We employ the Landé subtraction method and the spectral method to solve numerically the Schrödinger equation in momentum space with the Cornell and screened Cornell potentials in a unified approach. The calculated results are excellent, because singularities, especially the double-pole singularity, possessed by potentials are handled completely. Besides, we notice that the eigenvalues yielded by numerical methods have definite convergence directions. The convergence directions of the calculated eigenvalues are abnormal when potentials are singular and become normal as singularities are manipulated properly.

We study the process dependent nuclear $k_{\perp }$ broadening effect by employing the transverse momentum dependent (TMD) factorization approach in combination with the Mclerran-Venugopalan model. More specifically, we investigate how the parton transverse momentum distributions are affected by the process dependent gauge links in cold nuclear matter. In particular, our analysis also applies to the polarized cases including the nuclear quark Boer-Mulders function and the linearly polarized gluon distribution. Our main focus is on the nuclear TMDs at intermediate or large $x$.

Ascribing the large SU(3) violations in the singly Cabibbo suppressed decays of neutral $D$ mesons to the final state interactions, one gets large strong phase differences, necessary for substantial direct $CP$ violation. While the absolute value of the $CP$ violating asymmetries depend on the uncertain strength of the penguin contribution, we predict an asymmetry for the decays into charged pions more than twice as large and having opposite sign with respect to that for charged kaons.

We study in detail the impact of dynamical quarks on the gluon mass generation mechanism, in the Landau gauge, for the case of a small number of quark families. As in earlier considerations, we assume that the main bulk of the unquenching corrections to the gluon propagator originates from the fully dressed quark-loop diagram. The nonperturbative evaluation of this diagram provides the key relation that expresses the unquenched gluon propagator as a deviation from its quenched counterpart. This relation is subsequently coupled to the integral equation that controls the momentum evolution of the effective gluon mass, which contains a single adjustable parameter; this constitutes a major improvement compared to the analysis presented in Aguilar et al. [Phys. Rev. D 86, 014032 (2012)], where the behavior of the gluon propagator in the deep infrared was estimated through numerical extrapolation. The resulting nonlinear system is then treated numerically, yielding unique solutions for the modified gluon mass and the quenched gluon propagator, which fully confirms the picture put forth recently in several continuum and lattice studies. In particular, an infrared finite gluon propagator emerges, whose saturation point is considerably suppressed, due to a corresponding increase in the value of the gluon mass. This characteristic feature becomes more pronounced as the number of active quark families increases, and can be deduced from the infrared structure of the kernel entering in the gluon mass equation.

In this paper we study the identification of the $b$ quark inside a boosted hadronically decaying top quark in the center-of-mass frame of the jet. We demonstrate that the method can be used to greatly reduce the QCD jet background even in a very high pileup condition. The method has a much smaller fake rate for QCD jets compared to typical $b$ quark identification algorithms in jets at the same signal efficiency. When combining the $b$ quark identification in the center-of-mass frame of the jet with jet substructure information, we can improve the rejection rate of QCD jet background by almost an order of magnitude while maintaining the same identification efficiency for the boosted top quark.

We analyze the sensitivity of all experimentally observable asymmetries and energy distributions for the neutron ${\beta }^{-}$ decay with a polarized neutron and an unpolarized decay proton and electron, and the lifetime of the neutron to contributions of order ${10}^{-4}$ of interactions beyond the standard model (SM). We analyze the contributions of interactions beyond the SM in the linear approximation with respect to the Herczeg phenomenological coupling constants, introduced at the hadronic level. Such an approximation is good enough for the analysis of contributions of order ${10}^{-4}$ of interactions beyond the SM. We show that in such an approximation the correlation coefficients depend only on the axial coupling constant, which absorbs the contributions of the Herczeg left-left and left-right lepton-nucleon current-current interactions (vector and axial-vector interactions beyond the SM), and the Herczeg scalar and tensor coupling constants. In the lifetime of the neutron, in addition to the axial coupling constant, the contributions of the Herczeg left-left and left-right lepton-nucleon current-current interactions (vector and axial-vector interactions beyond the SM) are absorbed by the Cabibbo–Kobayashi–Maskawa matrix element.

We report the measurements of branching fractions and $CP$ violation asymmetries in $B^0\to \varphi K^{*}$ decays obtained in an angular analysis using the full data sample of $772\times {10}^{6}B\overline{B}$ pairs collected at the ${\rm Y}(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. We perform a partial wave analysis to distinguish among scalar [$B^0\to \varphi (K\pi {)}_0^{*}$], vector [$B^0\to \varphi K^{*}(892{)}^0$] and tensor [$B^0\to \varphi K_2^{*}(1430{)}^0$] components, and determine the corresponding branching fractions to be $\mathcal{B}[B^0\to \varphi (K\pi {)}_0^{*}]=(4.3\pm 0.4\pm 0.4)\times {10}^{-6}$, $\mathcal{B}[B^0\to \varphi K^{*}(892{)}^0]=(10.4\pm 0.5\pm 0.6)\times {10}^{-6}$ and $\mathcal{B}[B^0\to \varphi K_2^{*}(1430{)}^0]=({5.5}_{-0.7}^{+0.9}\pm 1.0)\times {10}^{-6}$. We also measure the longitudinal polarization fraction $f_L$ in $B^0\to \varphi K^{*}(892{)}^0$ and $B^0\to \varphi K_2^{*}(1430{)}^0$ decays to be $0.499\pm 0.030\pm 0.018$ and ${0.918}_{-0.060}^{+0.029}\pm 0.012$, respectively. The first quoted uncertainties are statistical and the second are systematic. In total, we measure 26 parameters related to branching fractions, polarization and $CP$ violation in the $B^0\to \varphi K^{*}$ system. No evidence for $CP$ violation is found.

We measure the asymmetry in the charge-weighted rapidity $q{y}_{\ell }$ of the lepton in semileptonic $t\overline{t}$ decays recorded with the CDF II detector using the full Tevatron Run II sample, corresponding to an integrated luminosity of $9.4{\mathrm{fb}}^{-1}$. A parametrization of the asymmetry as a function of $q{y}_{\ell }$ is used to correct for the finite acceptance of the detector and recover the production-level asymmetry. The result of $A_{\mathrm{FB}}^{\ell }={0.094}_{-0.029}^{+0.032}$ is to be compared to the standard model next-to-leading-order prediction of $A_{\mathrm{FB}}^{\ell }=0.038\pm 0.003$.

We report the first observation of the Cabibbo-suppressed decays ${\Xi }_c^0\to {\Xi }^{-}{K}^{+}$, ${\Xi }_c^0\to \Lambda K^{+}{K}^{-}$ and ${\Xi }_c^0\to \Lambda \varphi$, using a data sample of $711{\mathrm{fb}}^{-1}$ collected at the ${\rm Y}(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. We measure the ratios of branching fractions to be $\frac{\mathcal{B}({\Xi }_c^0\to {\Xi }^{-}{K}^{+})}{\mathcal{B}({\Xi }_c^0\to {\Xi }^{-}{\pi }^{+})}=(2.75\pm 0.51\pm 0.25)\times {10}^{-2}$, $\frac{\mathcal{B}({\Xi }_c^0\to \Lambda K^{+}{K}^{-})}{\mathcal{B}({\Xi }_c^0\to {\Xi }^{-}{\pi }^{+})}=(2.86\pm 0.61\pm 0.37)\times {10}^{-2}$ and $\frac{\mathcal{B}({\Xi }_c^0\to \Lambda \varphi )}{\mathcal{B}({\Xi }_c^0\to {\Xi }^{-}{\pi }^{+})}=(3.43\pm 0.58\pm 0.32)\times {10}^{-2}$, where the first uncertainty is statistical and the second is systematic.

We search for a low-mass scalar $CP$-odd Higgs boson, $A^0$, produced in the radiative decay of the upsilon resonance and decaying into a ${\tau }^{+}{\tau }^{-}$ pair: ${\rm Y}(1S)\to \gamma A^0$. The production of ${\rm Y}(1S)$ mesons is tagged by ${\rm Y}(2S)\to {\pi }^{+}{\pi }^{-}{\rm Y}(1S)$ transitions, using a sample of $(98.3\pm 0.9)\times {10}^6$ ${\rm Y}(2S)$ mesons collected by the BABAR detector. We find no evidence for a Higgs boson in the mass range $3.5\le m_{A^0}\le 9.2\mathrm{GeV}$, and combine these results with our previous search for the tau decays of the light Higgs in radiative ${\rm Y}(3S)$ decays, setting limits on the coupling of $A^0$ to the $b\overline{b}$ quarks in the range 0.09–1.9. Our measurements improve the constraints on the parameters of the next-to-minimal-supersymmetric Standard Model and similar theories with low-mass scalar degrees of freedom.

We study the question of complete gauge independence of the fermion pole mass by choosing a general class of gauge fixing, which interpolates between the covariant, the axial and the Coulomb gauges for different values of the gauge fixing parameters. We derive the Nielsen identity describing the gauge parameter variation of the fermion two point function in this general class of gauges. Furthermore, we relate the denominator of the fermion propagator to the two point function. This then allows us to study directly the gauge parameter dependence of the denominator of the propagator using the Nielsen identity for the two point function. This leads to a simple proof that, when infrared divergences and mass shell singularities are not present at the pole, the fermion pole mass is gauge independent, in the complete sense, to all orders in perturbation theory. Namely, the pole is not only independent of the gauge fixing parameters but also has the same value in both covariant and noncovariant gauges.

In this paper we compute the effective action at finite temperature and density for the dual fermion condensate in curved space with the fermions described by an effective field theory with four-point interactions. The approach we adopt refines a technique developed earlier to study chiral symmetry breaking in curved space and it is generalized here to include the U(1)-valued boundary conditions necessary to define the dual condensate. The method we present is general, includes the coupling between the fermion condensate and the Polyakov loop, and applies to any ultrastatic background spacetime with a nonsingular base. It also allows one to include inhomogeneous and anisotropic phases and therefore it is suitable to study situations where the geometry is not homogeneous. We first illustrate a procedure, based on heat kernels, useful to deal with situations where the dual and chiral condensates (as well as any smooth background field eventually present) are slowly or rapidly varying functions in space. Then we discuss a different approach based on the density of states method and on the use of Tauberian theorems to handle the case of arbitrary chemical potentials. As a trial application, we consider the case of constant curvature spacetimes and show how to compute numerically the dual fermion condensate in the case of both homogeneous and inhomogeneous phases.

We study the quantum mechanics of a Dirac fermion on a curved spacetime manifold. The metric of the spacetime is completely arbitrary, allowing for the discussion of all possible inertial and gravitational field configurations. In this framework, we find the Hermitian Dirac Hamiltonian for an arbitrary classical external field (including the gravitational and electromagnetic ones). In order to discuss the physical content of the quantum-mechanical model, we further apply the Foldy-Wouthuysen transformation, and derive the quantum equations of motion for the spin and position operators. We analyze the semiclassical limit of these equations and compare the results with the dynamics of a classical particle with spin in the framework of the standard Mathisson-Papapetrou theory and in the classical canonical theory. The comparison of the quantum-mechanical and classical equations of motion of a spinning particle in an arbitrary gravitational field shows their complete agreement.

The Fisher information matrix (FIM) has been the standard approximation to the accuracy of parameter estimation on gravitational-wave signals from merging compact binaries due to its ease of use and rapid computation time. While the theoretical failings of this method, such as the signal-to-noise ratio (SNR) limit on the validity of the lowest-order expansion and the difficulty of using non-Gaussian priors, are well understood, the practical effectiveness compared to a real parameter estimation technique (e.g., Markov-chain Monte Carlo) remains an open question. We present a direct comparison between the FIM error estimates and the Bayesian probability density functions produced by the parameter estimation code lalinference_mcmc. In addition to the low-SNR issues usually considered, we find that the FIM can greatly overestimate the uncertainty in parameter estimation achievable by the MCMC. This was found to be a systematic effect for systems composed of binary black holes, with the disagreement increasing with total mass. In some cases, the MCMC search returned standard deviations on the marginalized posteriors that were smaller by several orders of magnitude than the FIM estimates. We conclude that the predictions of the FIM do not represent the capabilities of real gravitational-wave parameter estimation.

We present an effective nonrelativistic theory of self-interacting dark matter. We classify the long-range interactions and discuss how they can be generated from quantum field theories. Generic dark sectors can generate singular potentials. We show how to consistently renormalize such potentials and apply this to the calculation of the Sommerfeld enhancement of dark matter interactions. We explore further applications of this enhancement to astrophysical probes of dark matter including the core vs cusp problem.

We present three distinct types of models of dark energy in the form of a scalar field which is explicitly coupled to dark matter. Our construction draws from the pull-back formalism for fluids and generalizes the fluid action to involve couplings to the scalar field. We investigate the cosmology of each class of model both at the background and linearly perturbed level. We choose a potential for the scalar field and a specific coupling function for each class of models and we compute the cosmic microwave background and matter power spectra.

We present a relativistic formulation of pion loop corrections to the coupling of photons with nucleons on the light front. Vertex and wave function renormalization constants are computed to lowest order in the pion field, including their nonanalytic behavior in the chiral limit, and studied numerically as a function of the ultraviolet cutoff. Particular care is taken to explicitly verify gauge invariance and Ward-Takahashi identity constraints to all orders in the $m_{\pi }$ expansion. The results are used to compute the chiral corrections to matrix elements of local operators, related to moments of deep-inelastic structure functions. Finally, comparison of results for pseudovector and pseudoscalar coupling allows the resolution of a longstanding puzzle in the computation of pion cloud corrections to structure function moments.

In this paper we consider the generation of naturally small neutrino masses from a dimension-7 operator. Such a term can arise in the presence of a scalar quadruplet and a pair of vectorlike fermion triplets and enables one to obtain small neutrino masses through the TeV scale linear seesaw mechanism. We study the phenomenology of the charged scalars of this model, in particular, the multilepton signatures at the Large Hadron Collider. Of special importance is the presence of the same-sign-tri-lepton signatures originating from the triply charged scalars. The Standard Model background for such processes is small, and hence this is considered as a confirming evidence of new physics. We also looked for events with three, four, five, and six leptons that have negligible contamination from the Standard Model. We further point out the spectacular lepton flavor violating the four-lepton signal that can be the hallmark for these types of models. We also compute the added contributions in the rate for the Standard Model Higgs decaying to two photons via the charged scalars in this model.

In light of recent results from the LHC, MEG and neutrino experiments, we revisit the issue of charged lepton flavor violation (LFV) in supersymmetric theories with massive neutrinos, where flavor-violating soft supersymmetry-breaking masses for sleptons are induced naturally by radiative corrections. We link our results to the expectations for light neutrinos with a normal mass hierarchy in SU(5), enhanced by an Abelian flavor symmetry, with particular focus on ${\theta }_{13}$. We focus on the radiative decays ${\ell }_i\to {\ell }_j\gamma$ and on detection prospects at the LHC and a linear collider (LC). We use supersymmetric parameters consistent with cosmological considerations and with LHC searches for supersymmetry and the Higgs mass. We find a class of scenarios where the LHC may be sensitive to LFV sparticle decays and LFV processes could be detectable at a LC with center-of-mass energy above 1 TeV, whereas LFV lepton decays may be suppressed by cancellations in the decay amplitudes.

In view of the advent of large-scale neutrino detectors such as IceCube, the future Hyper-Kamiokande and the ones proposed for the Laguna project in Europe, we reexamine the determination of the directional position of a Galactic supernova by means of its neutrinos using the triangulation method. We study the dependence of the pointing accuracy on the arrival-time resolution of supernova neutrinos at different detector locations. For a failed supernova, we expect better results due to the abrupt termination of the neutrino emission which allows one to measure the arrival time with higher precision. We found that for the time resolution of $\pm 2$ (4) ms, the supernova can be located with a precision of $\sim 5°$ (10°) on the declination and of $\sim 8°$ (15°) on the right ascension angle if we combine the observations from detectors at four different sites.