Birmingham Nuclear Physics Consolidated Grant

Lead Research Organisation: University of Birmingham
Department Name: School of Physics and Astronomy

Abstract

The project is an exploration of the nature of strongly interacting matter. The research will probe the nature of matter at extreme temperature and density where the nucleons inside a nucleus loose their individual identity and dissolve into their constituents of quarks and gluons - the state of matter which it is believed existed an instant after the Big Bang. Using the ALICE experiment at CERN (in which the Birmingham group have played a leading role building the trigger electronics), and collisions between Lead nuclei, the nature of this state of strongly interacting matter will be characterised in detail for the first time. The study of this exotic state of matter, known as a quark-gluon plasma, will help physicists understand more about the nature of the strong force and the evolution of the very early Universe. Nucleons in nuclei are bound via the strong interaction. On the nuclear scale, the interaction is complex and has yet to be fully characterised. Nevertheless, despite the complexity rather simple patterns emerge, such as shell structure and magic numbers or geometric arrangements of nucleons as clusters within nuclei. Due to the very high stability of the alpha-particle it is most often alpha-clusters that precipitate within the nucleus. The role of clusterisation in nuclei is central to understanding the structure of light-nuclei. For example, the famous Hoyle-state in 12C, through which carbon is synthesised in stars, has a structure which is composed of three alpha-particle. The characterisation of such systems forms a key element of the programme. As one adds more and more neutrons to a nucleus the limit of stability is reached where the last neutron no-longer 'sticks' to the nucleus, a point called the neutron drip-line. Studying nuclei close to this limit provides a unique test of our understanding of the nature of the strong interaction. One rather interesting possibility is that nuclei at the drip-line will have a rather exotic structure and behave as clusters embedded in a sea of neutrons. Part of the current programme will study how clusterisation changes as the drip-line approaches. One of the most precise tests of the structure of nuclei comes from an indirect technique. The energy levels of the electrons in an atom are largely determined by the properties of the nucleus; its overall charge, the nuclear shape and radius, the charge distribution and the magnetic moment of the nucleus. Hence, rather fundamental properties of a nucleus may be determined through an interrogation of the electronic energy levels using laser techniques. The Birmingham group has nearly 20 years accumulated experience in using laser-spectroscopy techniques to determine nuclear properties with high precision. The current work will focus on the cerium isotopes which lie at the edge of a region of shape transition due to the weakening of the Z=64 proton sub shell. To measure these isotopes new transitions using a metastable state populated by optical pumping will be needed as well as a more efficient light collection region.

Publications

10 25 50

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Abbas E (2013) J/? elliptic flow in Pb-Pb collisions at v(s(NN))=2.76 TeV. in Physical review letters

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Abelev B (2013) K(S)0 and ? production in Pb-Pb collisions at v(s(NN))=2.76 TeV. in Physical review letters

 
Description 1. In high energy collisions, normal nuclear matter melts to form a plasma of quarks and gluons, creating in the laboratory a "universe" in microcosm. At the LHC, this micro "universe" is larger, hotter and longer-lived than previous observed at lower energies.

2. In the early universe, strongly interacting matter behaved like a strongly-coupled liquid. Although approximately 50 times more dense than normal nuclear matter, the quark-gluon plasma is the most perfect example of a low viscosity liquid ever observed.

3. High momentum hadrons provide a connection to the early stages of heavy-ion collisions because they originate from quarks or gluons that have been scattered at large angles transverse to the beam. In the most violent collisions, high momentum hadrons have been found to be strongly suppressed giving insight into the energy density achieved and the nature of particle interactions in the quark-gluon plasma.

4. Identification of the dynamical symmetries of the nucleus carbon-12.

5. Determination of the excitation energy spectrum of the excited states of carbon-12 for the first time.

6. Spectreocopic measurements of a wide range of light nuclei.
Exploitation Route The work here is of interest to other scientists in the field, and in particular nuclear theory
Sectors Other

 
Description ALICE 
Organisation European Organization for Nuclear Research (CERN)
Department ALICE Collaboration
Country Switzerland 
Sector Public 
PI Contribution Support (maintenance and operation) of the Central Trigger Processor. Data Analysis.
Collaborator Contribution Access to an accelerator facility - the Large Hadron Collider. Provision of office space and central computing facility and network access. Access to shared data.
Impact Outputs are primarily through publications, listed in the relevant section of the form, which are the outcomes of collaborative research.
 
Description Catania 
Organisation University of Catania
Department Department of Physics and Astronomy
Country Italy 
Sector Academic/University 
PI Contribution Research collaboration on topics of common interest in nuclear structure - experimental techniques and experience
Collaborator Contribution Research collaboration on topics of common interest in nuclear structure - equipment
Impact Experimental measurements
Start Year 2014
 
Description RBI 
Organisation Ruder Boskovic Institute
Country Croatia 
Sector Public 
PI Contribution Joint experimental programme - experimentaql experience and scientific insight
Collaborator Contribution Research collaboration on topics of common interest in nuclear structure - experimental equipment/personel
Impact Publications
Start Year 2010
 
Description Multiple outreach activitives and public lectures to Schools, general public, teachers, and school children 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Schools
Results and Impact Professor Evans is involved in 20 to 25 outreach activities a year, mainly public lectures but also workshops, masterclasses, and summer schools.
All activities are physics based and most are related to the ALICE experiment in some way. The purpose of the activites are to inspire and encourage young people to take up physics (or other STEM subjects) at university.
Year(s) Of Engagement Activity 2015,2016,2017
URL http://www.birmingham.ac.uk/schools/physics/outreach/index.aspx
 
Description Outreach Activities 2015 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact Numerous outreach activities - including talks and quizes
Year(s) Of Engagement Activity 2015
 
Description Physics Summer School 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Type Of Presentation Workshop Facilitator
Geographic Reach National
Primary Audience Schools
Results and Impact 2 Day residential physics summer school - co-organiser

Encouraging A-level students to think about taking physics at degree level
Year(s) Of Engagement Activity 2009,2010,2011,2012,2013
 
Description Policy Commission 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Policymakers/politicians
Results and Impact co-chaired (with Lord Hunt) a review of "The future of nuclear energy in the UK". Published a report July 2012. Lots of media exposure invitations to present conclusions of report.

Influence on Govmt policy on funding of nuclear research and education.
Year(s) Of Engagement Activity 2011,2012
 
Description Quiz for Y9 Students 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Type Of Presentation Workshop Facilitator
Geographic Reach Regional
Primary Audience Schools
Results and Impact Physics based quiz for year 9 students from across the region for last 5 years. ..... attended by >250 students per year

Student engagement
Year(s) Of Engagement Activity 2009,2010,2011,2012,2013
 
Description Science Festival 2014 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact 1. Debate on Small modular reactors, with 4 panel members as part of Science Festival Programme.
2. Discussion on climate change for schools.

A lot of positive feedback. Voting using clickers showed debate changed peoples minds on nuclear, in particular small modular reactors
Year(s) Of Engagement Activity 2014
 
Description Talks 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact A variety of talks (>10) to Schools on nuclear science. Total audience of several thousand students.

Raising interest and awareness.
Year(s) Of Engagement Activity 2009,2010,2011,2012,2013