115397330
A Search for the Production of Technicolor Particles at the D-Zero Detector
A search for the Technicolor processes p{bar p} {yields} {rho}{sub T}{sup {+-}} {yields} W{sup {+-}}{pi}{sub T}{sup 0} {yields} {mu}{nu}b{bar b} and p{bar p} {yields} {rho}{sub T}{sup 0} {yields} W{sup {+-}}{pi}{sub T}{sup {+-}} {yields} {mu}{nu}b{bar c} is conducted at the D0 detector. Selection requirements are individually optimized for each of twenty mass hypotheses by means of a random grid search. No excess is seen in a 291 pb{sup -1} data set and 95% confidence level upper limits are set on the Technicolor production cross section. The mass combinations M{sub {rho}} = 195 GeV/c{sup 2}, M{sub {pi}} = 100 GeV/c{sup 2} and M{sub {rho}} = 200 GeV/c{sup 2}, M{sub {pi}} = 105 GeV/c{sup 2} are excluded for the choice of the Technicolor scale parameter M{sub V} = 500 GeV.
118867968
Production of a Higgs Boson Plus Two Jets in Hadronic Collisions
We consider the production of a Standard Model Higgs boson accompanied by two jets in hadronic collisions. We work in the limit that the top quark is much heavier than the Higgs boson and use an e ective Lagrangian for the interactions of gluons with the Higgs boson. In addition to the previously computed four-gluon process, we compute the the amplitudes involving two quarks, two gluons and the Higgs boson and those involving four quarks and the Higgs boson. We exhibit the form of our results in the small-pH and factorization limits. We present numerical results for p S = 14 TeV and p S = 2 TeV. We nd that the dominant processes are gg ! ggH and qg ! qgH with the former (latter) contributing about 60% (40%) of the cross section at p S = 14 TeV and the two processes each contributing about half the cross section at p S = 2 TeV. All other processes are negligible at both energies. September 1996
16162456
Production of a Higgs pseudoscalar plus two jets in hadronic collisions
We consider the production of a Higgs pseudoscalar accompanied by two jets in hadronic collisions. We work in the limit that the top quark is much heavier than the Higgs pseudoscalar and use an effective Lagrangian for the interactions of gluons with the pseudoscalar. We compute the amplitudes involving: 1) four gluons and the pseudoscalar, 2) two quarks, two gluons and the pseudoscalar and 3) four quarks and the pseudoscalar. We find that the pseudoscalar amplitudes are nearly identical to those for the scalar case, the only differences being the overall size and the relative signs between terms. We present numerical cross sections for proton-proton collisions with center-of-mass energy 14 TeV.
30114466
Amplitudes for Higgs bosons plus four partons
In this talk we consider amplitudes for processes involving a Higgs boson, either scalar or pseudoscalar, plus four light partons. These amplitudes are relevant to the production of a Higgs boson plus two jets in hadronic collisions. They are also relevant to calculating the transverse momentum spectrum for Higgs bosons at next-to-leading order in the strong coupling. We work in the limit that the top quark is much heavier than the Higgs bosons and use effective Lagrangians for the interactions of gluons with the Higgs bosons. We present the amplitudes involving a Higgs boson and: 1) four gluons, 2) two quarks and two gluons; and 3) four quarks. We show that the pseudoscalar amplitudes are nearly identical to those for the scalar case, the only differences being the overall size and the relative signs between terms.
113469755
Radiation Damage Study of the D0 Silicon Microstrip Tracker
The Run II DØ experiment at the Fermilab Tevatron collider ha s been operating since 2001. At the heart of the DØ tracking system is a silicon microstrip de tector. It is built from four layers of single sided and double sided sensors organized in six bar rels, and two sets of seven disks. An additional, very small radius layer of silicon sensors, c onsisting of eight barrels, was inserted during the spring of 2006. We monitor the silicon sensors for radiation damage. A bulk c arrier-type reversal was observed in the innermost layer of the original detector after 1.5 fb −1 of integrated luminosity. We present the results of aging studies and predictions for lifetime of the detector for the rest of Run II at the Tevatron.
125296528
Low-mass Higgs searches at the Tevatron
119346336
Search for neutrinos from gamma-ray bursts using Super-Kamiokande
Using the Super-Kamiokande neutrino observatory, a search was conducted for neutrinos produced in coincidence with gamma-ray bursts observed by the Burst and Transient Source Experiment detector. Super-Kamiokande data in the neutrino energy range of 7 MeV ~ 100 TeV were analyzed. For gamma-ray bursts that occurred between 1996 April and 2000 May, no statistically significant signal in excess of the background levels was detected. Implied upper limits on associated gamma-ray burst neutrino production are presented.
118278155
Reduced time delay for gravitational waves with dark matter emulators
We discuss the implications for gravitational wave detectors of a class of modified gravity theories which dispense with the need for dark matter. These models, which are known as dark matter emulators, have the property that weak gravitational waves couple to the metric that would follow from general relativity without dark matter whereas ordinary particles couple to a combination of the metric and other fields which reproduces the result of general relativity with dark matter. We show that there is an appreciable difference in the Shapiro delays of gravitational waves and photons or neutrinos from the same source, with the gravitational waves always arriving first. We compute the expected time lags for GRB 070201, for SN 1987a and for Sco-X1. We estimate the probable error by taking account of the uncertainty in position, and by using three different dark matter profiles.
7810209
Optical spectroscopy and velocity dispersions of galaxy clusters from the SPT-SZ survey
We present optical spectroscopy of galaxies in clusters detected through the Sunyaev-Zel'dovich (SZ) effect with the South Pole Telescope (SPT). We report our own measurements of 61 spectroscopic cluster redshifts, and 48 velocity dispersions each calculated with more than 15 member galaxies. This catalog also includes 19 dispersions of SPT-observed clusters previously reported in the literature. The majority of the clusters in this paper are SPT-discovered; of these, most have been previously reported in other SPT cluster catalogs, and five are reported here as SPT discoveries for the first time. By performing a resampling analysis of galaxy velocities, we find that unbiased velocity dispersions can be obtained from a relatively small number of member galaxies (≾30), but with increased systematic scatter. We use this analysis to determine statistical confidence intervals that include the effect of membership selection. We fit scaling relations between the observed cluster velocity dispersions and mass estimates from SZ and X-ray observables. In both cases, the results are consistent with the scaling relation between velocity dispersion and mass expected from dark-matter simulations. We measure a ~30% log-normal scatter in dispersion at fixed mass, and a ~10% offset in the normalization of the dispersion-mass relation when compared to the expectation from simulations, which is within the expected level of systematic uncertainty.
117749606
Baryon content of massive galaxy clusters at 0.57 < z < 1.33
We study the stellar, brightest cluster galaxy (BCG) and intracluster medium (ICM) masses of 14 South Pole Telescope (SPT) selected galaxy clusters with median redshift z = 0.9 and mass M-500 = 6 x 10(14) M-circle dot. We estimate stellar masses for each cluster and BCG using six photometric bands, the ICM mass using X-ray observations and the virial masses using the SPT Sunyaev-Zel'dovich effect signature. At z = 0.9, the BCG mass M-*(BCG) constitutes 0.12 +/- 0.01 per cent of the halo mass for a 6 x 10(14) M-circle dot cluster, and this fraction falls as M-500(-0.58 +/- 0.07). The cluster stellar mass function has a characteristic mass M-0 = 10(11.0 +/- 0.1) M-circle dot, and the number of galaxies per unit mass in clusters is larger than in the field by a factor of 1.65 +/- 0.20. We combine our SPT sample with previously published samples at low redshift and correct to a common initial mass function and for systematic virial mass differences. We then explore mass and redshift trends in the stellar fraction f(*), the ICM fraction f(ICM), the collapsed baryon fraction f(c) and the baryon fraction f(b). At a pivot mass of 6 x 10(14) M-circle dot and redshift z = 0.9, the characteristic values are f(*) = 1.1 +/- 0.1 per cent, f(ICM) = 9.6 +/- 0.5 per cent, f(c) = 10.7 +/- 1.1 per cent and f(b) = 10.7 +/- 0.6 per cent. These fractions all vary with cluster mass at high significance, with higher mass clusters having lower f(*) and f(c) and higher f(ICM) and f(b). When accounting for a 15 per cent systematic virial mass uncertainty, there is no statistically significant redshift trend at fixed mass. Our results support the scenario where clusters grow through accretion from subclusters (higher f(*), lower f(ICM)) and the field (lower f(*), higher f(ICM)), balancing to keep f(*) and f(ICM) approximately constant since z similar to 0.9.
13992842
Proposed method for searches of gravitational waves from PKS 2155-304 and other blazar flares
We propose to search for gravitational waves from PKS 2155-304 as well as other blazars. PKS 2155-304 emitted a long-duration energetic flare in July 2006 with total isotropic equivalent energy released in TeV gamma rays of approximately 1045 ergs. Possible gravitational wave signals associated with this outburst are expected to be seen at the same time as the electromagnetic signal. During this flare, the two LIGO interferometers at Hanford and the GEO detector were in operation and collecting data. For this search we will use the data from multiple gravitational wave detectors. The method we use for this purpose is a coherent network analysis algorithm which is called RIDGE. To estimate the sensitivity of the search, we perform numerical simulations. For a detection probability of 20%, we estimate that this method is sensitive to total isotropic equivalent energy at the source of about 2.5 × 1055 ergs. For this analysis, an end-to-end pipeline has been developed, which takes into account the motion of the source across the sky.