论文标题
衍射二极管的Gluon偶极分解
Gluon dipole factorisation for diffractive dijets
论文作者
论文摘要
在颜色偶极子图片中，用于小bjorken $ x $的深度非弹性散射，我们通过相干衍射研究了一对相对硬喷射的产生。通过“相对硬”，我们的意思是，两种喷气机的横向动量 - 夸克（$ q $）和Antiquark（$ \ bar {q} $）由虚拟光子的衰减产生的速度远大于目标饱和动量$ q_s（y_ _ _ _ {\ nathbb {p}} \ mathb {p}}） $ y _ {\ mathbb {p}} $。我们认为，典型的最终状态配置是这样的，即硬$ q \ bar q $ dijets伴有半硬gluon喷气机，横向动量的横向动量为$ q_s（y _ _ {\ mathbb {p {p}}）$。该第三射流的存在确保了散射很强，因此避免了由于颜色透明性而引起的独家（硬）二重产生的强烈抑制。对于这种“ 2+1”的喷射构型，我们证明了半硬gluon的发射及其用辐射靶的散射都可以根据有效的Gluon-Gluon偶极子进行分解。最初在[1-4]中提出的这种有效描述在颜色偶极子图片和共线分解之间建立了一个桥梁：衍射2+1喷头的横截面可以写作作为描述$ q \ bar {q} $ dijets的硬因子之间的产品，表达了表达近距离的gluon gluon extrymentegrated gluon的分布。后者受到黑色磁盘极限中的Gluon偶极子散射的控制，因此对Gluon饱和非常敏感。通过整合3架喷气机的运动学，我们获得了$ q \ bar {q} g $贡献对划线形式的衍射结构函数的贡献。
Within the colour dipole picture for deep inelastic scattering at small Bjorken $x$, we study the production of a pair of relatively hard jets via coherent diffraction. By "relatively hard" we mean that the transverse momenta of the two jets -- the quark ($q$) and the antiquark ($\bar{q}$) generated by the decay of the virtual photon -- are much larger than the target saturation momentum $Q_s(Y_{\mathbb{P}})$ evaluated at the rapidity gap $Y_{\mathbb{P}}$. We argue that the typical final-state configurations are such that the hard $q\bar q$ dijets are accompanied by a semi-hard gluon jet, with a transverse momentum of the order of $Q_s(Y_{\mathbb{P}})$. The presence of this third jet ensures that the scattering is strong and thus avoids the strong suppression of exclusive (hard) dijet production due to colour transparency. For such "2+1" jet configurations, we demonstrate that both the emission of the semi-hard gluon and its scattering with the hadronic target can be factorised in terms of an effective gluon-gluon dipole. This effective description, originally proposed in [1-4], builds a bridge between the colour dipole picture and collinear factorisation: the cross-section for diffractive 2+1 jets can be written as the product between a hard factor describing the $q\bar{q}$ dijets and a semi-hard factor expressing the unintegrated gluon distribution of the Pomeron. The latter is controlled by gluon dipole scattering in the black disk limit and hence is strongly sensitive to gluon saturation. By integrating out the kinematics of the 3 jets, we obtain the $q\bar{q}g$ contribution to the diffractive structure function in collinearly-factorised form.
