Constraints on new physics from observing B hadrons at the large hadron collider

随着大型强子对撞机(LHC)将于2008年投入使用，我们正在进入粒子物理学的一个新时代。这是迄今为止建造的最强大的粒子加速器，具有巨大的发现潜力。质子在这台机器中加速到接近光速，在探测器内部相互碰撞。这些非常高能量碰撞的产物是大量的基本粒子，它们足够重，需要产生大量的能量。希望通过分析这些粒子，我们可以追踪到一些我们以前没有见过的新粒子。这是新粒子发现的直接途径。我的研究建议是关于探测新粒子的间接方法。如上所述，我们可以看到大型强子对撞机有望产生大量的重夸克，也就是所谓的b夸克。因此，我们能够观察到这些夸克的非常罕见的衰变，这种衰变发生的可能性很小。这些罕见的衰变有时很容易受到重得多的粒子的干扰，这些粒子可能存在，但尚未被发现。我提议的调查是为了更好地了解这些干扰，然后将其与大型强子对撞机的实验数据进行比较。这一比较有望为我们提供一些线索，说明对于未知的重粒子来说，什么是可以接受的，什么是不能接受的。当我们大致知道在哪里寻找某物时，直接发现它要容易得多。

We are entering in a new era in particle physics as the Large Hadron Collider (LHC) will become operational in 2008. This is the most powerfull particle accelerator that has been constructed so far and has enormous discovery potentials. Protons are accelerated in this machine to close to the speed of light, made colliding with each other inside the detectors. The product of these very high energy collision are a large number of elementary particles that are heavy enough that require large energies to be produced. The hope is, through analyzing these particles we can trace some new particles that we have not seen before. This is the direct way of new particle discovery. My research proposal is about indirect methods of detecting new particles. As mentioned above, we can LHC is expected to produce a large number of heavy quarks known as b quarks. Therefore, we are able to observe even very rare decays of these quarks which have a small likelihood to happen. These rare decays are sometimes quite susceptible to the interference from much heavier particles that may be out there but have not been discovered yet. My proposed investigation is to have a better understanding of these interferences which can then be compared against the experimental data from LHC. This comparison will hopefully give us some clues on what is acceptable and what is not acceptable for unknown heavy particles. It is much easier to directly discover something when we know roughly where to look for it.