My Contributions

I work on many aspects of the Mu2e experiment. I am playing a key part in preparing for physics analysis and developing the tools and infrastructure we need, I am currently the Analysis Tools Convener, preparing our analysis framework and associated toolkit. For many years I have coordinated the development of the experiment's event visualization framework, developing a cutting-edge event display which is a vital part of our data-quality monitor as well as a useful tool for analysts. I was also our Monte Carlo Production Manager, building infrastructures to enable large-scale simulation campaigns and making our simulations as accurate as possible. Currently, I am preparing the most realistic "fake data" we have ever made, this will be used by the collaboration to develop an end-to-end analysis strategy which we will then apply to real data.

In 2020 I received a Fermilab Intensity Frontier Fellowship. Since then I have played a leading role in the Mu2e calorimetery group. The Mu2e calorimeter consists of 2 disks of 674 CsI crystals which collect scintillating light from potential conversion signals. I am currently playing a key role in the on-site calorimeter assembly and am the hardware Manager for the Radioactive Source Calibration system. This device is used to calibrate the energy scale of the calorimeter. I am leading the installation and operations of this source calibration system. I am developing the data-acquisition architecture for this system.

In 2022, I was the lead author and editor of the joint Mu2e/COMET/DeeMe Snowmass White Paper. The same year I also co-wrote a peer-reviewed paper documenting our Run-I sensitivity, published in a special edition of the Universe journal.

During my time on Mu2e, I have been on the Executive Board for two terms and the experiment's Institutional Board for one term, both to represent early career members. You can find some of my recent talks in the links above including seminars and my talk at the U. Chicago Rising Stars Symposium.

My Contributions

The Caltech group is working on developing the Hadronic Calorimeter (HCAL). The HCAL is crucial to help veto background events such as those originating from photonuclear events. In order to fully establish whether we have seen any beyond standard model physics signal, we need to ensure we veto all standard model events. The HCAL was tested in a beam at CERN this year, we are currently analyzing the data. I am also managing the database and e-log system at CERN, this system is a prototype for our real-life data-taking infrastructure.

Personally, I have been working on understanding how to veto wide-angle bremsstrahlung (or bremsstrahlung-like) backgrounds. These pose a specific challenge to our veto. Over the past year I have built many MadGraph simulations, varying aspects of our physics assumptions, and passed these through our reconstruction code. I have also been building clustering algorithms that can help improve our vetoing capacity by highlighting major differences between the dark matter signal and these bremsstrahlung backgrounds. I am also looking at our sensitivity to Axion Like Particles and developing algorithms to improve that.

I recently presented at the 30th Symposium on Lepton - Photon Interactions, my talk is in the link above. I also wrote a Proceedings which can be found under my Publications tab.

My Contributions

I am co-convening the Mu2e-II simulation group and we have submitted a White Paper to the Snowmass 2022 process. If approved Mu2e-II would come online at the end of the decade. I continue to work on the design of Mu2eII, specifically focusing on the optimization of the stopping target and it's physical design.

Along with some of my Caltech colleagues, I have worked to improve our understanding of the theory behind the choice of target material, which focuses on the complementarity between aluminum (which is used in Mu2e) and other materials. In the event of a signal in Mu2e, Mu2e-II and/or AMF would aim to measure conversion in another material.

The branching rate for coherent conversion in a nucleus has several factors describing the possible new physics responsible (scalar, dipole, or vector). These factors scale differently with the atomic number of the target. By choosing a complementary material to aluminium we can use this second target to help understand the nature of the physics responsible.

Our article was recently submitted to PRD (see above).

I have given several seminars on AMF, including one at Fermilab in May 2023 (See link above).

My Analyses

I conduct analyses using BaBar data. Most of these focus on searching for new particles which can explain several beyond Standard Model phenomena such as neutrino mass origins, baryogenesis, and the nature of dark matter.

Heavy Neutral Leptons (PhysRevD.107.052009)

I recently completed a search for additional heavy neutrino states that could mixing with standard model tau neutrinos. Heavy neutral leptons (HNLs) aremix hypothetical particles that could help explain all sorts of phenomena, such as why neutrinos oscillate, why matter is dominant in the universe, and can also be dark matter candidates. In my analysis, I applied statistical techniques to the full BaBar data set and placed limits on the mixing strength of these hypothetical particles with tau neutrinos across the 300 - 1300 MeV region.

Mixing with taus has long been looselyheavy-neutral constrained due to the lack of facilities able to produce large quantities of taus. The technique employed here utilized the 400 million taus in BaBar. No assumptions were made about the nature of the new heavy neutral lepton.

The limits were world-leading at the time of publication. Since publication, several new results have followed.

Dark Matter and Baryogenesis (PhysRevLett.131.201801)

In another analysis, I searched for missing mass in B meson decays, specifically in the case where the outgoing standard model particle is a proton. This channel is sensitive to several models of dark matter and those which explain the dominence of matter in the universe via Beryogenesis as well as R-parity violating super-symmetric models.

Specifically, I placed the first direct limits on the existence of a new dark-sector anti-baryon. This particle has a baryon number, thus conserving that quantity. This particle is also a dark matter candidate and can have a mass of 1-4GeV. I utilize the hadronic recoil method, reconstructing the two B mesons. In order to minimize background contamination a boosted decision tree is utilized to help characterize signal and background regions in the data. Background and signal regions are derived using Monte Carlo. A scanning method is employed allowing the first direct limits on the existence of this particle to be set.

The results of this study can be applied to other models with missing mass in the final state.

Initial State Radiation analyses for hadronic cross-sections (PhysRevD.104.112003, PhysRevD.107.072001)

In addition to producing my own physics results, I also chair analysis review committees including for two publications analyzing ee->hadrons+ISR cross-sections, which have implications for hadronic corrections to the muon g - 2. Given the attention gained by the g − 2 experimental results and
its discrepancy with SM prediction, it is important to get data-driven results such as these as precise as possible.

My Research Background

I am originally from the UK, and grew up in the city of Hull in East Yorkshire. I completed my undergraduate, masters and Ph.D. at Imperial College London. I graduated in 2018 with my Ph.D. thesis focusing on my work on the Muon Ionization Cooling Experiment (MICE). MICE published the first demonstration of ionization cooling of a muon beam. This is the first step toward constructing a multi-TeV muon collider. Such a machine would help elucidate many of the current phenomena that exist in particle physics, as well as help us gain precision measurements on the Higgs boson. I spent 4 years on MICE contributing to the hardware commissioning, operations, publications, and analysis efforts. My thesis focused on three separate analyses each measuring a different important systematic effect in the cooling channel.

I completed my Masters in 2012; my Masters thesis focussed on the analysis of data from the CMS experiment at the LHC. I showed competitive limits on the existence of a Higgs boson, created by Vector Boson Fusion, decaying to 2 tau particles. This signature did not, at that time, have the 5\sigma discovery reach.

During my time at Imperial College, I also developed a keen interest in dark matter and sterile neutrinos and I worked as a Research Assistant on both the LUX-Zeplin and SoLid experiments. Following my PhD I was a Research Associate at the University of Manchester (based at Fermilab) on Mu2e.