Studies of the Higgs boson properties with the ATLAS experiment in LHC.

托马斯将研究新发现的希格斯玻色子的性质，该数据是由ATLAS合作在大型强子对撞机上收集的，质量中心=13TeV。研究希格斯玻色子最有效的途径是H到ZZ(*)到4L通道，它使用的是碰撞，在这个碰撞中，一个希格斯玻色子已经产生并衰变成Z玻色子，然后每个Z玻色子衰变成一对相反带电的电子或介子。这种衰变通道具有大型强子对撞机中最好的希格斯信号与背景比，并允许对粒子特性进行完整的研究。该项目的具体目的是：-利用ATLAS跟踪器和量热仪的全部能力，促进电子重建和识别算法的进一步发展。这对于H到ZZ(*)到4L的通道至关重要，其中所有四个轻子都可以是电子。-改进和细化H到ZZ(*)到4L的搜索。这一努力的目的是加强信号与后台进程的分离。它与轻子重建和识别的性能改进密切相关。-尽可能准确地确定希格斯玻色子的质量。希格斯玻色子的质量是SM中的一个自由参数，它影响着它的产生和衰减率。H到ZZ(*)到4l是该测量的最重要的通道之一。这是一个对电子性能的了解起着关键作用的测量的极好例子。-通过使用不同的希格斯产生机制来测量耦合，胶子-胶子融合(GGF)，矢量玻色子融合(VBF)，与弱玻色子(WH/ZH)相关的产物，在H到ZZ(*)到4L通道中。这将是确定希格斯玻色子耦合的一个有价值的信息，也是更好地理解它的本质的关键一步。预期在H至ZZ(*)至4L通道中的VBF和WH/ZH的速率在SM中相对较小，并且它们需要与占主导地位的GGF生产分开。因此，他们在H到ZZ(*)到4l通道的观测需要发展分析来检验基本的SM预测。在接下来的三年里，大型强子对撞机预计将在第二次运行期间以13TeV的质量能量提供~100Fb-1。这将导致H到ZZ(*)到4L通道的可用统计增加~10倍。如果观察到与SM模型预测的重大偏差，将探索超越SM理论的丰富现象学。如果新的希格斯玻色子的性质与SM的期望一致，那么更高的可用能量和更大的数据量将允许对新发现的希格斯玻色子的性质进行精确测量。托马斯已经获得ATLAS作者的资格，并从事与ATLAS实验操作相关的服务工作。为此，他将为ATLAS电子性能小组做出贡献。其目的将是提高重建和识别电子的效率以及测量电子能量的精度。这将对希格斯玻色子质量和耦合的精确测量产生直接影响。

Thomas will study the properties of the newly discovered Higgs boson employing date collected by the ATLAS collaboration in LHC at centre of mass = 13 TeV.The most effective route for studying the Higgs boson is the H to ZZ(*) to 4l channel, that employs collisions in which a Higgs boson has been produced and decayed into Z bosons that in turn each decay into an oppositely charged pair of electrons or muons. This decay channel has the best Higgs signal to background ratio in LHC and allows for a complete study of the particle properties. In particular the project aims to:- Contribute to the further development of the electron reconstruction and identification algorithms exploiting the full capabilities of the ATLAS tracker and calorimeter. This is vital for the H to ZZ(*) to 4l channel, where all four leptons can be electrons.- Improve and refine the H to ZZ(*) to 4l search. This effort aims in enhancing the separation of the signal from background processes. It is tightly coupled to the performance improvements of lepton reconstruction and identification.- Determine the mass of the Higgs boson as accurately as possible. The mass of the Higgs boson is a free parameter in the SM which affects its production and decay rates. The H to ZZ(*) to 4l is one of the most important channels for this measurement. This is an excellent example of a measurement for which the understanding of electron performance plays a key role.- Measure the couplings by employing the different Higgs production mechanisms, gluon-gluon fusion (ggF), Vector Boson Fusion (VBF), associated productions with weak bosons (WH/ZH), in the H to ZZ(*) to 4l channel. This would be a valuable input in the determination of the couplings of the Higgs boson and a vital step in understanding better its nature. The expected rates for VBF and WH/ZH in the H to ZZ(*) to 4l channel are expected to be relatively small in the SM and they need to be separated from the dominant ggF production. Thus, their observation in the H to ZZ(*) to 4l channel requires the development of analyses that would test fundamental SM predictions.The LHC is expected to deliver ~ 100 fb-1 during RUN II with a centre of mass energy of 13 TeV over the next 3 years. This will lead to an increase of ~10 times in the available statistics of the H to ZZ(*) to 4l channel. If significant deviations from the SM model predictions are observed, the rich phenomenology of beyond the SM theories will be explored. If the properties of the new Higgs boson are consistent with the SM expectations then the higher available energy and the larger amount of data will allow for precision measurements of the properties of the newly discovered Higgs boson.Thomas has qualify as ATLAS author, and perform service work related to the ATLAS experiment operation. To this effect he will contribute to ATLAS electron performance group. The aim will be to increase the efficiency for reconstructing and identifying electrons and the precision with which their energy is measured. This will have direct implications on the precision measurement of the Higgs boson mass and couplings.