The BABAR Collaboration has pointed out that $D^0\to {\pi }^{+}{\pi }^{-}{\pi }^0$ is dominated by an isospin-zero final state, leading to nearly complete depletion of the Dalitz plot along all three diagonals. In flavor-SU(3) approaches to charmed particle decays to a light vector and a light pseudoscalar particle, this behavior is seen, but does not appear to have a fundamental origin. Instead, it arises as a result of approximate cancellation of higher-isospin combinations of several types of amplitudes: color-favored tree, color-suppressed tree, and exchange. Interpretation in terms of a direct-channel effect would require an exotic resonance, with spin, parity, and charge-conjugation eigenvalues $J^{PC}=0^{--}$.

We recalculated the coupling constants of $\rho (\omega )\to \eta \gamma$ and ${\eta }^{\prime }\to \rho (\omega )\gamma$ decays especially with loop contributions in the case of axial-vector coupling in the method of QCD sum rules for dimension $d=6$. A comparison of our prediction on the coupling constants with the result obtained from analysis of the experimental data and calculations done before is performed.

We perform fits to the available charged and neutral kaon-production data in $e^{+}+e^{-}\to K+X$, $K=K^{\pm }$, and $K_S^0$, and determine the nonsinglet combination of kaon fragmentation functions $D_u^{K^{\pm }}-D_d^{K^{\pm }}$ in a model independent way and without any correlations to the other fragmentation functions. Only nuclear isospin invariance is assumed. Working with nonsinglets allows us to include the data at very low momentum fractions, which have so far been excluded in global fits, and to perform a first next-next-to leading order fit to fragmentation functions. We find that the kaon nonsinglet fragmentation function at large $z$ is larger than that obtained by the other collaborations from global fit analysis and differs significantly at low $z$.

The computation of the $\mathcal{O}({\alpha }_s)$ QCD corrections to the cross sections for $W^{+}{W}^{-}\gamma$ and $ZZ\gamma$ production in hadronic collisions is presented. We consider the case of a real photon in the final state, but include full leptonic decays of the $W$ and $Z$ bosons. Numerical results for the LHC and the Tevatron are obtained through a fully flexible parton level Monte Carlo program based on the structure of the VBFNLO program, allowing an easy implementation of arbitrary cuts and distributions. We show the dependence on scale variations of the integrated cross sections and provide evidence that next-to-leading order (NLO) QCD corrections strongly modify the LO predictions for observables at the LHC both in magnitude and in shape.

This paper presents predictions for jet pseudorapidity ($\eta$) and transverse momentum ($p_T$) distributions for the production of the standard model Higgs boson in association with a high-$p_T$ hadronic jet. We discuss the contributions of electroweak loops and of bottom-quark parton processes to the cross section. The latter arise in the five-flavor scheme. Predictions for the Tevatron and the Large Hadron Collider with 10 TeV collision energy are presented. For Higgs boson masses of 120 GeV, 160 GeV, and 200 GeV, we find the maximal effects of the electroweak contributions to the Higgs plus jet $p_T$ and $\eta$ distribution to be $-13\%$ and $-4.8\%$, respectively, for the Tevatron, and $-2.6\%$ and $-1.9\%$, respectively, for the LHC. For the maximal contribution of bottom-quark parton processes to the $p_T$ and $\eta$ distribution, we find $+2.5\%$ and $+2\%$, respectively, for the Tevatron, and $+3.3\%$ and $+2.8\%$, respectively, for the LHC. A separate study of the $\mathrm{\text{Higgs}}+b$-jet cross section demonstrates that a calculational approach which respects the hierarchies of Yukawa couplings yields a leading-order cross section prediction which is more accurate in the high-$p_T$ regime than conventional approaches.

In this work we present an analysis of the one-loop Slavnov-Taylor identities in noncommutative ${\mathrm{QED}}_4$. The vectorial fermion-photon and the triple photon vertex functions were studied, with the conclusion that no anomalies arise.

The Planck spectrum of thermal scalar radiation is derived suggestively within classical physics by the use of an accelerating coordinate frame. The derivation has an analogue in Boltzmann’s derivation of the Maxwell velocity distribution for thermal particle velocities by considering the thermal equilibrium of noninteracting particles in a uniform gravitational field. For the case of radiation, the gravitational field is provided by the acceleration of a Rindler frame through Minkowski spacetime. Classical zero-point radiation and relativistic physics enter in an essential way in the derivation, which is based upon the behavior of free radiation fields and the assumption that the field correlation functions contain but a single correlation time in thermal equilibrium. The work has connections with the thermal effects of acceleration found in relativistic quantum field theory.

Dark matter in the form of weakly interacting massive particles is predicted to become gravitationally captured and accumulate in stars. While the subsequent annihilations of such particles lead to the injection of energy into stellar cores, elastically scattering dark matter particles do not generally yield enough energy to observably impact stellar phenomenology. Dark matter particles that scatter inelastically with nuclei (such that they reconcile the annual modulation reported by DAMA with the null results of CDMS and other experiments), however, can be captured by and annihilate in compact stars at a much higher rate. As a result, old white dwarf stars residing in high dark matter density environments can be prevented from cooling below several thousand degrees Kelvin. Observations of old, cool white dwarfs in dwarf spheroidal galaxies, or in the inner kiloparsec of the Milky Way, can thus potentially provide a valuable test of the inelastic dark matter hypothesis.

Superheavy dark matter (SHDM) exchanges energy with its environment much slower than particles with masses close to the electroweak scale and has therefore different small-scale clustering properties. Using the neutralino as candidate for the SHDM, we find that free-streaming allows the formation of DM clumps of all masses down to $\sim 260m_{\chi }$ in the case of bino. If small-scale clumps evolve from a nonstandard, spiky spectrum of perturbations, DM clumps may form during the radiation-dominated era. These clumps are not destroyed by tidal interactions and can be extremely dense. In the case of a bino, a “gravithermal catastrophe” can develop in the central part of the most dense clumps, increasing further the central density and thus the annihilation signal. In the case of a Higgsino, the annihilation signal is enhanced by the Sommerfeld effect. As a result annihilations of superheavy neutralinos in dense clumps may lead to observable fluxes of annihilation products in the form of ultrahigh energy particles, for both cases, Higgsinos and binos, as lightest supersymmetric particles.

The formation and evolution of superdense clumps (or subhalos) is studied. Such clumps of dark matter (DM) can be produced by many mechanisms, most notably by spiky features in the spectrum of inflationary perturbations and by cosmological phase transitions. Being produced very early during the radiation-dominated epoch, superdense clumps evolve as isolated objects. They do not belong to hierarchical structures for a long time after production, and therefore they are not destroyed by tidal interactions during the formation of larger structures. For DM particles with masses close to the electroweak mass scale, superdense clumps evolve towards a power-law density profile $\rho (r)\propto r^{-1.8}$ with a central core. Superdense clumps cannot be composed of standard neutralinos, since their annihilations would overproduce the diffuse gamma radiation. If the clumps are constituted of superheavy DM particles and develop a sufficiently large central density, the evolution of their central part can lead to a “gravithermal catastrophe.” In such a case, the initial density profile turns into an isothermal profile with $\rho \propto r^{-2}$ and a new, much smaller core in the center. Superdense clumps can be observed by gamma radiation from DM annihilations and by gravitational wave detectors, while the production of primordial black holes and cascade nucleosynthesis constrain this scenario.

A large fraction of cosmological information on dark energy and gravity is encoded in the nonlinear regime. Precision cosmology thus requires precision modeling of nonlinearities in general dark energy and modified gravity models. We modify the Gadget-2 code and run a series of $N$-body simulations on modified gravity cosmology to study the nonlinearities. The modified gravity model that we investigate in the present paper is characterized by a single parameter $\zeta$, which determines the enhancement of particle acceleration with respect to general relativity (GR), given the identical mass distribution ($\zeta =1$ in GR). The first nonlinear statistics we investigate is the nonlinear matter power spectrum at $k\lesssim 3h/\mathrm{Mpc}$, which is the relevant range for robust weak lensing power spectrum modeling at $\ell \lesssim 2000$. In this study, we focus on the relative difference in the nonlinear power spectra at corresponding redshifts where different gravity models have the same linear power spectra. This particular statistics highlights the imprint of modified gravity in the nonlinear regime and the importance of including the nonlinear regime in testing GR. By design, it is less susceptible to the sample variance and numerical artifacts. We adopt a mass assignment method based on wavelet to improve the power spectrum measurement. We run a series of tests to determine the suitable simulation specifications (particle number, box size, and initial redshift). We find that, the nonlinear power spectra can differ by $\sim 30\%$ for 10% deviation from GR ($|\zeta -1|=0.1$) where the rms density fluctuations reach 10. This large difference, on one hand, shows the richness of information on gravity in the corresponding scales, and on the other hand, invalidates simple extrapolations of some existing fitting formulae to modified gravity cosmology.

We calculate contained and upward muon flux and contained shower event rates from neutrino interactions, when neutrinos are produced from annihilation of the dark matter in the Galactic center. We consider model-independent direct neutrino production and secondary neutrino production from the decay of taus, W bosons, and bottom quarks produced in the annihilation of dark matter. We illustrate how muon flux from dark matter annihilation has a very different shape than the muon flux from atmospheric neutrinos. We also discuss the dependence of the muon fluxes on the dark matter density profile and on the dark matter mass and of the total muon rates on the detector threshold. We consider both the upward muon flux, when muons are created in the rock below the detector, and the contained flux when muons are created in the (ice) detector. We also calculate the event rates for showers from neutrino interactions in the detector and show that the signal dominates over the background for $150\mathrm{GeV}<m_{\chi }<1\mathrm{TeV}$ for $E_{\mathrm{sh}}^{\mathrm{th}}=100\mathrm{GeV}$.

We update phenomenological constraints on a two Higgs doublet model with lepton flavor nonconserving Yukawa couplings. We review that $\tan \beta$ is ambiguous in such “type III” models, and define it from the $\tau$ Yukawa coupling. The neutral scalars $\varphi$ could be searched for at hadron colliders in $\varphi \to \tau \overline{\mu }$ and are constrained by the rare decay $\tau \to \mu \gamma$. The Feynman diagrams for the collider process, with Higgs production via gluon fusion, are similar to the two-loop “Barr-Zee” diagrams, which contribute to $\tau \to \mu \gamma$. Some “tuning” is required to obtain a collider cross section of order the standard model expectation for $\sigma (gg\to h_{\mathrm{SM}}\to {\tau }^{+}{\tau }^{-})$, while agreeing with the current bound from $\tau \to \mu \gamma$.

We clarify the relationship between the conclusions of the previous Comment of A. Helfer [A. Helfer, preceding Comment, Phys. Rev. D 81, 108501 (2010)] and that of our Brief Report [I. Agulló, J. Navarro-Salas, G. J. Olmo, and L. Parker, Phys. Rev. D 80, 047503 (2009).].

I point out that the cutoff introduced by Agulló et al. [I. Agulló, J. Navarro-Salas, G. J. Olmo, and L. Parker, Phys. Rev. D 80, 047503 (2009)] has little impact on the trans-Planckian problem as it is usually understood; it excludes only a small fraction of the problematic modes.

We provide a supersymmetric generalization of $n$ quantum bits by extending the local operations and classical communication entanglement equivalence group $[SU(2){]}^n$ to the supergroup $[uOSp(1|2){]}^n$ and the stochastic local operations and classical communication equivalence group $[SL(2,\mathbb{C}){]}^n$ to the supergroup $[OSp(1|2){]}^n$. We introduce the appropriate supersymmetric generalizations of the conventional entanglement measures for the cases of $n=2$ and $n=3$. In particular, super-Greenberger-Horne-Zeilinger states are characterized by a nonvanishing superhyperdeterminant.

We construct a simple $\mathcal{N}=(0,2)$ deformation of the two-dimensional Wess-Zumino model. In addition to superpotential, it includes a “twisted” superpotential. Supersymmetry may or may not be spontaneously broken at the classical level. In the latter case an extra right-handed fermion field ${\zeta }_R$ involved in the $\mathcal{N}=(0,2)$ deformation plays the role of Goldstino.

We perform an $\mathcal{O}({\alpha }_s^2)$ perturbative calculation of the equation of state of cold but dense QCD matter with two massless and one massive quark flavor, finding that perturbation theory converges reasonably well for quark chemical potentials above 1 GeV. Using a running coupling constant and strange quark mass, and allowing for further nonperturbative effects, our results point to a narrow range where absolutely stable strange quark matter may exist. Absent stable strange quark matter, our findings suggest that quark matter in (slowly rotating) compact star cores becomes confined to hadrons only slightly above the density of atomic nuclei. Finally, we show that equations of state including quark matter lead to hybrid star masses up to $M\sim 2M_{\odot }$, in agreement with current observations. For strange stars, we find maximal masses of $M\sim 2.75M_{\odot }$ and conclude that confirmed observations of compact stars with $M>2M_{\odot }$ would strongly favor the existence of stable strange quark matter.

It is shown that 21 cm intensity mapping could be used in the near term to make cosmologically useful measurements. Large scale structure could be detected using existing radio telescopes, or using prototypes for dedicated redshift survey telescopes. This would provide a measure of the mean neutral hydrogen density, using redshift space distortions to break the degeneracy with the linear bias. We find that with only 200 hours of observing time on the Green Bank Telescope, the neutral hydrogen density could be measured to 25% precision at redshift $0.54<z<1.09$. This compares favorably to current measurements, uses independent techniques, and would settle the controversy over an important parameter that impacts galaxy formation studies. In addition, a 4000 hour survey would allow for the detection of baryon acoustic oscillations, giving a cosmological distance measure at 3.5% precision. These observation time requirements could be greatly reduced with the construction of multiple pixel receivers. Similar results are possible using prototypes for dedicated cylindrical telescopes on month time scales, or Square Kilometre Array pathfinder aperture arrays on day time scales. Such measurements promise to improve our understanding of these quantities while beating a path for future generations of hydrogen surveys.