Dr
Mario Giordani
(INFN Trieste (IT))
7/6/12, 9:00โฏAM
In 7 TeV proton - proton collisions at the LHC, pairs of top and anti-top quarks are expected to be mostly produced through gluon fusion, in contrast to production at the Tevatron, where quark annihilation dominates.
The ATLAS experiment has now recorded a large number of top quark pairs, allowing this domain to be explored in detail. We present measurements of top-quark charge asymmetry...
Dr
Thorsten Chwalek
(KIT - Karlsruhe Institute of Technology (DE))
7/6/12, 9:15โฏAM
Track 4 - Top Quark Physics
Parallel Sessions
A measurement is presented of the charge asymmetry in top-pair production in proton-proton collisions at the LHC at a centre-of-mass energy of 7 TeV. The data are collected by the CMS experiment during the year 2011. The analysis uses events with one charged lepton and at least four jets. In order to measure the charge asymmetry in charge-symmetric initial state processes, the difference of...
Dr
Chris Hays
(University of Oxford (UK))
7/6/12, 9:30โฏAM
Track 4 - Top Quark Physics
Parallel Sessions
The most intriguing property of top-quark physics observed so far is the forward-backward asymmetry in the production of top-quark pairs in proton anti-proton collisions at the Fermilab Tevatron. An unexpectedly sizable effect has observed in both the semi-leptonic and the all-leptonic decay channels of top-quark pairs, exceeding significantly the standard model predictions, and has motivated...
Dr
Alexander Josef Grohsjean
(DESY (DE) & Centre d'Etudes de Saclay (FR))
7/6/12, 9:45โฏAM
Track 4 - Top Quark Physics
Parallel Sessions
We present measurements of the forward-backward asymmetry and the lepton charge asymmetry in lepton plus jets and dilepton final states in top antitop quark pair production in proton antiproton collisions, using up to 10 fb-1 of data collected by D0 in Run II. We present unfolded results corrected for acceptance and resolution effects. In case of the lepton plus jets channel the analysis is...
Prof.
Kaladi S. Babu
(Oklahoma State University (US))
7/6/12, 10:00โฏAM
Track 4 - Top Quark Physics
Parallel Sessions
The CDF and D0 experiments have reported measurements of the top quark forward-backward asymmetry A_{FB} which are (2.5-3.5) sigma away from the standard model predictions. In this talk it will be shown that this anomaly can be explained by new physics that arises when the flavor symmetry of the standard model is gauged in a maximal way. The flavor gauge symmetry would provide an...
Dr
Sudhir Kumar Gupta
(Monash University (AU))
7/6/12, 11:00โฏAM
Track 4 - Top Quark Physics
Parallel Sessions
Recent measurements on the top-quark forward-backward asymmetry (A_FB) by the two (CDF & D0) Tevatron experiments show a more than 3 sigma deviation from the Standard Model prediction from the SM expectation of 5.2 ยฑ 0.6%. Later about 3.1sigma enhancement was established on the basis of considering top-pairs only from the large tt_bar invariant mass region. In this talk, we will discuss about...
Dr
Barbara Alvarez Gonzalez
(Michigan State University (US))
7/6/12, 11:15โฏAM
Track 4 - Top Quark Physics
Parallel Sessions
We present searches for single top-quark production in the s-channel at 7 TeV proton-proton collisions with the ATLAS detector at the Large Hadron Collider. Limits. The result of a search for an exotic Wโ boson production in the single top quark s-channel is also given.
Dr
Markus Cristinziani
(Universitaet Bonn (DE) & CERN)
7/6/12, 11:30โฏAM
Track 4 - Top Quark Physics
Parallel Sessions
Results on the search for flavor-changing neutral-currents (FCNC) in top-quark production and decay are reported, with data collected with the ATLAS detector at a center-of-mass energy of sqrt(s) = 7 TeV. The single top quark topology is used to place limits on sigma(qg -> t) x B(t -> Wb) (q=u,c). A search is also performed for top-quark pair events, with one top quark decaying through the...
Dr
Yuan Chao
(National Taiwan University (TW))
7/6/12, 11:45โฏAM
Track 4 - Top Quark Physics
Parallel Sessions
A search for flavor changing neutral currents in top quark decays is presented using a sample of top quark pair event candidates decaying via Wb and Zq into lฮฝb and llq events. The search is performed at the CMS experiment at the LHC, using a data sample recorded in proton-proton collisions at a center-of-mass energy of 7 TeV. The observed number of events agrees with the standard model...
Prof.
German Valencia
(Iowa State University (US))
7/6/12, 12:00โฏPM
Track 4 - Top Quark Physics
Parallel Sessions
The LHC will produce large numbers of top anti-top quark pairs providing an excellent opportunity to study in detail the properties of the top-quark. We discuss the use of T-odd correlations to extract information on the CP violating couplings of the top-quark at the LHC. We illustrate our discussion with two examples: CP violating anomalous top quark couplings; and CP violation in extended...
Dr
Azeddine Kasmi
(Baylor University (US))
7/6/12, 12:15โฏPM
Track 4 - Top Quark Physics
Parallel Sessions
We report a search for a narrow ttbar resonance that decays into a lepton+jets final state based on an integrated luminosity of 5.3/fb of proton-antiproton collisions at sqrt(s)=1.96 TeV collected by the D0 Collaboration at the Fermilab Tevatron Collider. We set upper limits on the production cross section of such a resonance multiplied by its branching fraction to ttbar which we compare to...
Prof.
Freya Blekman
(Inter-University Institute for High Energies (BE))
7/6/12, 2:00โฏPM
Track 4 - Top Quark Physics
Parallel Sessions
A measurement of the top-pair mass distribution in tt events is presented using proton-proton collision events at the LHC at a centre-of-mass energy of 7 TeV. The data are collected with the CMS experiment during the year 2011. The analysis is performed using several final states originating from top-pair production. The measurement is then used to search for massive resonances decaying into...
Dr
Marcel Vos
(Universidad de Valencia (ES))
7/6/12, 2:15โฏPM
Track 4 - Top Quark Physics
Parallel Sessions
Several extensions of the Stand ard Model predict the presence of new particles that couple to the top quark. With the dataset of proton - proton collisions collected by the ATLAS detector at the Large Hadron Collider we present searches for reson ances decaying to top - quark pairs.
Mr
Ken Mimasu
(University of Southampton (UK))
7/6/12, 2:30โฏPM
Track 4 - Top Quark Physics
Parallel Sessions
We study the sensitivity of top-antitop samples produced at all energy stages of the Large Hadron Collider (LHC) to the nature of an underlying Z' boson, in presence of full tree level standard model (SM) background effects and relative interferences. We concentrate on differential mass spectra as well as both spatial and spin asymmetries thereby demonstrating that exploiting combinations of...
Ms
Estefania Coluccio Leskow
(Buenos Aires University (AR))
7/6/12, 2:45โฏPM
Track 4 - Top Quark Physics
Parallel Sessions
We propose a phenomenological model with a flavour changing electrically-neutral but not self-conjugated Z' to simultaneously explain the large Tevatron ttbar forward-backward asymmetry and the compatible with zero LHC charge asymmetry. We find that the model produces a natural cancellation in pp collisions which is suppressed in Tevatron's ppbar collisions, leading to a large...
Prof.
Chung Kao
(University of Oklahoma (US))
7/6/12, 3:00โฏPM
Track 4 - Top Quark Physics
Parallel Sessions
We investigate the prospects for the discovery of a top quark decaying into one light Higgs boson along with a charm quark in top quark pair production at the CERN Large Hadron Collider (LHC). A general two Higgs doublet model is adopted to study the signature of flavor changing neutral Higgs interactions for $t \to c\phi^0$ or $\bar{t} \to \bar{c}\phi^0$ where $\phi^0$ is a CP-even scalar...
Prof.
Kenneth Bloom
(University of Nebraska-Lincoln (US))
7/6/12, 3:15โฏPM
Track 4 - Top Quark Physics
Parallel Sessions
We present new direct constraints on a general Wtb interaction using data corresponding to an integrated luminosity of 5.4 fb-1 collected by the D0 detector at the Tevatron ppbar collider. The standard model provides a purely left-handed vector coupling at the Wtb vertex, while the most general, lowest dimension Lagrangian allows right-handed vector and left- or right-handed tensor couplings...
Dr
Marcelle Soares-Santos
(Fermi National Accelerator Laboratory (US))
7/6/12, 4:00โฏPM
Track 11. Particle Astrophysics and Cosmology
Parallel Sessions
The Dark Energy Survey Collaboration will soon begin a 5000 sq. deg. imaging survey of the southern galactic cap using a new 3 sq. deg., 520 Megapixel CCD camera, the Dark Energy Camera (DECam), with 5 filters (g,r,i,z and Y) mounted on the Blanco 4-meter telescope at the Cerro-Tololo Inter-American Observatory. Construction of DECam is complete, and installation and commissioning on the...
Dr
Signe Riemer-Sorensen
(University of Queensland)
7/6/12, 4:15โฏPM
Track 11. Particle Astrophysics and Cosmology
Parallel Sessions
The absolute neutrino mass scale is currently unknown, but can be constrained from cosmology. We use the large-scale structure information from the WiggleZ Dark Energy Survey to constrain the sum of neutrino masses. The WiggleZ high redshift star-forming blue galaxy sample is less sensitive to systematic effects from non-linear structure formation, pairwise galaxy velocities, redshift-space...
Prof.
Kwang-Chang Lai
(Chang Gung University (TW))
7/6/12, 4:30โฏPM
Track 11. Particle Astrophysics and Cosmology
Parallel Sessions
The determination of neutrino flavor transition mechanisms by neutrino telescopes is discussed. We parametrize these mechanisms in a basis which is very convenient for classifying flavor transition models.At very high energies (>10PeV), It is investigated that the electron neutrino fraction can be extracted without identifying muon and tau neutrinos by the neutrino telescope, such as ARA. We...
Mr
Matthias Danninger
(Stockholm University (SE))
7/6/12, 4:45โฏPM
Track 11. Particle Astrophysics and Cosmology
Parallel Sessions
Construction of the IceCube neutrino observatory was completed in early 2011, including a low-energy in-fill extension. This DeepCore sub-detector offers exciting opportunities for neutrino physics in the energy range of 10 GeV to 1 TeV. IceCube searches indirectly for dark matter via neutrinos from dark matter self-annihilations and has a high discovery potential through striking signatures....
Dr
Juan de Dios Zornoza Gomez
(IFIC (ES))
7/6/12, 5:00โฏPM
Track 11. Particle Astrophysics and Cosmology
Parallel Sessions
ANTARES is the largest neutrino telescope Northern hemisphere. It consists of a three-dimensional array of 885 photomultipliers to collect the Cherenkov light induced by relativistic muons produced in CC interactions of high energy neutrinos. One of the main scientific goals of the experiment is the search for dark matter. We present here the analysis of the recently unblinded data taken...
Prof.
Yeongduk Kim
(Sejong University (KR))
7/6/12, 5:15โฏPM
Track 11. Particle Astrophysics and Cosmology
Parallel Sessions
KIMS (Korea Invisible Mass Search) experiment has run its 100kg setup for last three years. We have given a new WIMP interaction rates for spin-independent and spin-dependent limits with 24524 kgdays data. We have further analyzed for the annual modulation amplitude with the last 3 years data. An analysis will be presented which has a limit comparable to DAMA's modulation amplitude. We have...
Dr
Karen Gibson
(Case Western Reserve University (US))
7/6/12, 5:30โฏPM
Track 11. Particle Astrophysics and Cosmology
Parallel Sessions
The Large Underground Xenon (LUX) experiment consists of a two-phase xenon time projection chamber, which is being deployed at a depth of 4850 feet in the Homestake mine in Lead, South Dakota. When LUX begins operation in Fall 2012 it will be the worldโs most sensitive dark matter detector, with a fiducial target mass of 100 kg. Results from a surface lab commissioning and calibration run of...
Dr
Jelena Maricic
(Drexel University (US))
7/6/12, 5:45โฏPM
Track 11. Particle Astrophysics and Cosmology
Parallel Sessions
DarkSide represents a staged program for direct detection of dark matter utilizing two-phase argon time projection chamber with the goal of achieving a high sensitivity limit or convincing detection of dark matter.
The first stage in the program is DarkSide-10, a 10 kg prototype detector that was running in Laboratori Nazionali del Gran Sasso Counting Test Facility (CTF) during summer of...
