free nucleon is different from that in a bound nucleon. This work exposes the nuclear $A$ dependence of the gluon condensation effect, where $A$ refers to the baryon number. Our study reveals the gluon condensation under the condition of $A\to \infty$, which may open a new window for eavesdropping on the structure of compact stars on the subnuclear level.

It is considered in this work the phase transition patterns for a coupled two-scalar field system model under the combined effects of finite sizes and temperature. The scalar fields are taken as propagating in a $D=4$ Euclidean space with the usual periodic compactification in the Euclidean time direction (with dimension given by the inverse of the temperature) and also under a compact dimension in the space direction, which is restricted to size $L$. In the latter case, a Dirichlet boundary condition is considered. Finite-size variation of the critical temperature for the cases of symmetry restoration and inverse symmetry breaking are studied. At fixed finite-temperature values, the variation of the inverse correlation lengths with the size $L$ might display a behavior analogous to reentrant phase transitions. Possible applications of our results to physical systems of interest are also discussed.

In this work we demonstrate that a future accelerator-based neutrino experiment such as DUNE can greatly increase its sensitivity to a variety of new physics scenarios by operating in a mode where the proton beam impinges on a beam dump. We consider two new physics scenarios, namely light dark matter and axionlike particles and show that by utilizing a dump mode at a DUNE-like experiment, unexplored new regions of parameter space can be probed with an exposure of only 3 months with half of its expected initial beam power. Specifically, targetless configuration of future high intensity neutrino experiments will probe the parameter space for thermal relic dark matter as well as the QCD axion. The strength of such a configuration in the context of new physics searches stems from the fact that the neutrino flux is significantly reduced compared to that of the target, resulting in much smaller backgrounds from neutrino interactions. We have verified this in detail by explicitly computing neutrino fluxes which we make publicly available in order to facilitate further studies with a targetless configuration.

We computed the ${\mathrm{\Sigma }}^{-}\to n{\pi }^{+}{e}^{-}{\ell }^{-}$ ($\ell =e$, $\mu$), ${\mathrm{\Xi }}^{-}\to \mathrm{\Lambda }{\pi }^{+}{e}^{-}{e}^{-}$, and $\mathrm{\Lambda }\to p{\pi }^{+}{e}^{-}{e}^{-}$ lepton number violating (LNV) hyperon decays mediated by a resonant Majorana neutrino. The expected hyperon production rate of experiments like BESIII of around ${10}^6–{10}^8$ may allow searching for these rare hyperon decays at enough sensitivities. We illustrate the limits on the new heavy mixing parameters derived from these hyperon channels and compare them with other LNV meson decays in similar mass regions of the resonant neutrino state.

In the present work, we investigate the productions of the molecular states composed of $D_s^{(*)}{\overline{D}}^{(*)}$ and $D_s^{(*)}{\overline{D}}_s^{(*)}$ in the $B$ and $B_s$ decays by using an effective Lagrangian approach. The branching ratios in terms of the model parameter $\alpha$ and the binding energy $\mathrm{\Delta }E$ are estimated. Our estimations indicate that the branching fractions are of the order of ${10}^{-4}$ and the relative ratios are very weakly dependent on the model parameter $\alpha$ and the binding energy $\mathrm{\Delta }E$. The predicted ratios are helpful for searching the hidden-charm molecular states with strange quarks in the future experiments at Belle II and LHCb.

We study the stability of first-order dissipative spin-hydrodynamic frameworks. We considered two different first-order dissipative spin-hydrodynamic frameworks. The first one considers the spin-chemical potential (${\omega }^{\alpha \beta }$) to be first order [$\mathcal{O}(\partial )$] in the hydrodynamic gradient expansion. The hydrodynamic gradient ordering of the spin-chemical potential is a debatable issue within the frameworks of spin hydrodynamics. Therefore, as a second choice, we also consider the spin-hydrodynamic equations with ${\omega }^{\alpha \beta }\sim \mathcal{O}(1)$. We find that, for both frameworks, at the level of linear perturbations some spin modes can be unstable. To remove these generic instabilities, we consider the Frenkel condition. We argue that the Frenkel condition helps get rid of the unstable solutions in both cases but with a physical drawback for the case where ${\omega }^{\mu \nu }\sim \mathcal{O}(\partial )$.

We study the semileptonic decays of $B_{cc}\to B_c{\ell }^{+}{\nu }_{\ell }$ with the bag model, where $\ell =(e,\mu )$, $B_{cc}=({\mathrm{\Xi }}_{cc}^{++}$, ${\mathrm{\Xi }}_{cc}^{+}$, ${\mathrm{\Omega }}_{cc}^{+}$), and $B_c$ are the singly charmed baryons with $J^P=1/2^{+}$. We obtain the decay widths of $\mathrm{\Gamma }({\mathrm{\Xi }}_{cc}^{++}\to {\mathrm{\Xi }}_c^{+}{e}^{+}{\nu }_e,{\mathrm{\Xi }}_c^{\prime +}{e}^{+}{\nu }_e,{\mathrm{\Lambda }}_c^{+}{e}^{+}{\nu }_e,{\mathrm{\Omega }}_c^{+}{e}^{+}{\nu }_e)=(5.1\pm 0.1,11\pm 1,0.34\pm 0.06,0.76\pm 0.06)\times {10}^{-14}\mathrm{GeV}$, $\mathrm{\Gamma }({\mathrm{\Xi }}_{cc}^{+}\to {\mathrm{\Xi }}_c^0{e}^{+}{\nu }_e,{\mathrm{\Xi }}_c^{\prime 0}{e}^{+}{\nu }_e,{\mathrm{\Sigma }}_c^0{e}^{+}{\nu }_e)=(5.1\pm 0.6,11\pm 1,1.5\pm 0.1)\times {10}^{-14}\mathrm{GeV}$, and $\mathrm{\Gamma }({\mathrm{\Omega }}_{cc}^{+}\to {\mathrm{\Omega }}_c^0{e}^{+}{\nu }_e,{\mathrm{\Xi }}_c^0{e}^{+}{\nu }_e,{\mathrm{\Xi }}_c^{\prime 0}{e}^{+}{\nu }_e)=(22\pm 2,0.32\pm 0.04,0.77\pm 0.06)\times {10}^{-14}\mathrm{GeV}$. We also get that $\mathrm{\Gamma }(B_{cc}\to B_c{\mu }^{+}{\nu }_{\mu })/\mathrm{\Gamma }(B_{cc}\to B_c{e}^{+}{\nu }_e)=0.97–1.00$. In addition, we discuss the $SU(3)$ flavor breaking effects, classified into three aspects: phase space differences, spectator quarks, and overlappings of the transited quarks. In particular, we show that the breaking effects are dominated by the phase space differences, which can be as large as 25%. Explicitly, we find that $\mathrm{\Gamma }({\mathrm{\Xi }}_{cc}^{++}\to {\mathrm{\Lambda }}_c^{+}{e}^{+}{\nu }_e)V_{cs}^2/\mathrm{\Gamma }({\mathrm{\Xi }}_{cc}^{++}\to {\mathrm{\Xi }}_c^{+}{e}^{+}{\nu }_e)V_{cd}^2=1.24$, which is expected as 1 under the exact $SU(3)$ flavor symmetry.

Polarized proton-proton collisions provide leading-order access to gluons, presenting an opportunity to constrain gluon spin-momentum correlations within transversely polarized protons and enhance our understanding of the three-dimensional structure of the proton. Midrapidity open-heavy-flavor production at $\sqrt{s}=200\mathrm{GeV}$ is dominated by gluon-gluon fusion, providing heightened sensitivity to gluon dynamics relative to other production channels. Transverse single-spin asymmetries of positrons and electrons from heavy-flavor hadron decays are measured at midrapidity using the PHENIX detector at the Relativistic Heavy Ion Collider. These charge-separated measurements are sensitive to gluon correlators that can in principle be related to gluon orbital angular momentum via model calculations. Explicit constraints on gluon correlators are extracted for two separate models, one of which had not been constrained previously.

We report the results of the first search for the decay $B_s^0\to {\pi }^0{\pi }^0$ using $121.4{\mathrm{fb}}^{-1}$ of data collected at the $\mathrm{\Upsilon }(5\mathrm{S})$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. We observe no signal and set a 90% confidence level upper limit of $7.7\times {10}^{-6}$ on the $B_s^0\to {\pi }^0{\pi }^0$ decay branching fraction.