Conveners
Top Quark Physics: Chaired by Zack Sullivan
- Reinhard Schwienhorst (Michigan State University)
- Zack Sullivan (Argonne National Laboratory)
Top Quark Physics: Chaired by Kirill Melnikov
- Zack Sullivan (Argonne National Laboratory)
- Reinhard Schwienhorst (Michigan State University)
Top Quark Physics: Chaired by Liang Li
- Zack Sullivan (Argonne National Laboratory)
- Reinhard Schwienhorst (Michigan State University)
Top Quark Physics: Chaired by Nick Kidonakis
- Reinhard Schwienhorst (Michigan State University)
- Zack Sullivan (Argonne National Laboratory)
Top Quark Physics: Chaired by Venkat Kaushik
- Reinhard Schwienhorst (Michigan State University)
- Zack Sullivan (Argonne National Laboratory)
Top Quark Physics: Chired by Reinhard Schwienhorst
- Reinhard Schwienhorst (Michigan State University)
- Zack Sullivan (Argonne National Laboratory)
Kirill Melnikov
(Johns Hopkins University)
8/9/11, 2:00โฏPM
Top Quark Physics
Parallel contribution
I will present a theoretical overview of the top quark physics.
I will discuss the status of theoretical description of various processes at hadron colliders that are used to extract the information about dynamics of top quarks, and their quantum numbers such mass, spin and charge.
Liang Li
(University of California Riverside)
8/9/11, 2:30โฏPM
Top Quark Physics
Parallel contribution
We present measurements of the inclusive top quark pair production cross section in ppbar collisions at sqrt(s)=1.96 TeV utilizing data corresponding to an integrated luminosity of 5.3 fb-1 collected with the D0 detector at the Fermilab Tevatron collider. We both final states with one charged lepton, at least two jets and missing transverse energy, or final states with two charged leptons, at...
Prof.
Karl Ecklund
(Rice University)
8/9/11, 2:50โฏPM
Top Quark Physics
Parallel contribution
We give an overview of the most recent results on top quark properties and interactions, obtained using data collected with the CMS experiment during the years 2010-2011 at 7 TeV center-of-mass energy. Measurements are presented for both the inclusive top pair production cross section, using the dilepton, lepton+jets, hadronic and tau channels, as well as for various differential cross...
Dr
M Saleem
(University of Oklahoma, USA)
8/9/11, 3:10โฏPM
Top Quark Physics
Parallel contribution
We present measurements of the top-quark pair-production cross section
in proton-proton collisions at sqrt(s) = 7 TeV with the ATLAS detector
at the Large Hadron Collider. The cross sections are measured in the lepton+jets channels.
Daryl Hare
(Rutgers University)
8/9/11, 4:00โฏPM
Top Quark Physics
Parallel contribution
We present a measurement of the ttbar cross section as well as the first measurement of the top quark mass in hadronic tau + jets events from 1.96 TeV ppbar collisions at CDF. Events require a single lepton identified as a hadronic tau, missing Et, and 4 jets of which at least one must be tagged as a b jet. Both the cross section and the mass are extracted from unbinned likelihood functions....
Allison McCarn
(Department of Physics-Univ. Illinois at Urbana-Champaign)
8/9/11, 4:20โฏPM
Top Quark Physics
Parallel contribution
The top quark can be used as a probe of new physics, particularly when it decays into non-SM particles. One promising example is the decay of a top quark into a charged Higgs boson and b-quark. Charged Higgs bosons occur naturally in extended Higgs sectors and for a wide range of models can decay nearly exclusively into a tau lepton and a neutrino. In this talk, we summarize the searches for...
Prof.
Nikolaos Kidonakis
(Kennesaw State University)
8/9/11, 4:40โฏPM
Top Quark Physics
Parallel contribution
I present theoretical results for the top quark pair total cross section, and for the top quark transverse momentum and rapidity distributions at Tevatron and LHC energies. I also present results for single top quark production in the t- and s-channels and also via associated production with a W boson. The calculations include approximate NNLO corrections that are derived from NNLL soft-gluon...
Sadia Khalil
(Kansas State University)
8/9/11, 5:00โฏPM
Top Quark Physics
Parallel contribution
We present several measurements of the top-pair production cross section in proton-proton collisions at the LHC at a centre-of-mass energy of 7 TeV. We use data collected with the CMS experiment during the year 2011. Measurements are presented in the lepton+jets final state, where events are selected by requiring exactly one isolated and highly energetic muon or electron, and at least four...
Prof.
Zack Sullivan
(Illinois Institute of Technology)
8/9/11, 5:20โฏPM
Top Quark Physics
Parallel contribution
The observation of a peak in the dijet invariant mass of the Wjj signal by the CDF Collaboration has caused great excitement. We demonstrate that this peak can be explained as the same upward fluctuations CDF observes in both t-channel and s-channel single-top-quark production. A peak in the dijet spectrum is expected, because CDF used a Monte Carlo simulation to subtract the single-top...
Marco Bentivegna
8/9/11, 5:40โฏPM
Top Quark Physics
Parallel contribution
We present a search for a new particle T' decaying to a top quark via T'-> t + X, where X goes undetected. We use a data sample corresponding to 5.7 inverse fb of integrated luminosity of ppbar collisions with sqrt(s) = 1.96 TeV, collected at Fermilab Tevatron by the CDF II detector. Our search for pair production of T' is focused on the hadronic decay channel, ppbar -> T'Tbar' -> ttbar + XX...
Dr
Thomas Speer
(Department of Physics-Brown University)
8/10/11, 2:00โฏPM
Top Quark Physics
Parallel contribution
We present a measurement of the inclusive single top production cross section in proton-proton collisions at the LHC at a centre-of-mass energy of 7 TeV, using data collected with the CMS experiment during the year 2011. The analysis considers decay channels where the W from the top decays into electron-neutrino or muon-neutrino, and makes use of kinematic characteristics of electroweak single...
Reinhard Schwienhorst
(Michigan State University)
8/10/11, 2:20โฏPM
Top Quark Physics
Parallel contribution
We present measurements of the single top production cross in ppbar collisions at sqrt(s)=1.96 TeV using data collected with the D0 detector and corresponding to up to 5.4 fb-1 of integrated luminosity. We obtain both measurements of the inclusive production cross section as well measurements for the separate s- and t-channel production processes. These measurements are used to set constraints...
Zhenbin Wu
(Baylor University)
8/10/11, 2:40โฏPM
Top Quark Physics
Parallel contribution
The top quark was discovered at the CDF and D0 experiments in 1995.Its properties within the Standard Model are fully defined. The measurement of the top quark mass and the verification of the expected properties have been an important topic of experimental top quark physics since. We will present the recent measurements of top quark properties in CDF.
Jenny Holzbauer
(Michigan State University)
8/10/11, 3:00โฏPM
Top Quark Physics
Parallel contribution
We use 2011 data from the ATLAS detector to isolate the production of single-top quarks. This electroweak top-quark production is expected to be sensitive to new physics such as flavor changing neutral currents or W' production, and can also be an important background for processes like the Higgs boson production. The data for this analysis are collected from collisions occurring at 7 TeV...
Carrie McGivern
(University of Kansas)
8/10/11, 3:20โฏPM
Top Quark Physics
Parallel contribution
We present a search for flavor changing neutral currents
in decays of top quarks. The analysis is based on a search for
$t\bar{t}\rightarrow\ell'\nu\ell\bar{\ell}$+jets ($\ell, \ell' = e,\mu$) final
states using 4.1~{\rm fb}$^{-1}$ of integrated luminosity of $p\bar{p}$
collisions at $\sqrt{s} = 1.96$~{\rm TeV}. We extract limits on the branching
ratio $B(t\rightarrow Zq)$ ($q = u, c$...
Ms
Peisi Huang
(Department of Physics-University of Wisconsin-Madison)
8/10/11, 4:30โฏPM
Top Quark Physics
Parallel contribution
The LHC is a top factory: in the SM about 8,000 top pairs should have been produced with more than 47 pbโ1 integrated luminosity already taken per detector at 7 TeV. Since the LHC center-of-mass energy is high compared to the top mass, the tops will typically be highly boosted, so that the decay products are close to each other. Thus, in the detector, at first sight, the top decay products may...
Venkatesh Kaushik
(University Of Arizona)
8/10/11, 4:50โฏPM
Top Quark Physics
Parallel contribution
Several Beyond the Standard Model (BSM) theories predict the
existence of new resonances that decay into ttbar pairs.
We describe a search for such resonances using lepton plus
jet data collected by the ATLAS experiment in pp collisions
at Sqrt(s)=7 TeV. The selection criteria and search method
are presented. In the absence of signal, we produce
95% CL limits on the production cross...
Brock Tweedie
(Boston University)
8/10/11, 5:10โฏPM
Top Quark Physics
Parallel contribution
Top-antitop pairs produced in the decay of a new heavy resonance will exhibit spin correlations that contain valuable coupling information. When the tops decay, these correlations imprint themselves on the angular patterns of the final quarks and leptons. I will discuss how to probe the structure of a resonance's couplings to tops by measuring the azimuthal angles of the tops' decay products...
Salvatore Rappoccio
(Department of Physics and Astronomy-Johns Hopkins University (J)
8/10/11, 5:30โฏPM
Top Quark Physics
Parallel contribution
We present a measurement of the top-pair mass in tt events by using proton-proton collisions at the LHC at a centre-of-mass energy of 7 TeV. We use data collected with the CMS experiment during the year 2011. The analysis is performed in all possible final states originating from top-pair production, and the full event reconstruction is performed by using different reconstruction methods...
Kenneth Bloom
(Department of Physics and Astronomy-University of Nebraska)
8/10/11, 5:50โฏPM
Top Quark Physics
Parallel contribution
We measure the correlation between the spin of the top quark and the
spin of the anti-top quark in $t\bar{t} \rightarrow W^{+}bW^{-}\bar{b}$
final states produced in $p\bar{p}$ collisions at a center of mass energy $\sqrt{s}=1.96$~TeV,
using data collected with the D0 detector at the Fermilab Tevatron collider.
The correlation is extracted using a double differential angular...
Douglas Orbaker
(University of Rochester)
8/11/11, 10:30โฏAM
Top Quark Physics
Parallel contribution
We present measurements of the integrated forward-backward charge asymmetry in $t\bar{t}$ production in $p\bar{p}$ collisions using data collected with the D0 detector at the Fermilab Tevatron collider, using both the lepton+jets and dilepton final states. We present the raw measurement as well as results obtained after correcting for acceptance and detector effects and present also...
Dr
Edmond Berger
(ANL)
8/11/11, 10:50โฏAM
Top Quark Physics
Parallel contribution
The forward-backward asymmetry for top quarks measured in proton-antiproton collisions at the Tevatron shows a large deviation from
standard model expectations. Among possible interpretations, the exchange of a non-universal $Z^\prime$ is of some interest as it naturally predicts a top quark in the forward region of large rapidity. To reproduce the size of the Tevatron asymmetry, the...
Zhenyu Han
(Harvard University)
8/11/11, 11:10โฏAM
Top Quark Physics
Parallel contribution
We explore methods for improving the top quark forward-backward asymmetry measurement at the LHC. We identify variables which distinguish top pairs produced from gluons versus quarks. These variables include the top quark rapidity, mass and rapidity of the top-antitop system, the top quark polarization and the top-antitop spin correlation. We obtain the best axes for measuring the top quark...
Tobias Golling
(Physics Department-Yale University)
8/11/11, 11:30โฏAM
Top Quark Physics
Parallel contribution
With 7 TeV proton-proton collisions data collected by the ATLAS
detector we present searches for anomalous top-quark production and
decay in several channels , including a search for top-quark pair
production with anomalous missing transverse energy, top-quark pair
resonances, fourth generation quarks decaying to top quarks.
Such phenomena can arise from a number of Standard Model extensions.
Dr
Sudhir Gupta
(Iowa State University)
8/11/11, 11:50โฏAM
Top Quark Physics
Parallel contribution
Models with a non-universal Z' exhibit in general flavor changing neutral currents FCNC at tree-level. When the Z' couplings favor the third generation, flavor changing transitions of the form Z'tc and Z'tu could be large enough to be observable at the LHC. In this talk I will discuss some interesting LHC signatures of (a) associated production of a top with the Z', and, (b) the same sign tops...
Markus Schulze
(Johns Hopkins University)
8/12/11, 8:00โฏAM
Top Quark Physics
Parallel contribution
I would like to present results for hadronic top quark pair production in association with a photon at next-to-leading order accuracy.This process allows a direct measurement of the top quark electromagnetic couplings that, at the moment, are only loosely constraint. Top quark decays are treated in the narrow width approximation and spin correlations of all final state particles are accounted...
Aram Avetisyan
(Department of Physics-Brown University)
8/12/11, 8:40โฏAM
Top Quark Physics
Parallel contribution
The mass of the top quark is a fundamental parameter of the Standard Model. We present a measurements of the top quark mass in proton-proton collisions at the LHC at a centre-of-mass energy of 7 TeV using data collected by the CMS experiment during the year 2011. Measurements are presented in all possible final states originating from top-pair production, and the different reconstruction...
Yuriy Ilchenko
(Southern Methodist University (SMU))
8/12/11, 9:00โฏAM
Top Quark Physics
Parallel contribution
We present measurments of the top quark mass and width obtained using a data sample corresponding to 5.4 fb-1 of integrated luminosity collected with the D0 detector at the Fermilab Tevatron collider. The top quark mass is obtained via the direct reconstruction of the two t-->Wb decays in ttbar events selected in the dilepton+jets+missing transverse energy and lepton+jets+missing transverse...
Amitabha Das
(University of Arizona)
8/12/11, 9:20โฏAM
Top Quark Physics
Parallel contribution
We present a measurement of the helicity of the W boson produced in top quark decays using $t\bar{t}$ ~decays in the $\ell+$jets and dilepton final states selected from a sample of 5.4 fb$^{-1}$ of collisions recorded using the D0 detector at the Fermilab Tevatron $p\bar{p}$ collider. We measure the fractions of longitudinal and right-handed $W$ bosons to be $f_0 = 0.669 \pm 0.102 \mbox{ } [...
Michael Andrew Segala
(Department of Physics-Brown University)
8/12/11, 9:40โฏAM
Top Quark Physics
Parallel contribution
We present a measurement of the charge asymmetry in top-pair production in proton-proton collisions at the LHC at a centre-of-mass energy of 7 TeV. We use data 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...
