Periodic Reporting for period 1 - Nu Flavour (Nu Flavour: Novel Effective Field Theory and Simplified Model Approaches to Beyond-the-Standard Model Flavour Physics and Neutrino Phenomenology)
Okres sprawozdawczy: 2021-10-01 do 2023-09-30
The project aimed to formalize mathematical frameworks for studying Beyond-the-Standard Model (BSM) flavour and neutrino physics in a rigorous, model-independent manner. The researcher planned to achieve this by extending existing techniques exploiting the geometry of effective field theories (EFT) into the neutrino mass and mixing sector, and to then use the improved EFT formalisms (and related simplified models) to compare theory to data. The proposal also focused on devising novel phenomenological probes of flavour physics in BSM theories based on data from active neutrino and precision flavour experiments worldwide. The ultimate goal was to provide concrete and unambiguous bounds on realistic models which could explain the vast number of open questions in neutrino and flavour physics, and to simultaneously formalize obtaining such bounds in a bottom-up, model-independent way. These goals were largely met (see the outputs below).
Besides physics deliverables, the project also aimed to more widely disseminate the activities of the particle physics community to society more generally, and to share with aspiring young scientists different routes to becoming a professional physicist. This was also achieved via a number of careers-oriented outreach activities.
Besides physics deliverables, the project also aimed to more widely disseminate the activities of the particle physics community to society more generally, and to share with aspiring young scientists different routes to becoming a professional physicist. This was also achieved via a number of careers-oriented outreach activities.
Research contributions/papers from the project include:
--A novel leptoquark model was published which explains both categories of B-anomaly (neutral and charged currents). It was developed from the bottom up, in terms of its phenomenological signatures. The model included flavoured couplings to third generation fermions, inspired by well-known models of fermion masses based on flavour symmetries (i.e. in a family-non-trivial way). Low energy flavour data was used to bound the parameter space of the model, while novel LHC signals were also considered and calculated, which allowed the authors to put novel bounds on the leptoquark parameter space (mass and coupling).
--The geonuSMEFT was derived and a single-authored paper was written on the topic and published. The refactorization of the nuGEOSMEFT’s operator product expansion was shown to be possible, such that two- and three-point composite operator forms are dressed with field-space connections composed of towers of Higgs dressings and symmetry generators, valid at all-orders in the expansion parameter of the effective field theory. The route to predicting all-orders observables was outlined, along with the flavour-invariant theory required to understand the neutrino mass-eigenstate basis geometrically.
--Another published paper revisited the Universal Texture Zero model previously devised by the researcher. The phenomenology of the model (including fermion mass/mixing textures, CP-violating observables and beta-decay observables) was studied using an advanced Markov Chain Monte Carlo algorithm. The model was shown to be a successful fermion mass model, and therefore warrants continued interest and study from the community.
--Finally, shortly after the formal end of the project, a new paper extracting the strong coupling constant from electron-positron event shapes was made public by the researcher and his collaborators. This exploited state-of-the-art techniques in soft collinear effective theory, including a novel analysis of non-perturbative effects in these important physical observables.
Note that multiple of the research projects mentioned above were presented at international conferences (9) and invited seminars (11). Examples of the latter include the Universities of Vienna, Milano-Bicocca, Amsterdam, Southampton, Imperial, etc. Examples of the former include Pheno 2022, LoopFest 2022, Corfu 2022 and 2023, INT 2023, etc. The researcher also engaged in numerous outreach activities, including participation in a career day where he shared his love of particle physics with multiple classes of young men, a career-preparation / CV-review day at an all-girls school, and monthly mentoring sessions with a bright young aspiring student who aspires to study either biomedical sciences or clinical medicine.
As a final comment, note that the researcher also engaged in multiple research supervision projects, including two summer projects with Cambridge undergraduates (one on Markov Chain Monte Carlo algorithms and the other on automated event generation), and the co-supervision of a Cambridge University Masters thesis, for which the student received first-class marks.
--A novel leptoquark model was published which explains both categories of B-anomaly (neutral and charged currents). It was developed from the bottom up, in terms of its phenomenological signatures. The model included flavoured couplings to third generation fermions, inspired by well-known models of fermion masses based on flavour symmetries (i.e. in a family-non-trivial way). Low energy flavour data was used to bound the parameter space of the model, while novel LHC signals were also considered and calculated, which allowed the authors to put novel bounds on the leptoquark parameter space (mass and coupling).
--The geonuSMEFT was derived and a single-authored paper was written on the topic and published. The refactorization of the nuGEOSMEFT’s operator product expansion was shown to be possible, such that two- and three-point composite operator forms are dressed with field-space connections composed of towers of Higgs dressings and symmetry generators, valid at all-orders in the expansion parameter of the effective field theory. The route to predicting all-orders observables was outlined, along with the flavour-invariant theory required to understand the neutrino mass-eigenstate basis geometrically.
--Another published paper revisited the Universal Texture Zero model previously devised by the researcher. The phenomenology of the model (including fermion mass/mixing textures, CP-violating observables and beta-decay observables) was studied using an advanced Markov Chain Monte Carlo algorithm. The model was shown to be a successful fermion mass model, and therefore warrants continued interest and study from the community.
--Finally, shortly after the formal end of the project, a new paper extracting the strong coupling constant from electron-positron event shapes was made public by the researcher and his collaborators. This exploited state-of-the-art techniques in soft collinear effective theory, including a novel analysis of non-perturbative effects in these important physical observables.
Note that multiple of the research projects mentioned above were presented at international conferences (9) and invited seminars (11). Examples of the latter include the Universities of Vienna, Milano-Bicocca, Amsterdam, Southampton, Imperial, etc. Examples of the former include Pheno 2022, LoopFest 2022, Corfu 2022 and 2023, INT 2023, etc. The researcher also engaged in numerous outreach activities, including participation in a career day where he shared his love of particle physics with multiple classes of young men, a career-preparation / CV-review day at an all-girls school, and monthly mentoring sessions with a bright young aspiring student who aspires to study either biomedical sciences or clinical medicine.
As a final comment, note that the researcher also engaged in multiple research supervision projects, including two summer projects with Cambridge undergraduates (one on Markov Chain Monte Carlo algorithms and the other on automated event generation), and the co-supervision of a Cambridge University Masters thesis, for which the student received first-class marks.
All progress mentioned above is beyond the state-of-the-art, and encourages follow-up research from the MSCA researcher and the broader community. At least two further research projects were initiated during the action and will acknowledge the action's funding. The first aims to detail the one-loop matched effective field theory one obtains from Froggatt-Neilsen models of flavour. It is presently underway with a student and should be completed within the next month, at which point it too will be submitted to a high-quality scientific journal. This project represents a follow-on from the work and insights derived during the bulk of the action (see the outputs above), and will be the beginning of a novel line of important research also oriented to the action's ultimate goals. The second project aims to understand threshold corrections and renormalization group flow in models with light sterile neutrinos, which are popular in the neutrino mass and flavoured model-building community. This is underway with a senior researcher in Italy, and will also likely result in a publication in a high-quality scientific journal, not to mention a more thorough understanding of an extremely popular class of models provided through effective field theory techniques.
The goals of the action were thus largely successful, in that the community is much better positioned to understand the phenomenological signatures of BSM neutrino and flavour physics in a model-independent way. The action also paves the way for further state-of-the-art research on the topic, which is indeed gaining significant traction in the research community.
The action was also successful in its attempts to disseminate and communicate the broader impact and goals of the particle physics community to society at large, as hundreds of non-researchers were engaged and inspired over the course of the funding.
The goals of the action were thus largely successful, in that the community is much better positioned to understand the phenomenological signatures of BSM neutrino and flavour physics in a model-independent way. The action also paves the way for further state-of-the-art research on the topic, which is indeed gaining significant traction in the research community.
The action was also successful in its attempts to disseminate and communicate the broader impact and goals of the particle physics community to society at large, as hundreds of non-researchers were engaged and inspired over the course of the funding.