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相关论文: $A_{FB}$ in the SMEFT: precision Z physics at the …

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The Standard Model effective field theory (SMEFT) provides a general framework to include the dynamics of the beyond standard model physics residing at a certain higher energy scale $\Lambda$. We study the top-quark production along with a…

高能物理 - 唯象学 · 物理学 2022-12-07 Monoranjan Guchait , Arnab Roy

We discuss forward-backward charge asymmetries for lepton pair production in association with a large transverse momentum jet at hadron colliders. The measurement of the lepton charge asymmetry relative to the jet direction A_{FB}^j gives a…

高能物理 - 唯象学 · 物理学 2009-11-07 F. del Aguila , Ll. Ametller , P. Talavera

We study the cross section \sigma and Forward-Backward asymmetry A_{FB} in the process pp \to \gamma^*,Z \to \ell^+\ell^- (with \ell=e,\mu) for determinations of Parton Distribution Functions (PDFs) of the proton. We show that, once mapped…

高能物理 - 唯象学 · 物理学 2019-03-19 E. Accomando , J. Fiaschi , F. Hautmann , S. Moretti

It is notorious that, contrary to all other precision electroweak data, the forward-backward asymmetry for b quarks $A_{FB}^b$ measured in Z decays at LEP1 is nearly three standard deviations away from the predicted value in the Standard…

高能物理 - 唯象学 · 物理学 2008-11-26 Abdelhak Djouadi , Gregory Moreau , Francois Richard

We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH,…

The striking success of the Standard Model in explaining precision data and, at the same time, its lack of explanations for various fundamental phenomena, such as dark matter or the baryon asymmetry of the universe, suggests new physics at…

高能物理 - 唯象学 · 物理学 2025-04-23 Gino Isidori , Felix Wilsch , Daniel Wyler

We present a novel framework for carrying out global analyses of the Standard Model Effective Field Theory (SMEFT) at dimension-six: SMEFiT. This approach is based on the Monte Carlo replica method for deriving a faithful estimate of the…

高能物理 - 唯象学 · 物理学 2019-05-01 Nathan P. Hartland , Fabio Maltoni , Emanuele R. Nocera , Juan Rojo , Emma Slade , Eleni Vryonidou , Cen Zhang

The four LEP experiments and the SLD detector have measured the Z partial widths for Z decays into b and c quarks and the corresponding forward-backward asymmetries at centre-of-mass energies close to the Z boson mass. The results yield a…

高能物理 - 实验 · 物理学 2019-08-14 Wolfgang Liebig

Lepton and quark asymmetries at Z boson peak are a powerful means to test the couplings of the Z boson to fermions. The measurements performed at LEP and SLC colliders are reviewed, and their impact on the determination of the electroweak…

高能物理 - 实验 · 物理学 2007-05-23 Vitaliano Ciulli

This note gives an overview of the tools for the precision matching of ultraviolet theories to the Standard Model effective field theory (SMEFT) at the tree level and one loop. Several semi- and fully automated codes are presented, as well…

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…

高能物理 - 唯象学 · 物理学 2013-02-21 Sara Khatibi , Mojtaba Mohammadi Najafabadi

The CMS programme of indirect searches in the top-quark sector interprets precision measurements in the Standard Model Effective Field Theory (SMEFT) framework. These proceedings summarize recent CMS results highlighted in the TOP2025 talk:…

高能物理 - 实验 · 物理学 2026-01-12 Andrea Piccinelli

Forward-backward asymmetries $A_{FB}^t$ and $A_{FB}^\ell$ are observed in the top quark $t$ rapidity distribution and in the rapidity distribution of charged leptons $\ell$ from top quark decay at the Tevatron proton-antiproton collider,…

高能物理 - 唯象学 · 物理学 2014-03-11 Edmond L. Berger , Qing-Hong Cao , Chuan-Ren Chen , Hao Zhang

There have been several important recent developments in precision electroweak tests. These include: the new LEP energy scan during the 1993 run; the first high-precision results on the left-right asymmetry from the SLD Collaboration at…

高能物理 - 唯象学 · 物理学 2007-05-23 Paul Langacker

The forward-backward asymmetry of $b$-quarks measured at LEP in $e^+e^-$ collisions at the Z pole, $A_{FB}^{0,b}|^{\rm exp} = 0.0992\pm0.0016$, remains today the electroweak precision observable with the largest disagreement (2.8$\sigma$)…

高能物理 - 实验 · 物理学 2018-06-08 David d'Enterria , Cynthia Yan

The existence of Beyond Standard Model (BSM) physics is firmly suggested by both experimental observations (Dark Matter, neutrino masses) and theoretical arguments. In the hypothesis that the scale of new physics is considerably higher than…

高能物理 - 唯象学 · 物理学 2021-09-08 Luca Mantani

The Randall-Sundrum scenario with Standard Model fields in the bulk and a custodial symmetry is considered. We determine the several minimal quark representations allowing to address the anomalies in the forward-backward b-quark asymmetry…

高能物理 - 唯象学 · 物理学 2011-01-12 Charles Bouchart , Grégory Moreau

We present a measurement of the forward-backward charge asymmetry ($A_{FB}$) in $p\bar{p} \to Z/\gamma^{*}+X \to e^+e^-+X$ events at a center-of-mass energy of 1.96 TeV using 1.1 fb$^{-1}$ of data collected with the D0 detector at the…

高能物理 - 实验 · 物理学 2008-12-18 D0 Collaboration , V. M. Abazov

We compute the one-loop corrections to $Z$ decay properties from dimension-6 operators in the Standard Model Effective Field Theory (SMEFT) that contribute also to anomalous 3-gauge boson couplings and examine the relative sensitivity of…

高能物理 - 唯象学 · 物理学 2018-11-14 Sally Dawson , Ahmed Ismail

We discuss the impact of many previously neglected effects of higher dimensional operators when fitting to Electroweak Precision data (EWPD) in the Standard Model Effective Field Theory (SMEFT). We calculate the general case of $2…

高能物理 - 唯象学 · 物理学 2017-07-18 Laure Berthier , Michael Trott