A supersymmetric extension of the standard model, with maximal ${\tilde{s}}_R$–${\tilde{b}}_R$ mixing and a new source of $CP$ violation, contains all the necessary ingredients to account for a possible anomaly in the measured $CP$ asymmetry in $B\to \varphi K_S$ decay. In the same framework we study the decay $B\to J/\psi K^{*}$, paying particular attention to observables that can be extracted by performing a time-dependent angular analysis, and become nonzero because of new physics effects.

The properties of the momentum space quark propagator in Landau gauge and Gribov copy free Laplacian gauge are studied for the overlap quark action in quenched lattice QCD. Numerical calculations are done on two lattices with different lattice spacing $a$ and the same physical volume. We have calculated the nonperturbative wave-function renormalization function $Z(q)$ and the nonperturbative mass function $M(p)$ for a variety of bare quark masses and perform a simple linear extrapolation to the chiral limit. We focus on the comparison of the behavior of $Z(q)$ and $M(p)$ in the chiral limit in the two gauge fixing schemes as well as the behavior on two lattices with different lattice spacing $a$. We find that the mass functions $M(p)$ are very similar for the two gauges while the wave-function renormalization function $Z(q)$ is more strongly infrared suppressed in the Laplacian gauge than in the Landau gauge on the finer lattice. For Laplacian gauge, it seems that the finite $a$ error is large on the coarse lattice which has a lattice spacing $a$ of about 0.124 fm.

We present the results of a nonrelativistic constituent quark model study of the semileptonic decays ${\Lambda }_b^0\to {\Lambda }_c^{+}{l}^{-}{\overline{\nu }}_l$ and ${\Xi }_b^0\to {\Xi }_c^{+}{l}^{-}{\overline{\nu }}_l$ ($l=e,\mu$). We work on coordinate space, with baryon wave functions recently obtained from a variational approach based on heavy quark symmetry. We develop a novel expansion of the electroweak current operator, which supplemented with heavy quark effective theory constraints, allows us to predict the baryon form factors and the decay distributions for all $q^2$ (or equivalently $w$) values accessible in the physical decays. Our results for the partially integrated longitudinal and transverse decay widths, in the vicinity of the $w=1$ point, are in excellent agreement with lattice calculations. Comparison of our integrated ${\Lambda }_b$-decay width to experiment allows us to extract the $V_{cb}$ Cabbibo-Kobayashi-Maskawa matrix element for which we obtain a value of $|V_{cb}|=0.040\pm 0.005(\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t}{)}_{-0.002}^{+0.001}(\mathrm{t}\mathrm{h}\mathrm{e}\mathrm{o}\mathrm{r}\mathrm{y})$ also in excellent agreement with a recent determination by the DELPHI Collaboration from the exclusive ${\overline{\mathrm{B}}}_{\mathrm{d}}^0\to {\mathrm{D}}^{*+}{l}^{-}{\overline{\nu }}_l$ decay. Besides for the ${\Lambda }_b({\Xi }_b)$-decay, the longitudinal and transverse asymmetries and the longitudinal to transverse decay ratio are $⟨a_L⟩=-0.954\pm 0.001(-0.945\pm 0.002)$, $⟨a_T⟩=-0.665\pm 0.002(-0.628\pm 0.004)$, and $R_{L/T}=1.63\pm 0.02(1.53\pm 0.04)$, respectively.

We compute free energy of quark matter at asymptotically high baryon number density in the presence of nonzero strange quark mass including dynamics of pseudo Nambu-Goldstone bosons due to chiral symmetry breaking, extending previously existing analysis based on perturbative expansion in $m_s^2/4\mu \Delta .$ We demonstrate that the $\mathrm{C}\mathrm{F}\mathrm{L}{K}^0$ state has lower free energy than the symmetric CFL state for $0<m_s^2/4\mu \Delta <2/3$. We also calculate the spectrum of the fermionic quasiparticle excitations about the kaon condensed ground state in the regime $m_s^2/4\mu \Delta \sim 1$ and find that $(m_s^2/4\mu \Delta {)}_{\mathrm{c}\mathrm{r}\mathrm{i}\mathrm{t}}=2/3$ for the CFL-gCFL phase transition, the leading order result reported in [20], is not modified.

We revisit the computation of the 1-loop ${\mathrm{A}\mathrm{d}\mathrm{S}}_5\times S^5$ superstring sigma model correction to the energy of a closed circular string rotating in $S^5$. The string is spinning around its center of mass with two equal angular momenta $J_2=J_3$ and its center of mass angular momentum is $J_1$. We revise the argument that the 1-loop correction is suppressed by $\frac{1}{J}$ factor [$J=J_1+2J_2$ is the total SO(6) spin] relative to the classical $\frac{\lambda J_2}{J^2}$ term in the energy and use numerical methods to compute the leading 1-loop coefficient. The corresponding gauge-theory result is known only in the $J_1=0$ limit when the string solution becomes unstable and thus the 1-loop shift of the energy formally contains an imaginary part. While the comparison with gauge-theory may not be well defined in this case, our numerical string-theory value of the 1-loop coefficient seems to disagree with the gauge-theory one. A plausible explanation should be in the different order of limits taken on the gauge-theory and the string-theory sides of the anti-de Sitter/conformal field theory duality.

We investigate the quasinormal mode frequencies for the massless Dirac field in static four dimensional $AdS$ space-time. The separation of the Dirac equation is achieved for the first time in $AdS$ space. Besides the relevance that this calculation can have in the framework of the $AdS/CFT$ correspondence between M-theory on $Ad{S}_4\times S^7$ and $\mathrm{S}\mathrm{U}(N)$ super Yang-Mills theory on $M_3$, it also serves to fill in a gap in the literature, which has only been concerned with particles of integral spin $0,1,2$.

We consider the evolution of cosmological perturbations during radion stabilization, which we assume to happen after a period of inflation in the early universe. Concentrating on the Randall-Sundrum brane world scenario, we find that, if matter is present both on the positive and negative tension branes, the coupling of the radion to matter fields could have significant impact on the evolution of the curvature perturbation and on the production of entropy perturbations. We investigate both the case of a long-lived and a short-lived radion and outline similarities and differences to the curvaton scenario.

Belle data for the $\pi \pi$ mass spectrum in $X(3872)\to {\pi }^{+}{\pi }^{-}J/\Psi$ are well fitted by $\rho +J/\Psi$ with $J^{PC}=1^{++}$, but are poorly fitted by the $\pi \pi$ S-wave. This rules out quantum numbers $1^{+-}$, $2^{--}$ and $3^{--}$. Formulas for partial wave amplitudes are given for all likely $J^{PC}$ and decay modes of the 3941 MeV peak which Belle observe in $\omega +J/\Psi$. Angular correlations involving up to five angles may allow a spin-parity determination, even with quite low statistics. Special attention is given to the case where $X(3872)$ is a cusp or quasi-bound state with the same quantum numbers as the 3941 MeV peak.

Using the $1/N_c$ expansion of QCD, we analyze the spectrum of positive parity resonances with strangeness $S=0$, $-1$, $-2$, and $-3$ in the 2–3 GeV mass region, supposed to belong to the $[\mathbf{56},4^{+}]$ multiplet. The mass operator is similar to that of $[\mathbf{56},2^{+}]$, previously studied in the literature. The analysis of the latter is revisited. In the $[\mathbf{56},4^{+}]$ multiplet we find that the spin-spin term brings the dominant contribution and that the spin-orbit term is entirely negligible in the hyperfine interaction, in agreement with constituent quark model results. More data are strongly desirable, especially in the strange sector in order to fully exploit the power of this approach.

Implications of the recent new measurements of $B\to K_1\gamma$ by Belle are examined. It is shown that the new branching ratio $\mathcal{B}[B\to K_1(1270)\gamma ]$ requires very large form factor compared to the theoretically predicted one. This is an opposite case to $B\to K^{*}\gamma$ where theory expected larger branching ratio. Possible origins of the discrepancy are discussed.

The feasibility of tetraquark detection is studied. For the $cc\overline{u}\overline{d}$ tetraquark we show that in present (SELEX, Tevatron, RHIC) and future facilities (LHCb, ALICE) the production rate is promising and we propose some detectable decay channels.

Light strongly interacting supersymmetric particles may be treated as partonic constituents of nucleons in high energy scattering processes. We construct parton distribution functions for protons in which a light gluino is included along with standard model quark, antiquark, and gluon constituents. A global analysis is performed of a large set of data from deep-inelastic lepton scattering, massive lepton pair and vector boson production, and hadron jet production at large values of transverse momentum. Constraints are obtained on the allowed range of gluino mass as a function of the value of the strong coupling strength ${\alpha }_s(M_Z)$ determined at the scale of the $Z$ boson mass. We find that gluino masses as small as 10 GeV are admissible provided that ${\alpha }_s(M_Z)\ge 0.12$. Current hadron scattering data are insensitive to the presence of gluinos heavier than $\sim 100–150\mathrm{G}\mathrm{e}\mathrm{V}$.

We study photoproduction and radiative decays of pentaquarks paying particular attention to the differences between spin-$1/2$ and spin-$3/2$, positive and negative parities of pentaquarks. Detailed study of these processes can not only give crucial information about the spin, but also the parity of pentaquarks.

We present measurements of ${\mathcal{R}}_{\mathrm{K}\ell 3\gamma }\equiv \Gamma ({\mathrm{K}}_{\mathrm{L}}\to {\pi }^{\pm }{\ell }^{\mp }\nu \gamma ;{\mathrm{E}}_{\gamma }^{\star }>10\mathrm{M}\mathrm{e}\mathrm{V})/\Gamma ({\mathrm{K}}_{\mathrm{L}}\to {\pi }^{\pm }{\ell }^{\mp }\nu )$, where $\ell =\mu$ or $e$, and ${\mathrm{E}}_{\gamma }^{\star }$ is the photon energy in the kaon rest frame. These measurements are based on $K_L$ decays collected in 1997 by the KTeV (E832) experiment at Fermilab. With samples of 1385 ${\mathrm{K}}_{\mathrm{L}}\to {\pi }^{\pm }{\mu }^{\mp }\nu \gamma$ and 14221 ${\mathrm{K}}_{\mathrm{L}}\to {\pi }^{\pm }{\mathrm{e}}^{\mp }\nu \gamma$ candidates, we find ${\mathcal{R}}_{\mathrm{K}\mu 3\gamma }=(0.530\pm 0.019)\%$ and ${\mathcal{R}}_{\mathrm{K}\mathrm{e}3\gamma }=(4.942\pm 0.062)\%$. We also examine distributions of photon energy and lepton-photon angle.

We calculate the masses of the $1^{-+}$ four quark states which decay dominantly into $\rho \pi$ and $\eta \pi$, respectively, by QCD sum rules approach. We include the zero mode contribution and find it plays an important role in the sum rules. We predict that the masses of the states $\eta \pi$ and $\rho \pi$ both are 1.4–1.5 GeV. This is close to the experimental candidates ${\pi }_1(1370)$ and ${\pi }_1(1440)$.

I study the charmed $uudd\overline{c}$ resonance $D^{*-}p(3100)$ very recently discovered by H1 Collaboration at HERA, using a standard quark model with a quark-antiquark annihilation constrained by chiral symmetry. I find that repulsion excludes the $D^{*-}p(3100)$ as a $uudd\overline{c}$ $s$-wave pentaquark. I explore the $D^{*-}p(3100)$ as a heptaquark, equivalent to a $N-\pi -D^{*}$ borromean linear molecule, with positive parity and total isospin $I=0$. I find that the $N-D$ repulsion is canceled by the attraction existing in the $N-\pi$ and $\pi -D$ channels. Multiquark molecules $N-\pi -D$, $N-\pi -B^{*}$, and $N-\pi -B$ are also predicted.

We will address the question of the consistency of teleparallel theories in presence of spinning matter which has been a controversial subject of discussion over the last 20 years. We argue that the origin of the problem is not simply the symmetry or asymmetry of the stress-energy tensor of the matter fields, which has been recently analyzed by several authors, but arises at a more fundamental level, namely, from the invariance of the field equations under a frame change, a problem that has been discussed long time ago by Kopczynski in the framework of the teleparallel equivalent of general relativity. More importantly, we show that the problem is not only confined to the purely teleparallel theory but arises actually in every Poincaré gauge theory that admits a teleparallel geometry in the absence of spinning sources, i.e., in its classical limit.

We study cosmological solutions in the context of four-dimensional low energy heterotic M theory with moving bulk branes. First we present nontrivial, analytic axion solutions generated by new symmetries of the full potential-free action, and we discuss their relation to “triple axion” solutions found in Pre-Big-Bang cosmologies. Next we consider the presence of a nonperturbative superpotential with and without a background perfect fluid. In the absence of a fluid the dilaton and the $T$-modulus go to the potential-free solutions at late time, while the moving brane tries to avoid colliding with the boundary and stabilize within the bulk. When the fluid is included the dynamics of the fields change, and we study their behavior both numerically and analytically. In particular we examine the possibility of this setup being a realization of the quintessential scenario and the impact of the fluid on the cosmological stabilization of the moduli.

In this paper we present several ideas toward the solution to the giant graviton puzzle—the apparent multiplicity of supergravity states dual to field theory chiral primary operators. We use the fact that, for certain ranges of the angular momentum, giant gravitons can be mapped into vacua of a dual theory to argue that the sphere and AdS giant gravitons have very different boundary descriptions and that an unpolarized Kaluza Klein graviton is unphysical in the regime where giant gravitons exist. We also show that a generic boundary state can correspond to different giant graviton configurations, which have nonoverlapping ranges of validity.

We find renormalization group transformations for the compactified Randall-Sundrum scenario by integrating out an infinitesimal slice of ultraviolet degrees of freedom near the Planck brane. Under these transformations the coefficients of operators on the Planck brane experience RG evolution. The extra-dimensional radius also scales, flowing to zero in the IR. We find an attractive fixed point in the context of a bulk scalar field theory. Calculations are simplified in the low energy effective theory as we demonstrate with the computation of a loop diagram.