Heavy quarks, a window into New Physics at ATLAS
Lead Research Organisation:
University of Edinburgh
Department Name: Sch of Physics and Astronomy
Abstract
The goal of my proposal is fundamental research at the frontier of particle physics and the instrumentation that makes this research possible. I will search for signs of New Physics using the signature of multiple heavy quarks.
Particle Physics, is currently at a cross road. The description of particle interactions is called the Standard Model. From our understanding of this model, new particles and mechanisms are required in order to consistently sustain the theoretical framework at high energies. So far, the Standard Model has been very successful in explaining the existing data from high energy physics experiments, like the ATLAS experiment at the Large Hadron Collider (LHC), but it is not complete. It does not explain the observed dark matter and dark energy, that fill 95% of our universe. Nor does it have a satisfactory answer to why there is more matter than anti-matter in the universe. Lastly, one essential particle, the Higgs boson, has not been found so far.
The LHC at CERN operates at the energy frontier. The LHC collides protons at extremely high energy. The resulting energy density is comparable to the energy density shortly after the Big Bang. The particles produced in this collision will allow to further unravel the fundamental nature of matter and its interactions. Due to the large increase in energy with respect to previous experiments, exciting new discoveries are expected. Among the exhilarating possibilities are candidates for dark matter. This fundamental research will significantly extend the boundaries of our knowledge. The latest measurements at the LHC, have not shown a direct signal of New Physics yet, pointing to a discovery, where the mass scale of new particles is higher than anticipated. At the same time the data indicate a small mass window at low mass, for the missing Higgs Boson.
Heavy new particles are likely to couple to the top quark, the heaviest known elementary particle. The top has a unique signature, as one if its decay products is a so called bottom-quark. For an clean top reconstruction the b-jets need to be identified. This "b-tagging" makes use of the fact, that b-hadrons are long lived and show a clearly displaced secondary vertex. Traditional b-tagging does not determine the charge of b-jets. This is the realm of flavour tagging that distinguishes b and anti-b quarks. The knowledge of the charge of b-jet can considerable reduce combinatorial background. I will make b-physics flavour tagging techniques applicable to New Physics searches.
The ATLAS experiment is one of two general purpose detectors at the LHC. The gigantic apparatus has excellent capabilities to reconstruct the tracks and vertices of particles and measure their momenta and energy with high precision. These properties make the ATLAS detector a great apparatus to test for new physics. The reconstruction of vertices relies on tracking devices. Such a device is essentially a large 80 million channel digital camera, that records the passing of charged particles every 25 nanoseconds. To fully exploit any new discoveries and extend the physics reach for rare processes, an upgrade of the LHC and its detectors is necessary. The ATLAS tracker needs to be upgraded in order to guarantee continuing good tracking performance with increasing intensity of LHC collisions. Continuing good performance of the tracker is very important, as it is a prerequisite for the reconstruction of secondary vertices from b-jets. Therefore I propose to take a leading role in the ATLAS tracker and in particular the pixel upgrade project.
During the course of the fellowship I propose to use events with multiple b-jets collected by ATLAS to search for so far unknown physics phenomena. In addition I will lead research and development on the tracking device upgrade. New tracking devices have a wide range of applications, not only in particle physics, but for example also in medical imaging.
Particle Physics, is currently at a cross road. The description of particle interactions is called the Standard Model. From our understanding of this model, new particles and mechanisms are required in order to consistently sustain the theoretical framework at high energies. So far, the Standard Model has been very successful in explaining the existing data from high energy physics experiments, like the ATLAS experiment at the Large Hadron Collider (LHC), but it is not complete. It does not explain the observed dark matter and dark energy, that fill 95% of our universe. Nor does it have a satisfactory answer to why there is more matter than anti-matter in the universe. Lastly, one essential particle, the Higgs boson, has not been found so far.
The LHC at CERN operates at the energy frontier. The LHC collides protons at extremely high energy. The resulting energy density is comparable to the energy density shortly after the Big Bang. The particles produced in this collision will allow to further unravel the fundamental nature of matter and its interactions. Due to the large increase in energy with respect to previous experiments, exciting new discoveries are expected. Among the exhilarating possibilities are candidates for dark matter. This fundamental research will significantly extend the boundaries of our knowledge. The latest measurements at the LHC, have not shown a direct signal of New Physics yet, pointing to a discovery, where the mass scale of new particles is higher than anticipated. At the same time the data indicate a small mass window at low mass, for the missing Higgs Boson.
Heavy new particles are likely to couple to the top quark, the heaviest known elementary particle. The top has a unique signature, as one if its decay products is a so called bottom-quark. For an clean top reconstruction the b-jets need to be identified. This "b-tagging" makes use of the fact, that b-hadrons are long lived and show a clearly displaced secondary vertex. Traditional b-tagging does not determine the charge of b-jets. This is the realm of flavour tagging that distinguishes b and anti-b quarks. The knowledge of the charge of b-jet can considerable reduce combinatorial background. I will make b-physics flavour tagging techniques applicable to New Physics searches.
The ATLAS experiment is one of two general purpose detectors at the LHC. The gigantic apparatus has excellent capabilities to reconstruct the tracks and vertices of particles and measure their momenta and energy with high precision. These properties make the ATLAS detector a great apparatus to test for new physics. The reconstruction of vertices relies on tracking devices. Such a device is essentially a large 80 million channel digital camera, that records the passing of charged particles every 25 nanoseconds. To fully exploit any new discoveries and extend the physics reach for rare processes, an upgrade of the LHC and its detectors is necessary. The ATLAS tracker needs to be upgraded in order to guarantee continuing good tracking performance with increasing intensity of LHC collisions. Continuing good performance of the tracker is very important, as it is a prerequisite for the reconstruction of secondary vertices from b-jets. Therefore I propose to take a leading role in the ATLAS tracker and in particular the pixel upgrade project.
During the course of the fellowship I propose to use events with multiple b-jets collected by ATLAS to search for so far unknown physics phenomena. In addition I will lead research and development on the tracking device upgrade. New tracking devices have a wide range of applications, not only in particle physics, but for example also in medical imaging.
People |
ORCID iD |
Andreas Korn (Principal Investigator / Fellow) |
Publications
Aaboud M
(2017)
Performance of the ATLAS track reconstruction algorithms in dense environments in LHC Run 2.
in The European physical journal. C, Particles and fields
Aad G
(2014)
Search for the Standard Model Higgs boson decay to µ + µ - with the ATLAS detector
in Physics Letters B
Aad G
(2014)
Measurement of ? c1 and ? c2 production with s $$ \sqrt{s} $$ = 7 TeV pp collisions at ATLAS
in Journal of High Energy Physics
Aad G
(2014)
Measurement of the production cross section of prompt J/? mesons in association with a W ± boson in pp collisions at $ \sqrt{s} $ = 7 TeV with the ATLAS detector
in Journal of High Energy Physics
Abdallah J
(2015)
Simplified models for dark matter searches at the LHC
in Physics of the Dark Universe
ATLAS Collaboration
(2013)
Letter of Intent for the Phase-II Upgrade of the ATLAS Experiment
in CERN-LHCC-2012-022 ; LHCC-I-023
Burdin, S And Cornelissen, T And Debenedetti, C And Elles, S And Elsing, M And Gavrilenko, I And Hessey, N And Huettmann, A And Korn, A And Miglioranzi, S And Lisovyi, M And Maettig, P And Schaelicke, A And Salzburger, A And Selbach, K And Styles, N And Soldevila, U And Todorov, T And Tseng, J And Valencic, N And Vankov, P And Wells, P
(2013)
Tracking Performance of the Proposed Inner Tracker Layout for the ATLAS Phase-II Upgrade
Description | The research has restricted the possibilities for new heavy particles. This information is an important input for theorists. Unfortunately so far no new particles have been found. These new heavy particles are of particular interest as they might act as mediators to sought after dark matter candidates. |
Exploitation Route | The information is disseminated through publications and interactions in conferences, especially with theorists. This helps restricting theoretical parameter space. |
Sectors | Digital/Communication/Information Technologies (including Software),Other |
Description | A science half day at University: School Visit Queen Elizabeth's Girls' School |
Form Of Engagement Activity | Participation in an open day or visit at my research institution |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Schools |
Results and Impact | Two classes from the school visited UCL and got involved in talks and experiments at UCL's undergraduate lab |
Year(s) Of Engagement Activity | 2017 |
Description | BigBangFair 2014 |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | Yes |
Type Of Presentation | Workshop Facilitator |
Geographic Reach | Regional |
Primary Audience | Schools |
Results and Impact | Around 75,000 people attended the fair, pupils, teachers, parents as well as young children. At our stand we were constantly engaged with roughly 20 people at a time. Going through demonstrations of a particle accelerator, a detector mockup and Higgs field demonstrator, we spent roughly 10-20 minutes with each group. The Attendees also had the opportunity for hands on tryouts. to early to report |
Year(s) Of Engagement Activity | 2014 |
Description | BigBangFair 2015 |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Schools |
Results and Impact | Showcased and discussed particle physics research with pupils, parents and teachers attending the BigBangFair |
Year(s) Of Engagement Activity | 2015 |
URL | https://www.thebigbangfair.co.uk/View/?con_id=4297 |
Description | Life as a Physicist: Visit to Ray Lodge Primary School |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Schools |
Results and Impact | I supported a full day activity initiated by three of my MSc/BSc students. I talked for about an hour about life as a scientist and some of the ongoing research. I provided some physics demonstrations and activities. |
Year(s) Of Engagement Activity | 2017 |
Description | Particle Physics Talk: Visit to Drapers' Academy |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Schools |
Results and Impact | The Head of Physics at Drapers' Academy, Harold Hill will take a group of sixth form students to CERN in December. As a particle physicist I went into school and talked to the students about what I do. The students were happy to hear first hand from someone in this field. |
Year(s) Of Engagement Activity | 2017 |
URL | https://www.stem.org.uk/platform/activity/99242b86-2dee-4f27-bb6b-1e7fe0145615 |
Description | Public Talk at EMF 2018 |
Form Of Engagement Activity | A broadcast e.g. TV/radio/film/podcast (other than news/press) |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | A gave an outreach talk about recent LHC research at the EMF festival which was podcast. Good engagement with a very mixed international crowd. |
Year(s) Of Engagement Activity | 2018 |
URL | https://wiki.emfcamp.org/wiki/Electromagnetic_Field_2018 |
Description | Royal Society Summer Science Exhibition 2014 |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | Yes |
Geographic Reach | Regional |
Primary Audience | Public/other audiences |
Results and Impact | Informed the public about current and future work at the LHC. Answered questions in intense discussions and dispersed materials for further information/contact. Had several inquires on starting physics at UCL. |
Year(s) Of Engagement Activity | 2014 |
URL | http://sse.royalsociety.org/2014/higgs-boson/ |
Description | UCL Physics and Astronomy stall at Firs Farm Festival |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Public/other audiences |
Results and Impact | A stall with experiments and leaflets show casing research at UCL's Physics and Astronomy Department. Leaflets with further information and study options were distributed. The festival was attended by 2000 visitors of which a considerable fraction visited the stall during the course of the day. This included a discussion with local MP David Burrows, highlighting the need for science education. UCL graduate and undergraduate students participated in the activity. This was further supported by local festival organizers that work in the department workshop. |
Year(s) Of Engagement Activity | 2016 |
URL | http://www.firsfarmn21.org/category/latest-news/page/4/ |
Description | Your Universe 2017 |
Form Of Engagement Activity | Participation in an open day or visit at my research institution |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Schools |
Results and Impact | As has been tradition we provide a HEP stall at Your Universe explaining how we explore the microcosm of particles at LHC. This includes visual aides and small experiments. PhD students (including my own) are incorporated into the organization of the event and the interaction with the school children. |
Year(s) Of Engagement Activity | 2017 |
URL | http://www.ucl.ac.uk/your-universe |
Description | Your Universe 2018 |
Form Of Engagement Activity | Participation in an open day or visit at my research institution |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Schools |
Results and Impact | Yearly activity where a large number of school classes visit UCL over three days. |
Year(s) Of Engagement Activity | 2018 |
URL | https://www.ucl.ac.uk/your-universe/ |
Description | YourUniverse |
Form Of Engagement Activity | Participation in an open day or visit at my research institution |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Schools |
Results and Impact | Over three days presented particle physics research to about 20 classes and their teachers each day. Included current HEP PhD students in outreach. |
Year(s) Of Engagement Activity | 2015,2016 |
URL | https://www.ucl.ac.uk/youruniverse |