We consider the field theories on multiple stacks of D5-branes wrapped on four cycles of resolved/deformed conifold geometries fibered over a two-torus. The central charges of the D5-branes are slightly misaligned when the branes are wrapped on various rigid holomorphic two-cycles or when they have different charges with respect to a magnetic flux turned on the two-torus. The wrapped D5-branes preserve (0, 2) supersymmetry in two dimensions if the Kahler moduli and the magnetic flux are related. Our geometries are T-dual to the brane configurations considered by Kutasov-Lin, and we provide a geometric interpretation for their equality between the field theory D-terms and the magnetic fluxes. We also consider the geometric transitions for rigid holomorphic two-cycles fibered over a two-torus with magnetic flux and discuss the partial breaking of supersymmetry after the geometric transition.

For the periodic sphaleron potential in the electroweak theory, we find the one-dimensional time-independent Schrödinger equation with the Chern-Simons number as the coordinate, construct the Bloch wave function and determine the corresponding conducting (pass) band structure. We show that the baryon-lepton number violating processes can take place without the exponential tunneling suppression (at zero temperature) at energies around and above the barrier height (sphaleron energy) at 9.0 TeV. Phenomenologically, probable detection of such processes at the LHC is discussed.

We extend the investigation of the recently introduced class ${\mathcal{S}}_k$ of four-dimensional $\mathcal{N}=1$ superconformal field theories by considering a large family of quiver gauge theories within it, which we denote ${\mathcal{S}}_k^1$. These theories admit a realization in terms of ${\mathbb{Z}}_k$ orbifolds of Type IIA configurations of D4-branes stretched among relatively rotated sets of NS-branes. This fact permits a systematic investigation of the full family, which exhibits new features such as nontrivial anomalous dimensions differing from free field values and novel ways of gluing theories. We relate these ingredients to properties of compactification of the six-dimensional (1,0) superconformal ${\mathcal{T}}_N^k$ theories on spheres with different kinds of punctures. We describe the structure of dualities in this class of theories upon exchange of punctures, including transformations that correspond to Seiberg dualities, and exploit the computation of the superconformal index to check the invariance of the theories under them.

We examine the Chevallier–Polarski–Linder (CPL) parametrization, in the context of quintessence and barotropic dark energy models, to determine the subset of such models to which it can provide a good fit. The CPL parametrization gives the equation of state parameter $w$ for the dark energy as a linear function of the scale factor $a$, namely $w=w_0+w_a(1-a)$. In the case of quintessence models, we find that over most of the $w_0$, $w_a$ parameter space the CPL parametrization maps onto a fairly narrow form of behavior for the potential $V(\varphi )$, while a one-dimensional subset of parameter space, for which $w_a=\kappa (1+w_0)$, with $\kappa$ constant, corresponds to a wide range of functional forms for $V(\varphi )$. For barotropic models, we show that the functional dependence of the pressure on the density, up to a multiplicative constant, depends only on $w_i=w_a+w_0$ and not on $w_0$ and $w_a$ separately. Our results suggest that the CPL parametrization may not be optimal for testing either type of model.

There are attempts in the literature to theoretically explain the large breaking of isotopic invariance in the decay $\eta (1405)\to f_0(980){\pi }^0\to 3\pi$ by the mechanism containing the logarithmic (triangle) singularity, i.e., as being due to the transition $\eta (1405)\to (K^{*}\overline{K}+{\overline{K}}^{*}K)\to (K^{+}{K}^{-}+K^0{\overline{K}}^0){\pi }^0\to f_0(980){\pi }^0\to 3\pi$. The corresponding calculations were fulfilled for a hypothetic case of the stable $K^{*}$ meson. Here, we show that the account of the finite width of the $K^{*}$ (${\mathrm{\Gamma }}_{K^{*}\to K\pi }\approx 50\mathrm{MeV}$) smoothes the logarithmic singularities in the amplitude and results in the suppression of the calculated decay width $\eta (1405)\to f_0(980){\pi }^0\to 3\pi$ by the factor of 6–8 as compared with the case of ${\mathrm{\Gamma }}_{K^{*}\to K\pi }=0$. We also analyze the difficulties related with the assumption of the dominance of the $\eta (1405)\to (K^{*}\overline{K}+{\overline{K}}^{*}K)\to K\overline{K}\pi$ decay mechanism and discuss the possible dynamics of the decay $\eta (1405)\to \eta \pi \pi$. The decisive improvement of the experimental data on the $K\overline{K}$, $K\pi$, $\eta \pi$, and $\pi \pi$ mass spectra in the decay of the resonance structure $\eta (1405/1475)$ to $K\overline{K}\pi$ and $\eta \pi \pi$, and on the shape of the resonance peaks themselves in the $K\overline{K}\pi$ and $\eta \pi \pi$ decay channels is necessary for further establishing the $\eta (1405)\to 3\pi$ decay mechanism.

I consider models in which nonstandard supersymmetry-breaking terms, including Dirac gaugino masses, arise from $F$-term breaking mediated by operators with a $1/M^3$ suppression. In these models, the supersoft properties found in the case of $D$-term breaking are absent in general, but can be obtained as a special case that is a fixed point of the renormalization group equations. The $\mu$ term is replaced by three distinct supersymmetry-breaking parameters, decoupling the Higgs scalar potential from the Higgsino masses. Both holomorphic and nonholomorphic scalar cubic interactions with minimal flavor violation are induced in the supersymmetric Standard Model Lagrangian.

If the Standard Model (SM) is an effective theory, as currently believed, it is valid up to some energy scale $\mathrm{\Lambda }$ to which the Higgs vacuum expectation value is sensitive throughout radiative quadratic terms. The latter ones destabilize the electroweak vacuum and generate the SM hierarchy problem. For a given perturbative ultraviolet (UV) completion, the SM cutoff can be computed in terms of fundamental parameters. If the UV mass spectrum involves several scales, the cutoff is not unique and each SM sector has its own UV cutoff ${\mathrm{\Lambda }}_i$. We have performed this calculation assuming the minimal supersymmetric standard model (MSSM) is the SM UV completion. As a result, from the SM point of view, the quadratic corrections to the Higgs mass are equivalent to finite threshold contributions. For the measured values of the top quark and Higgs masses, and depending on the values of the different cutoffs ${\mathrm{\Lambda }}_i$, these contributions can cancel even at renormalization scales as low as multi-TeV, unlike the case of a single cutoff where the cancellation only occurs at Planckian energies, a result originally obtained by Veltman. From the MSSM point of view, the requirement of stability of the electroweak minimum under radiative corrections is incorporated into the matching conditions and provides an extra constraint on the focus point solution to the little hierarchy problem in the MSSM. These matching conditions can be employed for precise calculations of the Higgs sector in scenarios with heavy supersymmetric fields.

In this paper, we perform a combined study of $2S$ and $1D$ open-charm mesons with natural spin-parity. Our results indicate that $D_1^{*}(2600)/D_{s1}^{*}(2700)$ and $D_1^{*}(2760)/D_{s1}^{*}(2860)$ are predominantly the $2{}^3{S}_1$ and $1{}^3{D}_1$ charmed/charmed-strange mesons, respectively, while $D_3^{*}(2760)/D_{s3}^{*}(2860)$ can be regarded as the $1{}^3{D}_3$ charmed/charmed-strange mesons. In addition, some typical ratios of partial widths of the discussed natural states are predicted, by which future experiments can test these assignments, especially for the $2S\text{−}1D$ mixing scheme existing in $D_1^{*}(2600)/D_1^{*}(2760)$ and $D_{s1}^{*}(2700)/D_{s1}^{*}(2860)$.

In this paper it is proposed that the charged charmonium-like state $Z_c(3900)$ is a resonance above the threshold from the $D{\overline{D}}^{*}$ interaction. The $D{\overline{D}}^{*}$ interaction is described by the one-boson exchange model with light meson exchanges plus a short-range $J/\psi$ exchange. The scattering amplitude is calculated within a Bethe-Salpeter equation approach, and the poles near the $D{\overline{D}}^{*}$ threshold are searched. In the isoscalar sector, two poles found under the $D{\overline{D}}^{*}$ threshold—i.e., bound states—have the quantum numbers $I^G(J^{\mathrm{PC}})=0^{-}(1^{+-})$ and $0^{+}(1^{++})$. The latter can be related to the $X(3872)$. In the isovector sector, a bound state with $I^G(J^P)=1^{+}(1^{+})$ is found with a large cutoff at about 3 GeV. If a cutoff at about 2 GeV is adopted with which a pole carrying the quantum number of the $X(3872)$ is produced at an energy of about 3871 MeV, the pole for the bound state with $1^{+}(1^{+})$ runs across the threshold to a second Riemann sheet and becomes a resonance above the $D{\overline{D}}^{*}$ threshold, which can be identified with the $Z_c(3900)$. With such a cutoff, the $D{\overline{D}}^{*}$ invariant mass spectrum is also investigated and the experimental results found by BESIII can be reproduced.

We consider Yang-Mills theory with a matrix gauge group $G$ on a direct product manifold $M={\mathrm{\Sigma }}_2\times H^2$, where ${\mathrm{\Sigma }}_2$ is a two-dimensional Lorentzian manifold and $H^2$ is a two-dimensional open disc with the boundary $S^1=\partial H^2$. The Euler-Lagrange equations for the metric on ${\mathrm{\Sigma }}_2$ yield constraint equations for the Yang-Mills energy-momentum tensor. We show that in the adiabatic limit, when the metric on $H^2$ is scaled down, the Yang-Mills equations plus constraints on the energy-momentum tensor become the equations describing strings with a world sheet ${\mathrm{\Sigma }}_2$ moving in the based loop group $\mathrm{\Omega }G=C^{\infty }(S^1,G)/G$, where $S^1$ is the boundary of $H^2$. By choosing $G={\mathbb{R}}^{d-1,1}$ and putting to zero all parameters in $\mathrm{\Omega }{\mathbb{R}}^{d-1,1}$ besides ${\mathbb{R}}^{d-1,1}$, we get a string moving in ${\mathbb{R}}^{d-1,1}$. In another paper of the author, it was described how one can obtain the Green-Schwarz superstring action from Yang-Mills theory on ${\mathrm{\Sigma }}_2\times H^2$ while $H^2$ shrinks to a point. Here we also consider Yang-Mills theory on a three-dimensional manifold ${\mathrm{\Sigma }}_2\times S^1$ and show that in the limit when the radius of $S^1$ tends to zero, the Yang-Mills action functional supplemented by a Wess-Zumino-type term becomes the Green-Schwarz superstring action.

We consider inflation in a universe with a positive cosmological constant and a nonminimally coupled scalar field, in which the field couples both quadratically and quartically to the Ricci scalar. When considered in the Einstein frame and when the nonminimal couplings are negative, the field starts in slow roll and inflation ends with an asymptotic value of the principal slow-roll parameter, ${\epsilon }_E=4/3$. Graceful exit can be achieved by suitably (tightly) coupling the scalar field to matter, such that at late time the total energy density reaches the scaling of matter, ${\epsilon }_E={\epsilon }_m$. Quite generically the model produces a red spectrum of scalar cosmological perturbations and a small amount of gravitational radiation. With a suitable choice of the nonminimal couplings, the spectral slope can be as large as $n_s\simeq 0.955$, which is about one standard deviation away from the central value measured by the Planck satellite. The model can be ruled out by future measurements if any of the following is observed: (a) the spectral index of scalar perturbations is $n_s>0.960$; (b) the amplitude of tensor perturbations is above about $r\sim {10}^{-2}$; (c) the running of the spectral index of scalar perturbations is positive.

We present a unified analysis of the decays of bottomonia $\mathrm{\Upsilon }(mS)\to \mathrm{\Upsilon }(nS)\pi \pi$ ($m>n$, $m=2,3,4,5$, $n=1,2,3$), charmonia $J/\psi \to \varphi (\pi \pi ,K\overline{K})$, $\psi (2S)\to J/\psi \pi \pi$, and the isoscalar $S$-wave processes $\pi \pi \to \pi \pi ,K\overline{K},\eta \eta$. In this analysis we extend our recent study of low-lying $(m=2,3)$ radial excitations of bottomonia to modes involving higher $(m=4,5)$ excited states. Similarly as for the data on lower radial excitations, we confirm that the data for higher radially excited states from the BABAR and Belle collaborations can be described under conditions that the final bottomonium is a spectator and the multichannel $\pi \pi$ scattering is considered in a model-independent approach based on analyticity, unitarity and the uniformization procedure. Indeed we show that the dipion mass distributions in the two-pion transitions of both charmonia and bottomonia states are explained by a unified mechanism based on the contribution of the $\pi \pi$ and $K\overline{K}$ coupled channels including their interference (final-state interactions). Therefore, our main result is that the lower and higher radially excited states of charmonia and bottomonia have no specific features in mutual comparison and can be understood in a unified picture, e.g. proposed by our approach.

We discuss thermal production of (pseudo) Goldstinos, the Goldstone fermions emerging from (multiple) SUSY-breaking sectors, when the reheating temperature is well below the superpartner masses. In such a case, the production during the matter-dominated era induced by the inflaton decay stage is more important than after reheating. Depending on the SUSY-breaking scale, Goldstinos are produced by a freeze-in or freeze-out mechanism via $1\to 2$ decays and inverse decays. We solve the Boltzmann equation for the momentum distribution function of the Goldstino. In the freeze-out case, Goldstinos maintain chemical equilibrium far after they are kinetically decoupled by elastic scatterings and, consequently, Goldstinos with different momentum decouple at different temperatures. As a result, their momentum distribution function shows a peculiar shape, and the final yield is smaller than if kinetic equilibrium were assumed. We revisit the cosmological implications in both $R$-parity-conserving and $R$-parity-violating supersymmetric scenarios. For the former, thermally produced Goldstinos can still be abundant enough to be dark matter at present times even if the reheating temperature is low, of order 1 GeV. For the latter, if the reheating temperature is low, of order 0.1–1 GeV, they are safe from the BBN constraints.

We perform a detailed study of double Higgs production via gluon fusion in the effective field theory (EFT) framework where effects from new physics (NP) are parametrized by local operators. Our analysis provides a perspective broader than the one followed in most of the previous analyses, where this process was merely considered as a way to extract the Higgs trilinear coupling. We focus on the $hh\to b\overline{b}\gamma \gamma$ channel and perform a thorough simulation of signal and background at the 14 TeV LHC and a future 100 TeV proton-proton collider. We make use of invariant mass distributions to enhance the sensitivity on the EFT coefficients and give a first assessment of the impact of jet substructure techniques on the results. The range of validity of the EFT description is estimated, as required to consistently exploit the high-energy range of distributions, pointing out the potential relevance of dimension-8 operators. Our analysis contains a few important improvements over previous studies and identifies some inaccuracies there appearing in connection with the estimate of signal and background rates. The estimated precision on the Higgs trilinear coupling that follows from our results is less optimistic than previously claimed in the literature. We find that a $\sim 30\%$ accuracy can be reached on the trilinear coupling at a future 100 TeV collider with $3{\mathrm{ab}}^{-1}$. Only an $O(1)$ determination instead seems possible at the LHC with the same amount of integrated luminosity.

We determine the ground state and first excited state masses of singly and doubly charmed spin $1/2$ and $3/2$ baryons with positive and negative parity. Configurations with $N_f=2+1$ nonperturbatively improved Wilson-clover fermions were employed, with the same quark action also being used for the valence quarks, including the charm. The spectrum is calculated for pion masses in the range $M_{\pi }\sim 259–460\mathrm{MeV}$ at a lattice spacing $a\sim 0.075\mathrm{fm}$. Finite volume effects are studied comparing lattices with two different linear spatial extents (1.8 fm and 2.4 fm). The physical point is approached from the SU(3) limit keeping the flavor averaged light quark mass fixed. The baryon masses are extrapolated using expansions in the strange-light quark mass difference. Most particles fall into the expected SU(3) multiplets with well-constrained extrapolations, the exceptions having a possibly more complex internal structure. Overall agreement is found with experiment for the masses and splittings of the singly charmed baryons. As part of the calculation an analysis of the lower lying charmonium, $D$ and $D_s$ spectra was performed in order to assess discretization errors. The gross spectra are reproduced, including the $D_{s0}^{*}$, $D_{s1}$ and $D_1$ mesons, while at this single lattice spacing hyperfine splittings come out 10–20 MeV too low.

Measurements of the ${\mathrm{\Lambda }}_b\to p{\ell }^{-}{\overline{\nu }}_{\ell }$ and ${\mathrm{\Lambda }}_b\to {\mathrm{\Lambda }}_c{\ell }^{-}{\overline{\nu }}_{\ell }$ decay rates can be used to determine the magnitudes of the Cabibbo-Kobayashi-Maskawa matrix elements $V_{ub}$ and $V_{cb}$, provided that the relevant hadronic form factors are known. Here we present a precise calculation of these form factors using lattice QCD with $2+1$ flavors of dynamical domain-wall fermions. The $b$ and $c$ quarks are implemented with relativistic heavy-quark actions, allowing us to work directly at the physical heavy-quark masses. The lattice computation is performed for six different pion masses and two different lattice spacings, using gauge-field configurations generated by the RBC and UKQCD Collaborations. The $b\to u$ and $b\to c$ currents are renormalized with a mostly nonperturbative method. We extrapolate the form factor results to the physical pion mass and the continuum limit, parametrizing the $q^2$ dependence using $z$ expansions. The form factors are presented in such a way as to enable the correlated propagation of both statistical and systematic uncertainties into derived quantities such as differential decay rates and asymmetries. Using these form factors, we present predictions for the ${\mathrm{\Lambda }}_b\to p{\ell }^{-}{\overline{\nu }}_{\ell }$ and ${\mathrm{\Lambda }}_b\to {\mathrm{\Lambda }}_c{\ell }^{-}{\overline{\nu }}_{\ell }$ differential and integrated decay rates. Combined with experimental data, our results enable determinations of $|V_{ub}|$, $|V_{cb}|$, and $|V_{ub}/V_{cb}|$ with theory uncertainties of 4.4%, 2.2%, and 4.9%, respectively.

We present a method to smear (center projected) $Z(2)$ vortices in lattice gauge configurations such as to embed vortex physics into a full $SU(2)$ gauge configuration framework. In particular, we address the problem that using $Z(2)$ configurations in conjunction with overlap (or chirally improved) fermions is problematic due to their lack of smoothness. Our method allows us to regain this smoothness and simultaneously maintain the center vortex structure. We test our method with various gluonic and fermionic observables and investigate to what extent we are able to approach SU(2) gauge dynamics without destroying the original vortex structure.