Ultraforward particle production from color glass condensate and Lund fragmentation
Ultraforward particle production from color glass condensate and Lund fragmentation
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DOI：
10.1103/physrevd.94.054004
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发表时间：
2016-05
影响因子：
5
通讯作者：
J. Albacete;P. Rodr'iguez;Y. Nara
中科院分区：
文献类型：
--
作者：
J. Albacete;P. Rodr'iguez;Y. Nara
我们提出了一个分析的数据，在高能质子质子和质子核的超快，8.8\ensuremath {\le}y\ensuremath {\le}10.8$的LHCf合作测量的单包含π介子生产。我们还分析了正演RHIC数据的校准目的。我们的分析依赖于使用的Monte Carlo事件发生器相结合的基础上的混合形式主义的彩色玻璃凝聚体的强子化的框架内的隆德字符串碎裂模型的实施在部分子水平的基本散射过程的微扰描述。这个过程使我们能够达到产生的粒子的动量值，与实验检测到的一样低，${p}_{t}\ensuremath{\sim}0.1\text{ }\text{ }\mathrm{GeV}$。我们实现了一个很好的描述，在RHIC和LHC的带电粒子和中性π介子，分别和核修改因子的质子铅碰撞在LHC的单包谱。我们的研究结果增加了证据的想法，粒子生产在一个非常小的Bjorken $x$的域中的饱和效应编码的未整合的胶子分布的目标占主导地位。随着向前粒子生产的发展中的空气淋浴的关键重要性，我们强调，这种方法允许我们的结果的理论控制外推到超高能宇宙射线的规模，从而作为这个主题的未来工作的起点。
We present an analysis of data on single inclusive pion production measured by the LHCf Collaboration in high-energy proton-proton and proton-nucleus at ultraforward rapidities, $8.8\ensuremath{\le}y\ensuremath{\le}10.8$. We also analyze forward RHIC data for calibration purposes. Our analysis relies on the use of a Monte Carlo event generator that combines a perturbative description of the elementary scattering process at partonic level based on the hybrid formalism of the color glass condensate with an implementation of hadronization in the framework of the Lund string fragmentation model. This procedure allows us to reach values of the momenta of the produced particles as low as detected experimentally, ${p}_{t}\ensuremath{\sim}0.1\text{ }\text{ }\mathrm{GeV}$. We achieve a good description of single inclusive spectra of charged particles and neutral pions at the RHIC and the LHC, respectively, and nuclear modification factors for proton-lead collisions at the LHC. Our results add evidence to the idea that particle production in the domain of a very small Bjorken $x$ is dominated by the saturation effects encoded in the unintegrated gluon distribution of the target. With forward particle production being of key importance in the development of air showers, we stress that this approach allows for a theoretically controlled extrapolation of our results to the scale of ultra-high-energy cosmic rays, thus serving as the starting point for future works on this topic.