论文标题
Electron-Proton深度非弹性散射在HERA的横向能量能量相关性
Transverse Energy-Energy Correlations of jets in the electron-proton Deep Inelastic Scattering at HERA
论文作者
论文摘要
我们研究事件形状变量，横向能量相关性TEEC $（\ cos ϕ）$及其不对称的Ateec $（\ cos ϕ）$在Electron-Proton Collider Hera的深度无弹性散射（DIS）中，其中$ ϕ $是使用TransverseMentMentum $（K__T）定义的两个Jets的$ ϕ $。在HERA，在BREIT框架中定义了喷气机，而领先的非平凡横向能量相关性来自3射流构型。借助NloJet ++，这些功能以领先顺序（LO）和QCD的临近顺序（LO）计算，在Electron-Proton质量中心能量$ \ sqrt {s} = 314 $ GEV处。我们将角区域限制在$ -0.8 \ leq \ cos ϕ \ leq 0.8 $，因为前向和向后角区域需要重新亮相的对数校正，这在这项工作中已经忽略了。在HERA进行了实验性喷射分析后，我们限制了dis-variables $ x $，$ y = q^2/（x s）$，其中$ q^2 = -q^2 $是动量转移平方$ q^2 $的负数$（η^{\ rm {lab}}）$ to range $ -1 \ leqη^{\ rm {lab}} \ leq 2.5 $。 TEEC和ATEEC功能在$ q^2 $中的两个范围中进行了处理，定义为$ 5.5〜 {\ rm Gev}^2 \ leq Q^2 \ leq Q^2 \ leq 80〜 {\ rm gev}^2 $，称为低 - $ q^2 $ - range，and $ 150〜 { 1000〜 {\ rm gev}^2 $，称为高 - $ q^2 $ - range。我们显示了这些功能在Parton分布函数（PDF），分解$（μ_F）$和重新归一化$（μ_R）$ scales以及$α_S（M_z）$上的灵敏度。在这些相关性中，与改变比例$μ_f$和pdfs相关性是稳定的，但它们确实取决于$μ_r$。这些研究可用于分析HERA数据，包括从形状变量中确定$α_s（M_z）$。
We study the event shape variables, transverse energy energy correlation TEEC $(\cos ϕ)$ and its asymmetry ATEEC $(\cos ϕ)$ in deep inelastic scattering (DIS) at the electron-proton collider HERA, where $ϕ$ is the angle between two jets defined using a transverse-momentum $(k_T)$ jet algorithm. At HERA, jets are defined in the Breit frame, and the leading nontrivial transverse energy energy correlations arise from the 3-jet configurations. With the help of the NLOJET++, these functions are calculated in the leading order (LO) and the next-to-leading order (NLO) approximations in QCD at the electron-proton center-of-mass energy $\sqrt{s}=314$ GeV. We restrict the angular region to $-0.8 \leq \cos ϕ\leq 0.8$, as the forward- and backward-angular regions require resummed logarithmic corrections, which we have neglected in this work. Following experimental jet-analysis at HERA, we restrict the DIS-variables $x$, $y=Q^2/(x s)$, where $Q^2=-q^2$ is the negative of the momentum transfer squared $q^2$, to $0 \leq x \leq 1$, $0.2 \leq y \leq 0.6$, and the pseudo-rapidity variable in the laboratory frame $(η^{\rm {lab}})$ to the range $-1 \leq η^{\rm {lab}} \leq 2.5$. The TEEC and ATEEC functions are worked out for two ranges in $Q^2$, defined by $5.5~{\rm GeV}^2 \leq Q^2 \leq 80~{\rm GeV}^2$, called the low-$Q^2$-range, and $150~{\rm GeV}^2 \leq Q^2 \leq 1000~{\rm GeV}^2$, called the high-$Q^2$-range. We show the sensitivity of these functions on the parton distribution functions (PDFs), the factorization $(μ_F)$ and renormalization $(μ_R)$ scales, and on $α_s(M_Z)$. Of these the correlations are stable against varying the scale $μ_F$ and the PDFs, but they do depend on $μ_R$. These studies are useful in the analysis of the HERA data, including the determination of $α_s(M_Z)$ from the shape variables.
