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The top asymmetries measured at the Tevatron, and the discrepancy in the di-photon Higgs rate under investigation at the LHC represent two possible hints of physics beyond the Standard Model (SM). In this paper we address the possibility to…

High Energy Physics - Phenomenology · Physics 2015-06-12 Wei-Chih Huang , Alfredo Urbano

Motivated by a possible anomaly in the forward-backward (FB) asymmetry of top quark (A_{\rm FB}) observed at the Tevatron, we perform a model independent analysis on q \bar{q} \to t \bar{t} using an effective lagrangian with dim-6…

High Energy Physics - Phenomenology · Physics 2014-11-20 Dong-Won Jung , P. Ko , Jae Sik Lee , Soo-hyeon Nam

High precision data of lepton angular distributions in inclusive $Z$ boson production, reported by the CMS and ATLAS Collaborations, showed pronounced transverse momentum ($q_T$) dependencies of the $A_0$ and $A_2$ coefficients. Violation…

High Energy Physics - Phenomenology · Physics 2019-10-02 Jen-Chieh Peng , Wen-Chen Chang , Randall Evan McClellan , Oleg Teryaev

We introduce a new asymmetry in the decay t -> W b -> l nu b, which is shown to be directly proportional to the polarisation of the top quark along a chosen axis, times a sum of W helicity fractions. The latter have already been precisely…

High Energy Physics - Phenomenology · Physics 2015-06-11 J. A. Aguilar-Saavedra , R. V. Herrero-Hahn

The exchange of a light $t$-channel flavor-changing gauge boson, $\Vp$, with mass $\sim m_{top}$ remains a leading explanation for the anomalous forward backward asymmetry in top quark production at the Tevatron. Unlike other ideas,…

High Energy Physics - Phenomenology · Physics 2013-05-29 Sunghoon Jung , Aaron Pierce , James D. Wells

We propose two new observables to measure the charge asymmetry in hadronic top-quark pair production in association with a hard jet. The incline asymmetry, based on the inclination between the planes of initial- and final-state momenta,…

High Energy Physics - Phenomenology · Physics 2013-09-27 Stefan Berge , Susanne Westhoff

In these proceedings, a measurement of the differential cross section of top quark-antiquark pair ($\text{t}\bar{\text{t}}$) production in association with one additional jet ($\text{t}\bar{\text{t}}$+jet) as a function of the inverse of…

High Energy Physics - Experiment · Physics 2022-07-28 Sebastian Wuchterl

The measurements of the top quark charge asymmetry performed by the ATLAS and CMS experiments at the LHC are presented. The focus is on the single lepton and dilepton decay channels of the tt system. Both inclusive and differential top…

High Energy Physics - Experiment · Physics 2012-11-27 U. De Sanctis

We present a new observable, $\Delta \phi$, an azimuthal angle difference between $t$ and $\bar{t}$ quarks in $t\bar{t}$ pair production, at hadron colliders as an interesting probe of the radiative quantum chromodynamics process as well as…

High Energy Physics - Phenomenology · Physics 2013-05-30 Suyong Choi , Hyun Su Lee

We discuss lepton charge asymmetries in $t \bar t$ and $t \bar t \gamma$ production at the LHC, which can be measured in the semileptonic decay channel $t \bar t \to W^+ b \, W^- \bar b \to \ell^+ \nu b \, q \bar q' \bar b$ (or the charge…

High Energy Physics - Phenomenology · Physics 2018-07-04 J. A. Aguilar-Saavedra

I present results for high-order corrections from threshold resummation to cross sections and differential distributions in top-antitop pair production and in single-top production. I show aN$^3$LO results for the total $t{\bar t}$ cross…

High Energy Physics - Phenomenology · Physics 2015-09-28 Nikolaos Kidonakis

We determine the dominant missing Standard Model (SM) contribution to the top quark pair forward-backward asymmetry at the Tevatron. Contrary to past expectations, we find a large, around 27%, shift relative to the well-known value of the…

High Energy Physics - Phenomenology · Physics 2015-07-30 Michal Czakon , Paul Fiedler , Alexander Mitov

We investigate a charge asymmetry in $t \bar t \gamma$ production at the LHC that provides complementary information to the measured asymmetries in $t \bar t$ production. We estimate the experimental uncertainty in its measurement at the…

High Energy Physics - Phenomenology · Physics 2015-06-18 J. A. Aguilar-Saavedra , E. Alvarez , A. Juste , F. Rubbo

We study the determination of the top-quark mass using leptonic observables in t-channel single top-quark production at the LHC. We demonstrate sensitivity of transverse momentum of the charged lepton on the input top-quark mass. We present…

High Energy Physics - Phenomenology · Physics 2021-04-28 Mei Sen Gao , Shu Run Yuan , Jun Gao

A measurement of the correlations between the polar angles of leptons from the decay of pair-produced $t$ and $\bar{t}$ quarks in the helicity basis is reported, using proton-proton collision data collected by the ATLAS detector at the LHC.…

High Energy Physics - Experiment · Physics 2016-01-20 ATLAS Collaboration

The forward-backward asymmetry ($A_{FB}$) in the Drell-Yan process $pp/p\bar p \to Z/\gamma^* \to \ell^+\ell^-$ is sensitive to the proton structure information. Such information has been factorized into well-defined proton structure…

High Energy Physics - Experiment · Physics 2023-03-15 Mingzhe Xie , Siqi Yang , Yao Fu , Minghui Liu , Liang Han , Tie-Jiun Hou , Sayipjamal Dulat , C. -P. Yuan

The forward-backward asymmetry in top pair production at Tevatron has been reconfirmed by the CDF collaboration with 5.3 fb^{-1} of accumulated data. These measurements also report that the asymmetry is the largest in regions of high…

High Energy Physics - Phenomenology · Physics 2011-04-22 Ketan M. Patel , Pankaj Sharma

Stringent tests on top quark production and decay mechanisms are provided by the measurement of the top quark and W boson polarization. This paper presents a detailed study of these two measurements with the ATLAS detector, in the…

High Energy Physics - Experiment · Physics 2014-11-17 F. Hubaut , E. Monnier , P. Pralavorio , V. Simak , K. Smolek

In the presence of an electric dipole coupling of t-tbar to a photon, and an analogous "weak" dipole coupling to the Z, CP violation in the process e+e- --> t tbar results in modified polarization of the top and anti-top. This polarization…

High Energy Physics - Phenomenology · Physics 2008-11-26 Saurabh D. Rindani

An overview of the most recent measurements on top quark charge asymmetry in top quark pair production is presented. The results are obtained using data collected with ATLAS and CMS detectors in proton-proton collisions at centre-of-mass…

High Energy Physics - Experiment · Physics 2017-03-13 Mohsen Naseri
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