Searching for Physics Beyond the Standard Model

粒子物理学的最终目标是找到统一自然界中所有力和粒子的理论。第一步是将电磁力和弱力统一为单一的“电弱”力。粒子物理学的标准模型（SM），包括电弱和强作用力，成功地解释了基本上所有已知的实验数据。然而，它显然不是最终的理论——四种力中只有两种是统一的，而且SM留下了许多未解之谜。因此，必然存在“超越SM的物理学”，也就是说，不能仅用SM来解释的现象。寻找这种“新物理学”（NP）是当今粒子物理学家面临的最重要的问题。在过去的4-5年里，有许多NP的迹象，特别是在b - bbbb10的过渡中。这些是在“b工厂”BaBar和Belle在各种b介子衰变中首次发现的。强子实验CDF和DØ支持这一趋势，在其他几个B衰变模式中发现了与SM预测的分歧。把所有的结果放在一起，似乎b - bbb5np很可能存在。不幸的是，这并没有得到大型强子对撞机的支持：大型强子对撞机重新测量了上述一些量，并发现结果与SM一致。底线是现在NP的提示比以前少了。即便如此，在几个不同的领域仍然存在NP的潜在信号。在某些B和D衰变中，在强子对撞机的t- bar产生中，甚至在希格斯粒子的衰变中，都有NP的迹象。此外，NP模型通常预测可能在大型强子对撞机中产生的新的奇异粒子的存在。我的研究项目涉及许多这些领域。他们都有一个共同的目标：参与对新物理学的探索。

The ultimate goal of particle physics is to find the theory that unifies all the forces and particles in Nature. A first step has been taken with the unification of the electromagnetic and weak forces into a single "electroweak" force. The Standard Model (SM) of particle physics, which includes the electroweak and the strong forces, successfully explains essentially all known experimental data. Nevertheless, it is clearly not the final theory -- only two of the four forces are unified, and the SM leaves many questions unanswered. Thus, there must be "physics beyond the SM," that is, phenomena that cannot be explained by the SM alone. The search for this "new physics" (NP) is the most important problem facing particle physicists today.There were a number of hints of NP over the past 4-5 years, particularly in b -> s transitions. These were first seen at the "B-factories" BaBar and Belle in various B-meson decays. The hadronic experiments CDF and DØ supported this trend, finding disagreements with the SM predictions in several other B decay modes. Putting all the results together, it appeared that b -> s NP might well be present. Unfortunately, this has not been supported by the LHC: LHCb has remeasured a number of the above quantities, and finds results in agreement with the SM. The bottom line is that there are now fewer hints of NP than there were before.Even so, there are still potential signals of NP in several different areas. There are hints of NP in certain B and D decays, in t-tbar production at hadron colliders, and even in the decay of the Higgs. Furthermore, NP models generally predict the existence of new, exotic particles, which might be produced at the LHC. My research projects touch many of these areas. They all have one common goal: to participate in the search for new physics.