We investigate the widths of the recently observed charmonium like resonances $X(3872)$, $Z(4430)$, and $Z_2(4250)$ using QCD sum rules. Extending previous analyses regarding these states as diquark-antiquark states or molecules of $D$ mesons, we introduce the Breit-Wigner function in the pole term. We find that introducing the width increases the mass at the small Borel window region. Using the operator-product expansion up to dimension 8, we find that the sum rules based on interpolating current with molecular components give a stable Borel curve from which both the masses and widths of these resonances can be well obtained. Thus the QCD sum rule approach strongly favors the molecular description of these states.

We examine the possible extension of the parameter space of the minimal supersymmetric extension of the standard model (MSSM), as expressed via the renormalization-group equations in terms of universal soft supersymmetry-breaking terms at the unification scale, to include tachyonic input scalar masses. Many models with negative masses-squared for scalars at the unification scale may be viable because the small sizes of the masses-squared allow them to change signs during the renormalization-group evolution to the electroweak scale. However, in many cases, there is, in addition to the electroweak vacuum, a much deeper high-scale vacuum located along some F- and D-flat direction in the effective potential for the MSSM. We perform a numerical search for such vacua in both the constrained MSSM (CMSSM) and a variant with nonuniversal Higgs masses (NUHM). We discuss the circumstances under which the existence of such a deep charge- and color-breaking vacuum is consistent with standard cosmology. A crucial role is played by the inflation-induced scalar masses, whereas thermal effects are often irrelevant.

We investigate the possibility that a (light) hidden sector extra photon receives its mass via spontaneous symmetry breaking of a hidden sector Higgs boson, the so-called hidden-Higgs. The hidden-photon can mix with the ordinary photon via a gauge kinetic mixing term. The hidden-Higgs can couple to the standard model Higgs via a renormalizable quartic term—sometimes called the Higgs portal. We discuss the implications of this light hidden-Higgs in the context of laser polarization and light-shining-through-the-wall experiments as well as cosmological, astrophysical, and non-Newtonian force measurements. For hidden-photons receiving their mass from a hidden-Higgs, we find in the small mass regime significantly stronger bounds than the bounds on massive hidden sector photons alone.

Higgs singlet superfields are usually present in most extensions of the minimal supersymmetric standard model that address the $\mu$-problem, such as the next-to-minimal supersymmetric standard model and the minimal nonminimal supersymmetric standard model. Employing a gauge- and flavor- covariant effective Lagrangian formalism, we show how the singlet-Higgs bosons of such theories can have significant contributions to $B$-meson flavor-changing neutral current observables for large values of $\tan \beta \gtrsim 50$ at the 1-loop level. Illustrative results are presented including effects on the $B_s$ and $B_d$ mass differences and on the rare decay $B_s\to {\mu }^{+}{\mu }^{-}$. In particular, we find that depending on the actual value of the lightest singlet pseudoscalar mass in the next-to-minimal supersymmetric standard model, the branching ratio for $B_s\to {\mu }^{+}{\mu }^{-}$ can be enhanced or even suppressed with respect to the standard model prediction by more than 1 order of magnitude.

In a recent paper, Creutz has given a new action describing two species of Dirac fermions with exact chiral symmetry on the lattice. This action depends on parameters which may be fixed at certain values in order to get the right continuum limit. In this letter, we elaborate more on this idea and present an action which is free of any other parameter except the fermion mass.

We investigate the $B\to a_1(1260)(b_1(1235))\pi (K)$ decays under the factorization scheme and find many discrepancies between theoretical predictions and the experimental data. In the tree-dominated processes, large contributions from color-suppressed tree diagrams are required in order to accommodate the large decay rates of $B^{-}\to a_1^0{\pi }^{-}$ and $B^{-}\to a_1^{-}{\pi }^0$. For ${\overline{B}}^0\to (a_1^{+},b_1^{+})K^{-}$ decays which are induced by $b\to s$ transition, theoretical predictions on their decay rates are larger than the data by a factor of 2.8 and 5.5, respectively. Large electroweak penguins or some new mechanism are expected to explain the branching ratios of $B^{-}\to b_1^0{K}^{-}$ and $B^{-}\to a_1^{-}{\overline{K}}^0$. The soft-collinear effective theory has the potential to explain large decay rates of $B^{-}\to a_1^0{\pi }^{-}$ and $B^{-}\to a_1^{-}{\pi }^0$ via a large hard-scattering form factor ${\zeta }_J^{B\to a_1}$. We will also show that, with proper charming penguins, predictions on the branching ratios of ${\overline{B}}^0\to (a_1^{+},b_1^{+})K^{-}$ can also be consistent with the data.

We consider chiral loop corrections to the scalar form factor in $B_q\to D_{q}l\nu$ decays. First we consider chiral corrections to the $1/m_Q$ suppressed operators and then we propose a procedure for the extraction of the relevant form factor using lattice QCD results. In particular, the extraction of a $B^{*}\to D^{*}$ matrix element on the lattice can be used to determine all the necessary $1/m_Q$ suppressed contributions to the scalar form factor in $B\to D$ transitions. In the case of $(B_s\to D_s)/(B\to D)$ decay rate ratios we speculate that effects of kinematics and chiral corrections tend to cancel for the scalar form factor contributions. In particular the $1/m_Q$ suppression of chiral corrections is compensated by the potentially large $SU(3)$ flavor symmetry breaking corrections. The calculated corrections are relevant for the precise determination of possible new physics effects in $B_q\to D_{q}l\nu$ decays.

We study semileptonic $B$ meson decays $B\to K_1(1270){\ell }^{+}{\ell }^{-}$ and $K_1(1400){\ell }^{+}{\ell }^{-}$ ($\ell \equiv e$, $\mu$, $\tau$), where the strange $P$-wave mesons, $K_1(1270)$ and $K_1(1400)$, are the mixtures of the $K_{1A}$ and $K_{1B}$, which are the $1{}^{3}P_1$ and $1{}^{1}P_1$ states, respectively. We show that the ratio $R_{\ell }\equiv \mathcal{B}(B\to K_1(1400){\ell }^{+}{\ell }^{-})/\mathcal{B}(B\to K_1(1270){\ell }^{+}{\ell }^{-})$, insensitive to new-physics parameters, is suitable for determining the $K_1(1270)-K_1(1400)$ mixing angle, ${\theta }_{K_1}$. The forward-backward asymmetry shows a weak ${\theta }_{K_1}$ dependence for $B\to K_1(1270){\mu }^{+}{\mu }^{-}$, but relatively strong for $B\to K_1(1400){\mu }^{+}{\mu }^{-}$. We investigate model-independent new-physics corrections to operators relevant to the $b\to s{\ell }^{+}{\ell }^{-}$ electroweak-penguin and weak-box diagrams. Furthermore, for the $B\to K_1(1270){\mu }^{+}{\mu }^{-}$ decay the position of the forward-backward asymmetry zero, which is almost independent of the value of ${\theta }_{K_1}$, can be dramatically changed under variation of new-physics parameters.

We investigate hadronic unquenching effects in light quarks and mesons. To this end, we take into account the back-coupling of the pion onto the quark propagator within the nonperturbative continuum framework of Schwinger-Dyson equations (SDE) and Bethe-Salpeter equations (BSE). We improve on a previous approach by explicitly solving both the coupled system of SDEs and BSEs in the complex plane and the normalization problem for Bethe-Salpeter kernels depending on the total momentum of the meson. As a result of our study, we find considerable unquenching effects in the spectrum of light pseudoscalar, vector and axial-vector mesons.

In a simplified renormalizable model where the neutrinos have Pontecorvo-Maki-Nakagawa-Sakata (PMNS) mixings ${tan}^2{\theta }_{12}=\frac{1}{2}$, ${\theta }_{13}=0$, ${\theta }_{23}=\pi /4$ and with flavor symmetry $T^{\prime }$ there is a corresponding prediction where the quarks have Cabibbo-Kobayashi-Maskawa (CKM) mixings $\tan 2{\Theta }_{12}=\frac{\sqrt{2}}{3}$, ${\Theta }_{13}=0$, ${\Theta }_{23}=0$.

The Large Hadron Collider could be a discovery machine for the neutrino mass pattern and its Majorana nature in the context of a well-motivated TeV scale Type II seesaw model. This is achieved by identifying the flavor structure of the lepton-number violating decays of the charged Higgs bosons. The observation of either $H^{+}\to {\tau }^{+}\overline{\nu }$ or $H^{+}\to e^{+}\overline{\nu }$ will be particularly robust to determine the neutrino spectra since they are independent of the unknown Majorana phases, which could be probed via the $H^{++}\to e_i^{+}{e}_j^{+}$ decays. In a less favorable scenario when the leptonic channels are suppressed, one needs to observe the decays $H^{+}\to W^{+}{H}_1$ and $H^{+}\to t\overline{b}$ to confirm the triplet-doublet mixing that implies the Type II relation. The associated production $H^{\pm \pm }{H}^{\mp }$ is crucial in order to test the triplet nature of the Higgs field.

Conformal Galilei algebra contains $so(1,2)$ subalgebra which is the conformal algebra in one dimension. In this note, we generalize methods previously developed for one-dimensional many-body systems and construct a unitary map relating a quantum mechanics invariant under the conformal Galilean transformations to a set of decoupled particles for which the same symmetry is realized in a nonlocal way. Possible applications of the map are discussed.

We analytically calculate the low-lying gravitational quasinormal modes of a topological AdS black hole of arbitrary dimension in the high temperature limit. We show that they are in agreement with corresponding results from the hydrodynamics of the gauge theory plasma on the boundary, as required by the AdS/CFT (anti–de Sitter/conformal field theories) correspondence. For some of these modes, we obtain a lifetime which is comparable to or longer than the longest lifetime of perturbations of spherical black holes. These modes might play a significant role in the late-time behavior of the gauge theory plasma.

We investigate multidimensional universe with nonlinear scalar curvature terms to evaluate the probability of creation of primordial black holes. For this we obtain Euclidean instanton solution in two different topologies: (a) $S^{D-1}$—topology which does not accommodate primordial black holes and (b) $S^1\times S^{D-2}$—topology which accommodates a pair of black holes. The probability for quantum creation of an inflationary universe with a pair of black holes has been evaluated assuming a gravitational action which is described by a polynomial function of scalar curvature with or without a cosmological constant ($\Lambda$) using the framework of semiclassical approximation of Hartle-Hawking boundary conditions. We discuss here a class of new gravitational instantons solution in the $R^4$ theory which are relevant for cosmological model building.

We study the dynamics of the scalar field Friedmann-Lemaitre-Robertson-Walker flat cosmological models within the framework of the unified dark matter (UDM) scenario. In this model we find that the main cosmological functions such as the scale factor of the Universe, the scalar field, the Hubble flow, and the equation of state parameter are defined in terms of hyperbolic functions. These analytical solutions can accommodate an accelerated expansion, equivalent to either the dark energy or the standard $\Lambda$ models. Performing a joint likelihood analysis of the recent supernovae type Ia data and the baryonic acoustic oscillations traced by the Sloan Digital Sky Survey galaxies, we place tight constraints on the main cosmological parameters of the UDM cosmological scenario. Finally, we compare the UDM scenario with various dark energy models namely $\Lambda$ cosmology, parametric dark energy model and variable Chaplygin gas. We find that the UDM scalar field model provides a large and small scale dynamics which are in fair agreement with the predictions by the above dark energy models although there are some differences especially at high redshifts.

Quantum fast-roll initial conditions for the inflaton which are different from the classical fast-roll conditions and from the quantum slow-roll conditions can lead to inflation that lasts long enough. These quantum fast-roll initial conditions for the inflaton allow for kinetic energies of the same order of the potential energies and nonperturbative inflaton modes with nonzero wave numbers. Their evolution starts with a transitory epoch where the redshift due to the expansion succeeds to assemble the quantum excited modes of the inflaton in a homogeneous (zero mode) condensate, and the large value of the Hubble parameter succeeds to overdamp the fast roll of the redshifted inflaton modes. After this transitory stage the effective classical slow-roll epoch is reached. Most of the e-folds are produced during the slow-roll epoch, and we recover the classical slow-roll results for the scalar and tensor metric perturbations plus corrections. These corrections are important if scales which are horizon size today exited the horizon by the end of the transitory stage and, as a consequence, the lower cosmic microwave background (CMB) multipoles get suppressed or enhanced. Both for scalar and tensor metric perturbations, fast roll leads to a suppression of the amplitude of the perturbations (and of the low CMB multipoles), while the quantum precondensate epoch gives an enhancement of the amplitude of the perturbations (and of the low CMB multipoles). These two types of corrections can compete and combine in a scale dependent manner. They turn out to be smaller in new inflation than in chaotic inflation. These corrections arise as natural consequences of the quantum nonperturbative inflaton dynamics, and can allow a further improvement of the fitting of inflation plus the $\Lambda \mathrm{CMB}$ model to the observed CMB spectra. In addition, the corrections to the tensor metric perturbations will provide an independent test of this model. Thus, the effects of quantum inflaton fast-roll initial conditions provide a consistent and contrastable model for the origin of the suppression of the quadrupole and for other departures of the low CMB multipoles from the slow-roll inflation-$\Lambda \mathrm{CMB}$ model, which are to be contrasted with the TE and EE multipoles and with the forthcoming and future CMB data.

Gauge mediation models have two drawbacks, that is, the so-called $\mu$ problem and a lack of predictability of the gravitino dark matter abundance. We show that conformal sequestering in the supersymmetry breaking sector offers attractive solutions to both problems. The correct mass scale of the $\mu$ and $B_{\mu }$ terms is generated by taking the gravitino mass of $\mathcal{O}(100)\mathrm{GeV}$. This opens up a possibility that a neutralino, instead of gravitino, is the lightest supersymmetric particle and a candidate for dark matter, even in the gauge mediation. Surprisingly, a large anomalous dimension of the supersymmetry breaking field can naturally realize the small stau and neutralino mass difference required for the coannihilation to work yielding the right abundance of the neutralino dark matter.

We present results for the top quark pair cross section at the Tevatron and the LHC. We use the resummed double differential cross section, employing the fully kinematics-dependent soft-anomalous-dimension matrices, to calculate the soft-gluon contributions at next-to-next-to-leading order (NNLO). We improve and update our previous estimates by refining our methods, including further subleading terms, and employing the most recent parton distribution function sets. The NNLO soft corrections significantly enhance the NLO cross section while considerably reducing the scale dependence. We provide a detailed discussion of all theoretical uncertainties in our calculation, including kinematics, scale, and parton distribution uncertainties, and clarify the differences between our work and other approaches in the literature.

We investigate the physics potential of the NuSOnG experiment to probe new physics contributions to $Z\nu \nu$ couplings in muon-neutrino-electron elastic and neutral-current deep-inelastic scattering processes. We employ an effective Lagrangian approach and do not a priori assume universality of the coupling of neutrinos to $Z$. We obtain 95% C.L. limits on possible universality violating couplings.