We calculate the semileptonic and a subclass of sixteen nonleptonic two-body decays of the double charm baryon ground states ${\mathrm{\Xi }}_{cc}^{++},{\mathrm{\Xi }}_{cc}^{+}$ and ${\mathrm{\Omega }}_{cc}^{+}$ where we concentrate on the nonleptonic decay modes. We identify those nonleptonic decay channels in which the decay proceeds solely via the factorizing contribution precluding a contamination from $W$ exchange. We use the covariant confined quark model previously developed by us to calculate the various helicity amplitudes which describe the dynamics of the $1/2^{+}\to 1/2^{+}$ and $1/2^{+}\to 3/2^{+}$ transitions induced by the Cabibbo-favored effective ($c\to s$) and ($d\to u$) currents. We then proceed to calculate the rates of the decays as well as polarization effects and angular decay distributions of the prominent decay chains resulting from the nonleptonic decays of the double heavy charm baryon parent states.

The full complex phase structure of the meson-baryon reaction amplitude in coupled channels approach is investigated, including also the photon-baryon channel. The result may be viewed as a generalization of the well-known Watson’s theorem. Furthermore, the complex phase structure is exhibited for the pole and nonpole parts of the reaction amplitude in such a way that it will serve as a convenient common starting point for constructing models with different levels of approximation, in particular, for building isobar models where the basic properties of the $S$-matrix can be maintained. Such models should be useful, especially, in coupled multichannel calculations, where a large amount of experimental data are considered in resonance analyses, a situation encountered in modern baryon spectroscopy. In particular, it is shown that the unitarity of the pole part of the $T$-matrix arises automatically from the dressing mechanism inherent in the basic scattering equation. This implies that no separate conditions are required for making this part of the amplitude unitary as it has been done in some of the existing isobar models.

We show that the entanglement wedge cross section (EWCS) can become larger than the quantum entanglement measures such as the entanglement of formation in the AdS/CFT correspondence. We then discuss a series of holographic duals to the optimized correlation measures, finding a novel geometrical measure of correlation, the entanglement wedge mutual information (EWMI), as the dual of the $Q$-correlation. We prove that the EWMI satisfies the properties of the $Q$-correlation as well as the strong superadditivity, and that it can become larger than the entanglement measures. These results imply that both of the EWCS and the EWMI capture more than quantum entanglement in the entanglement wedge, which enlightens a potential role of classical correlations in holography.

We give exact results for the emission spectra of both nonlinear Breit-Wheeler pair production and nonlinear Compton scattering in ultraintense, ultrashort duration plane wave backgrounds, modeled as delta-function pulses. This includes closed form expressions for total scattering probabilities. We show explicitly that these probabilities do not exhibit the power-law scaling with intensity associated with the conjectured breakdown of (Furry picture) perturbation theory, instead scaling logarithmically in the high-intensity limit.

We determine the general form of the first order linear symmetry operators for the linearized field equation of metric perturbations in the spacetimes of dimension $D\ge 4$. Apart from the part derived easily from the invariance under general coordinate transformations, we find a part consisting of a Killing-Yano 3-form.

In this paper, the effects of adding spatial conformal symmetry to the asymptotic symmetry group of an asymptotically conformally flat spacetime are studied. It is shown that, in addition to the BMS group, only the dilations of the spatial conformal generators keep the corresponding boundary conditions conformally invariant under hypersurface deformations. We prove that in order to attain (i) a well-defined symplectic structure and (ii) a finite and (iii) integrable conserved charge, these conditions are satisfied simultaneously when admitting Regge-Teitelboim and twisted Henneaux-Troessaert parity conditions, where the latter also contain supertranslation invariance. The conserved dilation charge contains nonzero terms independent of the field variables, giving a nonvanishing effect on the boundary. The dilation symmetry also modifies the ADM mass, which is another physical effect of the conformal symmetry.

Time delay in Schwarzschild spacetime for null and timelike signals with arbitrary velocity $v$ is studied. The total travel time $t_{\text{if}}$ is evaluated both exactly and approximately in the weak field limit, with the result given as functions of signal velocity, source-lens, and lens-observer distances, angular position of the source and lens mass. Two time delays, $\mathrm{\Delta }{t}_v$ between signals with different velocities but coming from same side of the lens and $\mathrm{\Delta }{t}_{\mathrm{p}}$ between signals from different sides of the lens, as well as the difference $\mathrm{\Delta }{t}_{\mathrm{p}v}$ between two $\mathrm{\Delta }{t}_{\mathrm{p}}$’s are calculated. These time delays are applied to the gravitational-lensed supernova neutrinos and gravitational waves (GW). It is shown that the $\mathrm{\Delta }{t}_v$ between different mass eigenstates of supernova neutrinos can be related to the mass square difference of these eigenstates and therefore could potentially be used to discriminate neutrino mass orderings, while the difference $\mathrm{\Delta }{t}_{\mathrm{p}v}$ between neutrino and optical signals can be correlated with the absolute mass of neutrinos. The formula for time delay in a general lens mass profile is derived and the result is applied to the singular isothermal sphere case. For GWs, it is found that the difference $\mathrm{\Delta }{t}_{\mathrm{p}v}$ between GW and GRB can only reach $1.45\times {10}^{-5}$ second for very large source distance ($2\times {10}^4[\mathrm{Mpc}]$) and source angle (10 [as]) if $v_{\mathrm{GM}}=(1-3\times {10}^{-15})c$. This time difference is at least three orders smaller than uncertainties in time measurement of the recently observed GW/GRB signals and thus calls for improvement if $\mathrm{\Delta }{t}_{\mathrm{p}v}$ is to be used to further constrain the GW velocity.

Consistency relations for the large scale structure are exact equalities between correlation functions of different order. These relations descend from the equivalence principle and hold for primordial perturbations generated by single-field models of inflation. They are not affected by nonlinearities and hold also for biased tracers and in redshift space. We show that baryonic acoustic oscillations in the bispectrum (BS) in the squeezed limit are suppressed with respect to those in the power spectrum by a coefficient that depends on the BS configuration and on the bias parameter (and, in redshift space, also on the growth rate). We test these relations using large volume $N$-body simulations and show that they provide a novel way to measure large scale halo bias and, potentially, the growth rate. Since bias is obtained by comparing two directly observable quantities, the method is free from theoretical uncertainties both on the computational scheme and on the underlying cosmological model.

The nonclassicality of primordial gravitational waves (PGWs) is characterized in terms of sub-Poissonian graviton statistics. The sub-Poissonian statistics are realized when quantum states are squeezed coherent states. In the presence of matter fields, the Universe experiences the squeezed coherent state during inflation. The condition to realize the sub-Poissonian graviton statistics is translated into the frequency range of gravitational waves. If the initial state is the Bunch-Davies vacuum, there is another necessary condition between phases of squeezing and coherent parameters. Here, we extend the initial state to entangled states. We consider $\alpha$-vacua as the initial entangled state that are more general de Sitter invariant vacua than the Bunch-Davies vacuum. We find that, unlike the Bunch-Davies vacuum, PGWs generated in the initial entangled state become sub-Poissonian without requiring the condition between the phases.

Exotic duality suggests a link between gauge theories for differential $p$-forms and tensor fields of mixed symmetry $[D-2,p]$ in $D$ spacetime dimensions. On the other hand, standard Hodge duality relates $p$-form to $(D-p-2)$-form gauge potentials by exchanging their field equations and Bianchi identities. Following the methodology and the recent proposal of Henneaux et al. that the double dual of the free graviton is algebraically related to the original graviton and does not provide a new, independent description of the gravitational field, we examine the status of exotic duality for $p$-forms. We find that the exotic dual is algebraically related to the standard dual of a differential form, and therefore they provide equivalent descriptions as free fields. Introducing sources then leads to currents being proportional. This relation is extended in a straightforward way for higher exotic duals of the mixed symmetry type $[D-2,\dots ,D-2,p]$.

Spectral functions at finite temperature and two-loop order are investigated, for a medium consisting of massless particles. We consider them in the timelike and spacelike domains, allowing the propagating particles to be any valid combination of bosons and fermions. Divergences (if present) are analytically derived and set aside for the remaining finite part to be calculated numerically. To illustrate the utility of these “master” functions, we consider transverse and longitudinal parts of the QCD vector channel spectral function.

The spontaneous production of electron-positron pairs from the vacuum—in a field configuration composed of a high-frequency electric mode of weak intensity and a strong constant electric field—is investigated. Asymptotic expressions for the single-particle distribution function ruling this nonperturbative process are established by considering the low-density approximation in the Boltzmann-Vlasov equation. An analytical formula for the density rate of yielded particles is established and is shown to manifest a nonperturbative dependence on both the strong and weak electric fields and to generalize previous findings by interpolating between the tunneling and multiphoton regimes. It is shown that—under appropriate circumstances—the created plasma of electrons and positrons might reach densities for which their recombinations into high-energy photons occurs copiously. On the basis of this feature, an experimental setup for observing the dynamically assisted Schwinger effect is put forward.

The Polarized Atomic Hydrogen Gas Jet Target polarimeter (HJET) was designed to measure the absolute polarization of the proton beams at the Relativistic Heavy Ion Collider. In these measurements, the small scattering angle elastic $pp$ single $A_N(t)$ and double $A_{NN}(t)$ spin analyzing powers can be precisely determined. The experimental accuracy achieved at HJET requires corrections to the $A_N(t)$ parametrization, conventionally used for such studies. In this paper, we evaluate the corrections to the analyzing powers due to (i) the differences between the electromagnetic and hadronic form factors and (ii) the $m_p^2/s$ terms in the elastic spin-flip $pp$ electromagnetic amplitude. The corresponding alterations of the evaluated hadronic spin-flip amplitudes are about the same as the experimental uncertainties of the HJET measurements. The proposed corrections may have implications for the elastic $pp$ forward real-to-imaginary amplitude ratios $\rho$ determined in unpolarized $pp$ experiments.

In this paper, we give formal results of Schwinger pair production correction in thermal systems with external background field by using the evolution operator method of thermofield dynamics, in which especially tree-level correction of thermal photons is considered, within the approach of linear response to an effective mass shift. We consider initial systems in two types of vacuums as zero temperature and thermal vacuum, respectively, with the correction of thermal photons included or not. For an example, we give results of these corrections to pair production for a constant external background electric field.

We discuss a two-Higgs-doublet model with extra $U(1{)}_X$ gauge symmetry where lepton specific (type-X) structure for Yukawa interactions is realized by charge assignment of fields under the $U(1{)}_X$. Extra charged leptons are introduced to cancel gauge anomaly associated with extra gauge symmetry. In addition, we introduce scalar fields as dark matter candidates to which we assign $Z_2$ odd parity for guaranteeing stability of them. We then analyze the phenomenology of the model such as scalar potential, muon anomalous magnetic dipole moment, collider physics associated with $Z^{\prime }$ boson from $U(1{)}_X$, and dark matter physics. Carrying out numerical analysis we search for a phenomenologically viable parameter region.

We discuss under what circumstances a signal in upcoming laboratory searches for keV-scale sterile neutrinos would be compatible with those particles being a sizable part or all of dark matter. In the parameter space that will be experimentally accessible by KATRIN/TRISTAN, strong x-ray limits need to be relaxed and dark matter overproduction needs to be avoided. We discuss postponing the dark matter production to lower temperatures, a reduced sterile neutrino contribution to dark matter, and a reduction of the branching ratio in photons and active neutrinos through cancellation with a new physics diagram. Both the Dodelson-Widrow and the Shi-Fuller mechanisms for sterile neutrino dark matter production are considered. As a final exotic example, potential consequences of $CPT$ violation are discussed.

We examine the renormalization of flavor-diagonal vector currents in lattice QCD with the aim of understanding and quantifying the systematic errors from nonperturbative artifacts associated with the use of intermediate momentum-subtraction schemes. Our study uses the highly improved staggered quark action on gluon-field configurations that include $n_f=2+1+1$ flavors of sea quarks, but our results have applicability to other quark actions. Renormalization schemes that make use of the exact lattice vector Ward-Takahashi identity for the conserved current also have renormalization factors, $Z_V$, for nonconserved vector currents that are free of contamination by nonperturbative condensates. We show this by explicit comparison of two such schemes: that of the vector form factor at zero momentum transfer and the RI-SMOM momentum-subtraction scheme. The two determinations of $Z_V$ differ only by discretization effects (for any value of momentum transfer in the RI-SMOM case). The ${\mathrm{RI}}^{\prime }$-MOM scheme, although widely used, does not share this property. We show that $Z_V$ determined in the standard way in this scheme has $\mathcal{O}(1\%)$ nonperturbative contamination that limits its accuracy. Instead we define an ${\mathrm{RI}}^{\prime }$-MOM $Z_V$ from a ratio of local to conserved vector current vertex functions and show that this $Z_V$ is a safe one to use in lattice QCD calculations. We also perform a first study of vector current renormalization with the inclusion of quenched QED effects on the lattice using the RI-SMOM scheme.

A molecular model of the $P_c(4457)$ and $P_c(4440)$ LHCb states is proposed. The model relies on channels coupled by long-range pion-exchange dynamics with features that depend crucially on the novel addition of the ${\mathrm{\Lambda }}_c(2595)\overline{D}$ channel. A striking prediction of the model is the unusual combination of quantum numbers $J^P(4457)=1/2^{+}$ and $J^P(4440)=3/2^{-}$. Unlike in other models, a simultaneous description of both states is achieved without introducing additional short-range interactions. The model also gives a natural explanation for the relative widths of the states. We show that the usual molecular scenarios cannot explain the production rate of $P_c$ states in ${\mathrm{\Lambda }}_b$ decays and that this can be resolved by including ${\mathrm{\Lambda }}_c(2595)\overline{D}$ and related channels. Experimental tests and other states are discussed in the conclusions.

We compute masses of positive-parity spin-$1/2$ and -$3/2$ baryons composed of $u$, $d$, $s$, $c$ and $b$ quarks in a quark-diquark picture. The mathematical foundation for this analysis is implemented through a symmetry-preserving Schwinger-Dyson equations treatment of a vector-vector contact interaction, which preserves key features of quantum chromodynamics, such as confinement, chiral symmetry breaking and low-energy Goldberger-Treiman relations. This study requires a computation of diquark correlations containing these quarks which in turn are readily inferred from solving the Bethe-Salpeter equations of the corresponding mesons. Therefore, it serves as a unified formalism for a multitude of mesons and baryons. It builds on our previous works on the study of masses, decay constants and form factors of quarkonia and light mesons, employing the same model. We use two sets of parameters, one which remains exactly the same for both the light and heavy sector hadrons, and another where the coupling strength is allowed to evolve according to the available mass scales of quarks. Our results are in very good agreement with the existing experimental data as well as predictions of other theoretical approaches whenever comparison is possible.

The hadronization mechanism is described by the fragmentation functions (FFs) which are universal and process-independent quantities. They can be generally determined theoretically or phenomenologically. In the phenomenological approach which is based on the data analysis, we present the FFs of $D_s^{+}$ both at leading-order (LO) and next-to-leading order (NLO) and, for the first time, at next-to-next-to-leading order in the minimal subtraction factorization scheme with five massless quarks. These functions are determined by fitting all available experimental data of inclusive single $D_s^{+}$-meson production in electron-positron annihilation, from the OPAL Collaboration at CERN LEP1. We shall also estimate the uncertainties in these FFs as well as in the corresponding observables. In the theoretical approach, we apply the perturbative FFs formalism based on the Suzuki’s model and present our analytical results at LO and NLO perturbative QCD framework. For the first time, a comparison between both approaches will be presented in this work. We also apply our new FFs to generate theoretical predictions for the energy distribution of $D_s^{+}$ mesons produced through the decay of unpolarized top quarks, to be measured at the CERN LHC.