The distribution of interplanetary dust between 0.96 and 1.04 AU as inferred from impacts on the STEREO spacecraft observed by the Heliospheric Imagers
ArXiv 1111.4389 (2011)
Abstract:
The distribution of dust in the ecliptic plane between 0.96 and 1.04 AU has been inferred from impacts on the two STEREO spacecraft through observation of secondary particle trails and unexpected off-points in the Heliospheric Imager (HI) cameras. This study made use of analysis carried out by members of a distributed web-based project, Solar Stormwatch. A comparison between observations of the brightest particle trails and a survey of fainter trails shows consistent distributions. While there is no obvious correlation between this distribution and the occurrence of individual meteor streams at Earth, there are some broad longitudinal features in these distributions that are also observed in sources of the sporadic meteor population. The asymmetry in the number of trails seen by each spacecraft and the fact that there are many more unexpected off-points in the HI-B than in HI-A, indicates that the majority of impacts are coming from the apex direction. For impacts causing off-points in the HI-B camera these dust particles are estimated to have masses in excess of 10-17 kg with radii exceeding 0.1 μm. For off-points observed in the HI-A images, which can only have been caused by particles travelling from the anti-apex direction, the distribution is consistent with that of secondary 'storm' trails observed by HI-B, providing evidence that these trails also result from impacts with primary particles from an anti-apex source. It is apparent that the differential mass index of particles from the apex direction is consistently above 2. This indicates that the majority of the mass is within the smaller particles of this population. In contrast, the differential mass index of particles from the anti-apex direction (causing off-points in HI-A) is consistently below 2, indicating that the majority of the mass is to be found in larger particles of this distribution.Search for new phenomena with the monojet and missing transverse momentum signature using the ATLAS detector in s=7TeV proton-proton collisions
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 705:4 (2011) 294-312
Abstract:
A search for new phenomena in events featuring a high energy jet and large missing transverse momentum in proton-proton collisions at s=7TeV is presented using a dataset corresponding to an integrated luminosity of 33 pb-1 recorded with the ATLAS detector at the Large Hadron Collider. The number of observed events is consistent with the Standard Model prediction. This result is interpreted in terms of limits on a model of Large Extra Dimensions. © 2011 CERN.Search for high-mass resonances decaying into ZZ in p$\bar{p}$ collisions at $\sqrt{s}=1.96$\,TeV
(2011)
Analysis of the decay D0→KS0π0π0
Physical Review D - Particles, Fields, Gravitation and Cosmology 84:9 (2011)
Abstract:
We present the results of a Dalitz plot analysis of D0→KS0π0π0 using the CLEO-c data set of 818pb-1 of e+e- collisions accumulated at √s=3.77GeV. This corresponds to 3×106 D0D̄0 pairs from which we select 1259 tagged candidates with a background of 7.5±0.9 percent. Several models have been explored, all of which include the K*(892), K2*(1430), K *(1680), the f0(980), and the σ(500). We find that the combined π0π0 S-wave contribution to our preferred fit is (28.9±6.3±3.1)% of the total decay rate while D0→K ̄*(892)0π0 contributes (65.6±5. 3±2.5)%. Using three tag modes and correcting for quantum correlations we measure the D0→KS0π0π0 branching fraction to be (1.058±0. 038±0.073)%. © 2011 American Physical Society.Measurement of the tt̄ production cross section in pp collisions at 7 TeV in lepton+jets events using b-quark jet identification
Physical Review D - Particles, Fields, Gravitation and Cosmology 84:9 (2011)