Upgrades of the Tracker and Trigger of the CMS experiment at the CERN LHC

To allow deeper investigations of the physics of discoveries expected at the LHC, and the challenges presented by the very successful performance of the accelerator, upgrades to some key CMS sub-systems are required in the next few years. In addition, LHC operation is expected to continue for at least a decade longer than the experiments were designed for. Inevitable radiation damage to the tracking detector will require its replacement in 2022 and the new detector must be more granular and radiation hard. It must also perform better in an even harsher environment, with higher pileup of events in each beam crossing, to meet the required physics goals.
The LHC, which is the highest energy machine in the world, is the only accelerator capable of investigating some of the highest priority fundamental physics topics for the foreseeable future. In addition to the hoped for completion of the Standard Model by the discovery of the Higgs boson, it allows us to shed light on many other key questions in particle physics including the nature of dark matter, unification of forces, the existence of fundamental particles and their roles in the origin of the universe. The investment in the LHC programme has been significant and upgrades to the experiments will extend its working lifetime considerably, and improve their performance by taking advantage of technological progress in the last decade.
The most crucial sub-detectors to be modified are the tracker and trigger, in which UK groups have played significant roles and have undertaken successful R&D in recent years. We propose to build on this by delivering a significant part of the new calorimeter trigger system and continuing R&D to incorporate tracking data into the future Level 1 trigger. We will deliver a new data acquisition system for the new pixel detector, and contribute to construction of detector modules for the future tracker by providing major parts of the front end electronics. In each case, the UK will be providing hardware, firmware and software with substantial intellectual input and leadership roles.
These represent substantial contributions to the overall CMS upgrade plan consistent with proportionate sharing of construction responsibilities. We request appropriate resources to allow us to undertake these projects.

The deeper understanding of phenomena to be studied at the LHC will have repercussions for commercial manufacturers, the general public, and policy makers.
Substantial procurements will be necessary during the course of this project, in the form of advanced digital electronic processing boards and Application Specific Integrated Circuits (ASICs). These offer opportunities to commercial suppliers, mostly likely UK-based, as prototypes manufactured during the R&D phase preceding this proposal have successfully been manufactured to a high standard by UK companies. Future boards have even more demanding specifications so will push the limits of manufacturing technology.
Electronic components of a substantial value will be purchased during this project, offering opportunities for international producers and local suppliers.
The ASIC designs will be carried out in collaboration with UK engineering designers, based in RAL. Their expertise will increase as a consequence and there will be training opportunities and turnover of staff, with further benefits to industry.
Trained postgraduate students will reach doctoral standards in this project and they will provide additional expert researchers whose skills will be of high commercial value. Some of them are expected to migrate to the commercial world following graduation.
There is wide interest in the physics and technology of the LHC. This project will contribute to maintaining and enhancing that interest by producing world-class science opportunities and advanced technological by-products in the form of CMS instrumentation.
Finally, the scientific results from the LHC will shed deep light on the mysteries of nature by improving our understanding of the 5% of the world explained by the Standard Model of Particle Physics. The results are also likely to begin to allow us to probe the mystery of dark matter, which appears to make up about 25% of the universe, about whose composition we know almost nothing. Given past progress in science, it is unlikely that an improved understanding of nature at this level will not eventually lead to benefits to humankind, although it is impossible to predict in what way. The situation is analogous to that in the nineteenth century before the impact of classical electromagnetism, quantum theory, and relativity, all of which have had a profound effect on modern life and technology.