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Leïla Haegel

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Leïla Haegel Leïla Haegel I am a physicist whose research lies at the intersection of cosmology and particle physics. I use the faintest signals to probe the fundamental laws of physics and how it impacts the history and current composition of our Universe. Current research leila.haegel/a/uib.es Past research leila.haegel/a/ligo.org Outreach All my articles Current research I am a postdoctoral research fellow in the GRAVITY (formerly GRG) group of the University of Balearic Islands, sponsored by a grant from the Swiss National Science Foundation. I am working on gravitational waves, that are ripples in the space-time fabric of the Universe created by masses moving and deforming it. Predicted by Einstein’s theory of gravitation, general relativity, they have been detected only a century after by the LIGO detectors in 2015, opening a totally new window to astronomy and cosmology, as well a probe for the search of new fundamental theories. We can now detect black holes directly, leading to a new probe to investigate the nature of the strangest objects in the Universe. Gravitational waves are also a new channel to study the cosmos without relying on particles such as photons (optical astronomy) or leptons or hadrons (astroparticles astronomy). I belong the LIGO-Virgo collaboration, where I study how the signals detected by the ground-based Skymap of gravitational waves interferometers inform us about the nature of (Sept 2017). Source: LIGO-Caltech. gravitation. One of my area of research is the development of phenomenological models of gravitational waveforms for the data analysis of black holes and other very compact stars. I use such models to study the behaviour of the theory of general relativity in the strong field regime, as well as testing LEÏLA HAEGEL RESEARCH SUMMARY !1 alternative theories of gravitation. For my research, I am also interested in developing new statistical methods such as machine learning algorithms to enhance our analyses. ✦ Two articles about my research: The catalog of all the gravitational waves directly detected by LIGO and Virgo (detection and analysis performed with the phenomenological model of gravitational waveforms IMRPhenomP) LIGO and Virgo Collaboration GWTC-1: A Gravitational-Wave Transient Catalog of Compact Binary Mergers Observed by LIGO and Virgo during the First and Second Observing Runs arxiv:1811.12907 [astro-ph.HE] The phenomenological model of precessing gravitational waveforms IMRPhenomP M. Hannam, P. Schmidt, A. Bohé, L. Haegel, S. Husa, F. Ohme, G. Pratten, M. Püerrer A simple model of complete precessing black-hole-binary gravitational waveforms Phys. Rev. Lett. 113, 151101 (2014) ✦ Two presentations about my research: Gravitational waves: a new probe of the cosmos Seminar given at the Astrophysics division of the University of Bucharest, Romania. Testing general relativity with gravitational waves Seminar given at the Lawrence Berkeley National Laboratory, University of Berkeley, USA Previous research I conducted my PhD at the University of Geneva, where I worked on neutrino physics and its link to cosmology. Neutrinos are the least understood constituents of the Standard Model of particles physics as we don’t know their masses, neither how they acquire it, notably because they are the only particles known to exist in only one helicity state. However, we know that they are massive because of a the quantum phenomenon of oscillations, meaning that a neutrino created with a certain flavour (one of the three “families” of the Standard Model) can be detected with another flavour after a certain LEÏLA HAEGEL RESEARCH SUMMARY !2 time. The origin of the neutrino mass is one of the most substantiated area of research to probe physics beyond the Standard Model. For my thesis analysis, I used the data from the T2K experiment to measure four of the six neutrino oscillation parameters. Because there are three families of neutrinos, one of this parameter is a CP-violating phase, that could produce an asymmetry in the probability of ν_µ → ν_e oscillation probability at T2K . oscillation between neutrinos and antineutrinos. Source: arxiv:1609.04111 For this reason, this parameter is a key ingredient of scenarios (such as leptogenesis) aiming at explaining the baryon number asymmetry of the Universe, e.g. the fact that we observe more matter than antimatter. While CP violation has been measured in the hadronic sector from the decay of K and B mesons, it was never measured in the leptonic sector before. My thesis presented the first measurement at 2σ of the existence of leptonic CP violation, and the T2K collaboration is still pursuing its effort to measure it with better accuracy. ✦ Three articles about my research: The measurement of CP violation in the leptonic sector at 2σ, as well a measurement of other neutrino oscillation parameters (long article with method) T2K collaboration Measurement of neutrino and antineutrino oscillations by the T2K experiment including a new additional sample of νe interactions at the far detector Phys. Rev. D 96, 092006 (2017) The first measurement of CP violation in the leptonic sector (short article with results) T2K collaboration First combined analysis of neutrino and antineutrino oscillations at T2K Phys. Rev. Lett. 118 (2017) no.15, 151801 Probing beyond Standard-Model physics with (anti-)muon neutrino oscillations T2K collaboration Updated T2K measurements of muon neutrino and antineutrino disappearance using 1.5×1021 protons on target Phys. Rev. D 96 (2017) no.1, 011102(R) LEÏLA HAEGEL RESEARCH SUMMARY !3 ✦ Two presentations about my research: The latest T2K neutrino oscillation results Presentation given at the European Physical Society High Energy Physics Conference (EPS- HEP) of 2017. Evaluating neutrino oscillation parameters with Bayesian analysis Seminar given at the Particle Physics Department of the University of Sheffield, UK Outreach I still have to meet somebody who is not amazed by how our Universe work and how we try to make sense of it. I enjoy sharing scientific knowledge with people of different horizon and supporting other scientists. Here are some of my activities: • Association ADARA: I am the founder of the Association for the Development of Advanced Research in Arabic countries. We organise internships and seminars in Morocco. Erasmus students enjoy listening how CERN scientists probe the fundamental • Supernova Foundation: Mentoring female laws underlying our world. undergraduate physics students through the Source: ESN Genève Supernova foundation initiative. • Pint of Science España: Organization and speaker in the festival aiming at present scientific concepts in bars for the 2018 and 2019 editions of Pint of Science in Majorca. • CosmicPi: A CERN-based project where we designed and built a low-scale, low-cost particle detector for schools. It was chosen by CERN as a reward for the finalists of its Beamline4Schools competition. • Various events: demonstration at sciences fair in Spain and Switzerland, as well as organization of CERN visits for Erasmus students and general public. LEÏLA HAEGEL RESEARCH SUMMARY !4.
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