We present a renormalizable fermion mass model based on the symmetry $Q_4$ that accommodates all fermion masses and mixing angles in both the quark and lepton sectors. It requires the presence of only four $SU(2)$ doublet scalar fields transforming nontrivially under the flavor symmetry and the assumption of an alignment between first and second generation Yukawa couplings. No right-handed neutrinos are present in the model and neutrino masses are generated radiatively through the introduction of two additional $SU(2)$ singlet fields charged under both hypercharge and lepton number.

We study the propagation of nonrelativistic bound states moving at constant velocity across a homogeneous thermal bath and we develop the effective field theory which is relevant in various dynamical regimes. We consider values of the velocity of the bound state ranging from moderate to highly relativistic and temperatures at all relevant scales smaller than the mass of the particles that form the bound state. In particular, we consider two distinct temperature regimes, corresponding to temperatures smaller or higher than the typical momentum transfer in the bound state. For temperatures smaller or of the order of the typical momentum transfer, we restrict our analysis to the simplest system, a hydrogenlike atom. We build the effective theory for this system first considering moderate values of the velocity and then the relativistic case. For large values of the velocity of the bound state, the separation of scales is such that the corresponding effective theory resembles the soft collinear effective theory (SCET). For temperatures larger than the typical momentum transfer we also consider muonic hydrogen propagating in a plasma which contains photons and massless electrons and positrons, so that the system resembles very much a heavy quarkonium in a thermal medium of deconfined quarks and gluons. We study the behavior of the real and imaginary part of the static two-body potential, for various velocities of the bound state, in the hard thermal loop approximation. We find that Landau damping ceases to be the relevant mechanism for dissociation from a certain critical velocity on, in favor of screening. Our results are relevant for understanding how the properties of heavy quarkonia states produced in the initial fusion of partons in the relativistic collision of heavy ions are affected by the presence of an equilibrated quark-gluon plasma.

Constructing supersymmetric extensions of higher-dimensional models can have several motivations; it is, for instance, necessary in the context of string theories. Studying the supersymmetric version of the well-motivated model proposed by Randall and Sundrum, with the Higgs boson localized on the so-called TeV-brane, is not trivial since singularities appear in the Higgs couplings. Those are regularized by the contribution from the exchange of infinite towers of Kaluza-Klein (KK) scalar modes with Dirichlet-Dirichlet boundary conditions. Here we first derive the regularized four-dimensional (4D) effective Higgs couplings and induced sfermion mass matrices. A general method is provided for this regularization, based on the completeness relation. The sfermion masses must be obtained either from integrating out the mentioned KK towers or by treating their mixing effects, depending on the cases. We then use the obtained Higgs couplings and sfermion masses for some phenomenological applications. On one side, we show at the one-loop level how all quadratic divergences in the Higgs mass cancel out for any cutoff, due to 5D supersymmetry (SUSY) and to 5D anomaly cancellation; the analytical way followed here also allows a justification of the infinite KK summation required for the so-called KK regularization in 5D SUSY, which has motivated a rich literature. On the other side, we show that a certain pattern of SUSY breaking in the bulk would allow one to distinguish experimentally the minimal SUSY model à la Randall and Sundrum with bulk matter from the minimal 4D SUSY model, in the scenario where only superpartners were produced at the Large Hadron Collider. In this SUSY-breaking context, two of the discriminating tests developed make use of some different features arising in the squark or slepton mass spectrum. The other distinctive supersymmetric Randall-Sundrum feature is the possibly larger (even dominant) Higgs boson decay branching ratios into sleptons, compared to the 4D minimal supersymmetric standard model. In the same SUSY-breaking framework, techniques for pinning down the presence of soft SUSY-breaking terms on the TeV-brane are also suggested, based on the analysis of top squark pair production at the International Linear Collider.

We study the possibility of relaxing the indirect limits on extra neutral vector bosons by their interplay with additional new particles. They can be systematically weakened, even below present direct bounds at colliders, by the addition of more vector bosons and/or scalars designed for this purpose. Otherwise, they appear to be robust.

Within an AdS/CFT inspired model of electroweak symmetry breaking, the effects of various boundary terms and modifications to the background are studied. The effect on the $\widehat{S}$ precision parameter is discussed, with particular attention to its sign and whether the theory is unitary when $\widehat{S}<0$. Connections between the various possible AdS slice models of symmetry breaking are discussed.

The SciBooNE Collaboration reports $K^{+}$ production cross section and rate measurements using high-energy daughter muon neutrino scattering data off the SciBar polystyrene (${\mathrm{C}}_8{\mathrm{H}}_8$) target in the SciBooNE detector. The $K^{+}$ mesons are produced by 8 GeV protons striking a beryllium target in Fermilab Booster Neutrino Beam line (BNB). Using observed neutrino and antineutrino events in SciBooNE, we measure $\frac{d^2\sigma }{dpd\Omega }=(5.34\pm 0.76)\mathrm{mb}/(\mathrm{GeV}/c\times \mathrm{sr})$ for $p+Be\to K^{+}+X$ at mean $K^{+}$ energy of 3.9 GeV and angle (with respect to the proton beam direction) of 3.7 degrees, corresponding to the selected $K^{+}$ sample. Compared to Monte Carlo predictions using previous higher energy $K^{+}$ production measurements, this measurement, which uses the NUANCE neutrino interaction generator, is consistent with a normalization factor of $0.85\pm 0.12$. This agreement is evidence that the extrapolation of the higher energy $K^{+}$ measurements to an 8 GeV beam energy using Feynman scaling is valid. This measurement reduces the error on the $K^{+}$ production cross section from 40% to 14%.

Contrary to the claims of P. Bender [preceding Comment, Phys. Rev. D 84, 028101 (2011).], we show that the effects discussed therein do not impose significant constraints on the design of atomic interferometer gravity wave detectors. These higher-order effects are subordinate to backgrounds discussed in S. Dimopoulos, et al. [Phys. Rev. D 78, 122002 (2008).], and can be mitigated with straightforward design approaches.

The use of laser interferometers for detecting and studying gravitational-wave signals from many types of astronomical sources is being pursued actively by a number of groups in different countries. However, it has been suggested recently that cooled atom clouds in atom interferometers could be used to replace the test masses in space-based gravitational-wave detectors and the end mirrors in ground-based detectors [S. Dimopoulos, P. W. Graham, J. M. Hogan, M. A. Kasevich, and S. Rajendran, Phys. Rev. D 78, 122002 (2008).]. Some new error sources that apparently have not been included in proposals of atom interferometer gravitational-wave detectors will be discussed in this comment. They are based on additional effects of aberrations in the laser wave fronts that interact with the atom clouds.

We show how backreaction of the inflaton potential energy on heavy scalar fields can flatten the inflationary potential, as the heavy fields adjust to their most energetically favorable configuration. This mechanism operates in previous UV-complete examples of axion monodromy inflation—flattening a would-be quadratic potential to one linear in the inflaton field—but occurs more generally, and we illustrate the effect with several examples. Special choices of compactification minimizing backreaction may realize chaotic inflation with a quadratic potential, but we argue that a flatter potential such as power-law inflation $V(\varphi )\propto {\varphi }^p$ with $p<2$ is a more generic option at sufficiently large values of $\varphi$.

The Snyder model is an example of noncommutative spacetime admitting a fundamental length scale $\beta$ and invariant under Lorentz transformations, that can be interpreted as a realization of the doubly special relativity axioms. Here, we consider its nonrelativistic counterpart, i.e. the Snyder model restricted to three-dimensional Euclidean space. We discuss the classical and the quantum mechanics of a free particle in this framework, and show that they strongly depend on the sign of a coupling constant $\lambda$, appearing in the fundamental commutators and proportional to ${\beta }^2$. For example, if $\lambda$ is negative, momenta are bounded. On the contrary, for positive $\lambda$, positions and areas are quantized. We also give the exact solution of the harmonic oscillator equations both in the classical and the quantum case, and show that its frequency is energy dependent.

The QED trace anomaly is calculated at one-loop level based on the loop regularization method which is realized in 4-dimensional space-time and preserves gauge symmetry and Poincaré symmetry in spite of the introduction of two mass scales, namely, the ultraviolet (UV) cutoff $M_c$ and infrared (IR) cutoff ${\mu }_s$. It is shown that the dilation Ward identity which relates the three-point diagrams with the vacuum polarization diagrams gets the standard form of trace anomaly through quantum corrections in taking the consistent limit $M_c\to \infty$ and ${\mu }_s=0$ which recovers the original integrals. This explicitly demonstrates that the loop regularization method is indeed a self-consistent regularization scheme which is applicable to the calculations not only for the chiral anomaly but also for the trace anomaly, at least at one-loop level. It is also seen that the consistency conditions which relate the tensor-type and scalar-type irreducible loop integrals (ILIs) are crucial for obtaining a consistent result. As a comparison, we also present the one-loop calculations by using the usual Pauli-Villars regularization and the dimensional regularization.

We clarify the role of gauge invariance for the computation of quantum non-Gaussian correlators in inflation. A gauge invariant generating functional for $n$-point functions is given and the special status of the spatially flat gauge is pointed out. We also comment on the relation between gauge transformations, field redefinitions, the choice of $t=\mathrm{const}$ hypersurfaces and the use of boundary terms in computations of non-Gaussianity.

We study inclusive dipion decays using a sample of $108\times {10}^6{\rm Y}(3S)$ events recorded with the BABAR detector. We search for the decay mode ${\rm Y}(3S)\to {\pi }^{+}{\pi }^{-}{h}_b(1P)$ and find no evidence for the bottomonium spin-singlet state $h_b(1P)$ in the invariant mass distribution recoiling against the ${\pi }^{+}{\pi }^{-}$ system. Assuming the $h_b(1P)$ mass to be $9.900\mathrm{GeV}/c^2$, we measure the upper limit on the branching fraction $\mathcal{B}[{\rm Y}(3S)\to {\pi }^{+}{\pi }^{-}{h}_b(1P)]<1.2\times {10}^{-4}$, at 90% confidence level. We also investigate the ${\chi }_{bJ}(2P)\to {\pi }^{+}{\pi }^{-}{\chi }_{bJ}(1P)$, ${\rm Y}(3S)\to {\pi }^{+}{\pi }^{-}{\rm Y}(2S)$, and ${\rm Y}(2S)\to {\pi }^{+}{\pi }^{-}{\rm Y}(1S)$ dipion transitions and present an improved measurement of the branching fraction of the ${\rm Y}(3S)\to {\pi }^{+}{\pi }^{-}{\rm Y}(2S)$ decay and of the ${\rm Y}(3S)-{\rm Y}(2S)$ mass difference.

In the framework of the induced matter theory of gravity, we derive a five-dimensional solution of the field equations that can describe a four-dimensional cosmological scenario where the dark fluid (dark matter plus dark energy) equation of state has a geometrical origin. There is not a natural separation of the dark sector into different components, and so the model may provide a geometrical explanation for the existence of a dark degeneracy in cosmological scenarios.

We study tunneling between vacua in multidimensional field spaces in the thin wall approximation. The thin wall action generically gives rise to two types of saddle points. The first type corresponds to the well-known spherical instantons, but when the field space is multidimensional we find that it is necessary to include codimension two junctions to regulate and compute the fluctuation determinant and the tunneling rate. The second type of saddle point is novel and is present only when the field space is more than one dimensional. These saddle points have two or more negative modes, which confirms that in the presence of additional field directions spherical instantons continue to dominate vacuum decay. We identify regimes in parameter space in which additional field directions may quench certain channels of vacuum decay.

Motivated by recent works of Neyrinck et al. 2009 and Scherrer et al. 2010, we proposed a Gaussian transformation to Gaussianize the non-Gaussian lensing convergence field $\kappa$. It performs a local monotonic transformation $\kappa \to y$ pixel by pixel to make the fine-scale one-point probability distribution function of the new variable $y$ Gaussian. We tested whether the whole $y$ field is Gaussian through $N$-body simulations. (1) We found that the proposed Gaussianization suppresses the non-Gaussianity by orders of magnitude, in measures of the skewness, the kurtosis, the 5th- and 6th-order cumulants of the $y$ field smoothed over various angular scales, relative to that of the corresponding smoothed $\kappa$ field. The residual non-Gaussianities are often consistent with zero within the statistical errors. (2) The Gaussianization significantly suppresses the bispectrum. Furthermore, the residual scatters about zero, depending on the configuration in the Fourier space. (3) The Gaussianization works with even better performance for the 2D fields of the matter density projected over $\sim 300h^{-1}\mathrm{Mpc}$ distance interval centered at $z\in (0,2)$, which can be reconstructed from the weak lensing tomography. (4) We identified imperfectness and complexities of the proposed Gaussianization. We noticed weak residual non-Gaussianity in the $y$ field. We verified the widely used logarithmic transformation as a good approximation to the Gaussian transformation. However, we also found noticeable deviations.

We use cosmological constraints from current data sets and a figure of merit approach in order to probe any deviations from general relativity at cosmological scales. The figure of merit approach is used to study and compare the constraining power of various combinations of data sets on the modified gravity (MG) parameters. We use the recently refined HST-COSMOS weak-lensing tomography data, the ISW-galaxy cross correlations from 2MASS and SDSS luminous red galaxy surveys, the matter power spectrum from SDSS-DR7 (MPK), the WMAP7 temperature and polarization spectra, the baryon acoustic oscillations from Two-Degree Field and SDSS-DR7, and the Union2 compilation of type Ia supernovae, in addition to other bounds from Hubble parameter measurements and big bang nucleosynthesis. We use three parametrizations of MG parameters that enter the perturbed field equations. In order to allow for variations of the parameters with the redshift and scale, the first two parametrizations use recently suggested functional forms while the third is based on binning methods. Using the first parametrization, we find that the $\mathrm{CMB}+\mathrm{ISW}+\mathrm{WL}$ combination provides the strongest constraints on the MG parameters followed by $\mathrm{CMB}+\mathrm{WL}$ or $\mathrm{CMB}+\mathrm{MPK}+\mathrm{ISW}$. Using the second parametrization or the binning methods, we find that the combination $\mathrm{CMB}+\mathrm{MPK}+\mathrm{ISW}$ consistently provides some of the strongest constraints. This shows that the constraints are parametrization dependent. We find that adding up current data sets does not improve consistently the uncertainties on MG parameters due to tensions between the best-fit MG parameters preferred by different data sets. Furthermore, some functional forms imposed by the parametrizations can lead to an exacerbation of these tensions. Next, unlike some studies that used the CFHTLS lensing data, we do not find any deviation from general relativity using the refined HST-COSMOS data, confirming previous claims in those studies that their result may have been due to some systematic effect. Finally, for all the parametrizations and binning methods used, we find that the values corresponding to general relativity are within the 95% confidence level contours for all data set combinations.

The different ground-state energies of $N$-pion and $M$-kaon systems for $N+M\le 12$ are studied in lattice QCD. These energies are then used to extract the various two- and three-body interactions that occur in these systems. Particular attention is paid to additional thermal states present in the spectrum because of the finite temporal extent. These calculations are performed using one ensemble of $2+1$ flavor anisotropic lattices with a spatial lattice spacing $a_s\sim 0.125\mathrm{fm}$, an anisotropy factor $\xi =a_s/a_t=3.5$, and a spatial volume $L^3\sim (2.5\mathrm{fm}{)}^3$. The quark masses used correspond to pion and kaon masses of $m_{\pi }\sim 383\mathrm{MeV}$ and $m_K\sim 537\mathrm{MeV}$, respectively. The isospin and strangeness chemical potentials of these systems are found to be in the region where chiral perturbation theory and hadronic models predict a phase transition between a pion-condensed phase and a kaon-condensed phase.

The existing predictions for the like-sign dimuon charge asymmetry at the Tevatron are expressed in terms of parameters related to $B$ mesons’ mixing and inclusive production fractions. We show that in the realistic case when phase-space cuts are applied, the asymmetry depends also on the details of the production mechanism for the $B$ mesons. In particular, it is sensitive to the difference in the fragmentation functions of $B_d^0$ and $B_s^0$ mesons. We estimate these fragmentation effects and find that they shift the theory prediction for this observable by approximately 10%. We also point out the approximately 20% sensitivity of the asymmetry depending on which set of values for the $B$ meson production fractions is used: as measured at the $Z$ pole or at the Tevatron. The impact of these effects on the extraction of $A_{\mathrm{SL}}^s$ from the D0 measurement is presented.

We study the photon-triggered light and heavy meson production in both $\mathrm{p}+\mathrm{p}$ and $\mathrm{A}+\mathrm{A}$ collisions. We find that a parton energy loss approach that successfully describes inclusive hadron attenuation in nucleus-nucleus reactions at RHIC can simultaneously describe well the experimentally determined photon-triggered light hadron fragmentation functions. Using the same framework, we generalize our formalism to study photon-triggered heavy meson production. We find that the nuclear modification of photon-tagged heavy meson fragmentation functions in $\mathrm{A}+\mathrm{A}$ collision is very different from that of the photon-tagged light hadron case. While photon-triggered light hadron fragmentation functions in $\mathrm{A}+\mathrm{A}$ collisions are suppressed relative to $\mathrm{p}+\mathrm{p}$, photon-triggered heavy meson fragmentation functions can be either enhanced or suppressed, depending on the specific kinematic region. The anticipated smaller energy loss for $b$-quarks manifests itself as a flatter photon-triggered $B$-meson fragmentation function compared to that for the $D$-meson case. We make detailed predictions for both RHIC and LHC energies. We conclude that a comprehensive comparative study of both photon-tagged light and heavy meson production can provide new insights in the details of the jet quenching mechanism.