Radiative corrections to the forward-backward asymmetry in $e^+e^-\toπ^+π^-$
Gilberto Colangelo, Martin Hoferichter, Joachim Monnard, Jacobo Ruiz de Elvira
备注：
16 pages, 3 figures; numerical results for the corrections included as supplemental material; corrected treatment of endpoint singularity, including mixed term in real part
We present a calculation of the $C$-odd radiative corrections to $e^+e^-\to π^+π^-$ in a dispersive formalism, concentrating on the leading pion-pole contribution in the virtual box diagrams. In particular, we show how the effect of a general pion vector form factor in the loop integral can be incorporated in a model-independent way and how the cancellation of infrared singularities proceeds in this case. The numerical results, dominated by the infrared enhanced contributions, indicate significant corrections beyond scalar QED, essentially confirming recent findings in generalized vector-meson-dominance models.
Mass dependent top forward backward asymmetry in the effective Lagrangian approach: Addendum to "Model independent analysis of the forward-backward asymmetry of top quark production at the Tevatron"
We compute the order $α_s^2$ QCD corrections to the $b$-quark forward-backward asymmetry in $e^+e^-\to b{\bar b}$ collisions at the $Z$ boson resonance, taking the non-zero mass of the $b$ quark into account. We determine these corrections with respect to both the $b$-quark axis and the thrust axis definition of the asymmetry. We compute also the distributions of these axes with respect to the electron beam. If one neglects the flavor singlet contributions to the $b$-quark asymmetry, as was done in previous computations for massless $b$ quarks, then the second-order QCD corrections for $m_b\ne…
Possible Common Origin of the Top Forward-backward Asymmetry and the CDF Dijet Resonance
色单中性矢量玻色子被认为是顶部前后不对称和CDF双射流共振的可能共同起源。我们确定手性和风味结构的耦合，这种新的矢量玻色子的标准模型夸克，其中一个可以容纳这两个数据。我们还证明了，非零观测量涉及纵向顶部偏振可以提供有用的标准可能存在的宇称违反新的物理在q q^bar -> t t^bar过程中，和区分的味道保存和味道违反的情况。
We review in some detail the QCD corrections to the measurement of the forward-backward charge asymmetry of heavy quarks in the $\mathrm{e^+e^-\rightarrow Q\overline{Q}(g)}$ process at the Z pole. We show that the size of these corrections can be reduced by an order of magnitude by using simple cuts on jet acollinearity. Such a reduction is expected to lead to systematic uncertainties at the $Δ\mathrm{A_{FB}^{0,Q}} \approx 10^{-4}$ level, opening up the path to high precision electroweak measurements with heavy flavors at future high luminosity $\mathrm{e^+e^-}$ colliders like the FCC-ee.
Cross section and single transverse target spin asymmetry for backward pion electroproduction
核子-介子跃迁分布振幅（TDA）是核子-介子态之间非定域三夸克算符的非对角矩阵元，它是在共线因式分解描述的介子从核子反向排斥电生过程中产生的.下面我们将讨论π介子到核子时间分辨模型的问题。我们提出了一个因式分解的四重分布与软π介子定理的输入π N TDAs的。为了满足多项式性质在其完整的形式的频谱表示补充与D-项一样的贡献，从核子交换的u-通道的反应。我们提出了我们的估计后向π介子电产生非极化截面和它的横向目标单自旋不对称性在我们的复合模型为π N TDAs。
The QED initial state corrections are calculated to the forward-backward asymmetry for $e^+e^- \rightarrow γ^*/{Z^{0}}^*$ in the leading logarithmic approximation to $O(α^6 L^6)$ extending the known corrections up to $O(α^2 L^2)$ in analytic form. We use the method of massive on-shell operator matrix elements and present the radiators both in Mellin-$N$ and momentum fraction $z$-space. Numerical results are presented for various energies around the $Z$-peak by also including energy cuts. These corrections are of relevance for the precision measurements at the FCC$\_$ee.
The bottom quark forward-backward asymmetry $A_{\rm{FB}}$ is a key observable in electron-positron collisions at the $Z^{0}$ peak. In this paper, we employ the Principle of Maximum Conformality (PMC) to fix the $α_s$-running behavior of the next-to-next-to-leading order QCD corrections to $A_{\rm{FB}}$. The resulting PMC scale for this $A_{\rm{FB}}$ is an order of magnitude smaller than the conventional choice $μ_r=M_Z$. This scale has the physically reasonable behavior and reflects the virtuality of its QCD dynamics, which is independent to the choice of renormalization scale. Our analyses sh…
We study the impact of the inclusion of Neutral Current (NC) DY data from LHC mapped in the Forward-Backward Asymmetry ($A_{\rm FB}$) observable on PDF uncertainties, using the open source platform \texttt{xFitter}. We find that $A_{\rm FB}$ enables new PDF sensitivity at current and future luminosity stages of LHC.
Forward-backward (charge) asymmetry in the processes of $e^+e^-$ annihilation into a pair of charged pseudoscalar mesons is recalculated in the one-loop approximation. The exact dependence on the meson masses is taken into account. Results known in the literature are partially corrected. The bulk of the charge asymmetry appears due to double-photon exchange in $s$ channel. Experimental studies of the asymmetry can be used to verify the point-like approximation used in calculation of radiative corrections due to emission of photons by pions or kaons.
