In this article, we take the point of view that the pentaquark state ${\Theta }^{+}(1540)$ has negative parity, and choose the diquark-triquark type interpolating current to calculate the strong coupling constant $g_{\Theta NK}$ in the QCD sum rules approach. Our numerical results indicate the values of the strong coupling constant $g_{\Theta NK}$ are very small, $|g_{\Theta NK}|=0.175\pm 0.084$, and the width is ${\Gamma }_{\Theta }<4\mathrm{MeV}$, which can explain the narrow width $\Gamma \le 10\mathrm{MeV}$ naturally.

We present a measurement of the parameters of the ${\rm Y}(10580)$ resonance based on a dataset collected with the BABAR detector at the SLAC PEP-II asymmetric $B$ factory. We measure the total width ${\Gamma }_{\mathrm{tot}}=(20.7\pm 1.6\pm 2.5)\mathrm{MeV}$, the electronic partial width ${\Gamma }_{ee}=(0.321\pm 0.017\pm 0.029)\mathrm{keV}$ and the mass $M=(10579.3\pm 0.4\pm 1.2)\mathrm{MeV}/c^2$.

We search for $B^{-}\to {\tilde{D}}^0{K}^{-}$ and $B^{-}\to {\tilde{D}}^{*0}{K}^{-}$ and charge conjugates. Here the symbol ${\tilde{D}}^0$ indicates decay of a $D^0$ or ${\overline{D}}^0$ into $K^{+}{\pi }^{-}$, while the symbol ${\tilde{D}}^{*0}$ indicates decay of a $D^{*0}$ or ${\overline{D}}^{*0}$ to ${\tilde{D}}^0{\pi }^0$ or ${\tilde{D}}^0\gamma$. These final states can be reached through the $b\to c$ transition $B^{-}\to D^{(*)0}{K}^{-}$ followed by the doubly Cabibbo-Kobayashi-Maskawa (CKM)-suppressed $D^0\to K^{+}{\pi }^{-}$, or the $b\to u$ transition $B^{-}\to {\overline{D}}^{(*)0}{K}^{-}$ followed by the CKM-favored ${\overline{D}}^0\to K^{+}{\pi }^{-}$. The interference of these two amplitudes is sensitive to the angle $\gamma$ of the unitarity triangle. Our results are based on $232\times {10}^6$ ${\rm Y}(4S)\to B\overline{B}$ decays collected with the BABAR detector at SLAC. We find no significant evidence for these decays. We set a limit $r_B\equiv |A(B^{-}\to {\overline{D}}^0{K}^{-})/A(B^{-}\to D^0{K}^{-})|<0.23$ at 90% C.L. using the most conservative assumptions on the values of the CKM angle $\gamma$ and the strong phases in the $B$ and $D$ decay amplitudes. In the case of the $D^{*}$ we set a 90% C.L. limit $r_B^{*2}\equiv |A(B^{-}\to {\overline{D}}^{*0}{K}^{-})/A(B^{-}\to D^{*0}{K}^{-}){|}^2<(0.16{)}^2$ which is independent of assumptions on $\gamma$ and strong phases.

We propose a scenario in which the cosmological domain wall and monopole problems are solved without any fine tuning of the initial conditions or parameters in the Lagrangian of an underlying filed theory. In this scenario domain walls sweep out (unwind) the monopoles from the early universe, then the fast primordial black holes perforate the domain walls, change their topology and destroy them. We find further that the (old vacuum) energy density released from the domain walls could alleviate but not solve the cosmological flatness problem.

We consider the familiar junction conditions described by Israel for thin timelike walls in Einstein-Hilbert gravity. One such condition requires the induced metric to be continuous across the wall. Now, there are many spacetimes with sources confined to a thin wall for which this condition is violated and the Israel formalism does not apply. However, we explore the conjecture that the induced metric is in fact continuous for any thin wall which models spacetimes containing only positive energy matter. Thus, the usual junction conditions would hold for all positive energy spacetimes. This conjecture is proven in various special cases, including the case of static spacetimes with spherical or planar symmetry as well as settings without symmetry which may be sufficiently well approximated by smooth spacetimes with well-behaved null geodesic congruences.

We study the stability of static spherically symmetric exact solutions of Einstein equations coupled with nonlinear electrodynamics, in the magnetic sector. These solutions satisfy the heuristic model proposed by Ashtekar, Corichi, and Sudarsky for hairy black holes, meaning that the horizon mass is related to their Arnowitt-Deser-Misner (ADM) mass and to the corresponding particlelike solution. We test the unstability conjecture that emerges for hairy black holes and it turned out that it becomes confirmed except for the Einstein-Born-Infeld solutions.

The “in-in” formalism is reviewed and extended, and applied to the calculation of higher-order Gaussian and non-Gaussian correlations in cosmology. Previous calculations of these correlations amounted to the evaluation of tree graphs in the in-in formalism; here we also consider loop graphs. It turns out that for some though not all theories, the contributions of loop graphs as well as tree graphs depend only on the behavior of the inflaton potential near the time of horizon exit. A sample one-loop calculation is presented.

We discuss the flow equations in the context of general braneworld cosmologies with a modified Friedmann equation, for either an ordinary scalar field or a Dirac-Born-Infeld tachyon as inflaton candidates. The 4D, Randall-Sundrum, and Gauss-Bonnet cases are compared, using the patch formalism which provides a unified description of these models. The inflationary dynamics is described by a tower of flow parameters that can be evolved in time to select a particular subset of points in the space of cosmological observables. We analyze the stability of the fixed points in all the cosmologies (our results in the 4D case already extending those in the literature). Numerical integration of the flow equations shows that the predictions of the Gauss-Bonnet braneworld differ significantly as compared to the Randall-Sundrum and 4D scenarios, whereas tachyon inflation gives tensor perturbations smaller than those in the presence of a normal scalar field. These results are extended to the realization of a noncommutative space-time preserving maximal symmetry. In this case the tensor-to-scalar signal is unchanged, while blue-tilted spectra are favored.

We study a baryogenesis mechanism operating in the context of hyperextended inflation and making use of a coupling between the scalar field and a standard model global current, such as $B$ or $B-L$. The method is efficient at temperatures at which these currents are not conserved due to some higher dimensional operator. The particle physics and cosmological phenomenology are discussed. We consider constraints stemming from nucleosynthesis and solar system experiments.

We show that brane-induced gravity can be realized as a low energy effective theory of brane worlds with asymmetric warped compactification. A self-accelerating universe without cosmological constant on the brane can be realized in a model where one side of the bulk has finite volume, but the other side has infinite volume. The spin-2 perturbations for brane-induced gravity and asymmetric warped compactification models have the same spectrum at low energies. For a de Sitter brane, the spin-2 graviton has mass in the range $0<m^2\le 2H^2$, with $m^2=2H^2$ in the self-accelerating universe.

We systematically analyze the primordial non-Gaussianity estimator used by the Wilkinson Microwave Anisotropy Probe (WMAP) science team with the basic ideas of estimation theory in order to see if the limited cosmic microwave background (CMB) data is being optimally utilized. The WMAP estimator is based on the implicit assumption that the CMB bispectrum, the harmonic transform of the three-point correlation function, contains all of the primordial non-Gaussianity information in a CMB map. We first demonstrate that the signal-to-noise $(S/N)$ of an estimator based on CMB three-point correlation functions is significantly larger than the $S/N$ of any estimator based on higher-order correlation functions; justifying our choice to focus on the three-point correlation function. We then conclude that the estimator based on the three-point correlation function, which was used by WMAP, is optimal, meaning it saturates the Cramer-Rao inequality when the underlying CMB map is nearly Gaussian. We quantify this restriction by demonstrating that the suboptimal character of our estimator is proportional to the square of the fiducial non-Gaussianity, which is already constrained to be extremely small, so we can consider the WMAP estimator to be optimal in practice. Our conclusions do not depend on the form of the primordial bispectrum, only on the observationally established weak levels of primordial non-Gaussianity.

We study the spontaneous breaking of discrete symmetries in theories with broken gauge symmetry. The intended application is to $CP$ breaking in theories with gauged flavor symmetries, but the analysis described here is preliminary. We dispense with matter fields and take the gauge theory to be weakly coupled and broken spontaneously by unspecified, short-distance forces. We develop an effective-field-theory description of the resultant low-energy theory, and ask whether this theory by itself can describe the subsequent breaking of discrete symmetries. We conclude that this can happen depending on the parameters of the effective theory, and that the intrinsic violation is naturally of order unity.

We study the effects of new-physics contributions to $B\to \pi \pi$ decays, which can be parametrized as four new complex quantities. A simple analysis is provided by utilizing the reparametrization invariance of the decay amplitudes. We find that six quantities can be reabsorbed into the definitions of Standard Model-like parameters. As a result, the usual isospin analysis provides only two constraints on new physics which are independent of estimates for the Standard Model contributions. In particular, we show that one is not sensitive to new physics affecting the $I=0$ amplitudes. On the other hand, $I=2$ new physics can be detected, and its parameters can be measured by using independent determinations of the weak phases. We obtain constraints on these new-physics parameters through a fit to the current experimental data.

We investigate the mass spectrum of the pentaquark baryon ($udud\overline{s}$) in quenched lattice QCD with exact chiral symmetry. Using three different interpolating operators for $\Theta$, we measure the $3\times 3$ correlation matrix and obtain the eigenvalues $A^{\pm }(t)$ with $\pm$ parity for 100 gauge configurations generated with Wilson gauge action at $\beta =6.1$ on the ${20}^3\times 40$ lattice. For the lowest-lying $J^P=1/2^{-}$ state, its mass is almost identical to that of the $KN$ $s$ wave, while for the lowest-lying $J^P=1/2^{+}$ state, its mass is smaller than that of the $KN$ $p$ wave, especially for the regime $m_u<m_s$. By chiral extrapolation (linear in $m_{\pi }^2$) to $m_{\pi }=135\mathrm{MeV}$, we obtain the masses of the lowest-lying states: $m(1/2^{-})=1424(57)\mathrm{MeV}$ and $m(1/2^{+})=1562(121)\mathrm{MeV}$, in agreement with the masses of $m_K+m_N\simeq 1430\mathrm{MeV}$ and ${\Theta }^{+}(1540)$, respectively.

We present the first results for lattice QCD at finite temperature $T$ and chemical potential $\mu$ with four flavors of Wilson quarks. The calculations are performed using the imaginary chemical potential method at $\kappa =0,0.001,0.15,0.165,0.17\mathrm{and}0.25$, where $\kappa$ is the hopping parameter, related to the bare quark mass $m$ and lattice spacing $a$ by $\kappa =1/(2ma+8)$. Such a method allows us to do large scale Monte Carlo simulations at imaginary chemical potential $\mu =i{\mu }_I$. By analytic continuation of the data with ${\mu }_I<\pi T/3$ to real values of the chemical potential, we expect at each $\kappa \in [0,{\kappa }_{\mathrm{chiral}}]$, a phase transition line on the $(\mu ,T)$ plane, in a region relevant to the search for quark-gluon plasma in heavy-ion collision experiments. The transition is first order at small or large quark mass, and becomes a crossover at intermediate quark mass.

We present a calculation of the next-to-leading order QCD corrections to the partonic cross sections contributing to single-inclusive high-$p_T$ hadron production in collisions of transversely polarized hadrons. We use a recently developed projection technique for treating the phase-space integrals in the presence of the $\cos (2\Phi )$ azimuthal-angular dependence associated with transverse polarization. Our phenomenological results show that the double-spin asymmetry $A_{\mathrm{TT}}^{\pi }$ for neutral-pion production is expected to be very small for polarized $pp$ scattering at RHIC and could be much larger for the proposed experiments with an asymmetric $\overline{p}p$ collider at the GSI.

The effects of charmed meson loops on the spectrum of charmonium are considered, with special attention paid to the levels above open-charm threshold. It is found that the coupling to charmed mesons generates a structure at the $D{\overline{D}}^{*}$ threshold in the $1^{++}$ partial wave. The implications for the nature of the $X(3872)$ state are discussed.

We discuss the possibilities of high precision measurement of the solar neutrino mixing angle ${\theta }_{\odot }\equiv {\theta }_{12}$ in solar and reactor neutrino experiments. The improvements in the determination of ${sin}^2{\theta }_{12}$, which can be achieved with the expected increase of statistics and reduction of systematic errors in the currently operating solar and KamLAND experiments, are summarized. The potential of LowNu $\nu -e$ elastic scattering experiment, designed to measure the $pp$ solar neutrino flux, for high precision determination of ${sin}^2{\theta }_{12}$, is investigated in detail. The accuracy in the measurement of ${sin}^2{\theta }_{12}$, which can be achieved in a reactor experiment with a baseline $L\sim (50–70)\mathrm{km}$, corresponding to a survival probability minimum (SPMIN), is thoroughly studied. We include the effect of the uncertainty in the value of ${sin}^2{\theta }_{13}$ in the analyses. A LowNu measurement of the $pp$ neutrino flux with a 1% error would allow to determine ${sin}^2{\theta }_{12}$ with an error of 14% (17%) at $3\sigma$ from a two-generation (three-generation) analysis. The same parameter ${sin}^2{\theta }_{12}$ can be measured with an uncertainty of 2% (6%) at $1\sigma$ ($3\sigma$) in a reactor experiment with $L\sim 60\mathrm{km}$, statistics of $\sim 60$ GWkTy and systematic error of 2%. For the same statistics, the increase of the systematic error from 2% to 5% leads to an increase in the uncertainty in ${sin}^2{\theta }_{12}$ from 6% to 9% at $3\sigma$. The inclusion of the ${sin}^2{\theta }_{13}$ uncertainty in the analysis changes the error on ${sin}^2{\theta }_{12}$ to 3% (9%). The effect of ${sin}^2{\theta }_{13}$ uncertainty on the ${sin}^2{\theta }_{12}$ measurement in both types of experiments is considerably smaller than naively expected.

We discuss the relation between the absolute neutrino mass scale, the effective mass measured in neutrinoless double beta decay, and the Majorana $CP$ phases. Emphasis is placed on estimating the upper bound on the nuclear matrix element entering calculations of the double beta decay half-life. Combining the claimed evidence for neutrinoless double beta decay with the neutrino mass bound from cosmology, one of the Majorana $CP$ phases can be constrained.

We study $e^{+}{e}^{-}\to J/\psi c\overline{c}$ by measuring the invariant mass distribution recoiling against fully reconstructed $J/\psi$ decays, using $124{\mathrm{fb}}^{-1}$ of data collected at a center-of-mass energy of 10.6 GeV with the BABAR detector. We observe signals for ${\eta }_c(1S)$, ${\chi }_{c0}$, and ${\eta }_c(2S)$ in the recoil mass distribution, thus confirming previous measurements. We measure $\sigma (e^{+}{e}^{-}\to J/\psi +c\overline{c})\mathcal{B}(c\overline{c}\to >2\mathrm{\text{charged}})$ to be $17.6\pm 2.8{(\mathrm{stat})}_{-2.1}^{+1.5}(\mathrm{syst})\mathrm{fb}$, $10.3\pm 2.5{(\mathrm{\text{stat}})}_{-1.8}^{+1.4}(\mathrm{\text{syst}})\mathrm{fb}$, and $16.4\pm 3.7{(\mathrm{\text{stat}})}_{-3.0}^{+2.4}(\mathrm{\text{syst}})\mathrm{fb}$ with $c\overline{c}={\eta }_c(1S)$, ${\chi }_{c0}$, and ${\eta }_c(2S)$, respectively.