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年投入运行，我们正在进入粒子物理学的新时代。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。质子在这台机器中被加速到接近光速，在探测器内相互碰撞。这些高能碰撞的产物是大量的基本粒子，它们足够重，需要很大的能量才能产生。希望是，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。这是发现新粒子的直接途径。我的研究计划是关于间接检测新粒子的方法。如上所述，我们可以预期大型强子对撞机将产生大量的重夸克，即b夸克。因此，我们能够观察到这些夸克非常罕见的衰变，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更重的粒子的干扰，这些粒子可能在那里，但尚未被发现。我建议的调查是更好地理解这些干扰，然后与LHC的实验数据进行比较。这种比较有望给我们一些线索，告诉我们对于未知的重粒子，什么是可以接受的，什么是不可接受的。当我们大致知道在哪里寻找某样东西时，直接发现它就容易得多。

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.