INTERACTING SUSY PARTICLES AT HADRON COLLIDERS
INTERACTING SUSY PARTICLES AT HADRON COLLIDERS
复制标题
强子对撞机上的多相粒子相互作用
DOI：
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发表时间：
1994
期刊：
影响因子：
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通讯作者：
P. Zerwas
中科院分区：
文献类型：
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作者：
J. Ohnemus;T. Walsh;P. Zerwas
非强相互作用的超对称粒子--slepton、charginos、neutralinos和带电的希格斯玻色子--很难在大型强子对撞机上被探测到。因此，我们研究了在LHC的虚拟γγ碰撞中产生这种粒子的可能性。由于光子可以从在辐射过程中不分裂的质子中发射出来，因此可以产生非常干净的事件，在一定程度上补偿了小事件数。对于一个或两个质子分裂的事件，以牺牲杂散强子为代价，预计会有更高的速率。大型强子对撞机（LHC）将大量产生有色超对称粒子--方子和胶子[1]。在这一领域，可以研究高达约2 TeV的质量范围。非强相互作用的超对称粒子--slepton、charginos/neutralinos和带电的Higgs玻色子--可以在ee对撞机上很容易地检测到。然而，在强子对撞机上找到这些粒子更具挑战性。Drell-Yan和gg聚变机制产生这些粒子的低生产率，然而，感兴趣的过程嵌入在一个复杂的，充满射流的环境中。带电的希格斯玻色子可以作为顶夸克的衰变产物被观察到，如果它们的质量足够小。夸克和胶子的级联衰变可以导致包括电荷伴子和中性伴子的最终态。然而，分析包含几种类型的未知粒子的级联不是一个简单的实验任务。因此，人们可能想知道是否可以利用其他反应来补充这些实验研究。本文研究了在强子对撞机γ-γ碰撞中寻找非强相互作用超对称粒子的可能性。这种方法的缺点显然是γγ亮度低，基本上被α的两次幂抑制，并且仅部分地被大的对数增强因子抵消。然而，低生产率的缺点在某种程度上被初始状态的简单拓扑结构和最终状态的潜在清洁环境所补偿。如果高能光子在辐射过程中不破坏初始质子或通过激发低质量态而发射，则情况在实验上是简单的。由于质子或低质量强子束碎片继续沿束方向行进，将产生干净的虚光子束。光子的横向动量被质子的半径（或其他较小但固定的小质量碎片半径）切断，因此光子光谱是标度不变的。基于严格弹性通道pp → pp+γγ的γ γ光度由图1中标记为[e e]的曲线表示。对于小光子能量，质子发射的光子的光谱由fγ/p（x）= α π 1 x log（
Non–strongly interacting supersymmetric particles – sleptons, charginos, neutralinos, and charged Higgs bosons – are difficult to detect at the Large Hadron Collider. We therefore examine the possibility of producing particles of this type in virtual γγ collisions at the LHC. Since photons can be emitted from protons which do not break up in the radiation process, very clean events can be generated, compensating to some extent for the small event numbers. Higher rates are expected, at the expense of stray hadrons, for events in which one or two protons break up. 1 γγ Luminosities Colored supersymmetric particles – squarks and gluinos – will be produced copiously at the Large Hadron Collider (LHC) [1]. The mass range up to about 2 TeV can be investigated in this sector. Non–strongly interacting supersymmetric particles – sleptons, charginos/neutralinos, and charged Higgs bosons – can be easily detected at ee colliders. However, it is much more challenging to find these particles at hadron colliders. The Drell–Yan and gg fusion mechanisms yield low production rates for these particles, futhermore, the processes of interest are embedded in a complicated, jet-filled environment. Charged Higgs bosons can be observed as decay products of top quarks if their mass is sufficiently small. Cascade decays of squarks and gluinos can lead to final states which include charginos and neutralinos. However, the analysis of cascades containing several types of unknown particles is not a simple experimental task. Thus one may wonder whether other reactions could be exploited to supplement these experimental searches. In this note we examine the possibility of searching for non–strongly interacting SUSY particles in γγ collisions at hadron colliders. The disadvantage of this method is obviously the low γγ luminosity, suppressed essentially by two powers of α and counterbalanced only partly by large logarithmic enhancement factors. However, the disadvantage of the low production rates is compensated to some extent by the simple topology of the initial state and the potentially clean environment of the final state. If the high energy photons are emitted without breaking up the initial protons in the radiation process or by exciting low-mass states, the situation is experimentally simple. Since the protons or the low mass hadron beam fragments continue travelling in the beam directions, a clean virtual photon beam will be generated. The transverse momentum of the photon is cut off by the radius of the proton (or some other smaller but fixed radius for low mass fragments) so that the photon spectrum is scale–invariant. The γγ luminosity based on the strictly elastic channel pp → pp+γγ is shown by the curve labeled [e∗e] in Fig. 1. For small photon energies the spectrum of photons emitted from protons is given by fγ/p(x) = α π 1 x log (