We systematically derive the analytical expressions of the magnetic moments of the spin-$\frac{1}{2}$ singly charmed baryons to the next-to-next-to-leading order in the heavy baryon chiral perturbation theory (HBChPT). We discuss the analytical relations between the magnetic moments. We estimate the low-energy constants (LECs) in two scenarios. In the first scenario, we use the quark model and Lattice QCD simulation results as input. In the second scenario, the heavy quark symmetry is adopted to reduce the number of the independent LECs, which are then fitted using the data from the Lattice QCD simulations. We give the numerical results to the next-to-leading order for the antitriplet charmed baryons and to the next-to-next-to-leading order for the sextet states.

We study the electromagnetic form factors of the doubly charmed baryons, using covariant chiral perturbation theory within the extended on-mass-shell scheme. Vector-meson contributions are also taken into account. We present results for the baryon magnetic moments, charge, and magnetic radii. While some of the chiral Lagrangian parameters could be set to values determined in previous works, the available lattice results for ${\mathrm{\Xi }}_{cc}^{+}$ and ${\mathrm{\Omega }}_{cc}^{+}$ only allow for robust constraints on the low-energy constant combination, $c_{89}(=-\frac{1}{3}{c}_8+4c_9)$. The couplings of the doubly charmed baryons to the vector mesons have been estimated assuming the Okubo-Zweig-Iizuka rule. We also give the expressions for the form factors of the double-beauty baryons considering the masses predicted in the framework of quark models. A comparison of our results with those obtained in heavy baryon chiral perturbation theory at the same chiral order is made.

We study the quark Wigner distributions of the pion meson which are the phase-space distributions containing the most general one-parton information. Using the pion wave functions deduced from a light-cone quark model, we calculate the Wigner distributions of the unpolarized, longitudinally polarized and transversely polarized valence quarks inside the pion meson via the Fock-state overlap representation, respectively. We present the numerical results of the transverse Wigner distributions in which the longitudinal momentum fraction is integrated out. The mixed Wigner distributions as functions of $b_y$ and $k_x$ are also presented. As an intermediate step, we provide the analytic results for the generalized transverse-momentum dependent distributions of the pion meson in the same model.

We discuss the necessary, albeit not sufficient, conditions for tetraquark poles to occur in the $1/N$ expansion of QCD and find the minimum order at which such poles may appear. Assuming tetraquark poles, we find a new nonplanar solution with the minimal number of topologies and tetraquark species. The solution implies narrow states. Mixing with quarkonium states is allowed so that $P$-wave tetraquarks with $J^{\mathrm{P}\mathrm{C}}=1^{--}$ would couple to $e^{+}{e}^{-}$.

Inspired by the report of D0 Collaboration on the state $X(5568)$ with four different flavors, a similar state, $ud\overline{s}\overline{b,}$ is investigated in the present work. The advantage of looking for this state over the state $X(5568)$ with quark contents, $bu\overline{d}\overline{s}$ or $bd\overline{u}\overline{s}$, is that the $BK$ threshold is 270 MeV higher than that of $B_s\pi$, and it allows a large mass region for $ud\overline{s}\overline{b}$, which cannot decay to $B_s\pi$, to be stable. The chiral quark model and Gaussian expansion method are employed to do the calculations of four-quark states, $ud\overline{s}\overline{b}$, with quantum numbers $I{J}^P$ ($I=0,1;J=0,1,2;P=+$). Two structures, diquark-antidiquark and meson-meson, with all possible color configurations are considered. The results indicate that energies of the tetraquark with diquark-antiquark configuration are all higher than the threshold of $BK$, but the resonances are still possible because of their structures. For the state of $I{J}^P=00^{+}$ in the meson-meson structure, the energies are just below the corresponding thresholds, where the color channel coupling plays an important role. The bound state is possible. The distances between two objects (quark/antiquark) show that the state is a molecular one.

The spectroscopic parameters and partial widths of the strong decay channels of the vector meson $Y(4660)$ are calculated by treating it as a bound state of a diquark and antidiquark. The mass and coupling of the $J^{PC}=1^{--}$ tetraquark $Y(4660)$ are evaluated in the context of the two-point sum rule method by taking into account the quark, gluon, and mixed condensates up to dimension 10. The widths of the $Y(4660)$ resonance’s strong $S$-wave decays to $J/\psi f_0(980)$ and $\psi (2S)f_0(980)$ as well as to $J/\psi f_0(500)$ and $\psi (2S)f_0(500)$ final states are computed. To this end, strong couplings in the relevant vertices are extracted from the QCD sum rule on the light cone supplemented by the technical methods of the soft approximation. The obtained result for the mass of the resonance $m_Y=4677_{-63}^{+71}\mathrm{MeV}$, and prediction for its total width ${\mathrm{\Gamma }}_Y=(64.8\pm 10.8)\mathrm{MeV}$ is in nice agreements with the experimental information.

We compute perturbative matching coefficients to the heavy quark effective theory (HQET) representation for the QCD effective local $\mathrm{\Delta }B=2$ Hamiltonian that determines the mass difference in the $B^0\text{−}{\overline{B}}^0$ system of states. We report on the results at next-to-next-to-leading order in the strong coupling constant for matching coefficients of two physical operators in HQET. Our results provide firm confirmation that the recent next-to-leading order sum rules analysis of the bag parameter $B_q$ is stable with regard of inclusion of higher order radiative corrections. As a byproduct of our calculation we give a fully analytical solution for the one-loop QCD-to-HQET matching problem: we present the explicit formulas for the renormalization of four-quark operators of the full bases in both QCD and HQET and the expressions for matching coefficients in a closed form.

In light of the recent discovery of the ${\mathrm{\Xi }}_{cc}^{++}$ by the LHCb Collaboration, we study the stable doubly heavy tetraquarks. These states are compact exotic hadrons which can be approximated as the diquark-antidiquark correlations. In the flavor SU(3) symmetry, they form a SU(3) triplet or antisextet. The spectra of the stable doubly heavy tetraquark states are predicted by the Sakharov-Zeldovich formula. We find that the $T_{bb\overline{u}\overline{d}}^{-}(\mathbf{3})$ is about 73 MeV below the $B{B}^{*}$ threshold at SET I. We then study the semileptonic and nonleptonic weak decays of the stable doubly heavy tetraquark states. The doubly heavy tetraquark decay amplitudes are parametrized in terms of flavor SU(3)-irreducible parts. Ratios between decay widths of different channels are also derived. At the end, we collect the Cabibbo allowed two-body and three-body decay channels, which are most promising to search for the stable doubly heavy tetraquark states at the LHCb and Belle II experiments.

We compute modifications to the jet spectrum in the presence of a dense medium. We show that in the large-$N_c$ approximation and at leading logarithmic accuracy the jet nuclear modification factor factorizes into a quenching factor associated to the total jet color charge and a Sudakov suppression factor which accounts for the energy loss of jet substructure fluctuations. This factor, called the jet collimator, implements the fact that subjets, that are not resolved by the medium, lose energy coherently as a single color charge, whereas resolved large angle fluctuations suffer more quenching. For comparison, we show that neglecting color coherence results in a stronger suppression of the jet nuclear modification factor.

Several swampland conjectures suggest that there is a critical field range beyond which the effective field theory (EFT) description breaks down in quantum gravity. In applications of these conjectures, however, the field range of interest is the field space distance traced by the physical trajectory that solves the equations of motion. We refer to this field space distance as the dynamical field range. We show that in the absence of a mass hierarchy between the light and heavy fields, the trajectory of the light field does not, in general, follow a geodesic in field space. Then, stabilizing the heavy fields at the minimum of their potential does not accurately describe the dynamics of the light field in general. A mass hierarchy can delay the breakdown of the EFT and extend the effective field range. We illustrate these subtleties of multifield dynamics with axions in type II string compactifications.

We employ the Hadamard-Papapetrou method of field discontinuities to determine the effective metric that describes the propagation of acoustic perturbations in isentropic fluids. It is shown that, when dissipative effects are present, small perturbations in fast-moving fluids have a natural description in terms of an effective acoustic geometry. As an application of our results, a model for an acoustic black hole in viscous fluid is investigated.

We propose a double inflection points inflationary model in supergravity with a single chiral superfield. Such a model allows for the generation of primordial black holes (PBHs) at small scales, which can account for a significant fraction of dark matter. Moreover, in vacuum it is possible to give a small and adjustable supersymmetry breaking with a tiny cosmological constant.

I consider the thermal conductivity and shear viscosity of leptons (electrons and muons) in the nucleon neutron star cores where protons are in the superconducting state. I restrict the consideration to the case of not too high temperatures $T\lesssim 0.35T_{\mathrm{c}p}$, where $T_{\mathrm{c}p}$ is the critical temperature of the proton pairing. In this case, lepton collisions with protons can be neglected. Charged lepton collision frequencies are mainly determined by the transverse plasmon exchange and are mediated by the character of the transverse plasma screening. In our previous works [Shternin and Yakovlev, Phys. Rev. D 75, 103004 (2007); Phys. Rev. D 78, 063006 (2008)] the superconducting proton contribution to the transverse screening was considered in the Pippard limit $\mathrm{\Delta }\ll \hslash q{v}_{\mathrm{F}p}$, where $\mathrm{\Delta }$ is the proton pairing gap, $v_{\mathrm{F}p}$ is the proton Fermi velocity, and $\hslash q$ is the typical transferred momentum in collisions. However, for large critical temperatures (large $\mathrm{\Delta }$) and relatively small densities (small $q$) the Pippard limit may become invalid. In the present study I show that this is indeed the case and that the older calculations severely underestimated the screening in a certain range of the parameters appropriate to the neutron star cores. As a consequence, the kinetic coefficients at $T\ll T_{\mathrm{c}p}$ are found to be smaller than in previous calculations.

We compute the dynamical relaxation times for chiral transport phenomena in a strongly coupled regime using the $\mathrm{AdS}/\mathrm{CFT}$ correspondence. These relaxation times can be a useful proxy for the dynamical timescale for achieving equilibrium spin polarization of quasiparticles in the presence of a magnetic field and fluid vorticity. We identify the Kubo relations for these relaxation times and clarify some previous issues regarding time dependence of the chiral vortical effect. We study the consequences of imposing time-reversal invariance on parity-odd thermal noise fluctuations that are related to chiral transport coefficients by the fluctuation-dissipation relation. We find that time-reversal invariance dictates the equality between some of the chiral transport coefficients as well as their relaxation times.

This paper explores the effect of an extra spatial dimension on a Morris-Thorne wormhole. After proposing a suitable model, it is shown that under certain conditions, the throat of the wormhole can be threaded with ordinary matter, while the unavoidable violation of the null energy condition can be attributed to the existence of the extra dimension.

Simple models of single-field inflation in the very early universe can generate the observed amplitude and scale dependence of the primordial density perturbation, but models with multiple fields can provide an equally good fit to current data. We show how future observations will be able to distinguish between currently favored models. If a curvaton field generates the primordial perturbations after inflation, we show how the total duration of inflation can be measured.

The purpose of line-intensity mapping (IM), an emerging tool for extragalactic astronomy and cosmology, is to measure the integrated emission along the line of sight from spectral lines emitted from galaxies and the intergalactic medium. The observed frequency of the line then provides a distance determination allowing the three-dimensional distribution of the emitters to be mapped. Here we discuss the possibility to use these measurements to seek monoenergetic photons from dark-matter decay or possibly annihilation. The photons from decays or annihilations (should such lines arise) will be correlated with the mass distribution, which can be determined from galaxy surveys, weak-lensing surveys, or the IM mapping experiments themselves. We discuss how to seek this cross-correlation and then estimate the sensitivity of various IM experiments in the dark-matter mass-lifetime parameter space. We find prospects for improvements of nine orders of magnitude in sensitivity to decaying/annihilating dark matter in the frequency bands targeted for IM experiments.

Obtaining realistic supersymmetry preserving vacua in the minimal renormalizable supersymmetric $Spin(10)$ GUT model introduces considerations of the nontrivial topology of the vacuum manifold. The $D$-parity of low energy unification schemes gets lifted to a one-parameter subgroup $U(1{)}_D$ of $Spin(10)$. Yet, the choice of the fields signaling spontaneous symmetry breaking leads to disconnected subsets in the vacuum manifold related by the $D$-parity. The resulting domain walls, existing due to topological reasons but not stable, are identified as topological pseudodefects. We obtain a class of one-parameter paths connecting $D$-parity flipped vacua and compute the energy barrier height along the same. We consider the various patterns of symmetry breaking which can result in either intermediate scale gauge groups or a supersymmetric extension of the standard model. If the onset of inflation is subsequent to grand unified theory (GUT) breaking, as could happen also if inflation is naturally explained by the same GUT, the existence of such pseudo-defects can leave signatures in the CMB. Specifically, this could have an impact on the scale invariance of the CMB fluctuations and Large Scale Structure data at the largest scale.

Motivated by the possibility that the laws of physics could be different in other regions of space-time, we consider nuclear processes in universes where the weak interaction is either stronger or weaker than observed. We focus on the physics of both big bang nucleosynthesis (BBN) and stellar evolution. For sufficiently ineffective weak interactions, neutrons do not decay during BBN, and the baryon-to-photon ratio $\eta$ must be smaller in order for protons to survive without becoming incorporated into larger nuclei. For stronger weak interactions, neutrons decay before the onset of BBN, and the early Universe is left with nearly a pure hydrogen composition. We then consider stellar structure and evolution for the different nuclear compositions resulting from BBN, a wide range of weak force strengths, and the full range of stellar masses for a given universe. We delineate the range of this parameter space that supports working stars, along with a determination of the dominant nuclear reactions over the different regimes. Deuterium burning dominates the energy generation in stars when the weak force is sufficiently weak, whereas proton-proton burning into helium-3 dominates for the regime where the weak force is much stronger than in our Universe. Although stars in these universes are somewhat different, they have comparable surface temperatures, luminosities, radii, and lifetimes so that a wide range of such universes remain potentially habitable.

Self-induced flavor conversions near the supernova (SN) core can make the fluxes for different neutrino species become almost equal, potentially altering the dynamics of the SN explosion and washing out all further neutrino oscillation effects. We present a new model-independent analysis strategy for the next galactic SN signal that will distinguish this flavor equalization scenario from a matter-effects-only scenario during the SN accretion phase. Our method does not rely on fitting or modeling the energy-dependent fluences of the different species to a known function, but rather uses a model-independent comparison of charged-current and neutral-current events at large next-generation underground detectors. Specifically, we advocate that the events due to elastic scattering on protons in a scintillator detector, which is insensitive to oscillation effects and can be used as a model-independent normalization, should be compared with the events due to inverse beta decay of ${\overline{\nu }}_e$ in a water Cherenkov detector and/or the events due to charged-current interactions of ${\nu }_e$ in an argon detector. The ratio of events in these different detection channels allow one to distinguish a complete flavor equalization from a pure matter effect, for either of the neutrino mass orderings, as long as the spectral differences among the different species are not too small.