The flavour of New Physics in the loops of hadronic beauty decays
Lead Research Organisation:
UNIVERSITY OF CAMBRIDGE
Department Name: Physics
Abstract
The Standard Model (SM) of Particle Physics, whilst incredibly successfully, is known not to provide an
adequate description for various observed physical phenomena. Precision measurements in the flavour
sector are an ideal laboratory to search for New Physics (NP) beyond the SM at very high energy scales.
This proposal will make precise measurements of highly NP sensitive decay rate ratios and weak phases,
which arise in beauty-quark to strange- or down-quark transitions, using data collected at the Large
Hadron Collider beauty (LHCb) experiment.
The weak phase under consideration, called phi-s, has a very small and precisely known value in the SM
making its determination a prime avenue for exploration of NP. However, interpretation of the experimental
measurement, within the framework of the SM, is complicated by unknown polluting contributions. This
issue is overcome in this proposal using a novel analysis technique, which simultaneously extracts the
unknown contribution by exploiting flavour symmetries that are known to hold for the decays under study.
This proposal will make the world's first precision measurement of phi-s using this analysis method.
A family of seven inter-related decay modes of neutral B-mesons to hadrons, via vector-vector states, will
be investigated. Beyond extraction of the weak phase, phi-s, understanding of the complex amplitude
structure of these decays will provide insights into the role of New Physics in their decay dynamics. This
proposal will make world's first and world's most precise measurements of various compelling decay rate
parameters and phases which probe the fundamental nature of these processes.
During the timeline of this proposal the available datasets will increase by a factor of forty and the
project will deliver cutting-edge developments in analysis techniques and software tools. The outcome is
a step-change in the physics reach, which will permit these precision measurements to be made for the
first time.
adequate description for various observed physical phenomena. Precision measurements in the flavour
sector are an ideal laboratory to search for New Physics (NP) beyond the SM at very high energy scales.
This proposal will make precise measurements of highly NP sensitive decay rate ratios and weak phases,
which arise in beauty-quark to strange- or down-quark transitions, using data collected at the Large
Hadron Collider beauty (LHCb) experiment.
The weak phase under consideration, called phi-s, has a very small and precisely known value in the SM
making its determination a prime avenue for exploration of NP. However, interpretation of the experimental
measurement, within the framework of the SM, is complicated by unknown polluting contributions. This
issue is overcome in this proposal using a novel analysis technique, which simultaneously extracts the
unknown contribution by exploiting flavour symmetries that are known to hold for the decays under study.
This proposal will make the world's first precision measurement of phi-s using this analysis method.
A family of seven inter-related decay modes of neutral B-mesons to hadrons, via vector-vector states, will
be investigated. Beyond extraction of the weak phase, phi-s, understanding of the complex amplitude
structure of these decays will provide insights into the role of New Physics in their decay dynamics. This
proposal will make world's first and world's most precise measurements of various compelling decay rate
parameters and phases which probe the fundamental nature of these processes.
During the timeline of this proposal the available datasets will increase by a factor of forty and the
project will deliver cutting-edge developments in analysis techniques and software tools. The outcome is
a step-change in the physics reach, which will permit these precision measurements to be made for the
first time.
Publications
Aaij R
(2023)
A study of $$C\!P$$ violation in the decays $${ {B} ^\pm } \rightarrow [{ {K} ^+} { {K} ^-} { {\uppi } ^+} { {\uppi } ^-} ]_{D} h^{\pm }$$ ($$h = K, \pi $$) and $${ {B} ^\pm } \rightarrow [{ {\uppi } ^+} { {\uppi } ^-} { {\uppi } ^+} { {\uppi } ^-} ]_{D} h^{\pm }$$
in The European Physical Journal C
Aaij R
(2024)
Improved Measurement of C P Violation Parameters in B s 0 ? J / ? K + K - Decays in the Vicinity of the ? ( 1020 ) Resonance
in Physical Review Letters
Amhis Y
(2023)
Averages of b -hadron, c -hadron, and t -lepton properties as of 2021
in Physical Review D
Amhis Y
(2024)
Prospects for searches of $$ b\to s\nu \overline{\nu} $$ decays at FCC-ee
in Journal of High Energy Physics
Related Projects
| Project Reference | Relationship | Related To | Start | End | Award Value |
|---|---|---|---|---|---|
| EP/X014746/1 | 02/10/2022 | 23/04/2023 | £1,284,265 | ||
| EP/X014746/2 | Transfer | EP/X014746/1 | 31/05/2023 | 30/04/2028 | £1,260,011 |
| Description | Getting a flavour for New Physics with precision measurements of tree-level beauty decays |
| Amount | £60,038 (GBP) |
| Funding ID | ST/R004536/3 |
| Organisation | Science and Technologies Facilities Council (STFC) |
| Sector | Public |
| Country | United Kingdom |
| Start | 03/2023 |
| End | 03/2024 |
| Description | LHCb Upgrade II: Maximising HL-LHC Discovery Potential |
| Amount | £143,386 (GBP) |
| Funding ID | ST/V003755/1 |
| Organisation | Science and Technologies Facilities Council (STFC) |
| Sector | Public |
| Country | United Kingdom |
| Start | 09/2021 |
| End | 09/2024 |
| Description | The Experimental Study of Particle Interactions at High Energy |
| Amount | £2,502,326 (GBP) |
| Funding ID | ST/S000712/1 |
| Organisation | Science and Technologies Facilities Council (STFC) |
| Sector | Public |
| Country | United Kingdom |
| Start | 09/2019 |
| End | 09/2023 |
| Description | Future Circular Collider (FCC) Collaboration |
| Organisation | European Organization for Nuclear Research (CERN) |
| Country | Switzerland |
| Sector | Academic/University |
| PI Contribution | Made us of FCC-ee simulation and centralised data production to perform studies of the physics reach and detector design. |
| Collaborator Contribution | Production of centralised simulation samples with the IDEA detector concept. Light touch internal review of methods and publication. |
| Impact | Publication of physics reach (listed under publications) for b -> s nunu searches at FCC-ee: https://doi.org/10.1007/JHEP01(2024)144 Input to European Collaboration for Future Accelerators (ECFA) focus topics on Higgs / Top / EW factories: https://doi.org/10.48550/arXiv.2401.07564 |
| Start Year | 2022 |
| Description | Heavy Flavour Averaging Group (HFLAV) |
| Organisation | Heavy Flavor Averaging Group |
| Sector | Public |
| PI Contribution | I perform the world averages for CKM angles alpha, beta and gamma. Write the section of the HFLAV document on Unitarity Angles. |
| Collaborator Contribution | There are roughly 20 collaborators in this group and between us we produce a large report of many important measurement in heavy flavour physics every 2 years. |
| Impact | Publication of the HFLAV report on heavy flavour averages every 2 years. We also provide input to the European Strategy for Particle Physics. |
| Start Year | 2016 |
| Description | LHCb Collaboration |
| Organisation | European Organization for Nuclear Research (CERN) |
| Department | CERN LHC LHCb |
| Country | Switzerland |
| Sector | Public |
| PI Contribution | I have been working on analysis of LHCb data and contributing to performance tasks for the experiment. I have acted as an internal reviewer on several occasions for the collaboration. I currently hold a management position within the collaboration. |
| Collaborator Contribution | Have input of common software and data formats. Sharing of resources. |
| Impact | Several publications. |
| Start Year | 2014 |
| Description | Particle Data Group (PDG) |
| Organisation | Particle Data Group |
| Country | United States |
| Sector | Academic/University |
| PI Contribution | I provide the numbers for the world averages of CKM angles (alpha, beta and gamma). I have written the review on "Determination of CKM angles from B hadrons" |
| Collaborator Contribution | The PDG comprises many authors from many institutes. Between us we put together the world averages for almost all measurements made in particle and nuclear physics. |
| Impact | Publication of the Particle Data Group 2020 (in progress) with online update in 2019. |
| Start Year | 2019 |
| Title | GammaCombo framework |
| Description | A package for statistical analysis in High Energy Physics. |
| Type Of Technology | Software |
| Year Produced | 2019 |
| Open Source License? | Yes |
| Impact | Used in several LHCb collaboration publications and studies |
| URL | https://gammacombo.github.io |
| Description | 3-body problem podcast |
| 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 | I am the science advisor on the Netflix show, "3 Body Problem". This podcast was recorded in late 2023 with Dame Maggie Aderin-Pocock and discussed many of the science aspects in the show. |
| Year(s) Of Engagement Activity | 2023 |
| Description | Masterclass in High Energy Physics |
| 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 | Every year the University of Cambridge High Energy Physics group runs a Masterclass in Particle Physics. This consists of a day-long set of activities for schools in the local area (we run the same program on two consecutive days to reach an audience of about 100). The day consists of four practical activities and three lectures. I give a lecture on "Proving the existence of something you can't see". |
| Year(s) Of Engagement Activity | 2023 |
| URL | https://www.hep.phy.cam.ac.uk/Masterclass |
| Description | Science Advisor for Netflix Show |
| 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 | I am the scientific advisor on a Netflix science-fiction show called "Three Body Problem" which will be released later in 2023. |
| Year(s) Of Engagement Activity | 2022,2023 |