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.
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.
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.
125296528
Low-mass Higgs searches at the Tevatron
19993933
Analysis of Sunyaev-Zel'dovich effect mass-observable relations using South Pole Telescope observations of an X-ray selected sample of low-mass galaxy clusters and groups
We use microwave observations from the South Pole Telescope (SPT) to examine the Sunyaev–Zel'dovich effect (SZE) signatures of a sample of 46 X-ray selected groups and clusters drawn from ∼6 deg^2 of the XMM–Newton Blanco Cosmology Survey. These systems extend to redshift z = 1.02 and probe the SZE signal to the lowest X-ray luminosities (≥10^(42) erg s^(−1)) yet; these sample characteristics make this analysis complementary to previous studies. We develop an analysis tool, using X-ray luminosity as a mass proxy, to extract selection-bias-corrected constraints on the SZE significance and Y500 mass relations. The former is in good agreement with an extrapolation of the relation obtained from high-mass clusters. However, the latter, at low masses, while in good agreement with the extrapolation from the high-mass SPT clusters, is in tension at 2.8σ with the Planck constraints, indicating the low-mass systems exhibit lower SZE signatures in the SPT data. We also present an analysis of potential sources of contamination. For the radio galaxy point source population, we find 18 of our systems have 843 MHz Sydney University Molonglo Sky Survey sources within 2 arcmin of the X-ray centre, and three of these are also detected at significance >4 by SPT. Of these three, two are associated with the group brightest cluster galaxies, and the third is likely an unassociated quasar candidate. We examine the impact of these point sources on our SZE scaling relation analyses and find no evidence of biases. We also examine the impact of dusty galaxies using constraints from the 220 GHz data. The stacked sample provides 2.8σ significant evidence of dusty galaxy flux, which would correspond to an average underestimate of the SPT Y_(500) signal that is (17 ± 9) per cent in this sample of low-mass systems. Finally, we explore the impact of future data from SPTpol and XMM-XXL, showing that it will lead to a factor of 4 to 5 tighter constraints on these SZE mass–observable relations.
118858625
High energy neutrino astrophysics with Super-Kamiokande
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.
118949476
Upward Showering Muons in Super‐Kamiokande
A small subset of neutrino‐induced upward going muons in the Super‐Kamiokande detector consists of high energy muons that undergo radiative energy losses through bremsstrahlung, e+e− pair production and photo‐nuclear interactions. The mean energy of the parent neutrinos of these showering upward muons is approximately 1 TeV, allowing the selection of a high energy sample of neutrinos. We present physics(mainly oscillation analysis) as well as astrophysical results with the upward showering muon dataset using about 1680 days of Super‐K‐I data.
324538
Constraints on the CMB temperature evolution using multiband measurements of the Sunyaev–Zel'dovich effect with the South Pole Telescope
The adiabatic evolution of the temperature of the cosmic microwave background (CMB) is a key prediction of standard cosmology. We study deviations from the expected adiabatic evolution of the CMB temperature of the form T(z) = T_0(1 + z)^(1 − α) using measurements of the spectrum of the Sunyaev–Zel'dovich effect with the South Pole Telescope (SPT). We present a method for using the ratio of the Sunyaev–Zel'dovich signal measured at 95 and 150 GHz in the SPT data to constrain the temperature of the CMB. We demonstrate that this approach provides unbiased results using mock observations of clusters from a new set of hydrodynamical simulations. We apply this method to a sample of 158 SPT-selected clusters, spanning the redshift range 0.05 < z < 1.35, and measure α=0.017^(+0.030)_(−0.028), consistent with the standard model prediction of α = 0. In combination with other published results, we find α = 0.005 ± 0.012, an improvement of ∼10 per cent over published constraints. This measurement also provides a strong constraint on the effective equation of state in models of decaying dark energy w_(eff) = −0.994 ± 0.010.