A recent study indicates that the ${\alpha }^2{\alpha }_s^2$ order QED processes of ${\rm Y}\to J/\psi +X$ decay are compatible with those of QCD processes. However, in the endpoint region, the nonrelativistic QED calculation breaks down since the collinear degrees of freedom are missing under the framework of this effective theory. In this paper we apply the soft-collinear effective theory (SCET) to study the color-singlet QED process at the kinematic limit. Within this approach we are able to sum the kinematic logarithms by running operators using the renormalization group equations of soft-collinear effective theory, which will lead to a dramatic change in the momentum distribution near the endpoint and the spectrum shape consistent with the experimental results.

We present a Monte Carlo approach to prompt-photon production, where photons and QCD partons are treated democratically. The photon fragmentation function is modeled by an interleaved $\mathrm{QCD}+\mathrm{QED}$ parton shower. This known technique is improved by including higher-order real-emission matrix elements. To this end, we extend a recently proposed algorithm for merging matrix elements and truncated parton showers. We exemplify the quality of the Monte Carlo predictions by comparing them to measurements of the photon fragmentation function at LEP and to measurements of prompt photon and diphoton production from the Tevatron experiments.

In this paper we consider a sequential “meson emission” mechanism for charmonium decays of the type $\Psi \to N\overline{N}m$, where $\Psi$ is a generic charmonium state, $N$ is a nucleon, and $m$ is a light meson. This decay mechanism, which may not be dominant in general, assumes that an $N\overline{N}$ pair is created during charmonium annihilation, and the light meson $m$ is emitted from the outgoing nucleon or antinucleon line. A straightforward generalization of this model can incorporate intermediate $N^{*}$ resonances. We derive Dalitz plot event densities for the cases $\Psi ={\eta }_c$, $J/\psi$, ${\chi }_{c0}$, ${\chi }_{c1}$, and ${\psi }^{\prime }$; and $m={\pi }^0$, $f_0$, and $\omega$ (and implicitly, any $0^{-+}$, $0^{++}$, or $1^{--}$ final light meson). It may be possible to separate the contribution of this decay mechanism to the full decay amplitude through characteristic event densities. For the decay subset $\Psi \to p\overline{p}{\pi }^0$ the two model parameters are known, so we are able to predict absolute numerical partial widths for $\Gamma (\Psi \to p\overline{p}{\pi }^0)$. In the specific case $J/\psi \to p\overline{p}{\pi }^0$ the predicted partial width and $M_{p\pi }$ event distribution are intriguingly close to experiment. We also consider the possibility of scalar meson and glueball searches in $\Psi \to p\overline{p}{f}_0$. If the meson emission contributions to $\Psi \to N\overline{N}m$ decays can be isolated and quantified, they can be used to estimate meson-nucleon strong couplings $\{g_{NNm}\}$, which are typically poorly known, and are a crucial input in meson exchange models of the $NN$ interaction. The determination of $g_{NN\pi }$ from $J/\psi \to p\overline{p}{\pi }^0$ and the (poorly known) $g_{NN\omega }$ and the anomalous “strong magnetic” coupling ${\kappa }_{NN\omega }$ from $J/\psi \to p\overline{p}\omega$ are considered as examples.

We present results for the moments of observed spectra in inclusive semileptonic $B$-meson decays to charm hadrons $\overline{B}\to X_c{\ell }^{-}\overline{\nu }$. Moments of the hadronic-mass and the combined mass-and-energy spectra for different minimum electron or muon momenta between 0.8 and $1.9\mathrm{GeV}/c$ are obtained from a sample of $232\times {10}^6$ ${\rm Y}(4S)\to B\overline{B}$ events, collected with the BABAR detector at the PEP-II asymmetric-energy $B$-meson factory at SLAC. We also present a reevaluation of the moments of electron-energy spectra and partial decay fractions $\mathcal{B}(\overline{B}\to X_c{e}^{-}\overline{\nu })$ for minimum electron momenta between 0.6 and $1.5\mathrm{GeV}/c$ based on a sample of $51\times {10}^6$ ${\rm Y}(4S)\to B\overline{B}$ events. The measurements are used for the extraction of the total decay fraction, the Cabibbo-Kobayashi-Maskawa (CKM) matrix element $|V_{cb}|$, the quark masses $m_b$ and $m_c$, and four heavy-quark QCD parameters in the framework of a Heavy-Quark Expansion (HQE). We find $\mathcal{B}(\overline{B}\to X_c{\ell }^{-}\overline{\nu })=(10.64\pm 0.17\pm 0.06)\%$ and $|V_{cb}|=(42.05\pm 0.45\pm 0.70)\times {10}^{-3}$.

In strong magnetic fields the transport coefficients of strange quark matter become anisotropic. We determine the general form of the complete set of transport coefficients in the presence of a strong magnetic field. By using a local linear response method, we calculate explicitly the bulk viscosities ${\zeta }_{\perp }$ and ${\zeta }_{\parallel }$ transverse and parallel to the $B$ field, respectively, which arise due to the nonleptonic weak processes $u+s\leftrightarrow u+d$. We find that for magnetic fields $B<{10}^{17}\mathrm{G}$, the dependence of ${\zeta }_{\perp }$ and ${\zeta }_{\parallel }$ on the field is weak, and they can be approximated by the bulk viscosity for the zero magnetic field. For fields $B>{10}^{18}\mathrm{G}$, the dependence of both ${\zeta }_{\perp }$ and ${\zeta }_{\parallel }$ on the field is strong, and they exhibit de Haas–van Alphen–type oscillations. With increasing magnetic field, the amplitude of these oscillations increases, which eventually leads to negative ${\zeta }_{\perp }$ in some regions of parameter space. We show that the change of sign of ${\zeta }_{\perp }$ signals a hydrodynamic instability. As an application, we discuss the effects of the new bulk viscosities on the $r$-mode instability in rotating strange quark stars. We find that the instability region in strange quark stars is affected when the magnetic fields exceed the value $B={10}^{17}\mathrm{G}$. For fields which are larger by an order of magnitude, the instability region is significantly enlarged, making magnetized strange stars more susceptible to $r$-mode instability than their unmagnetized counterparts.

Using the method of perturbative quantization in the first order approximation, we quantize a nonlocal QED-like theory including fermions and bosons whose interactions are described by terms containing higher order space-time derivatives. As an example, the two-dimensional space-time noncommutative QED (NC-QED) is quantized perturbatively up to $\mathcal{O}(e^2,{\theta }^3)$, where $e$ is the NC-QED coupling constant and $\theta$ is the noncommutativity parameter. The resulting modified Lagrangian density is shown to include terms consisting of first order time-derivative and higher order space-derivatives of the modified field variables that satisfy the ordinary equal-time commutation relations up to $\mathcal{O}(e^2,{\theta }^3)$. Using these commutation relations, the canonical current algebra of the modified theory is also derived.

We revisit the production of cosmic rays by cusps on cosmic strings. If a scalar field (“Higgs”) has a linear interaction with the string world sheet, such as would occur if there is a bosonic condensate on the string, cusps on string loops emit narrow beams of very high energy Higgses which then decay to give a flux of ultrahigh energy cosmic rays. The ultrahigh energy flux and the gamma to proton ratio agree with observations if the string scale is $\sim {10}^{13}\mathrm{GeV}$. The diffuse gamma ray and proton fluxes are well below current bounds. Strings that are lighter and have linear interactions with scalars produce an excess of direct and diffuse cosmic rays and are ruled out by observations, while heavier strings ($\sim {10}^{15}\mathrm{GeV}$) are constrained by their gravitational signatures. This leaves a narrow window of parameter space for the existence of cosmic strings with bosonic condensates.

We suggest a path-integral formulation for the tunneling cosmological state, which admits a consistent renormalization and renormalization group improvement in particle physics applications of quantum cosmology. We apply this formulation to the inflationary cosmology driven by the standard model Higgs boson playing the role of an inflaton with a strong nonminimal coupling to gravity. In this way a complete cosmological scenario is obtained, which embraces the formation of initial conditions for the inflationary background in the form of a sharp probability peak in the distribution of the inflaton field and the ongoing generation of the cosmic microwave background (CMB) spectrum on this background. Formation of this probability peak is based on the same renormalization group mechanism which underlies the generation of the CMB spectrum which was recently shown to be compatible with the WMAP data in the Higgs mass range $135.6\mathrm{GeV}\lesssim M_{\mathrm{H}}\lesssim 184.5\mathrm{GeV}$. This brings to life a convincing unification of quantum cosmology with the particle phenomenology of the standard model, inflation theory, and CMB observations.

We estimate the rates of lepton flavor violating decays of the vector mesons $\rho$, $\omega$, and $\varphi \to e\mu$. The theoretical tools are based on an effective Lagrangian approach without referring to any specific realization of the physics beyond the standard model responsible for lepton flavor violation (${\mathrm{L̸}}_f$). The effective lepton-vector meson couplings are extracted from the existing experimental bounds on the nuclear ${\mu }^{-}-e^{-}$ conversion. In particular, we derive an upper limit for the ${\mathrm{L̸}}_f$ branching ratio $\mathrm{Br}(\varphi \to e\mu )\le 1.3\times {10}^{-21}$ which is much more stringent than the recent experimental result $\mathrm{Br}(\varphi \to e\mu )<2\times {10}^{-6}$ presented by the SND Collaboration. Very tiny limits on ${\mathrm{L̸}}_f$ decays of vector mesons derived in this paper make direct experimental observation of these processes unrealistic.

We discuss central exclusive production (CEP) of the tensor ${\chi }_c(2^{+})$ meson in proton-(anti)proton collisions at Tevatron, RHIC, and LHC energies. The amplitude for the process is derived within the $k_t$-factorization approach. Differential and total cross sections are calculated for several unintegrated gluon distribution functions (UGDFs). We compare exclusive production of all charmonium states ${\chi }_c(0^{+})$, ${\chi }_c(1^{+})$ and ${\chi }_c(2^{+})$. Good description of the recent Tevatron data is achieved both with Martin-Ryskin phenomenological UGDF and UGDF based on unified BFKL-DGLAP approach. Unlike for Higgs production, the main contribution to the diffractive amplitude of heavy quarkonia comes from nonperturbative region of gluon transverse momenta $Q_{\perp }<1\mathrm{GeV}$. At $y\approx 0$, depending on UGDF we predict the contribution of ${\chi }_c(1^{+},2^{+})$ to the $J/\Psi +\gamma$ channel to be comparable or larger than that of the ${\chi }_c(0^{+})$ one. This is partially due to a significant contribution from lower polarization states $\lambda =0$ for ${\chi }_c(1^{+})$ and $\lambda =0$, $\pm 1$ for ${\chi }_c(2^{+})$ meson. Corresponding theoretical uncertainties are discussed.

Recently, spherically symmetric, static wormholes supported by exotic dust and a radial magnetic field have been derived and argued to be stable with respect to linear radial fluctuations. In this report we point out that these wormholes are unstable due to the formation of shell-crossing singularities when the nonlinearities of the theory are taken into account.

In this paper we study the one- and two-loop contribution to the free energy in QED with Lorentz symmetry breaking introduced via constant $CPT$-even Lorentz-breaking parameters at the high temperature limit. We find the impact of the Lorentz-violating term for the free energy and carry out a numerical estimation for the Lorentz-breaking parameter.

Motivated by the increasing interest in models which consider scalar fields as viable dark matter candidates, we have constructed a generalization of relativistic boson btars (BS) composed of two coexisting states of the scalar field, the ground state and the first excited state. We have studied the dynamical evolution of these multistate boson stars (MSBS) under radial perturbations, using numerical techniques. We show that stable MSBS can be constructed, when the number of particles in the first excited state, $N^{(2)}$, is smaller than the number of particles in the ground state, $N^{(1)}$. On the other hand, when $N^{(2)}>N^{(1)}$, the configurations are initially unstable. However, they evolve and settle down into stable configurations. In the stabilization process, the initially ground state is excited and ends in a first excited state, whereas the initially first excited state ends in a ground state. During this process, both states emit scalar field radiation, decreasing their number of particles. This behavior shows that even though BS in the first excited state are intrinsically unstable under finite perturbations, the configuration resulting from the combination of this state with the ground state produces stable objects. Finally we show in a qualitative way, that stable MSBS could be realistic models of dark matter galactic halos, as they produce rotation curves that are flatter at large radii than the rotation curves produced by BS with only one state.

Under certain conditions, we offer a new way to prove the uniqueness of the static black hole in higher dimensional asymptotically flat spacetimes. In the proof, the Penrose inequality plays a key role in higher dimensions as well as four dimensions.

In this paper, we explore some features of $f–g$ theory in three dimensions. We show that the theory has both anti–de Sitter and de Sitter solutions, the wave solutions in both cases are also obtained. In particular, at a critical value of the coupling constant, we see that the model admits log gravity solutions, reminiscent of topologically massive gravity and new massive gravity. We have also studied a class of exact static spherically symmetric black hole solutions in the model.

Using the recently proposed new solution generating technique, we construct the charged version of the Pomeranski-Senkov doubly rotating black ring in the $U(1{)}^3$ five-dimensional supergravity. For arbitrary values of charges the solution is unbalanced, but the Dirac-Misner string is removed when two of the charges are set to zero. In this particular case our solution can be uplifted to some solutions of six-dimensional vacuum gravity.

We construct nonstationary exact solutions to five-dimensional Einstein-Maxwell-Chern-Simons theory with positive cosmological constant. The solutions are based on four-dimensional Atiyah-Hitchin space. In asymptotic regions, the solutions approach Gibbons-Perry-Sorkin monopole solutions. On the other hand, near the four-dimensional bolt of Atiyah-Hitchin space, our solutions show a bolt structure in five dimensions. The $c$ function for the solutions shows monotonic increase in time, in agreement with the general expected behavior of the $c$ function in asymptotically de Sitter spacetimes.

We consider the renormalization of general gauge theories on curved space-time background, with the main assumption being the existence of a gauge-invariant and diffeomorphism invariant regularization. Using the Batalin-Vilkovisky formalism, one can show that the theory possesses gauge invariant and diffeomorphism invariant renormalizability at quantum level, up to an arbitrary order of the loop expansion. Starting from this point, we discuss the locality of the counterterms and the general prescription for constructing the power-counting renormalizable theories on curved background.

We measure the skewness power spectrum of the CMB anisotropies optimized for a detection of the secondary bispectrum generated by the correlation of the CMB lensing potential with integrated Sachs-Wolfe effect and the Sunyaev-Zel’dovich effect. The covariance of our measurements is generated by Monte Carlo simulations of Gaussian CMB fields with noise properties consistent with WMAP 5-year data. When interpreting multifrequency measurements we also take into account the confusion resulting from unresolved radio point sources. We analyze Q, V and W-band WMAP 5-year raw and foreground-cleaned maps using the KQ75 mask out to $l_{\max }=600$. We find no significant evidence for a nonzero non-Gaussian signal from the lensing-secondary correlation in all three bands and we constrain the overall amplitude of the cross-power spectrum between CMB lensing potential and the sum of SZ and ISW fluctuations to be $0.42\pm 0.86$ and $1.19\pm 0.86$ in combined V and W-band raw and foreground-cleaned maps provided by the WMAP team, respectively. The point-source amplitude at the bispectrum level measured with this skewness power spectrum is higher than previous measurements of point-source non-Gaussianity. We also consider an analysis where we also account for the primordial non-Gaussianity in addition to lensing-secondary bispectrum and point sources. The focus of this paper is on secondary anisotropies. Consequently the estimator is not optimized for primordial non-Gaussianity and the limit we find on local non-Gaussianity from the foreground-cleaned $\mathrm{V}+\mathrm{W}$ maps is $f_{\mathrm{NL}}=-13\pm 62$, when marginalized over point sources and lensing-ISW/SZ contributions to the total bispectrum.