16294141
Alternative supersymmetric spectra
Abstract We describe the features of supersymmetric spectra, alternative to and qualitatively different from that of most versions of the MSSM. The spectra are motivated by extensions of the MSSM with an extra U (1)′ gauge symmetry, expected in many grand unified and superstring models, which provide a plausible solution to the μ problem, both for models with supergravity and for gauge-mediated supersymmetry breaking. Typically, many or all of the squarks are rather heavy (larger than one TeV), especially for the first two families, as are the sleptons in the supergravity models. However, there is a richer spectrum of Higgs particles, neutralinos, and (possibly) charginos. Concrete examples of such spectra are presented, and the phenomenological implications are briefly discussed.
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.
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.
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.
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.
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.
34691754
Searches for heavy Higgs bosons in two-Higgs-doublet models and for t -> ch decay using multilepton and diphoton final states in pp collisions at 8 TeV
Searches are presented for heavy scalar (H) and pseudoscalar (A) Higgs bosons posited in the two doublet model (2HDM) extensions of the standard model (SM). These searches are based on a data sample of pp collisions collected with the CMS experiment at the LHC at a center-of-mass energy of sqrt(s) = 8 TeV and corresponding to an integrated luminosity of 19.5 inverse femtobarns. The decays H to hh and A to Zh, where h denotes an SM-like Higgs boson, lead to events with three or more isolated charged leptons or with a photon pair accompanied by one or more isolated leptons. The search results are presented in terms of the H and A production cross sections times branching fractions and are further interpreted in terms of 2HDM parameters. We place 95% CL cross section upper limits of approximately 7 pb on sigma times B for H to hh and 2 pb for A to Zh. Also presented are the results of a search for the rare decay of the top quark that results in a charm quark and an SM Higgs boson, t to ch, the existence of which would indicate a nonzero flavor-changing Yukawa coupling of the top quark to the Higgs boson. We place a 95% CL upper limit of 0.56% on B(t to ch).
26127397
Search for top squarks in R-parity-violating supersymmetry using three or more leptons and b-tagged jets.
A search for anomalous production of events with three or more isolated leptons and bottom-quark jets produced in pp collisions at √s=8 TeV is presented. The analysis is based on a data sample corresponding to an integrated luminosity of 19.5 fb(-1) collected by the CMS experiment at the LHC in 2012. No excess above the standard model expectations is observed. The results are interpreted in the context of supersymmetric models with signatures that have low missing transverse energy arising from light top-squark pair production with R-parity-violating decays of the lightest supersymmetric particle. In two models with different R-parity-violating couplings, top squarks are excluded below masses of 1020 GeV and 820 GeV when the lightest supersymmetric particle has a mass of 200 GeV.
2838195
DESIGN OF THE JLC/NLC RDDS STRUCTURE USING PARALLEL EIGENSOLVER Omega3P
The complexity of the Round Damped Detuned Structure (RDDS) for the JLC/NLC main linac is driven by the considerations of rf efficiency and dipole wakefield suppression. As a time and cost saving measure for the JLC/NLC, the dimensions of the 3D RDDS cell are being determined through computer modeling to within fabrication precision so that no tuning may be needed once the structures are assembled. The tolerances on the frequency errors for the RDDS structure are about one MHz for the fundamental mode and a few MHz for the dipole modes. At the X-band frequency, these correspond to errors of a micron level on the major cell dimensions. Such a level of resolution requires highly accurate field solvers and vast amount of computer resources. A parallel finite-element eigensolver Omega3P was developed at SLAC that runs on massively parallel computers such as the Cray T3E at NERSC. The code was applied in the design of the RDDS cell dimensions that are accurate to within fabrication precision. We will present the numerical approach of using these codes to determine the RDDS dimensions and compare the numerical predictions with the cold test measurements on RDDS prototypes that are diamond-turned using these dimensions.
18255171
INTEGRAL and Swift/XRT observations of IGR J19405-3016
Aims. IGR J19405-3016 is reported in the 3rd IBIS catalog as one of its lowest significance sources (similar to 4.6 sigma under an exposure of about 371 ks). This leads to a caveat in multi-wavelength studies, although the source was identified in the optical as a Seyfert 1. The currently available INTEGRAL data on the source have increased to an exposure time of similar to 1376 ks, which stimulates us to investigate the reality of this source again by using all the available data from INTEGRAL and Swift/XRT. Methods. We analyzed all available observations carried out by the International Gamma-Ray Astrophysics Laboratory (INTEGRAL) on IGR J19405-3016. The data were processed by using the latest version OSA 7.0. In addition, we analyzed all the available Swift/XRT data on this source. Results. We find that IGR J19405-3016 has a detection significance of similar to 9.4 sigma in the 20-60 keV band during the observational period between March 2003 and March 2008. This confirms a real source detection reported previously. The source position and error location are therefore updated. The source is found to be constant over years at the hard X-rays. We analyzed the Swift/XRT observations on IGR J19405-3016 as well, and find that the spectrum can be fitted with a simple power law model. Over the three XRT observations, the source flux varied by up to 39% from the average, and the spectrum is generally soft. The combined XRT/ISGRI spectrum is well fitted with a simple power law model (photon index 2.11 +/- 0.03) with a column density fixed at 8.73 x 10(20) atoms/cm(2). Such a photon index is consistent with the mean value 1.98 (dispersion 0.27) obtained from Swift/BAT AGN samples at 14-195 keV. The spectral slope of IGR J19405-3016 is softer than the average spectral slope found elsewhere. A similar discrepancy is found with other results regarding Seyfert 1 AGNs. A possible explanation for this simple spectral description may be that the low level of the column density allows for the "true" spectrum to appear at soft X-rays as well.
209834301
Search for supersymmetry in events with photons, bottom quarks, and missing transverse momentum in proton–proton collisions at a centre-of-mass energy of 7 TeV with the ATLAS detector
A search has been performed for the experimental signature of an isolated photon with high transverse momentum, at least one jet identified as originating from a bottom quark, and high missing transverse momentum. Such a final state may originate from supersymmetric models with gauge-mediated supersymmetry breaking in events in which one of a pair of higgsino-like neutralinos decays into a photon and a gravitino while the other decays into a Higgs boson and a gravitino. The search is performed using the full dataset of 7 TeV proton–proton collisions recorded with the ATLAS detector at the LHC in 2011, corresponding to an integrated luminosity of 4.7 fb−1. A total of 7 candidate events are observed while 7.5±2.2 events are expected from the Standard Model background. The results of the search are interpreted in the context of general gauge mediation to exclude certain regions of a benchmark plane for higgsino-like neutralino production.