Measurement of dijet cross-sections in pp collisions at 7 TeV centre-of-mass energy using the ATLAS detector
Measurement of dijet cross-sections in pp collisions at 7 TeV centre-of-mass energy using the ATLAS detector
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DOI：
10.1007/jhep05(2014)059
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发表时间：
2014-05-14
影响因子：
5.4
通讯作者：
Zwalinski, L.
中科院分区：
文献类型：
--
作者：
Aad, G.;Abajyan, T.;Zwalinski, L.
在大型强子对撞机上质心能量为7TeV的PP碰撞中测得的双微分双喷流截面是双喷流质量和两个最高p(T)喷流快度分离的一半的函数。这些测量值是使用ATLAS探测器在2011年记录的4.5fb(-1)的积分光度数据获得的。数据针对探测器效应进行了校正，以便在粒子水平上显示横截面。用喷流半径参数为0.4和0.6的反k(T)算法重建的喷注，测量了5TeV喷注质量以下的截面。用NLOJET++对截面进行了修正，将截面与次前导微扰QCD计算进行了比较，以考虑非微扰效应。文中还给出了与POWHEG预测的比较结果，该预测使用的是与部分子簇射蒙特卡罗模拟相连接的次要阶矩阵元计算。在这两种情况下，都考虑了电弱效应。用频域方法对用部分子分布函数的各种参数得到的数据和理论预测进行了定量比较。总的来说，当使用CT10、NNPDF2.1和MSTW 2008 PDF集时，NLOJET++理论预测与数据符合得很好。当使用ABM11和HERAPDF1.5PDF集合时，观察到在某些范围的喷射质量和一半的快速分离时不一致。给出了一个设置接触相互作用模型合成比例下限的例子，表明展开的结果可以用来限制对喷气生产的贡献，而不是标准模型所预测的贡献。
Double-differential dijet cross-sections measured in pp collisions at the LHC with a 7 TeV centre-of-mass energy are presented as functions of dijet mass and half the rapidity separation of the two highest-p(T) jets. These measurements are obtained using data corresponding to an integrated luminosity of 4.5 fb(-1), recorded by the ATLAS detector in 2011. The data are corrected for detector effects so that cross-sections are presented at the particle level. Cross-sections are measured up to 5 TeV dijet mass using jets reconstructed with the anti-k(t) algorithm for values of the jet radius parameter of 0.4 and 0.6. The cross-sections are compared with next-to-leading-order perturbative QCD calculations by NLOJet++ corrected to account for non-perturbative effects. Comparisons with POWHEG predictions, using a next-to-leading-order matrix element calculation interfaced to a parton-shower Monte Carlo simulation, are also shown. Electroweak effects are accounted for in both cases. The quantitative comparison of data and theoretical predictions obtained using various parameterizations of the parton distribution functions is performed using a frequentist method. In general, good agreement with data is observed for the NLOJet++ theoretical predictions when using the CT10, NNPDF2.1 and MSTW 2008 PDF sets. Disagreement is observed when using the ABM11 and HERAPDF1.5 PDF sets for some ranges of dijet mass and half the rapidity separation. An example setting a lower limit on the compositeness scale for a model of contact interactions is presented, showing that the unfolded results can be used to constrain contributions to dijet production beyond that predicted by the Standard Model.