Sussex EPP seminars: 2020/21
Thursdays at 12:55 in Pevensey-3 5C11 or over Zoom
Fall term: 01 October 2020 (first seminar) till 10 December 2020 (last seminar)
01/10/2020 : Mr. Meirin Evans (Sussex) Connecting teaching to research: ATLAS Open Data in Sussex courses over Zoom
Open Data are a crucial cornerstone of science and their benefits to society are numerous. Using Open Data brings benefits such as direct access to cutting edge research, tools to promote public understanding of science and training for scientists of the future. This talk will describe the enormous potential of ATLAS Open Data and how it’s used for education at Sussex, from undergraduate to postgraduate teaching and beyond.
22/10/2020 : Mr. Fabrizio Trovato (Sussex) Searches for chargino and neutralino production in decays to three-lepton final states via intermediate bosons using √s= 13 TeV pp collisions with the ATLAS detector over Zoom
Searches for electroweak supersymmetry play a crucial role in finding possible hints of New Physics at the Large Hadron Collider. With respect to previous results at colliders, the data collected by the ATLAS detector at 13-TeV proton-proton collisions between 2015-2018, corresponding to 139 fb−1, allows a deeper exploration of challenging scenarios in the MSSM parameter phase-space. In this seminar, the results for searches for the production of the lightest chargino and the next-to-lightest neutralino are presented. The targeted simplified models assume decays into the lightest neutralino and Standard Model bosons, yielding final states with three leptons and missing transverse momentum.
29/10/2020 : Dr. Shingo Hayashida (Imperial) The SoLid experiment : search for new oscillations with very short baseline reactor antineutrino over Zoom
In the recent periods, anomalies have been found in the flux and spectrum of reactor antineutrinos. Those phenomena could be caused by the existence of a sterile neutrino state with a mass around 1 MeV. The SoLid experiment searches new oscillation with the very short baseline (6-9 m) of the SCK•CEN BR2 research reactor. The detector employs a new technology combining PVT (cubes of 5x5x5 cm3) and 6LiF:ZnS(Ag) scintillators (films of thickness ~250 μm), which enables to detect the IBD signals with the strong identification power. The detector is highly segmented, and the signals are read out by a network of wavelength shifting fibers and MPPCs. It allows for the good reconstruction of the topology of events and the strong rejection of the backgrounds, cosmic induced events and BiPo decay events. To improve the signal to background ratio, the analysis adopting the machine learning technologies such as uniform BDT. The detector has been taking physics data with a total fiducial mass of 1.6 tons since 2018. In addition, for improving the IBD identification capability, the project is now upgrading the detector to achieve a higher light yield and developing a new particle identification method using convolutional neural networks (CNNs).
05/11/2020 : Dr. Yanyan Gao (Edinburgh) The Circular Electron Positron Collider Project - Physics and detector over Zoom
A future electron-positron collider, operating as “Higgs factory”, has been recognised as high priority by the 2020 update of the European Strategy for Particle Physics (ESPPU), together with a future hadron collider at higher energy frontier. It represents an important experimental pursuit of fundamental physics. Several electron-positron colliders have been proposed internationally, including linear colliders ILC/CLIC and circular colliders FCC-ee and CEPC. The CEPC, with a main accelerator ring of 100 km in circumference, is a large international scientific project proposed by the Chinese HEP community soon after the Higgs boson discovery in 2012. It is designed to operate at three centre-of-mass energies, including 91.2 GeV as a Z factory, at 160 GeV around the W pair production threshold, and 240 GeV as a Higgs factory. In its planned ten-year operation with two detectors, the CEPC will deliver integrated luminosities of about 16, 2.6, and 5.6 ab-1 for the Z, W and Higgs operation, respectively, producing close to one trillion Z bosons, 20 million W bosons and over one million Higgs bosons. This will allow for detailed studies of the Higgs boson, connected with the fundamental fabrics of the universe, with an unprecedented precision. Its clean collision environments provide access to many new exciting experimental signatures that are otherwise difficult to trigger on or reconstruct at hadron colliders. The decays of the vastly produced Z, W, and Higgs bosons also offer excellent opportunities for flavour physics, tau-lepton physics, and QCD physics.
This talk will summarise the latest progress of the CEPC project, focusing on physics potential, detector R&D, international collaborations, and opportunities for the UK involvement.
12/11/2020 : Pr. Mercedes Paniccia (Geneva) High-precision cosmic-ray and space radiation measurements with the Alpha Magnetic Spectrometer on the International Space Station and development of the PAN instrument for deep space exploration. over Zoom
The Alpha Magnetic Spectrometer (AMS) is the most powerful and sensitive cosmic-ray detector ever deployed in space to produce a complete inventory of charged particles and nuclei in cosmic rays near Earth in the rigidity (momentum/charge) range from GV to the TV. Its physics goals are the study of cosmic-ray properties, indirect search for Dark Matter and direct searches for primordial antimatter and exotic forms of matter. The improvement in accuracy over previous measurements is made possible through its long duration time in space, large acceptance, built-in redundant systems and its thorough pre-flight calibration in the CERN test beam. Since its installation on the International Space Station in May 2011, AMS has collected more than 166 billion cosmic-ray events and has produced precision measurements of electron, positron, proton, antiproton, helium to silicon nuclei fluxes in cosmic rays of rigidity ranging from GV to 3 TV, isotopic composition of helium nuclei in the 2.1 GV to 21 GV rigidity range, and time series of electron, positron, proton and helium nuclei fluxes. The percent precision of the AMS results is revealing unexpected features in cosmic-ray spectra that challenge the current understanding of the origin and of the acceleration and propagation mechanisms of cosmic rays in the galaxy. The AMS time series of specie-resolved cosmic-ray fluxes are giving important information on solar modulation effects on cosmic rays and a better understanding of near-Earth space radiation hazards. The Penetrating Particle Analyzer (PAN), currently under development, will employ a small-size magnetic spectrometer to specifically address space radiation monitoring filling the experimental gap in the energy window between the AMS and the Voyager measurements. In this talk, after a brief introduction to cosmic-ray physics and Sun’s effect on cosmic rays, I will present the latest AMS results and ongoing studies, pointing out their implication for modelling of cosmic-rays and space radiation ; then I will present the status of the development of the PAN instrument and its possible impact on space radiation studies.
26/11/2020 : Pr. Etienne Liénard (Caen/GANIL) Search for new physics beyond the Standard Model with precision measurements in nuclear beta decays over Zoom
Precision measurements in nuclear beta decays provide sensitive tools to test the foundations and symmetries of the Standard electroweak Model and to search for exotic couplings presently excluded by the V-A theory in processes involving the lightest quarks. The main aim of such measurements is to highlight deviations from the Standard Model predictions as possible indications of new physics, complementing other searches at large-scale facilities such as the LHC. The sensitive parameters are often deduced from correlation studies between the very few bodies involved in the decay. This requires to perform very precise measurements using advanced technical methods, such as ion or atom traps installed on-line in radioactive nuclei production facilities. Data analysis also requires generating the most realistic simulations to take into account the relevant parameters of the experimental setup and their systematic effects on the measured quantities.
In this seminar, I will present different experimental projects in which LPC Caen is involved, starting from the development of LPCTrap at GANIL to search for exotic tensor currents in the decay of 6He1+ ions. This pioneer experiment laid the foundations of our present projects, not only in the search for exotic currents (WISArD, b-STILED), but also with other perspectives comprising the test of CVC from the study of mirror transitions and the quest for new sources of CP violation (MORA) needed to explain the large matter-antimatter asymmetry observed in the universe. The status and goals of these projects will be discussed.
10/12/2020 : Mr. Iker de Icaza Astiz (Sussex) The Short Baseline Near Detector at Fermilab over Zoom
The Short-Baseline Near Detector (SBND) will be a 112 ton liquid argon time projection chamber devoted to researching neutrino oscillations. Located 110 m downstream of the Booster Neutrino Beam (BNB) target, SBND is the near detector of the three-detector Short Baseline Neutrino (SBN) program at Fermilab. The SBN program will probe neutrino oscillations at the ~1 eV2 scale. SBND will have a rich cross-section measurement program and is also a testbed for R&D of new technology for DUNE. Additionally, the detector’s fine spatial resolution and relative high rate of interactions, make it a prime candidate to look for BSM physics. In this talk, I’ll give an overview of the LSND and MiniBooNE anomalies, the current landscape of oscillations at the $\sim 1 eV^2$ scale, and briefly discuss the shrinking potential for light sterile neutrinos to explain observations. Finally, I’ll present a novel dark sector model that tackles MiniBooNE’s low energy excess, and simulations of this exotic interaction in SBND.
14/01/2021 : Dr. Pierre Nouvellet (Sussex/Imperial) SARS-CoV2 dynamics and transmission, attempting to make sense of some numbers over Zoom
As Part of the COVID-19 team at Imperial College London, Pierre Nouvellet has been working on COVID-19 since March last year. In this presentation, he will explore some of the available data and try to make sense of some signals to 1) predict short-term incidence of COVID-19, 2) understand and characterise transmission level, 3) interpret figures related to testing.
21/01/2021 : Dr. Sammy Valder (Sussex) Measuring electron neutrino cross-sections using the T2K near detector over Zoom
Over the last few decades our understanding of the physics that governs neutrino oscillations has evolved rapidly. The Tokai-to-Kamioka (T2K) experiment aims to make precise measurements of the neutrino oscillation parameters. A muon neutrino beam is generated at the J-PARC facility and travels 295 km across Japan to the Super-Kamiokande (SK) far detector, where studies of muon neutrino disappearances and electron neutrino appearances are made. Intrinsic electron neutrino contamination in the beam is the single largest background in the measurement of electron neutrino appearances. This seminar will discuss the development of constraints on this background through electron neutrino cross-section measurements in the near detector ND280. Furthermore, an analysis is presented to provide a first cross-section measurement of electron neutrino positive pion production, which can shed light on a potential far detector excess.
28/01/2021 : Dr. Asher Kaboth (RHUL) LUX-ZEPLIN: A Rare Event Observatory over Zoom
The LUX-ZEPLIN experiment is a xenon-based rare event observatory under construction at SURF in South Dakota. This talk will discuss the design and construction of this detector, focusing on how it will reach physics targets of 1 event/year, as well as the physics prospects for the detector.
18/02/2021 : Dr. Angela Romano (Birmingham) Recent results from the NA62 experiments at CERN SPS over Zoom
The decay K+ -> pi+ nu nu-bar, with a very precisely predicted branching ratio of less than 10e-10, is one of the best candidates to reveal indirect effects of new physics at the highest mass scales. The NA62 experiment at CERN SPS is designed to measure Br(K+ -> pi+ nu nu-bar) with a decay-in-flight technique, novel for this channel. NA62 took data in 2016, 2017 and 2018. Statistics collected in 2016 and 2017 allows NA62 to reach the Standard Model sensitivity for K+ -> pi+ nu nu-bar; the analysis of the 2018 data leads to the most precise measurement ever performed. The preliminary result of Br(K+ -> pi+ nu nu-bar measurement from the analysis of the full data set 2016-2017-2018 is presented, and other recents results will be reviewed. Prospects for future NA62 data-taking, beginning in 2021, are also discussed.
11/03/2021 : Ana Sofia Inacio (LIP) Optical Calibration of the SNO+ Detector in the Water Phase with Deployed Sources over Zoom
SNO+ is a large volume liquid scintillator experiment for neutrino physics located at SNOLAB. SNO+ will study solar neutrinos, geo and reactor anti-neutrinos, supernova neutrinos, and it will search for the neutrinoless double beta decay of the isotope Te-130. In order to measure and search for such rare events, both the backgrounds and the detector response must be well understood. The latter is achieved with a full calibration of the detector, including an Optical Calibration that characterizes the propagation and ollection of the light created by physics events.
The laserball is a light source used for the Optical Calibration, producing a pulsed, near-isotropic light distribution throughout the detector. Data with the laserball in several positions inside the detector, and emitting light at different wavelengths, allows to extract a complete set of parameters of an optical model, from the light attenuation of the different detector media, to the angular response of the PMTs+optical concentrators. There were two main laserball data-taking campaigns during the Water Phase of the SNO+ experiment, that greatly increased our knowledge of the detector response. In this seminar, I will motivate the importance of the Optical Calibration, show how it is performed using the laserball, and present the analysis steps and results from the Water Phase.
18/03/2021 : Dr. Thiago Bezerra (Sussex) θ13 : From the 'discovery' to the percent precision era (2000 - 2030) over Zoom
The standard neutrino oscillation parametrization is defined by six independent parameters: three mixing angles (θ23, θ12 and θ13), two squared mass differences and a CP violation phase (δCP). By 2010, only θ13 and δCP were still unknown. Despite the non-zero measured values of θ12and θ23, a non-zero value of θ13 is also necessary to open the window to explore CP violation in the lepton sector. In 2011, T2K (accelerator based) and Double Chooz (reactor based) experiments showed an evidence of non-zero θ13. Nowadays, it is measured with a 1.8% uncertainty, led by the Daya Bay reactor experiment. θ13 is today the most precisely known mixing angle. However, with the next generation of experiments, such as JUNO, DUNE and HK, it will become the least precise one. In this seminar, I shall review the past and present θ13 measurement status that I have witnessed for the past decade, putting it into perspective with respect to the general neutrino oscillation scenario. I addition I shall highlight the different ways, challenges, and limitations to perform such a measurement, and what we can expect from the future projects under consideration.
25/03/2021 : Dr. Matteo Agostini (UCL) Borexino CNO over Zoom
22/04/2021 : Dr. Rodrigo Gamboa () ATLAS over Zoom
29/04/2021 : Dr. Leon Pickard (UC Davis) THEIA over Zoom
13/05/2021 : Dr. Clara Hormigos-Feliu (Dortmund/Rome) (Theory) Multi-lepton signatures of vector-like leptons with flavor over Zoom
20/05/2021 : Dr. Geneviève Bellanger (Annecy) (Theory) Two component Dark matter over Zoom
03/06/2021 : Dr. Chantal Nobs (Culham) Fusion reactor over Zoom
17/06/2021 : Mr. Mario Spina (Sussex) ATLAS SUSY bbMET over Zoom