Hunt for Exotic Particles: Dibaryons

Lead Research Organisation: University of York
Department Name: Physics

Abstract

The vast majority of the "mass" of visible matter around us is in fact not really mass. It arises from the interaction energy of the components of the proton and neutron, the quarks and gluons. Because of Einstein's famous equivalence of mass and Energy (E=mc^2) the violent interactions of these subatomic particles can generate mass. For the matter around us on Earth and the matter visible in the stars of the night sky these mass generation mechanisms are much more relevant than the mass arising from the recently discovered Higgs, which accounts for less than 1% of the mass of the atomic nucleus. The mechanism of how quarks and gluons are confined into the bound systems of nucleons, which are the building blocks of the nuclei around us, is not well established. The basic theory of how they interact (Quantum Chromo Dynamics or QCD) has been proposed for some time, but how QCD manifests at the scale of the nucleon or other hadrons is not well understood. It is one of the biggest unsolved scientific problem in modern physics.
Based on the QCD theory describing how quarks interact (specifically color confinement) one expects that there should be many possible bound states of quarks and gluons. Until very recent years the zoo of bound systems comprised only baryons (qqq) and mesons (qqbar). However in addition the gg and ggg glueball states, tetra-quark systems and possibly pentaquark states are not ruled out by the basic principles of QCD. The field has been revolutionized by the recently discovered system Zc(c cbar d ubar). The race is on to establish the other exotic beasts of QCD which will give a totally new constraint and perspective on the nature of strongly interacting matter. I lead one of the most promising future directions to further our knowledge of the nature of matter, the hunt for dibaryons - mysterious six-quark states.
The possibility of exotic dibaryonic states was first proposed by F. Dyson in 1964, just half a year after the Gell-Mann's publication of the quark model. However, this topic received particular attention only after Jaffe's proposal of the so-called H-dibaryon, a uuddss state. I recently led research which has established the existence of a particle made from 6 quarks - the d* dibaryon: a uuuddd state. This is one of the biggest results in the field of strongly interacting matter in the past decade and provides a new window to investigate our understanding of QCD. This exotic object has a high angular momentum, with all six quarks in the ground state having their spins aligned. This d* resonance was investigated in reactions of proton beams on nuclei by the WASA collaboration, largely under my leadership, and is part of an ongoing program. I wish to lead a completely new research branch to investigate this object using beams of high energy photons and electrons to search for it's sister particles. These are the crucial missing piece of the jigsaw needed to unambiguously establish the new exotic particle. I will also establish how the new dibaryon particle interacts with the photon and the electron - it's electromagnetic properties. This will allow the size of the dibaryon to be constrained, enabling the genuine dibaryon with all 6 quarks tightly packed to be distinguished from a molecular-type object with two packages of 3 quarks each.
The new field of dibaryon physics will have major impact on a wide range of research areas including primordial nucleosynthesis, star dynamics, dark matter searches and the nature of quark confinement.

Publications

10 25 50
 
Description Strongly interacting particles are typically made of quarks. Until recently we believed that 2&3 quark configurations are the only options. A discovery of a first non-trivial hexaquark, the d*(2380) showed us that our options are more reach. According to our current understanding a six-quark state can be constructed in a two possible ways: a compact hexaquark and a diluted molecule made of two three-quark configurations. Our research showed that a d*(2380) is likely to be a compact state with a very large transition octupole magnetic moment.
It was also shown that the d* might play a crucial role in neutron star equation of state or even contribute to a dark matter.
Exploitation Route One can use our constrains on multiquark dynamics to better understand the physics of early Universe and high density environments. It also help to predict the properties of other multiquark states
Sectors Other

 
Description Dr Mikhail Bashkanov
Amount £23,680 (GBP)
Funding ID ST/W005433/1 
Organisation Science and Technologies Facilities Council (STFC) 
Sector Public
Country United Kingdom
Start 01/2022 
End 03/2022
 
Description EIC Detector R&D
Amount £242,438 (GBP)
Funding ID ST/W004852/1 
Organisation Science and Technologies Facilities Council (STFC) 
Sector Public
Country United Kingdom
Start 09/2021 
End 03/2024
 
Description Elucidating Neutron Star Composition From Cutting-edge Hadron Physics (International Exchanges With Khon Kaen Thailand)
Amount £46,383 (GBP)
Funding ID IES\R3\203149 
Organisation The Royal Society 
Sector Charity/Non Profit
Country United Kingdom
Start 02/2021 
End 02/2023
 
Description Elucidating the fundamental nature of hadrons with Particle Identification Detector
Amount £35,394 (GBP)
Funding ID ST/W005433/1 
Organisation Science and Technologies Facilities Council (STFC) 
Sector Public
Country United Kingdom
Start 01/2022 
End 03/2022
 
Description International Exchanges
Amount £11,320 (GBP)
Funding ID IES\R3\203149 
Organisation The Royal Society 
Sector Charity/Non Profit
Country United Kingdom
Start 03/2021 
End 12/2023
 
Title High acceptance neutron polarymetry 
Description Method allow the measurement of neutron polarisation in very large angular range and neutron energy ranges. Will be applied for the main measurements proposed in grant application to be performed in summer 2016. 
Type Of Material Improvements to research infrastructure 
Provided To Others? No  
Impact Many baryon resonance decays have neutron in the final state, measuring polarisation of the outgoing neutron allow determination of the resonance properties. Verification of the method will be performed at upcoming summer 2016 beamtime. 
 
Title high acceptance neutron detection and reconstruction 
Description Develop a method of reliable use of detected neutrons in high acceptance calorimeter at Mainz for many-body reactions. 
Type Of Material Improvements to research infrastructure 
Year Produced 2015 
Provided To Others? Yes  
Impact Use of detected neutrons instead of treating them as "unidentified particles" allows strong background suppression in reactions where neutrons are involved. Use of Kinematical Fit detected neutrons further improve detector resolution providing better accuracy in particle spectroscopy. 
 
Title radioactive isotope production method for PET 
Description A novel, potentially cheaper method to produce radioactive isotopes for Positron Emission tomography. The production system was build an prepared for testing 
Type Of Material Technology assay or reagent 
Year Produced 2018 
Provided To Others? No  
Impact Positron tomography is a fast developing area in medicine. The limiting factor for further development is a cost (~1000 GBP per scan) which is largely determined by a price of PET isotopes (500 GBP per scan). Any improvement in PET isotope production has enormous influence to a billion pounds market of positron tomography and humongous effect on society extending affordability of modern medical techniques to larger fraction of population. 
 
Description A2 collaboration (Crystal Ball, Mainz[Germany]) 
Organisation Johannes Gutenberg University of Mainz
Country Germany 
Sector Academic/University 
PI Contribution 1) Analysis of the data 2) Detector maintenance and running (shift) 3) Construction of new detector components (Start construction of new polarymeter and particle identification detector as proposed in grant application)
Collaborator Contribution Detector maintenance, calibration, accelerator maintenance, target maintenance
Impact 1) New insight into nuclear and particle physics. 2) High quality polarisation measurements 3) Baryon spectroscopy
 
Description A2 collaboration (Crystal Ball, Mainz[Germany]) 
Organisation National Institute for Nuclear Physics
Department National Institute for Nuclear Physics - Pavia
Country Italy 
Sector Academic/University 
PI Contribution 1) Analysis of the data 2) Detector maintenance and running (shift) 3) Construction of new detector components (Start construction of new polarymeter and particle identification detector as proposed in grant application)
Collaborator Contribution Detector maintenance, calibration, accelerator maintenance, target maintenance
Impact 1) New insight into nuclear and particle physics. 2) High quality polarisation measurements 3) Baryon spectroscopy
 
Description A2 collaboration (Crystal Ball, Mainz[Germany]) 
Organisation Ruhr University Bochum
Country Germany 
Sector Academic/University 
PI Contribution 1) Analysis of the data 2) Detector maintenance and running (shift) 3) Construction of new detector components (Start construction of new polarymeter and particle identification detector as proposed in grant application)
Collaborator Contribution Detector maintenance, calibration, accelerator maintenance, target maintenance
Impact 1) New insight into nuclear and particle physics. 2) High quality polarisation measurements 3) Baryon spectroscopy
 
Description A2 collaboration (Crystal Ball, Mainz[Germany]) 
Organisation University of Basel
Country Switzerland 
Sector Academic/University 
PI Contribution 1) Analysis of the data 2) Detector maintenance and running (shift) 3) Construction of new detector components (Start construction of new polarymeter and particle identification detector as proposed in grant application)
Collaborator Contribution Detector maintenance, calibration, accelerator maintenance, target maintenance
Impact 1) New insight into nuclear and particle physics. 2) High quality polarisation measurements 3) Baryon spectroscopy
 
Description A2 collaboration (Crystal Ball, Mainz[Germany]) 
Organisation University of Bonn
Country Germany 
Sector Academic/University 
PI Contribution 1) Analysis of the data 2) Detector maintenance and running (shift) 3) Construction of new detector components (Start construction of new polarymeter and particle identification detector as proposed in grant application)
Collaborator Contribution Detector maintenance, calibration, accelerator maintenance, target maintenance
Impact 1) New insight into nuclear and particle physics. 2) High quality polarisation measurements 3) Baryon spectroscopy
 
Description A2 collaboration (Crystal Ball, Mainz[Germany]) 
Organisation University of Glasgow
Department Physics and Astronomy Department
Country United Kingdom 
Sector Academic/University 
PI Contribution 1) Analysis of the data 2) Detector maintenance and running (shift) 3) Construction of new detector components (Start construction of new polarymeter and particle identification detector as proposed in grant application)
Collaborator Contribution Detector maintenance, calibration, accelerator maintenance, target maintenance
Impact 1) New insight into nuclear and particle physics. 2) High quality polarisation measurements 3) Baryon spectroscopy
 
Description EIC UG 
Organisation Brookhaven National Laboratory
Department RIKEN-BNL Research Center
Country United States 
Sector Academic/University 
PI Contribution Simulations and design of the future EIC collider
Collaborator Contribution New detector simulations, polarised detector development, polarimeter studies
Impact new development of polarised detectors
Start Year 2021
 
Description Elucidating Neutron Star Composition From Cutting-edge Hadron Physics (International Exchanges With Khon Kaen Thailand) 
Organisation Khon Kaen University
Country Thailand 
Sector Academic/University 
PI Contribution Project 1417720: Elucidating Neutron Star Composition From Cutting-edge Hadron Physics (International Exchanges With Khon Kaen Thailand) new collaboration to implant our data on dibaryons into theoretical description of hexaquarks with subsequent use of them in a neutron star EOS studies.
Collaborator Contribution Providing experimental data and guiding theoretical calculations
Impact grant Project 1417720: Elucidating Neutron Star Composition From Cutting-edge Hadron Physics (International Exchanges With Khon Kaen Thailand) from Royal society. Publication is on its way
Start Year 2021
 
Description Hall-B (Clas, Clas-12, [JLab, USA]) 
Organisation JLab
Sector Private 
PI Contribution 1) Data analysis 2) Simulations 3) Construction of new detector components
Collaborator Contribution 1) Data analysis 2) Simulations 3) Construction of new detector components
Impact 1) New spectroscopy data 2) Baryon and meson spectroscopy 3) high-energy photon beams
 
Description IOP public engagement event, physics master class 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact Nuclear physics public engagement activity
Year(s) Of Engagement Activity 2020
URL https://events.iop.org/level-nuclear-physics-masterclass
 
Description KLong collaboration invited talk at Meson2021 conference 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Invited talk at the international conference Meson 2021
Year(s) Of Engagement Activity 2021
 
Description MOOC lecture "Neutron stars" 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Schools
Results and Impact A lecture as a part of Massive Online lecture course organised by the UoY
Year(s) Of Engagement Activity 2022
 
Description Organisation of Exotic Hadron Spectroscopy workshop 2019, York. 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Fruitful discussions, a lot of new ideas and links
Year(s) Of Engagement Activity 2019
URL https://www.iopconferences.org/iop/frontend/reg/thome.csp?pageID=884741&eventID=1401&language=1&CSPC...
 
Description South African nuclear physics summer school 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Undergraduate students
Results and Impact South African, nuclear physics summer school. Set of nuclear and medical physics lectures and master classes.
Year(s) Of Engagement Activity 2019
URL http://www.unizulu.ac.za/unizulu-hosts-9th-tastes-of-nuclear-physics-conference/
 
Description Strong2020 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Organisation of Strong2020 workshop
Year(s) Of Engagement Activity 2021
URL https://agenda.infn.it/event/27658/
 
Description University of Manchester Seminar 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Postgraduate students
Results and Impact I was invited to make a general seminar at the University of Manchester to introduce our discoveries
Year(s) Of Engagement Activity 2018