Skip to main content Skip to navigation

Alex Ward

Ph.D. Research

I am a 2nd year Ph.D. candidate with the Monash-Warwick Alliance in Particle PhysicsLink opens in a new window. My research is conducted at the Large Hadron Collider beauty (LHCbLink opens in a new window) experiment based at CERNLink opens in a new window, Geneva. I am focusing primarily on rare electroweak penguin decays, specifically the angular analysis of the B0 (Bs0) -> pi+ pi- mu+ mu- decay modes.

My supervisors are Dr Michal KrepsLink opens in a new window and Dr. Tom BlakeLink opens in a new window at the University of Warwick and Professor Ulrik EgedeLink opens in a new window at Monash University.

This year I took up the roles of the LHCb UK Student Meeting Organiser, organising seminars which take place at CERN, and LHCb UK Social Media Coordinator, where I have launched and ran the @lhcb_uk_studentsLink opens in a new window instagram account as well as helping to run the @LHCb_UKLink opens in a new window twitter account.

Research Topic

The Standard Model (SM) is our best description of the subatomic world and an incredibly successful theoretical model; It is the combination of the electromagnetic, weak, and strong interactions, and has been used to predict almost all experimental physics results since the early 1970’s, including the Higgs boson and the top quark. However the SM is incomplete, it doesn’t explain known phenomena such as neutrino oscillations and baryon-anti baryon asymmetry, therefore there is a push within the particle physics community to probe the limits of the SM in search of New Physics (NP).

The LHCb experiment at the Large Hadron Collider (LHCLink opens in a new window), CERN, is specially designed to detect b-hadrons which are produced in a forward cone, thrown forward from the collision point. The b-hadrons are used in the analysis of Rare Decays to probe the SM in search of these NP effects. Rare decays are suppressed by the SM and therefore sensitive to NP. Recent results in the field have produced some interesting tension with the SM and promising signs of NP, for example the measurement of the P5 angular observable [2].

My research project involves analysing the B0 (Bs0) -> pi+ pi- mu+ mu- decay modes. These decays occur via same-charge quark transitions (b->s and b->d), known as "flavour-changing neutral currents" (FCNC) decays, which are highly suppressed within the SM and are mediated by higher-order Feynman diagrams known as “electroweak penguin” and “box” diagrams [3], as shown below.

Lowest level FCNC Feynman diagrams for a b! d`􀀀`+ process.Lowest level FCNC Feynman diagrams for a b! d`􀀀`+ process.

My analysis will produce the measurements of multiple observables related to the angular distribution between the decay components, as shown below, which will provide a comparison with the predictions of the Standard Model [4]. This analysis aims to be a promising test of the current predictions [5].

Angular Topology of the B0 (Bs0) -> pi+ pi- mu+ mu- decay modes.

Previous Education

I graduated in 2017 from Swansea University having conducted a final year project entitled 'Detecting Radiation from a CERN Detector' in which I used a portable Medipix pixel detector to measure radiation attenuation.

In 2019 I embarked upon a Masters by Research degree at the University of Glasgow. Here I gained my first experience of working within the LHCb experiment where I researched the lifetime of charm baryons, culminating in the writing of my thesis entitled 'Measurement of the Omega_c0 baryon lifetime with LHCb'.

This experience led me to having a vested interest in the research of the LHCb and in pursuing a Ph.D. within the collaboration.


[1] T. Blake et al., Rare b-hadron decays at the lhc, Annu. Rev. Nucl. Part. Sci. 65 (2015) 113. [arxiv.1501.03309Link opens in a new window]

[2] LHCb collaboration, R. Aaij et al., Measurement of CP-Averaged Observables in the B0 → K∗0μ+μ− Decay, Phys. Rev. Lett. 125 (2020) 011802, [arXiv:2003.04831Link opens in a new window]

[3] Egede, Ulrik and Nishida, Shohei and Patel, Mitesh and Schune, Marie-Hélène, Electroweak Penguin Decays of b-Flavoured Hadrons, (2022), [arxiv.2205.05222Link opens in a new window]

[4] C. Bobeth, G. Hiller, and G. Piranishvili, Cp asymmetries in B -> Kbar* (-> Kbar pi) l+ l- and Untagged B_s (Bbar_s) -> phi (-> K+ K-) l+ l- decays at nlo, JHEP 0807 (2008) 106. [arxiv.0805.2525]Link opens in a new window

[5] L. Cappiello, O. Cata, and G. DAmbrosio, Standard model prediction and new physics tests for D0 -> hhll JHEP 2013 (2013) . [arxiv.9808289Link opens in a new window]

Contact Details:


Email: alex dot ward at warwick dot ac dot uk

Office: P449

Address: Department of Physics, University of Warwick, Coventry, CV4 7AL


  • LHCb UK Student Meeting Organiser
  • LHCb UK Social Media Coordinator

Social Media: