9104388
A Low-energy solution to the mu problem in gauge mediation
In the gauge-mediation framework the soft supersymmetry breaking mass parameters of the supersymmetric standard model are induced by the gauge interactions of some messenger fields. The parameters exhibit flavor universality which is dictated by the gauge interactions and which efficiently eliminates new dangerous contributions to flavor changing neutral currents. However, the Higgs potential in this framework typically contains an unacceptable hierarchy between its dimensionful parameters (the $\ensuremath{\mu}$ problem of gauge mediation). We show that the problem can be resolved if the Higgs potential arises dynamically once an intermediate ${U(1)}^{\ensuremath{'}}$ sector is integrated out rather than arising radiatively from some Yukawa interactions at the messenger scale. As an added benefit, such models may naturally avoid new contributions to $\mathrm{CP}$ violating amplitudes. The proposed framework is described, explicit examples are given and its phenomenology is explored. The $\ensuremath{\mu}$ problem is resolved in this case by the low-energy ${U(1)}^{\ensuremath{'}}$ dynamics which could be tested in future collider experiments.
122602751
Application of the complex scaling method in relativistic mean-field theory
We develop the complex scaling method within the framework of the relativistic mean-field (RMF) model. With the self-consistent nuclear potentials from the RMF model, the complex scaling method is used to study single-particle resonant states in spherical nuclei. As examples, the energies and widths of low-lying neutron resonant states in {sup 120}Sn are obtained. The results are compared with those from the real stabilization method, the scattering phase-shift method, and the analytic continuation in the coupling constant approach and satisfactory agreements are found.
16398417
Three family type IIB orientifold string vacua with non-abelian Wilson lines
We address the implementation of non-abelian Wilson lines in D = 4 N = 1 type IIB orientifold constructions. We present an explicit three-family example with the gauge group (U(4) × U(2) × SU(2) × SU(2))2 × (U(6) × Spp(4))2 and give the particle spectrum and the trilinear superpotential. Emphasizing the new subtleties associated with the introduction of non-abelian Wilson lines, we show that the abelian gauge anomalies are cancelled by the Green-Schwarz-type mechanism, and calculate the Fayet-Iliopoulos terms and gauge coupling corrections. The analysis thus sets a stage for further investigations of the phenomenological implications of this model.
7377062
Gauge invariant effective Lagrangian for Kaluza-Klein modes
We construct a manifestly gauge invariant Lagrangian in $3+1$ dimensions for N Kaluza-Klein modes of an $\mathrm{SU}(m)$ gauge theory in the bulk. For example, if the bulk is $4+1,$ the effective theory is ${\ensuremath{\Pi}}_{i=1}^{N+1}{\mathrm{SU}(m)}_{i}$ with N chiral $(\overline{m},m)$ fields connecting the groups sequentially. This can be viewed as a Wilson action for a transverse lattice in ${x}^{5},$ and is shown explicitly to match the continuum $4+1$ compactified Lagrangian truncated in momentum space. Scale dependence of the gauge couplings is described by the standard renormalization group technique with threshold matching, leading to effective power law running. We also discuss the unitarity constraints, and chiral fermions.
22640928
Proposal for direct measurement of a pure spin current by a polarized light beam.
The photon helicity may be mapped to a spin-1/2, whereby we put forward an intrinsic interaction between a polarized light beam as a "photon spin current" and a pure spin current in a semiconductor, which arises from the spin-orbit coupling in valence bands as a pure relativity effect without involving the Rashba or the Dresselhaus effect due to inversion asymmetries. The interaction leads to linear and circular optical birefringence, which are similar to the Voigt effect and the Faraday rotation in magneto-optics but nevertheless involve no net magnetization. The birefringence effects provide a direct, nondemolition measurement of pure spin currents.
18179490
Toward a Unified Model for the “Diffuse Ionized Medium” in Normal and Starburst Galaxies
The "diffuse ionized medium" (DIM) makes up a significant fraction of the mass and ionization requirements of the interstellar medium of the Milky Way and is now known to be an energetically significant component in most normal star-forming galaxies. Observations of the ionized gas in starburst galaxies have revealed the presence of gas with striking similarities to the DIM in normal galaxies: relatively low surface brightness and strong emission from low-ionization forbidden lines like [S II] λλ6716, 6731. In this paper we analyze Hα images and long-slit spectra of samples of normal and starburst galaxies to better understand the nature of this diffuse, low surface brightness gas. We find that in both samples there is a strong inverse correlation between the Hα surface brightness (ΣHα) and the [S II]/Hα line ratio at a given location in the galaxy. However, the correlation for the starbursts is offset brightward by an order of magnitude in Hα surface brightness at a given line ratio. In contrast, we find that all the galaxies (starburst and normal alike) define a universal relation between line ratio and the relative Hα surface brightness (ΣHα/Σe, where Σe is the mean Hα surface brightness within the galaxy half-light radius). We show that such a universal correlation is a natural outcome of a model in which the DIM is photoionized gas that has a characteristic thermal pressure (P) that is proportional to the mean rate of star formation per unit area in the galaxy (ΣSFR). Good quantitative agreement with the data follows if we require the constant of proportionality to be consistent with the values of P and ΣSFR in the local disk of the Milky Way. Such a scaling between P and ΣSFR may arise either because feedback from massive stars heats the ISM or because ΣSFR is determined (or limited) by the mean gas pressure.
197509312
Jet and underlying event properties as a function of charged-particle multiplicity in proton–proton collisions at √s = 7 TeV
Characteristics of multi-particle production in proton-proton collisions at √ s = 7 TeV are studied as a function of the charged-particle multiplicity, Nch. The produced particles are separated into two classes: those belonging to jets and those belonging to the underlying event. Charged particles are measured with pseudorapidity |η| < 2.4 and transverse momentum pT > 0.25 GeV/c. Jets are reconstructed from chargedparticles only and required to have pT > 5 GeV/c. The distributions of jet pT, average pT of charged particles belonging to the underlying event or to jets, jet rates, and jet shapes are presented as functions of Nch and compared to the predictions of the PYTHIA and HERWIG event generators. Predictions without multi-parton interactions fail completely to describe the Nch-dependence observed in the data. For increasing Nch, PYTHIA systematically predicts higher jet rates and harder pT spectra than seen in the data, whereas HERWIG shows the opposite trends. At the highest multiplicity, the data–model agreement is worse for most observables, indicating the need for further tuning and/or new model ingredients. Published in the European Physical Journal C as doi:10.1140/epjc/s10052-013-2674-5. c © 2013 CERN for the benefit of the CMS Collaboration. CC-BY-3.0 license ∗See Appendix A for the list of collaboration members ar X iv :1 31 0. 45 54 v2 [ he pex ] 1 3 D ec 2 01 3 FERMILAB-PUB-13-627-CMS
118415484
UNVEILING THE PHYSICAL PROPERTIES AND KINEMATICS OF MOLECULAR GAS IN THE ANTENNAE GALAXIES (NGC 4038/9) THROUGH HIGH-RESOLUTION CO (J=3-2) OBSERVATIONS
We present a similar to 1 '' (100 pc) resolution (CO)-C-12 (3-2) map of the nearby intermediate-stage interacting galaxy pair NGC 4038/9 (the Antennae galaxies) obtained with the Submillimeter Array. We find that half the CO (3-2) emission originates in the overlap region where most of the tidally induced star formation had been previously found in shorter wavelength images, with the rest being centered on each of the nuclei. The gross distribution is consistent with lower resolution single-dish images, but we show for the first time the detailed distribution of the warm and dense molecular gas across this galaxy pair at resolutions comparable to the size of a typical giant molecular complex. While we find that 58% (33/57) of the spatially resolved Giant Molecular Associations (a few x 100 pc) are located in the overlap region, only <= 30% spatially coincides with the optically detected star clusters, suggesting that the bulk of the CO (3-2) emission traces the regions with very recent or near future star formation activity. The spatial distribution of the CO (3-2)/CO (1-0) integrated brightness temperature ratios mainly ranges between 0.3 and 0.6, which suggests that on average the CO (3-2) line in the Antennae is not completely thermalized and similar to the average values of nearby spirals. A higher ratio is seen in both nuclei and the southern complexes in the overlap region. A higher radiation field associated with intense star formation can account for the nucleus of NGC 4038 and the overlap region, but the nuclear region of NGC 4039 shows relatively little star formation or active galactic nucleus activity and cannot be easily explained. We show kinematical evidence that the high line ratio in NGC 4039 is possibly caused by gas inflow into the counter-rotating central disk.
14779036
Analysis and application of microwave radiation from the damping manifolds of the SLAC damped detuned structures (DDS)
The power spectrum emerging from the damping manifolds of a DDS provides valuable quasi-local information on the displacement of a drive beam from the axis of individual cells, where the displacement may be due to beam offset, small cell misalignment, or a combination of the two. The degree of localization and the indexing of frequency to cell number is determined directly from the spectral function theory. Examples for specific DDS designs are presented. These relations can be used to determine geometrical misalignment patterns.
122200845
Search for same-sign top-quark pair production at $ \sqrt {s} = 7 $ TeV and limits on flavour changing neutral currents in the top sector
An inclusive search for same-sign top-quark pair production in pp collisions at $ \sqrt {s} = 7 $ TeV is performed using a data sample recorded with the CMS detector in 2010, corresponding to an integrated luminosity of 35 pb−1. This analysis is motivated by recent studies of $ \text{p}\bar{\text{p}} \to \text{t}\bar{\text{t}} $ reporting mass-dependent forward-backward asymmetries larger than expected from the standard model. These asymmetries could be due to Flavor Changing Neutral Currents (FCNC) in the top sector induced by t-channel exchange of a massive neutral vector boson (Z′). Models with such a Z′ also predict enhancement of same-sign top-pair production in pp or $ \text{p}\bar{\text{p}} $ collisions. Limits are set as a function of the Z′ mass and its couplings to u and t quarks. These limits disfavour the FCNC interpretation of the Tevatron results.
118547314
Automatic computations at next-to-leading order in QCD for top-quark flavor-changing neutral processes
Computations at next-to-leading order in the Standard Model offer new technical challenges in presence of higher dimensional operators. We introduce a framework that, starting from the top-quark effective field theory at dimension six, allows to make predictions for cross sections as well as distributions in a fully automatic way. As an application, we present the first complete results at NLO in QCD for flavor changing neutral interactions including parton shower effects, for $tZ$, $th$, $t\gamma$ associated production at the LHC.