U.S.-Switzerland Research: A Study of the Heavy Quark Content of b-Jets

本论文将研究欧洲核子研究中心ATLAS探测器产生的b夸克喷注的重夸克含量。这项研究将在玛丽亚·斯米赞斯卡博士的主持下与欧洲核子研究中心实验室合作进行。这项研究将探索b喷流在其最有效地检测到的衰变模式下具有重建的魅力强子的碎裂特性。分析将使用对包含Muon+JET和Z+JET的事件敏感的数据流，这些数据流将由ATLAS子探测器中基于Muon+JET和Dimuon模式的无偏置ATLAS触发器捕获。这将是对蒙特卡罗发生器中编码的碎片模型与大型强子对撞机能量前沿的数据进行的第一次测试。它将允许ATLAS校准其能源等级。重建的Charm粒子衰变有助于将g-b反b分裂过程的贡献与单个b的贡献分开。正确的碎裂模型对于描述b喷流光谱是至关重要的，因此对于适当地减去背景以寻找包括希格斯粒子在内的新物理也是至关重要的。这项建议将支持一名研究生的国际学位论文研究。

This dissertation research will investigate the heavy quark content of b-quark jets produced in the ATLAS detector at CERN. The research will be conducted in collaboration with CERN Laboratory under the auspices of Dr. Maria Smizanska. This study will probe the fragmentation properties of b-jets with reconstructed charmed hadrons in their most efficiently detected decay modes. The analysis will use data streams sensitive to events containing muon + jet and Z + jet which will be captured by unbiased ATLAS triggers based on muon + jet and dimuon patterns in the ATLAS subdetectors. This will be the first test of the fragmentation models encoded in Monte Carlo generators against data at the energy frontier of the Large Hadron Collider. It will allow ATLAS to calibrate its energy scale. The reconstructed charm particle decays can be useful in disentangling the contribution of g-b anti-b splitting processes from single-b contributions. The correct fragmentation model is essential to the description of b-jet spectra and is consequently crucial for a proper subtraction of backgrounds to searches for new physics including the Higgs. This proposal will support the international dissertation research for one graduate student.