Simulations and analysis for FASER and the Forward Physics Facility

除了大型强子对撞机的运行外，在欧洲核子研究中心的超越对撞机物理计划下，已经启动了几个在暗区寻找新物理的新实验。RHUL加速器科学小组利用RHUL独特的BDSIM专业知识和领导地位，提供多物理模拟能力来了解实验光束线。前向搜索实验(Faser)将提供对暗光子、轴子状粒子和轻规玻色子的灵敏搜索。Faser探测器位于ATLAS相互作用点下游480米处，位于大型强子对撞机探测器无法到达的低PT盲点，也是提供对大型强子对撞机产生的高能中微子的第一次探测和研究的理想位置。在2020-21年度，大型强子对撞机第三次运行期间安装了Faser原型探测器。对于计划在第三次大型强子对撞机运行期间收集的150FB-1的积分光度，假设SM截面，1300e，20,000和20将在Faser中相互作用，平均能量为600Ge到1Te。有了这样的速度和能量，Faser将打开新物理学的窗口，为目前尚未探索的能量的中微子截面提供新的约束，并约束正向粒子产生的模型。对这种测量至关重要的是对到达Faser探测器的粒子光谱、通量和能量的准确模拟。这个由吉布森指导的PHD项目将模拟ATLAS中PP碰撞事件的完全传播，通过加速器光学装置和周围材料，包括强子簇射和二次产生，直到Faser探测器，在那里将评估信号和背景通量。学生将使用RHUL的BDSIM软件为Faser创建一个精致的480米长的Geant4模型，从ATLAS洞穴开始，包含加速器晶格、孔、磁铁和屏蔽的完整细节。应用这个模型，学生将计算中微子和µ子通量，以便与大型强子对撞机第三次运行期间的测量信号进行比较，从而为Faser提供第一个结果。学生将有助于探测器的校准、操作，并帮助分析第一个实验数据，在理解预期信号和背景方面发挥及时和关键的作用。在第一阶段取得成功之前，学生将更新加速器模型，以研究和优化Faser 2的设计，Faser 2是计划用于HL-LHC时代的更大探测器，将进一步增强发现潜力。

Alongside operation of the Large Hadron Collider, several new experiments searching for new physics in the Dark Sector have been initiated at CERN under the Physics Beyond Colliders programme. The RHUL Accelerator Science group provides multi-physics simulation capability to understand the experimental beamlines, using RHUL's unique BDSIM expertise and leadership.The ForwArd Search ExpeRiment (FASER) will provide sensitive searches for dark photons, axion-like particles, and light gauge bosons. Placed 480 m downstream of the ATLAS interaction point in the low pT blind spot that is inaccessible to the LHC collider detectors, the FASER detector is also ideally located to provide the first detection and studies of high-energy neutrinos produced at the LHC. In 2020-21, the FASER prototype detector was installed for operation during LHC Run3. For an integrated luminosity of 150 fb-1 planned to be collected during LHC Run 3, assuming SM cross sections, 1300 e, 20,000 , and 20 will interact in FASER, with mean energies of 600 Ge to 1 Te. With such rates and energies, FASER will open up windows on new physics, provide new constraints on neutrino cross sections at currently unexplored energies, and constrain models for forward particle production. Vital to such measurements are accurate simulations of the particle spectra, flux and energies reaching the FASER detector. This PhD project, supervised by Gibson, will simulate the full propagation of events from pp collisions in ATLAS, through the accelerator optics and surrounding material, including hadronic shower development and secondary production, up to the FASER detector, where both the signal and background flux will be evaluated. The student will use RHUL's BDSIM software to create an exquisite 480m long Geant4 model for FASER, starting from the ATLAS cavern, with full details of the accelerator lattice, apertures, magnets and shielding. Applying this model, the student will calculate the neutrino and muon flux to allow comparison with measured signals during Run 3 of the LHC, enabling first results for FASER. The student will contribute to detector calibration, operation, and help to analyse first experimental data, playing a timely and key role to understand the anticipated signal and backgrounds. Pending the successful first phase, the student will update the accelerator model to study and optimise the design of FASER 2, a larger detector planned for the HL-LHC era, that further enhances the discovery potential.