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We measure proton structure parameters sensitive primarily to valence quarks using 8.6 fb$^{-1}$ of data collected by the D0 detector in $\sqrt{s}=1.96$ TeV $p\bar{p}$ collisions at the Fermilab Tevatron. We exploit the property of the…

High Energy Physics - Experiment · Physics 2024-03-15 D0 Collaboration

The forward-backward charge asymmetry (AFB) at hadron colliders is sensitive to both the electroweak (EW) symmetry breaking represented by the effective weak mixing angle, and the proton structure information in the initial state modeled by…

High Energy Physics - Phenomenology · Physics 2022-08-17 Siqi Yang , Yao Fu , Minghui Liu , Liang Han , Tie-Jiun Hou , C. -P. Yuan

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

We quantify the constraints on the flavour separation between the quarks and antiquarks in the proton provided by the recent forward weak gauge boson production data from the LHCb experiment at $\sqrt{s}=7$ and 8 TeV. Performed in the…

High Energy Physics - Phenomenology · Physics 2017-05-15 Juan Rojo

The increasing precision of the measurements on the proton structure and an improved treatment of the correlated systematic experimental errors constitute a major step forward in our understanding of the flavour decomposition of the proton…

High Energy Physics - Experiment · Physics 2009-11-07 Martin Erdmann

Global analyses of Parton Distribution Functions (PDFs) have provided incisive constraints on the up and down quark components of the proton, but constraining the other flavor degrees of freedom is more challenging. Higher-order theory…

High Energy Physics - Phenomenology · Physics 2012-05-29 A. Kusina , T. Stavreva , S. Berge , F. I. Olness , I. Schienbein , K. Kovarik , T. Jezo , J. Y. Yu , K. Park

In this paper, forward-backward asymmetry and differential cross section of top quark in flavor violating $Z'$ model up to $\mathscr{O}(\alpha_s^2 \alpha_X)$ at Tevatron are calculated. In order to account for the top observed large…

High Energy Physics - Phenomenology · Physics 2010-09-21 Bo Xiao , You-kai Wang , Shou-hua Zhu

The fundamental building blocks of the proton, quarks and gluons, have been known for decades. However, we still have an incomplete theoretical and experimental understanding of how these particles and their dynamics give rise to the…

Background: The spatial distribution of charge and magnetization in the proton and neutron are encoded in the nucleon electromagnetic form factors. The form factors are all approximated by a simple dipole function, normalized to the charge…

Nuclear Experiment · Physics 2013-05-30 I. A. Qattan , J. Arrington

Among different measured observables of top-antitop quark pairs at hadron colliders, the forward-backward asymmetry ($A_{\text{FB}}$) measured by the CDF and D0 collaborations has inconsistency with the Standard Model prediction. The…

High Energy Physics - Phenomenology · Physics 2013-02-21 Sara Khatibi , Mojtaba Mohammadi Najafabadi

The difference in angular distributions between top quarks and antiquarks, commonly referred to as the charge asymmetry, is measured in pp collisions at the LHC with the CMS experiment. The data sample corresponds to an integrated…

High Energy Physics - Experiment · Physics 2012-08-27 CMS Collaboration

Over the years, comprehensive experiments have shown a fact that the nucleons, such as the proton and neutron, are formed by not only the "valence" up and down quarks which were thought to comprise the nucleons in a simple constituent…

High Energy Physics - Experiment · Physics 2025-10-13 WenHao Ma , Siqi Yang , Mingzhe Xie , Minghui Liu , Liang Han , C. -P. Yuan

In this study, the proton is taken as an ensemble of quark-gluon Fock states. Using the principle of detailed balance, the probabilities of finding every Fock states of the proton are obtained without any parameter. A new origin of the…

High Energy Physics - Phenomenology · Physics 2008-11-26 Yong-Jun Zhang , Bin Zhang , Bo-Qiang Ma

In this article we present a review of the structure of the proton and the current status of our knowledge of the parton distribution functions (PDFs). The lepton-nucleon scattering experiments which provide the main constraints in PDF…

High Energy Physics - Experiment · Physics 2013-03-20 Emmanuelle Perez , Eram Rizvi

The experimental data taken from both Drell-Yan and deep-inelastic scattering (DIS) experiments suggest a sign-change in $\bar d(x) - \bar u(x)$ flavor asymmetry in the proton at large values of momentum fraction $x$. In this work, we…

High Energy Physics - Phenomenology · Physics 2017-12-21 Maral Salajegheh , Hamzeh Khanpour , S. Mohammad Moosavi Nejad

At the LHC, top quark pairs are dominantly produced from gluons, making it difficult to measure the top quark forward-backward asymmetry. To improve the asymmetry measurement, we study variables that can distinguish between top quarks…

High Energy Physics - Phenomenology · Physics 2015-05-28 Yang Bai , Zhenyu Han

The energy-momentum tensor form factors furnish information on the mechanics of the proton. It is essential to compute the generalized isovector-vector form factors to examine the flavor structure of the energy-momentum tensor form factors.…

High Energy Physics - Phenomenology · Physics 2024-02-07 Ho-Yeon Won , Hyun-Chul Kim , June-Young Kim

We present an improved determination of the up- and down-quark distributions in the proton using recent data on charged lepton asymmetries from $W^\pm$ gauge-boson production at the LHC and Tevatron. The analysis is performed in the…

High Energy Physics - Phenomenology · Physics 2017-01-04 S. Alekhin , J. Bluemlein , S. Moch , R. Placakyte

The excess in top quark forward-backward asymmetry has been a hot topic in recent years. Although there are many proposals to explain it, most of them can not fit the differential distributions well. The color octet axial-vector like…

High Energy Physics - Phenomenology · Physics 2013-06-18 Li Tianjun , Wan Xia , Wang You-kai , Zhu Shou-hua

We present a new measurement of the forward-backward asymmetry in ttbar production in ppbar collisions in the lepton+jets channel at D0. We measure asymmetries from two different observables and unfold the data to allow the results to be…

High Energy Physics - Experiment · Physics 2019-08-14 Douglas Orbaker
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