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# Alex Ward

### Ph.D. Research

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.

### Research Topic

The study of Rare Decays within particle physics has produced some interesting results in recent years which have produced tension with the Standard Model and promising signs of New Physics. The particle decays pertinent to my research project involve same-charge, namely $b -> s$ and $b -> d$ quark transitions. These FCNC (Flavour Changing Neutral Currents) decays are rare and occur only at loop level [1], shown below in examples of the penguin and box Feynman diagrams.

My research involves the analysis of the angular distribution of the $B0 (Bs0) -> pi+ pi- mu+ mu-$ decay modes. The measurement of multiple observables related to the angles between the decay components, as shown below, will provide a comparison with the predictions of the Standard Model [2]. The nature of the 4-body decay gives sensitivity to potential New Physics and is a promising test of the current predictions [3].

### 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.

### References

[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] 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

[3] 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

Roles:

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