17111273
Detection of SUSY Signals in Stau Neutralino Co‐annihilation Region at the LHC
We study the prospects of detecting the signal in the stau neutralino (τ1−χ10) co‐annihilation region at the LHC using tau (τ) leptons. The co‐annihilation signal is characterized by the τ1 and χ10 mass difference (ΔM) to be 5–15 GeV to be consistent with the WMAP measurement of the cold dark matter relic density as well as all other experimental bounds within the minimal supergravity model. Focusing on τ’s from χ20 → ττ → ττχ10 decays in g and q production, we consider inclusive E/T+jet+3 τ production, with two τ’s above a high ET threshold and a third τ above a lower threshold. Two observables, the number of opposite‐signed τ pairs minus the number of like‐signed τ pairs and the peak position of the di‐tau invariant mass distribution, allow for the simultaneous determination of ΔM and Mg. For ΔM = 9 GeV and Mg = 850 GeV with 30 fb−1 of data, we can measure ΔM to 15% and Mg to 6%.
116433170
Measurement of $\sigma(p \bar{p} \to Z) . {\rm Br}(Z \to 2\tau)$ in $p\bar{p}$ collisions at $sqrt{s}=1.96$ TeV
208867113
Search for anomalous production of events with a photon, jet, b-quark jet, and missing transverse energy
We thank Stephen Mrenna for teaching us how to implement the matching of matrix element n-jet channels. We 
also would like to thank Zack Sullivan for helpful discussions and Michel Herquet and Johann Alwall for providing 
resources and support for MADGRAPH. We thank the Fermilab staff and the technical staffs of the participating institutions for their vital contributions. This work was supported by the U.S. Department of Energy and National Science Foundation; the Italian Istituto Nazionale di Fisica Nucleare; the Ministry of Education, Culture, Sports, Science and Technology of Japan; the Natural Sciences and Engineering Research Council of Canada; the National Science Council of the Republic of China; the Swiss National Science Foundation; the A.P. Sloan Foundation; the Bundesministerium fur Bildung und Forschung, Germany; the Korean Science and Engineering Foundation and the Korean Research Foundation; the Science and Technology Facilities Council and the Royal Society, UK; the Institut National de Physique Nucleaire et Physique des Particules/CNRS; the Russian Foundation for Basic Research; the Ministerio de Ciencia e Innovacion, and Programa Consolider-Ingenio 2010, Spain; the Slovak RD and the Academy of Finland.
208261990
Precision measurement of the top quark mass from dilepton events at CDF II
We report a measurement of the top quark mass, M{sub t}, in the dilepton decay channel of t{bar t} {yields} b{ell}{prime}{sup +} {nu}{sub {ell}}, {bar b}{ell}{sup -}{bar {nu}}{sub {ell}} using an integrated luminosity of 1.0 fb{sup -1} of p{bar p} collisions collected with the CDF II detector. We apply a method that convolutes a leading-order matrix element with detector resolution functions to form event-by-event likelihoods; we have enhanced the leading-order description to describe the effects of initial-state radiation. The joint likelihood is the product of the likelihoods from 78 candidate events in this sample, which yields a measurement of M{sub t} = 164.5 {+-} 3.9(stat.) {+-} 3.9(syst.) GeV/c{sup 2}, the most precise measurement of M{sub t} in the dilepton channel.
199683787
Search for the Rare Radiative Decay: $W\rightarrow\pi\gamma$ in $p\bar{p}$ Collisions at $\sqrt{s} = 1.96$ TeV
We present a search for the rare radiative decay \wpigamma\ using data corresponding to an integrated luminosity of 4.3 \invfb\ of proton-antiproton collisions at a center of mass energy of 1.96 TeV collected by the CDF experiment at Fermilab. As no statistically significant signal is observed, we set a 95% confidence level upper limit on the relative branching fraction \bratio\ at $6.4\times 10^{-5}$, a factor of 10 improvement over the previous limit.
209832886
Model-independent and quasi-model-independent search for new physics at CDF
Data collected in run II of the Fermilab Tevatron are searched for indications of new electroweak scale physics. Rather than focusing on particular new physics scenarios, CDF data are analyzed for discrepancies with respect to the standard model prediction. A model-independent approach (Vista) considers the gross features of the data and is sensitive to new large cross section physics. A quasi-model-independent approach (Sleuth) searches for a significant excess of events with large summed transverse momentum and is particularly sensitive to new electroweak scale physics that appears predominantly in one final state. This global search for new physics in over 300 exclusive final states in 927pb-1 of pp collisions at s=1.96TeV reveals no such significant indication of physics beyond the standard model. © 2008 The American Physical Society.
18284065
PHASE MIXING IN MOND
Dissipationless collapses in Modified Newtonian Dynamics (MOND) have been studied by using our MOND particle-mesh N-body code, finding that the projected density profiles of the final virialized systems are well described by Sersic profiles with index m<4 (down to m~2 for a deep-MOND collapse). The simulations provided also strong evidence that phase mixing is much less effective in MOND than in Newtonian gravity. Here we describe "ad hoc" numerical simulations with the force angular components frozen to zero, thus producing radial collapses. Our previous findings are confirmed, indicating that possible differences in radial orbit instability under Newtonian and MOND gravity are not relevant in the present context.