In this work we study the dynamical generation of mass in the massless $\mathcal{N}=1$ Wess-Zumino model in a three-dimensional spacetime. Using the tadpole method to compute the effective potential, we observe that supersymmetry is dynamically broken together with the discrete symmetry $A(x)\to -A(x)$. We show that this model, different from nonsupersymmetric scalar models, exhibits a consistent perturbative dynamical generation of mass after two-loop corrections to the effective potential.

We review the uncertainties in the spin-independent and spin-dependent elastic scattering cross sections of supersymmetric dark matter particles on protons and neutrons. We propagate the uncertainties in quark masses and hadronic matrix elements that are related to the $\pi$-nucleon $\sigma$ term and the spin content of the nucleon. By far the largest single uncertainty is that in spin-independent scattering induced by our ignorance of the $⟨N|\overline{q}q|N⟩$ matrix elements linked to the $\pi$-nucleon $\sigma$ term, which affects the ratio of cross sections on proton and neutron targets as well as their absolute values. This uncertainty is already impacting the interpretations of experimental searches for cold dark matter. We plead for an experimental campaign to determine better the $\pi$-nucleon $\sigma$ term. Uncertainties in the spin content of the proton affect significantly, but less strongly, the calculation of rates used in indirect searches.

A novel strategy to handle divergences typical of perturbative calculations is implemented for the Nambu–Jona-Lasinio model and its phenomenological consequences investigated. The central idea of the method is to avoid the critical step involved in the regularization process, namely, the explicit evaluation of divergent integrals. This goal is achieved by assuming a regularization distribution in an implicit way and making use, in intermediary steps, only of very general properties of such regularization. The finite parts are separated from the divergent ones and integrated free from effects of the regularization. The divergent parts are organized in terms of standard objects, which are independent of the (arbitrary) momenta running in internal lines of loop graphs. Through the analysis of symmetry relations, a set of properties for the divergent objects are identified, which we denominate consistency relations, reducing the number of divergent objects to only a few. The calculational strategy eliminates unphysical dependencies of the arbitrary choices for the routing of internal momenta, leading to ambiguity-free, and symmetry-preserving physical amplitudes. We show that the imposition of scale properties for the basic divergent objects leads to a critical condition for the constituent quark mass such that the remaining arbitrariness is removed. The model becomes predictive in the sense that its phenomenological consequences do not depend on possible choices made in intermediary steps. Numerical results are obtained for physical quantities at the one-loop level for the pion and sigma masses and pion-quark and sigma-quark coupling constants.

We study three-flavor collective neutrino transformations in the dense-neutrino region above the neutrino sphere of a supernova core. We find that two-flavor conversions driven by the atmospheric mass difference and the 13-mixing angle capture the full effect if one neglects the second-order difference between the ${\nu }_{\mu }$ and ${\nu }_{\tau }$ refractive index. Including this “mu-tau matter term” provides a resonance at a density of $\rho \approx 3\times {10}^7\mathrm{g}{\mathrm{cm}}^{-3}$ that typically causes significant modifications of the overall ${\nu }_e$ and ${\overline{\nu }}_e$ survival probabilities. This effect is surprisingly sensitive to deviations from maximal 23-mixing, being different for each octant.

Using the techniques of quasi-Hermitian quantum mechanics and quantum field theory we use a similarity transformation to construct an equivalent Hermitian Hamiltonian for the Lee model. In the field theory confined to the $V/N\theta$ sector it effectively decouples $V$, replacing the three-point interaction of the original Lee model by an additional mass term for the $V$ particle and a four-point interaction between $N$ and $\theta$. While the construction is originally motivated by the regime where the bare coupling becomes imaginary, leading to a ghost, it applies equally to the standard Hermitian regime where the bare coupling is real. In that case the similarity transformation becomes a unitary transformation.

We exploit the expression for the anomalous (chiral) effective action to obtain the Hawking radiation from a Garfinkle-Horowitz-Strominger (stringy) black hole falling in the class of the most general spherically symmetric black holes ($\sqrt{-g}\ne 1$), using only covariant boundary conditions at the event horizon. The connection between the anomalous and the normal energy-momentum tensors is also established from the effective action approach.

We develop an analytical model to study the production spectrum of loops in the cosmic string network. In the scaling regime, we find two different scales corresponding to large (one order below horizon) and small (few orders below horizon) loops. The very small (tiny) loops at the gravitational backreaction scale are absent, and thus, our model has no ultraviolet divergences. We calculate the spectrum of loops and derive analytical expressions for the positions and magnitudes of the small and large scale peaks. The small loops are produced by large bursts of similar loops moving with very high velocities in the same direction. We describe the shape of the large loops, which would usually consist of few kinks and few cusps per oscillation cycle. We also argue that the typical size of large loops is set by the correlation length, which does not depend on the intercommutation probability $p$, while the interstring distance scales as $p^{1/3}$.

We study the Friedmann equation for the warped codimension-two braneworld background which most closely resembles the Randall-Sundrum model. Extra matter on the (Planck) 4-brane, with equation of state $p_{\theta }=(\alpha -1)\rho$ for the azimuthal pressure, is required to satisfy the junction conditions. For $1<\alpha <5$, we show that there are two static solutions to the Einstein equations for given values of the brane stress-energies. Close to the static solutions, the relation between Hubble expansion rate $H$ and brane tension reproduces the standard 4D result for small $H$, but exhibits unusual deviations when $H$ is of order of the anti-de Sitter (AdS) curvature scale. The two static branches for $1<\alpha <5$ are shown to come together smoothly at a maximum value of $H$; however the radion is shown to be unstable in the branch with higher $H$. This remains true even with a mechanism for stabilization of the radion, i.e., the Goldberger-Wise (GW) mechanism, since large enough $H$ overcomes the force of stabilization. Even in the unstabilized case, cosmological constraints on the time and spatial variation of Newton’s constant are typically satisfied; only fifth-force constraints require the stabilization. For $\alpha >5$ the model is intrinsically stable, without the need for a GW field, and in this case we show that inflationary predictions can be modified by the nonstandard Friedmann equation; in particular, it is possible to get an upper limit on the spectral index, large deviations from the consistency condition between the tensor spectrum and ratio $r$, and large running of the spectral index even though the slow-roll parameters remain small.

We develop a new approach to study the nonlinear evolution in the large-scale structure of the Universe both in real space and in redshift space, extending the standard perturbation theory of gravitational instability. Infinite series of terms in standard Eulerian perturbation theory are resummed as a result of our starting from a Lagrangian description of perturbations. Delicate nonlinear effects on scales of the baryon acoustic oscillations are more accurately described by our method than the standard one. Our approach differs from other resummation techniques recently proposed, such as the renormalized perturbation theory, etc., in that we use simple techniques and thus resulting equations are undemanding to evaluate, and in that our approach is capable of quantifying the nonlinear effects in redshift space. The power spectrum and correlation function of our approach are in good agreement with numerical simulations in literature on scales of baryon acoustic oscillations. Especially, nonlinear effects on the baryon acoustic peak of the correlation function are accurately described both in real space and in redshift space. Our approach provides a unique opportunity to analytically investigate the nonlinear effects on baryon acoustic scales in observable redshift space, which is requisite in constraining the nature of dark energy, the curvature of the Universe, etc., by redshift surveys.

We describe the design and construction of a new apparatus for detecting or constraining deviations from Newtonian gravity at short length scales. The apparatus consists of a new type of probe with rotary mass actuation and cantilever-based force detection which is used to directly measure the force between two micromachined masses separated by tens of microns. We present the first data from the experiment, and discuss the prospects of more precisely constraining or detecting non-Newtonian effects using this probe. Currently, the sensitivity to attractive mass-dependent forces is equal to the best existing limits at length scales near $5\mu \mathrm{m}$. No non-Newtonian effects are detected at that level.

We study the behavior with the number of colors ($N_c$) of the two poles associated to the $\Lambda (1405)$ resonance obtained dynamically within the chiral unitary approach. The leading order chiral meson-baryon interaction manifests a nontrivial $N_c$ dependence for SU(3) baryons, which gives a finite attractive interaction in some channels in the large $N_c$ limit. As a consequence, the SU(3) singlet ($\overline{K}N$) component of the $\Lambda (1405)$ survives in the large $N_c$ limit as a bound state, while the other components dissolve into the continuum. The $N_c$ dependence of the decay widths shows different behavior from the general counting rule for a $qqq$ state, indicating the dynamical origin of the two poles for the $\Lambda (1405)$ resonance.

We study the flavor changing neutral current $B_s\to \varphi \gamma$, $\varphi \nu \overline{\nu }$ and ${\Lambda }_b\to \Lambda \gamma$, $\Lambda \nu \overline{\nu }$ transitions in the standard model and in a scenario with a single universal extra dimension. In particular, we focus on the present knowledge of the hadronic uncertainties and on possible improvements. We discuss how the measurements of these modes can be used to constrain the new parameter involved in the extra-dimensional scenario, the radius $R$ of the extra dimension, completing the information available from $B$-factories. The rates of these $b\to s$ induced decays are within the reach of new experiments, such as LHCb.

We consider a $3+1$ lattice QCD model with three quark flavors, local $\mathrm{SU}(3{)}_c$ gauge symmetry, global $\mathrm{SU}(3{)}_f$ flavor symmetry, in an imaginary-time formulation and with strong coupling (a small hopping parameter $\kappa >0$ and a plaquette coupling $\beta >0$, $0<\beta \ll \kappa \ll 1$). Associated with the model there is an underlying physical quantum mechanical Hilbert space $\mathcal{H}$ which, via a Feynman-Kac formula, enables us to derive spectral representations for correlations and obtain the low-lying energy-momentum spectrum exactly. Using the decoupling of hyperplane method and concentrating on the subspace ${\mathcal{H}}_e\subset \mathcal{H}$ of vectors with an even number of quarks, we obtain the one-particle spectrum showing the existence of 36 meson states from dynamical first principles, i.e. directly from the quark-gluon dynamics. The particles are detected by isolated dispersion curves $w(\overrightarrow{p})$ in the energy-momentum spectrum. Besides the $\mathrm{SU}(3{)}_f$ quantum numbers (total hypercharge, quadratic Casimir $C_2$, total isospin and its 3rd component), the basic excitations also carry spin labels. The total spin operator $J$ and its $z$-component $J_z$ are defined using $\pi /2$ rotations about the spatial coordinate axes and agree with the infinitesimal generators of the continuum for improper zero-momentum meson states. The eightfold way meson particles are given by linear combinations of these 36 states and can be grouped into three $\mathrm{SU}(3{)}_f$ nonets associated with the vector mesons ($J=1$, $J_z=0$, $\pm 1$) and one nonet associated with the pseudoscalar mesons ($J=0$). Each nonet admits a further decomposition into a $\mathrm{SU}(3{)}_f$ singlet ($C_2=0$) and an octet ($C_2=3$). For $\beta =0$, the particle dispersion curves are all of the form $w(\overrightarrow{p})=-2\ln \kappa -3{\kappa }^2/2+(1/4){\kappa }^2\sum _{j=1}^{3}2(1-\cos p^j)+{\kappa }^{4}r(\kappa ,\overrightarrow{p})$, with $\overrightarrow{p}\in (-\pi ,\pi {]}^3$ and $|r(\kappa ,\overrightarrow{p})|\le \mathrm{const}$. For the pseudoscalar mesons, $r(\kappa ,\overrightarrow{p})$ is jointly analytic in $\kappa$ and $p^j$, for $|\kappa |$ and $|\mathcal{I}\mathrm{m}{p}^j|$ small. At $\beta =0$ the meson masses are given by $m(\kappa )=-2\ln \kappa -3{\kappa }^2/2+{\kappa }^{4}r(\kappa )$, with $r(0)\ne 0$ and $r(\kappa )$ real analytic; for $\beta \ne 0$ the nonsingular part of the mass, $m(\kappa ,\beta )+2\ln \kappa$, is jointly analytic in $\kappa$ and $\beta$. For a fixed nonet, the mass of the vector mesons are independent of $J_z$ and are all equal within each octet. All singlet masses are also equal for the vector mesons. For $\beta =0$, up to and including $\mathcal{O}({\kappa }^4)$, for each nonet, the masses of the octet and the singlet are found to be equal. All members of each octet have identical dispersions. Other dispersion curves may differ. Indeed, there is a pseudoscalar, vector meson mass splitting (between $J=0$ and $J=1$) given by $2{\kappa }^4+\mathcal{O}({\kappa }^6)$ at $\beta =0$, analytic in $\beta$ and the splitting persists for $\beta \ll \kappa$. Using a correlation subtraction method, we show the 36 meson states give the only spectrum in ${\mathcal{H}}_e$ up to near the two-meson threshold of $\approx -4\ln \kappa$. Combining our present result with a similar one for baryons (of asymptotic mass $-3\ln \kappa$) shows that the model does exhibit confinement up to near the two-meson threshold.

We show that an intermediate scale supersymmetric left-right seesaw scenario with automatic $R$-parity conservation can cure the problem of tachyonic slepton masses that arise when supersymmetry is broken by anomaly mediation, while preserving ultraviolet insensitivity. The reason for this is the existence of light $B-L=2$ Higgses with Yukawa couplings to the charged leptons. We find these theories to have distinct predictions compared to the usual mSUGRA and gauge mediated models as well as the minimal anomaly mediated supersymmetry breaking models. Such predictions include a condensed gaugino mass spectrum and possibly a correspondingly condensed sfermion spectrum.

Anomalies in the large-scale cosmic microwave background (CMB) temperature sky measured by the Wilkinson Microwave Anisotropy Probe have been suggested as possible evidence for a violation of statistical isotropy on large scales. In any physical model for broken isotropy, there are testable consequences for the CMB polarization field. We develop simulation tools for predicting the polarization field in models that break statistical isotropy locally through a modulation field. We study two different models: dipolar modulation, invoked to explain the asymmetry in power between northern and southern ecliptic hemispheres, and quadrupolar modulation, posited to explain the alignments between the quadrupole and octopole. For the dipolar case, we show that predictions for the correlation between the first 10 multipoles of the temperature and polarization fields can typically be tested at better than the 98% CL. For the quadrupolar case, we show that the polarization quadrupole and octopole should be moderately aligned. Such an alignment is a generic prediction of explanations which involve the temperature field at recombination and thus discriminate against explanations involving foregrounds or local secondary anisotropy. Predicted correlations between temperature and polarization multipoles out to $\ell =5$ provide tests at the $\sim 99\%$ CL or stronger for quadrupolar models that make the temperature alignment more than a few percent likely. As predictions of anomaly models, polarization statistics move beyond the a posteriori inferences that currently dominate the field.

We consider the noncommutative standard model based on $SU(3)\times SU(2)\times U(1)$. We study the gauge transformation of right-handed neutrinos and its direct interaction with photons in the noncommutative space-time. We show that the massive Dirac neutrinos, through the Higgs mechanism, cannot accommodate this extension of the standard model, while the massive Majorana neutrinos are consistent with the gauge symmetry of the model. The electromagnetic properties and the dispersion relations for the neutrino in the noncommutative standard model is examined. We also compare the results with the noncommutative standard model based on $U(3)\times U(2)\times U(1)$.

In this article, we take the point of view that the bottomed $(0^{+},1^{+})$ mesons $B_{s0}$ and $B_{s1}$ are the conventional $b\overline{s}$ meson and calculate the strong coupling constants $g_{B_{s0}BK}$ and $g_{B_{s1}{B}^{*}K}$ with the light-cone QCD sum rules. The numerical values of strong coupling constants $g_{B_{s1}{B}^{*}K}$ and $g_{B_{s0}BK}$ are very large and support the hadronic dressing mechanism. Just like the scalar mesons $f_0(980)$, $a_0(980)$, $D_{s0}$ and axial-vector meson $D_{s1}$, the $(0^{+},1^{+})$ bottomed mesons $B_{s0}$ and $B_{s1}$ may have small $b\overline{s}$ kernels of the typical $b\overline{s}$ meson size. The strong couplings to the hadronic channels (or the virtual mesons loops) may result in smaller masses than the conventional $b\overline{s}$ mesons in the potential quark models and enrich the pure $b\overline{s}$ states with other components.

We study the phase diagram of the three flavor Polyakov-Nambu-Jona-Lasinio (PNJL) model and, in particular, the interplay between chiral symmetry restoration and deconfinement crossover. We compute chiral condensates, quark densities, and the Polyakov loop at several values of temperature and chemical potential. Moreover we investigate on the role of the Polyakov loop dynamics in the transition from nuclear matter to quark matter.

We have carried out a new evaluation of the eighth-order contribution to the electron $g-2$ using FORTRAN codes generated by an automatic code generator gencode$N$. Comparison of the new result with the old one has revealed an inconsistency in the treatment of the infrared divergences in the latter. With this error corrected we now have two independent determinations of the eighth-order term. This leads to the revised value $1159652182.79(7.71)\times {10}^{-12}$ of the electron $g-2$, where the uncertainty comes mostly from that of the best non-QED value of the fine structure constant $\alpha$. The new value of $\alpha$ derived from the revised theory and the latest experiment is ${\alpha }^{-1}=137.035999084(51)[0.37\mathrm{ppb}]$, which is about 4.7 ppb smaller than the previous ${\alpha }^{-1}$.

We extend previous work on the minimal D-term inflation model modified by right-handed (RH) sneutrino fields to include additional inflaton-sector supergravity corrections and two-field inflation effects. We show that supergravity corrections simultaneously allow $n_s$ to be within 3-year Wilkinson Microwave Anisotropy Probe limits and the cosmic string contribution to the cosmic microwave background (CMB) power spectrum to be less than 5%. For gauge coupling $g\le 1$, the CMB contribution from cosmic strings is predicted to be at least 1% while the spectral index is predicted to be less than 0.968 for a CMB string contribution less than 5%. Treating the inflaton-RH sneutrino system as a two-field inflation model, we show that the time-dependence of the RH sneutrino field strongly modifies the single-field results for values of RH sneutrino mass $m_{\Phi }>0.1H$. The running spectral index is $\alpha \approx -0.0002$ when $m_{\Phi }<0.1H$ but increases to positive values as $m_{\Phi }/H$ increases, with $\alpha >0.008$ for $m_{\Phi }>1.0H$.