Next-to-Leading Order Corrections to Single Top Quark Production and Decay at the Tevatron: 2. tt-channel Process

We present a study of the $t$-channel mode of single top quark production at the upgraded Tevatron $p\bar{p}$ collider, including the next-to-leading order (NLO) QCD corrections to the production and the decay of a single top quark. The narrow width approximation was adopted in order to preserve the spin of the top quark in its production and decay. We discuss the effects of different $O(\alpha_s)$ contributions on the inclusive cross section as well as various kinematic distributions after imposing the relevant cuts to select $t$-channel single top signal events.Comment: 46 pages, 47 figures. One typo in LaTeX source file is correcte

Space-Dependent Symmetries and Fractons

There has been a surge of interest in effective non-Lorentzian theories of excitations with restricted mobility, known as fractons. Examples include defects in elastic materials, vortex lattices or spin liquids. In the effective theory novel coordinate-dependent symmetries emerge that shape the properties of fractons. In this review we will discuss these symmetries, cover the effective description of gapless fractons via elastic duality, and discuss their hydrodynamics

Weak Lensing Analysis of the z~0.8 cluster CL 0152-1357 with the Advanced Camera for Surveys

We present a weak lensing analysis of the X-ray luminous cluster CL 0152-1357 at z~0.84 using HST/ACS observations. The unparalleled resolution and sensitivity of ACS enable us to measure weakly distorted, faint background galaxies to the extent that the number density reaches ~175 arcmin^-2. The PSF of ACS has a complicated shape that also varies across the field. We construct a PSF model for ACS from an extensive investigation of 47 Tuc stars in a modestly crowded region. We show that this model PSF excellently describes the PSF variation pattern in the cluster observation when a slight adjustment of ellipticity is applied. The high number density of source galaxies and the accurate removal of the PSF effect through moment-based deconvolution allow us to restore the dark matter distribution of the cluster in great detail. The direct comparison of the mass map with the X-ray morphology from Chandra observations shows that the two peaks of intracluster medium traced by X-ray emission are lagging behind the corresponding dark matter clumps, indicative of an on-going merger. The overall mass profile of the cluster can be well described by an NFW profile with a scale radius of r_s =309+-45 kpc and a concentration parameter of c=3.7+-0.5. The mass estimates from the lensing analysis are consistent with those from X-ray and Sunyaev-Zeldovich analyses. The predicted velocity dispersion is also in good agreement with the spectroscopic measurement from VLT observations. In the adopted WMAP cosmology, the total projected mass and the mass-to-light ratio within 1 Mpc are estimated to be 4.92+-0.44 10^14 solar mass and 95+-8 solar mass/solar luminosity, respectively.Comment: Accepted for publication in Astrophysical Journal. 58 pages, 26 figures. Figures have been degraded to meet size limit; a higher resolution version available at http://acs.pha.jhu.edu/~mkjee/ms_cl0152.pd

A Gamified Approach Towards Identifying Key Opportunities and Potential Sponsors for the Future of F1 Racing in a Declining Car Ownership Environment

This research work aims to propose new approaches towards identifying key opportunities and potential sponsors for the future of F1 racing in an environment with declining car ownership, without resorting to endless licensing agreements. The paper presents a gamification approach on which an innovative and disruptive operations framework can be developed to help, without operational complexity and commitment, F1 teams gain new customers (fans) and recapture essential markets and targets groups. The paper also contributes on establishing a base for effective strategy development based on the user’s/player’s engagement and behavior. Furthermore, this work extends towards the analysis of the game’s operations and the marketing initiatives needed to succeed. The proposed approach varies from OHH (out of home advertising), interactive marketing, celebrities, F1 drivers’ endorsements, and other related supportive initiatives such as search engine optimization on online research platforms and other promotion and marketing dissemination initiatives

A Semi-Empirical Model of the Infra-Red Universe

We present a simple model of the infra-red universe, based as much as possible on local observations. We model the luminosity and number evolution of disk and starburst galaxies, including the effects of dust, gas and spectral evolution. Although simple, our approach is able to reproduce observations of galaxy number counts and the infra-red and sub-millimeter extra-galactic backgrounds. It provides a useful probe of galaxy formation and evolution out to high redshift. The model demonstrates the significant role of the starburst population and predicts high star formation rates at redshifts 3 to 4, consistent with recent extinction-corrected observations of Lyman break galaxies. Starbursting galaxies are predicted to dominate the current SCUBA surveys. Their star formation is driven predominantly by strong tidal interactions and mergers of galaxies. This leads to the creation of spheroidal stellar systems, which may act as the seeds for disk formation as gas infalls. We predict the present-day baryonic mass in bulges and halos is comparable to that in disks. From observations of the extra-galactic background, the model predicts that the vast majority of star formation in the Universe occurs at z<5.Comment: 23 pages including 9 figures. To appear in ApJ. Model results available electronically at http://astro.berkeley.edu/~jt/irmodel.htm

ACS Observations of a Strongly Lensed Arc in a Field Elliptical

We report the discovery of a strongly lensed arc system around a field elliptical galaxy in Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) images of a parallel field observed during NICMOS observations of the HST Ultra-Deep Field. The ACS parallel data comprise deep imaging in the F435W, F606W, F775W, and F850LP bandpasses. The main arc is at a radius of 1.6 arcsec from the galaxy center and subtends about 120 deg. Spectroscopic follow-up at Magellan Observatory yields a redshift z=0.6174 for the lensing galaxy, and we photometrically estimate z_phot = 2.4\pm0.3 for the arc. We also identify a likely counter-arc at a radius of 0.6 arcsec, which shows structure similar to that seen in the main arc. We model this system and find a good fit to an elliptical isothermal potential of velocity dispersion $\sigma \approx 300$ \kms, the value expected from the fundamental plane, and some external shear. Several other galaxies in the field have colors similar to the lensing galaxy and likely make up a small group.Comment: Accepted for publication in ApJ Letters. 10 pages, 3 figures. Figures have been degraded to meet size limit; a higher resolution version and addtional pictures available at http://acs.pha.jhu.edu/~jpb/UDFparc

Super-Resonant Transport of Topological Surface States Subjected to In-Plane Magnetic Fields

Magnetic oscillations of Dirac surface states of topological insulators are typically expected to be associated with the formation of Landau levels or the Aharonov-Bohm effect. We instead study the conductance of Dirac surface states subjected to an in-plane magnetic field in the presence of a barrier potential. Strikingly, we find that, in the case of large barrier potentials, the surface states exhibit pronounced oscillations in the conductance when varying the magnetic field, in the absence of Landau levels or the Aharonov-Bohm effect. These novel magnetic oscillations are attributed to the emergence of super-resonant transport by tuning the magnetic field, in which many propagating modes cross the barrier with perfect transmission. In the case of small and moderate barrier potentials, we identify a positive magnetoconductance due to the increase of the Fermi surface by tilting the surface Dirac cone. Moreover, we show that for weak magnetic fields, the conductance displays a shifted sinusoidal dependence on the field direction with period p and phase shift determined by the tilting direction with respect to the field direction. Our predictions can be applied to various topological insulators, such as HgTe and Bi2Se3, and provide important insights into exploring and understanding exotic magnetotransport properties of topological surface states

Chandra detection of the intracluster medium around 3C294 at z=1.786

We present a Chandra observation of the powerful radio galaxy 3C294 showing clear evidence for a surrounding intracluster medium. At a redshift of 1.786 this is the most distant cluster of galaxies yet detected in X-rays. The radio core is detected as a point source, which has a spectrum consistent with a heavily-absorbed power law implying an intrinsic 2-10 keV luminosity of ~10^45 erg/s. A small excess of emission is associated with the southern radio hotspots. The soft, diffuse emission from the intracluster medium is centred on the radio source. It has an hour-glass shape in the N-S direction, extending to radii of at least 100 kpc, well beyond the radio source. The X-ray spectrum of this extended component is fit by a thermal model with temperature ~5 keV, or by gas cooling from above 7 keV at rates of ~400-700 Msolar/yr. The rest-frame 0.3-10 keV luminosity of the cluster is ~4.5x10^44 erg/s. The existence of such a cluster is consistent with a low density universe.Comment: 5 pages, 6 figures, accepted by MNRA

LBQS 1429-0053: a binary quasar rather than a lensed quasar

Very deep ESO/VLT FORS1 and ISAAC images, as well as HST NICMOS2 data are used to infer the nature of the quasar pair LBQS 1429-0053 A and B, either a binary quasar or a doubly-imaged lensed quasar. Direct search of a putative lensing galaxy is unsuccessful . Moreover, no galaxy overdensity close to the quasar pair is found. A weak shear analysis of the field also fails at detecting any concentration of dark matter and weakens the hypothesis of a dark lens. The only sign of a possible lens consists in a group of 5 objects at z~1, within a radius of 5'', from the quasar pair. Considering this group as the lensing potential does not allow to reproduce the image position and flux ratio of the quasars. Our deep R-band image shows a blue, extended object at the position of quasar A, which is consistent with either being the lensed quasar A host, or being an intervening galaxy at lower redshift. Unless future very deep optical images demonstrate that this object is actually the lensed host of LBQS 1429-0053, we conclude that there is very little evidence for this quasar being lensed. Therefore, we are led to declare LBQS 1429-0053 A and B a genuine binary quasar.Comment: 9 pages, 6 jpg images, accepted for publication in A&

Extracting W Boson Couplings from the e+e−e^{+}e^{-} Production of Four Leptons

We consider the processes $e^{+}e^{-}\rightarrow \ell^{+} \ell^{\prime -}\nu \bar{\nu}^{\prime}$, including all possible charged lepton combinations, with regard to measuring parameters characterizing the $W$ boson. We calculate at what level these processes can be used to measure anamolous triple-boson vertice coupling parameters for the cases of $e^{+}e^{-}$ colliders at 500 $GeV$ and 1 $TeV$ center of mass energies.Comment: 13 pages,OCIP/C-93-