QCD corrections to Upsilon production via color-octet states at the Tevatron and LHC

The NLO QCD corrections to Upsilon production via S-wave color-octet states Upsilon(^1S_0^8,^3S_1^8) at the Tevatron and LHC is calculated. The K factors of total cross section (ratio of NLO to LO) are 1.313 and 1.379 for Upsilon(^1S_0^8) and Upsilon(^3S_1^8) at the Tevatron, while at the LHC they are 1.044 and 1.182, respectively. By fitting the experimental data from the D0, the matrix elements for S-wave color-octet states are obtained. And new predictions for Upsilon production are presented. The prediction for the polarization of inclusive Upsilon contains large uncertainty rising from the polarization of Upsilon from feed-down of chi_b. To further clarify the situation, new measurements on the production and polarization for direct Upsilon are expected.Comment: 13 pages, 10 Figure

The masses and residues of doubly heavy spin--3/2 baryons

The masses and residues of the spin--3/2 doubly heavy baryons are calculated within the QCD sum rules method. A comparison of our predictions with those existing in the literature is also made.Comment: 11 Pages and 4 Table

Galactic microwave emission at degree angular scales

We cross-correlate the Saskatoon Ka and Q-Band Cosmic Microwave Background (CMB) data with different maps to quantify possible foreground contamination. We detect a marginal correlation (2 sigma) with the Diffuse Infrared Background Experiment (DIRBE) 240, 140 and 100 microm maps, but we find no significant correlation with point sources, with the Haslam 408 MHz map or with the Reich and Reich 1420 MHz map. The rms amplitude of the component correlated with DIRBE is about 20% of the CMB signal. Interpreting this component as free-free emission, this normalization agrees with that of Kogut et al. (1996a; 1996b) and supports the hypothesis that the spatial correlation between dust and warm ionized gas observed on large angular scales persists to smaller angular scales. Subtracting this contribution from the CMB data reduces the normalization of the Saskatoon power spectrum by only a few percent.Comment: Minor revisions to match published version. 14 pages, with 2 figures included. Color figure and links at http://www.sns.ias.edu/~angelica/foreground.htm

Magnetic Fields in Quasar Cores II

Multi-frequency polarimetry with the Very Long Baseline Array (VLBA) telescope has revealed absolute Faraday Rotation Measures (RMs) in excess of 1000 rad/m/m in the central regions of 7 out of 8 strong quasars studied (e.g., 3C 273, 3C 279, 3C 395). Beyond a projected distance of ~20 pc, however, the jets are found to have |RM| < 100 rad/m/m. Such sharp RM gradients cannot be produced by cluster or galactic-scale magnetic fields, but rather must be the result of magnetic fields organized over the central 1-100 pc. The RMs of the sources studied to date and the polarization properties of BL Lacs, quasars and galaxies are shown to be consistent so far with the predictions of unified schemes. The direct detection of high RMs in these quasar cores can explain the low fractional core polarizations usually observed in quasars at centimeter wavelengths as the result of irregularities in the Faraday screen on scales smaller than the telescope beam. Variability in the RM of the core is reported for 3C 279 between observations taken 1.5 years apart, indicating that the Faraday screen changes on that timescale, or that the projected superluminal motion of the inner jet components samples a new location in the screen with time. Either way, these changes in the Faraday screen may explain the dramatic variability in core polarization properties displayed by quasars.Comment: Accepted to the ApJ. 27 pages, 9 figures including figure 6 in colo

Effects of Foreground Contamination on the Cosmic Microwave Background Anisotropy Measured by MAP

We study the effects of diffuse Galactic, far-infrared extragalactic source, and radio point source emission on the cosmic microwave background (CMB) anisotropy data anticipated from the MAP experiment. We focus on the correlation function and genus statistics measured from mock MAP foreground-contaminated CMB anisotropy maps generated in a spatially-flat cosmological constant dominated cosmological model. Analyses of the simulated MAP data at 90 GHz (0.3 deg FWHM resolution smoothed) show that foreground effects on the correlation function are small compared with cosmic variance. However, the Galactic emission, even just from the region with |b| > 20 deg, significantly affects the topology of CMB anisotropy, causing a negative genus shift non-Gaussianity signal. Given the expected level of cosmic variance, this effect can be effectively reduced by subtracting existing Galactic foreground emission models from the observed data. IRAS and DIRBE far-infrared extragalactic sources have little effect on the CMB anisotropy. Radio point sources raise the amplitude of the correlation function considerably on scales below 0.5 deg. Removal of bright radio sources above a 5 \sigma detection limit effectively eliminates this effect. Radio sources also result in a positive genus curve asymmetry (significant at 2 \sigma) on 0.5 deg scales. Accurate radio point source data is essential for an unambiguous detection of CMB anisotropy non-Gaussianity on these scales. Non-Gaussianity of cosmological origin can be detected from the foreground-subtracted CMB anisotropy map at the 2 \sigma level if the measured genus shift parameter |\Delta\nu| >= 0.02 (0.04) or if the measured genus asymmetry parameter |\Delta g| >= 0.03 (0.08) on a 0.3 (1.0) deg FWHM scale.Comment: 26 pages, 7 figures, Accepted for Publication in Astrophysical Journal (Some sentences and figures modified

New Cosmological Structures on Medium Angular Scales Detected with the Tenerife Experiments

We present observations at 10 and 15 GHz taken with the Tenerife experiments in a band of the sky at Dec.=+35 degrees. These experiments are sensitive to multipoles in the range l=10-30. The sensitivity per beam is 56 and 20 microK for the 10 and the 15 GHz data, respectively. After subtraction of the prediction of known radio-sources, the analysis of the data at 15 GHz at high Galactic latitude shows the presence of a signal with amplitude Delta Trms ~ 32 microK. In the case of a Harrison-Zeldovich spectrum for the primordial fluctuations, a likelihood analysis shows that this signal corresponds to a quadrupole amplitude Q_rms-ps=20.1+7.1-5.4 microK, in agreement with our previous results at Dec.+=40 degrees and with the results of the COBE DMR. There is clear evidence for the presence of individual features in the RA range 190 degrees to 250 degrees with a peak to peak amplitude of ~110 microK. A preliminary comparison between our results and COBE DMR predictions for the Tenerife experiments clearly indicates the presence of individual features common to both. The constancy in amplitude over such a large range in frequency (10-90 GHz) is strongly indicative of an intrinsic cosmological origin for these structures.Comment: ApJ Letters accepted, 13 pages Latex (uses AASTEX) and 4 encapsulated postscript figures

The VLA Low-frequency Sky Survey

The Very Large Array (VLA) Low-frequency Sky Survey (VLSS) has imaged 95% of the 3*pi sr of sky north of declination = -30 degrees at a frequency of 74 MHz (4 meter wavelength). The resolution is 80" (FWHM) throughout, and the typical RMS noise level is ~0.1 Jy/beam. The typical point-source detection limit is 0.7 Jy/beam and so far nearly 70,000 sources have been catalogued. This survey used the 74 MHz system added to the VLA in 1998. It required new imaging algorithms to remove the large ionospheric distortions at this very low frequency throughout the entire ~11.9 degree field of view. This paper describes the observation and data reduction methods used for the VLSS and presents the survey images and source catalog. All of the calibrated images and the source catalog are available online (http://lwa.nrl.navy.mil/VLSS) for use by the astronomical community.Comment: 53 pages, including 3 tables and 15 figures. Has been accepted for publication in the Astronomical Journa

X-ray Properties of the GigaHertz-Peaked and Compact Steep Spectrum Sources

We present {\it Chandra} X-ray Observatory observations of Giga-Hertz Peaked Spectrum (GPS) and Compact Steep Spectrum (CSS) radio sources. The {\it Chandra} sample contains 13 quasars and 3 galaxies with measured 2-10 keV X-ray luminosity within $10^{42} - 10^{46}$ erg s$^{-1}$. We detect all of the sources, five of which are observed in X-ray for the first time. We study the X-ray spectral properties of the sample. The measured absorption columns in the quasars are different than those in the galaxies in the sense that the quasars show no absorption (with limits $\sim 10^{21} \rm cm^{-2}$) while the galaxies have large absorption columns ($> 10^{22} \rm cm^{-2}$) consistent with previous findings. The median photon index of the sources with high S/N is $\Gamma=1.84 \pm0.24$ and it is larger than the typical index of radio loud quasars. The arcsec resolution of {\it Chandra} telescope allows us to investigate X-ray extended emission, and look for diffuse components and X-ray jets. We found X-ray jets in two quasars (PKS 1127-145, B2 0738+32), an X-ray cluster surrounding a CSS quasar (z=1.1, 3C 186), detected a possible binary structure in 0941-080 galaxy and an extended diffuse emission in galaxy PKS B2 1345+12. We discuss our results in the context of X-ray emission processes and radio source evolution. We conclude that the X-ray emission in these sources is most likely unrelated to a relativistic jet, while the sources' radio-loudness may suggest a high radiative efficiency of the jet power in these sources.Comment: 15 pages, to be published in Ap