论文标题
差速器$ t \ bar {t} $横截面测量，使用全速度最终状态中的增强顶夸克，用139 fb $^{ - 1} $ a atlas data
Differential $t\bar{t}$ cross-section measurements using boosted top quarks in the all-hadronic final state with 139 fb$^{-1}$ of ATLAS data
论文作者
论文摘要
在LHC上，Atlas检测器记录的单个，双分和三差横截面的测量值以13 $ \ text {tev} $ proton-proton碰撞为提升。顶部的夸克通过其强烈的衰变观察，并以大型射流喷气机的形式重建，而领先的射流具有横向动量（$ p _ {\ text {t}} $）大于500 GEV。展开观察到的数据以消除检测器效应。粒子水平的横截面乘以$ t \ bar {t} \ rightarrow w w w w w w b \ bar {b} $分支分支，并在信托相空间中测量，通过要求领先和第二个领先的喷气机以$ p _ {\ text}}> 500 $ geev和$ p _ _ {分别为$ 331 \ pm 3 \ text {（stat。）} \ pm 39 \ text {（syst。）} $ fb。这比$ 398^{+48} _ { - 49} $ fb的预测低约20 $ \％$，Powheg+Pythia 8具有近代订购（NLO）的精度，但在理论不确定性中保持一致。结果还显示在Parton级别上，其中Quark衰减，Parton淋浴和强膦的影响被去除，以便可以将它们与固定阶近级临时到领先阶（NNLO）计算进行比较。 Parton级横截面以类似于粒子级别的基准相空间测量，为$ 1.94 \ pm 0.02 \ text {（stat。）} \ pm 0.25 \ pm 0.25 \ text {（syst。）} $ pb。这与$ 1.96^{+0.02} _ { - 0.17} $ pb的NNLO预测一致。对于大多数NLO模型，发现与差分横截面的合理一致性，而NNLO计算通常与数据吻合。使用标准模型有效的现场理论形式主义来解释差分横截面，并将限制设置为几个四弗里尔式操作员的威尔逊系数。
Measurements of single-, double-, and triple-differential cross-sections are presented for boosted top-quark pair-production in 13 $\text{TeV}$ proton-proton collisions recorded by the ATLAS detector at the LHC. The top quarks are observed through their hadronic decay and reconstructed as large-radius jets with the leading jet having transverse momentum ($p_{\text{T}}$) greater than 500 GeV. The observed data are unfolded to remove detector effects. The particle-level cross-section, multiplied by the $t\bar{t} \rightarrow W W b \bar{b}$ branching fraction and measured in a fiducial phase space defined by requiring the leading and second-leading jets to have $p_{\text{T}} > 500$ GeV and $p_{\text{T}} > 350$ GeV, respectively, is $331 \pm 3 \text{(stat.)} \pm 39 \text{(syst.)}$ fb. This is approximately 20$\%$ lower than the prediction of $398^{+48}_{-49}$ fb by Powheg+Pythia 8 with next-to-leading-order (NLO) accuracy but consistent within the theoretical uncertainties. Results are also presented at the parton level, where the effects of top-quark decay, parton showering, and hadronization are removed such that they can be compared with fixed-order next-to-next-to-leading-order (NNLO) calculations. The parton-level cross-section, measured in a fiducial phase space similar to that at particle level, is $1.94 \pm 0.02 \text{(stat.)} \pm 0.25 \text{(syst.)}$ pb. This agrees with the NNLO prediction of $1.96^{+0.02}_{-0.17}$ pb. Reasonable agreement with the differential cross-sections is found for most NLO models, while the NNLO calculations are generally in better agreement with the data. The differential cross-sections are interpreted using a Standard Model effective field-theory formalism and limits are set on Wilson coefficients of several four-fermion operators.
