I am a third year PhD candidate in the LHCb WarwickLink opens in a new window group, supervised by Prof. Tim GershonLink opens in a new window and Dr. Tom BlakeLink opens in a new window. I joined the group in 2021, but had been working in the LHCb Collaboration since 2020. My main research is focused on rare B meson decays containing electrons.

I also teach first year undergraduate Physics problem classes, in Classical Mechanics, Electromagnetism, and Quantum Mechanics.

Rare B decays as a Standard Model testbench

The Standard Model of Particle Physics (known as SM) is our best current theory to describe the behaviour of elementary particles. It is an exceptionally successful theory, developed over decades of synergetic experimental and theoretical work, and has shown outstanding agreement between measurements and predictions.

The Standard Model is, however, known to be incomplete. Now more than ever, the goal of Particle Physics experiments is to find signs of physics beyond the Standard Model.

An interesting way of looking for such signs is to perform high precision tests of the Standard Model's predictions. In particular, rare B meson days offer an ideal testing ground: since these processes are highly suppressed (with probabilities of less than one in a million!) any enhancement in their rates could only come from new particles.

My research focuses on a particular decay process, the decay of a B⁰_s meson into a φ meson and a lepton-antilepton pair, either μ⁺μ^- or e⁺e^-. I am contributing to an analysis of data collected at the LHCb experiment, which will test whether the electron and its heavier cousin, the muon, interact through the weak nuclear force with the same strength. This can be done by measuring the ratio R_φ, which compares how many times a decay contains an electron pair instead of a muon pair.

Furthermore, my research covers other properties of the electron mode , in particular the way that the electrons from this process orientate themselves in space, through a technique called an angular analysis. The expected distribution of the directions of the electronsof will show some preferred configuration, which is more likely than others; by studying what that configuration looks like, we can further put the SM's predictions to the test.

LHCb was especially designed to study B mesons, and has already published measurements of other ratios and observables which showed hints of deviation, the biggest being at the level of three standard deviations away from the theoretical prediction. The measurement of R_φ, and the angular analysis of the decay will offer a complementary piece of information useful to get to a deeper level of understanding of our current observations.

Commissioning of the LHCb Muon Detector

As the LHC has begun to re-start its operations in 2022 for the third data taking run, the LHCb detector is undergoing its commissioning phase: the new upgrades set up in the last three years are now being put to the test, and optimised to get the most out of the proton-proton collisions delivered by the LHC. I have contributed to the commissioning of one of the main sub-detectors, the Muon Detector.

Previous work

I grew up in Rome, Italy, and I obtained first a Bachelor's degree in Physics in 2019, with a thesis in experimental Cosmology, and then a Master's degree in Experimental Particle Physics in 2021, at the University of Rome La SapienzaLink opens in a new window. During the summer of my first year of MSc, I worked for two months as a Summer Student at Laboratori Nazionali di FrascatiLink opens in a new window, working on software for the LHCb Muon Detector. There, I met my Master thesis supervisor, Dr. Marcello RotondoLink opens in a new window, and worked in my second year on the measurement of another Lepton Flavour Universality ratio, R(D^*_s), which tests the Standard Model with processes known as semileptonic B decays.

During that time, I kept also contributing to the Muon Detector software, which gave me the opportunity to spend time during the summer of 2021 at LHCb at CERNLink opens in a new window, Geneva.

Contacts

Email: lorenzo dot paolucci at warwick dot ac dot uk

lorenzo dot paolucci at cern dot ch

Twitter: @hyperlollo

Office: PS0.01

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