University at Albany, Albany, New York, USA.
Nat Commun. 2011 Sep 6;2:463. doi: 10.1038/ncomms1472.
The dependence of the rate of proton-proton interactions on the centre-of-mass collision energy, √s, is of fundamental importance for both hadron collider physics and particle astrophysics. The dependence cannot yet be calculated from first principles; therefore, experimental measurements are needed. Here we present the first measurement of the inelastic proton-proton interaction cross-section at a centre-of-mass energy, √s, of 7 TeV using the ATLAS detector at the Large Hadron Collider. Events are selected by requiring hits on scintillation counters mounted in the forward region of the detector. An inelastic cross-section of 60.3 ± 2.1 mb is measured for ξ > 5×10⁻⁶, where ξ is calculated from the invariant mass, M(X), of hadrons selected using the largest rapidity gap in the event. For diffractive events, this corresponds to requiring at least one of the dissociation masses to be larger than 15.7 GeV.
质子-质子相互作用速率对质心碰撞能量 √s 的依赖性对于强子对撞机物理和粒子天体物理都具有重要的基础性意义。这种依赖性目前还不能从第一性原理进行计算；因此，需要进行实验测量。在这里，我们使用大型强子对撞机上的 ATLAS 探测器首次测量了质心能量为 √s = 7 TeV 时的非弹性质子-质子相互作用截面。通过要求探测器前向区安装的闪烁计数器有信号来选择事例。对于 ξ > 5×10⁻⁶，我们测量到的非弹性截面为 60.3 ± 2.1 mb，其中 ξ 是根据事件中最大横动量间隔选择的强子的不变质量 M(X) 计算得到的。对于散裂事件，这对应于至少有一个离解质量大于 15.7 GeV。
