ALICE Upgrade 2 (Silicon Physicist post)

Quantum-ChromoDynamics (QCD) is the theory of the strong force and understanding its properties has been the focus of
intense World-wide research over the past half century. QCD forms a major part of the Standard Model and its
understanding is crucial in producing an overall theory to describe the properties of matter and the fundamental forces of
nature including a grand unification theory to explain how the Universe evolved from the Big Bang.
The principal purpose of our research is to use ultra-relativistic heavy-ion interactions to study QCD at extreme energy
densities. Theoretical models predict that under very extreme conditions of high energy densities the quarks, which are
confined in normal nuclear matter, will be freed and nuclear matter will undergo a phase transition into a hot, dense plasma
of free quarks and gluons known as a Quark-Gluon Plasma (QGP). It is thought that such a state of matter would have
existed until about 10^-5 seconds after the Big Bang, after which time the Universe would have cooled sufficiently for
protons and neutrons to form.
The physics aim of this research is to study the strong force under these extreme conditions and, in particular, explore the
properties of this exotic state of matter. By studying the QGP, we hope to address the fundamental questions of quark
confinement and how quarks gain a large effective mass in hadrons due to the strong force (accounting for 99% of atomic
mass).
In order to create the conditions required to produce a QGP we must collide heavy nuclei together at the highest possible
energies, creating tiny hot (~10^13K) and dense fireballs. As the resulting QGP will only last for about 10-22 seconds,
before condensing in to thousands of elementary particles, we must also use the most sophisticated detectors to analyse
these collisions.
The LHC collides lead ions at centre-of-mass energies of 2.76 TeV in ALICE. We also collide protons together as this forms
an excellent reference data set. Moreover, the excellent particle identification and tracking make ALICE an ideal detector
to study the global aspects of proton-proton collisions in their own right.
This field of research employs about two thousand physicists around the world and ALICE is the most sophisticated
experiment ever built in the field, studying heavy-ion collisions at centre-of-mass energies over an order of magnitude
greater than its nearest rival. It hence represents the pinnacle of research in this field.
The ALICE collaboration is now preparing for the second LHC Upgrade scheduled to start in 2018. These upgrades are
required to cope with the anticipated increase in lead beam luminosity which will increase beam intensities by an order of
magnitude. The main motivation for the luminosity upgrade is to achieve a precise, quantitative understand of the
properties of the QGP by focusing on rare probes both at low and high transverse momenta as well as on multidimensional
analysis of such probes with respect to centrality, event plane, multi-particle correlations, etc.

The main beneficiaries of this upgrade will be experimentalists and theorists working in the field of hot Quantum
Chromodynamics. They will directly benefit from the new insights that will arise out of the research, made possible by this
Upgrade. The results of the subsequent research will be disseminated in high impact journals, through conference talks
and seminars so as to reach as wide an audience as possible. More broadly, both the technologies developed during the
Upgrade and the resulting research will also be of relevance to researchers in other fields, including other areas of nuclear
physics, particle physics, astrophysics and cosmology. Some of the hardware developments related to the Birmingham
design of the original ALICE trigger subsystem have already had impact, having been adopted by another experiment at
CERN. Future developments that are foreseen in this proposal will potentially have relevance to a new generation of
experiments planning to run in continuous data taking mode. The ITS Upgrade project will develop MAPS technologies, an
area where the UK is already considered to be a world leader. Such technologies will not only have applications for other
particle detectors but are likely to have applications in the areas of medicine and security.
Another strand revolves around the public understanding of science. The research that is related to this proposal has the
potential to capture the imagination and to inspire a new generation of scientists. The research programme which will arise
from this Upgrade is involved in studying matter as it would have existed a fraction of a second after the Big Bang. This
aspect is relevant to the evolution of the Early Universe and the possible existence of (strange) quark matter stars.
Members of the ALICE-UK collaboration have given over 70 public lectures over the past five years and been involved in
many other public outreach events to school children, teachers, and members of the general public.