The LHC di-photon Higgs signal predicted by little Higgs models

Little Higgs theory naturally predicts a light Higgs boson whose most important discovery channel at the LHC is the di-photon signal $pp\to h\to \gamma\gamma$. In this work we perform a comparative study for this signal in some typical little Higgs models, namely the littlest Higgs model (LH), two littlest Higgs models with T-parity (named LHT-I and LHT-II) and the simplest little Higgs modes (SLH). We find that compared with the Standard Model prediction, the di-photon signal rate is always suppressed and the suppression extent can be quite different for different models. The suppression is mild (\lsim 10%) in the LH model but can be quite severe ($\simeq 90$) in other three models. This means that discovering the light Higgs boson predicted by the little Higgs theory through the di-photon channel at the LHC will be more difficult than discovering the SM Higgs boson.Comment: 17 pages, 4 figures, 1 tabl

The Energy of the Gamma Metric in the M{\o}ller Prescription

We obtain the energy distribution of the gamma metric using the energy-momentum complex of M{\o}ller. The result is the same as obtained by Virbhadra in the Weinberg prescription

Spin torque ferromagnetic resonance with magnetic field modulation

We demonstrate a technique of broadband spin torque ferromagnetic resonance (ST-FMR) with magnetic field modulation for measurements of spin wave properties in magnetic nanostructures. This technique gives great improvement in sensitivity over the conventional ST-FMR measurements, and application of this technique to nanoscale magnetic tunnel junctions (MTJs) reveals a rich spectrum of standing spin wave eigenmodes. Comparison of the ST-FMR measurements with micromagnetic simulations of the spin wave spectrum allows us to explain the character of low-frequency magnetic excitations in nanoscale MTJs.Comment: Also see: http://faculty.sites.uci.edu/krivorotovgroup

Single/Few Bunch Space Charge Effects at 8-GeV in the Fermilab Main Injector

For Project X, it is planned to inject a beam of 3x10**11 particles per bunch into the Main Injector. Therefore, at 8-GeV, there will be increased space charge tune shifts and an increased incoherent tune spread. In preparation for these higher intensity bunches exploratory studies have commenced looking at the transmission of different intensity bunches at different tunes. An experiment is described with results for bunch intensities between 20 and 300 10**9 particles. To achieve the highest intensity bunches coalescing at 8-GeV is required, resulting in a longer bunch length. Comparisons show that similar transmission curves are obtained when the intensity and bunch length have increased by factors of 3.2 and 3.4 respectively, indicating the incoherent tune shifts are similar, as expected from theory. The results of these experiments will be used in conjugation with simulations to further study high intensity bunches in the Main Injector.Comment: 3 pp. 3rd International Particle Accelerator Conference (IPAC 2012) 20-25 May 2012, New Orleans, Louisian

Propionibacterium acnes infections in patients with idiopathic scoliosis: a case-control study and review of the literature.

Purpose:Surgical site infection (SSI) caused by Propionibacterium acnes is an infrequent but devastating complication after spinal fusion. The purpose of this study was to identify risk factors for SSI with Propionibacterium acnes after spinal fusion for juvenile and adolescent idiopathic scoliosis (JIS and AIS). Methods:A case-control study was performed. Each case was matched 2:1 for age, gender and diagnosis. Retrospective chart review was performed to obtain relevant demographic, surgical and clinical data for all cases and controls. Statistical analysis included paired t-test and McNemar test, as well as exact logistic regression and robust regression models. Results:This study included ten infection cases (eight AIS, two JIS) and 20 controls (16 AIS, four JIS). In total, six infected cases presented within two weeks of the index procedure (acute infection) and four infected cases presented more than one year from the index procedure (delayed infection). The most common presentation for acute infections was wound drainage, while back pain was more common in delayed infections. All infections were successfully treated with surgical irrigation and debridement and postoperative antibiotics. Hardware was removed for patients with delayed infections. The strongest risk factor for infection was increased requirement for blood transfusion, but it did not reach statistical significance. Conclusion:SSI with Propionibacterium acnes is an important complication after spinal fusion for idiopathic scoliosis. These infections can be successfully treated, but larger studies are needed to further identify risk factors and establish standardized guidelines for the treatment and prevention of this complication. Level of Evidence Level III

Higher-order vortex solitons, multipoles, and supervortices on a square optical lattice

We predict new generic types of vorticity-carrying soliton complexes in a class of physical systems including an attractive Bose-Einstein condensate in a square optical lattice (OL) and photonic lattices in photorefractive media. The patterns include ring-shaped higher-order vortex solitons and supervortices. Stability diagrams for these patterns, based on direct simulations, are presented. The vortex ring solitons are stable if the phase difference \Delta \phi between adjacent solitons in the ring is larger than \pi/2, while the supervortices are stable in the opposite case, \Delta \phi <\pi /2. A qualitative explanation to the stability is given.Comment: 9 pages, 4 figure

Modifying the photodetachment near a metal surface by a weak electric field

We show the photodetachment cross sections of H near a metal surface can be modified using a weak static electric field. The modification is possible because the oscillatory part of the cross section near a metal surface is directly connected with the transit-time and the action of the detached-electron closed-orbit which can be changed systematically by varying the static electric field strength. Photodetachment cross sections for various photon energies and electric field values are calculated and displayed.Comment: 16 pages, 7 figure