Sussex Experimental Particle Physics 2015 Consolidated Grant

The Sussex Experimental Particle Physics group is involved in various strands of Particle Physics: the ATLAS experiment at CERN's Large Hadron Collider; the SNO+ neutrino experiment at SNOLAB in Canada; the nEDM experiment at PSI, Zurich, Switzerland; the NOvA experiment and other future long-baseline neutrino projects at FNAL, Chicago, USA. All of these experiments probe some of the most fundamental properties of Nature, seeking to find evidence for new physics phenomena. Sussex makes leading contributions to the analysis of ATLAS data, searching for evidence of supersymmetry (SUSY) in proton-proton interactions, focusing on the search for electroweak SUSY particles, known as charginos and neutralinos, and of the supersymmetric scalar partners of the top quark. The discovery of supersymmetry would not only provide evidence for the existence of new physics, but also potentially establish a link between particle physics and cosmology, by uncovering the nature of the elusive Dark Matter in our universe. Sussex also makes important contribution to the ATLAS trigger system (which acts like the experiment's "brain") -- through participation in trigger operations and in the development and maintenance of core software for the trigger system. The group is also involved in preparations for future upgrades of the ATLAS trigger system. Sussex provides substantial intellectual leadership in the ongoing search for an electric dipole moment (EDM) of the neutron. Finding an EDM would represent unambiguous evidence for physics beyond the SM; conversely, the absence of any EDM, at the sensitivity for which we are aiming, would provide severe constraints on models of new physics. This work also provides a link to cosmology, since the size of any neutron EDM is determined by the same CP-violating mechanism that underlies the dominance of matter over antimatter in the Universe. Sussex plays a crucial role in the field of neutrino physics, through participation in the SNO+ and NOvA experiments, and through involvement in the future programme of long-baseline neutrinos in the USA. On SNO+, Sussex leads calibration and the dataflow activities and is involved in preparations for physics analysis, with focus on the crucial neutrinoless double-beta decay analysis. This could both determine the mass of the neutrino and answer the long-standing question of whether the neutrino is its own antiparticle. The group has a major role in the analysis of NOvA data and is becoming involved in LBNE/LBNF via contributions to the data-acquisition software and liquid argon time-projection chamber prototypes.

Members of Sussex Experimental Particle Physics (EPP) group have leading involvement in three high-priority areas of experimental particle physics: LHC physics (ATLAS); neutrino physics; and precision measurements of the properties of the neutron. Secondary research activities of the group include detector R&D for future experiments, and Grid computing. The blue-skies research at the heart of Sussex EPP's activities resonates very favourably with the general public, as demonstrated by regular coverage in national and international media. Experimental particle physics is also the kind of science that tends to attract talented undergraduates to study physics or other science subjects at university level. Therefore, building on our strengths, our impact agenda focuses in large part around public engagement and graduate training. In parallel to these core priorities, the group is dedicated to exploring the potential for extension of state-of-the-art particle physics experimental techniques to other fields, with particular interest in medical physics applications. The group is fortunate to have a number of experienced science communicators; we continue to nurture these skills in our young members, providing speakers and demonstrators to national and international science outreach events such as the Royal Society Summer Science Exhibition, CERN Open Days, and TEDx. In 2013 and 2014, in collaboration with other UK experimental particle physics groups involved in LHC physics. In 2013, we contributed to the "Discovering the Higgs Boson" stand (Birmingham-led), for which Sussex researchers and technicians (De Santo, Salvatore, White) designed and realized an electronic display of an ATLAS detector "slice". This was animated using purpose-built electronics, and was used to explain the principles of particle detection at a collider. For the 2014 edition of the exhibition, we took part in "The Higgs boson: what next?" stand (co-led by Edinburgh and Birmingham led). For this, De Santo and Salvatore designed and realized a set of soft toys, the "Sussex SUSY Softies", which became very popular at the exhibition and on social media. They became the most "re-tweeted" item on the ATLAS Twitter account (which has more than 20,000 followers) during the week of the 2014 Royal Society exhibition, and had a guest appearance at the 2014 European Researchers' Night in Glasgow. The activities used for the 2013 and 2014 Royal Society exhibitions were also displayed at the 2014 Big Bang Fair in Birmingham, and at the 2014 Brighton Science Festival. More appearances are planned for other science fairs in 2015 and beyond. Another high-impact, Sussex-led public engagement activity is the LHC Sound project, led by Asquith. She has worked with sound engineers on the "sonification" of LHC data, where particles going through different detector layers are each associated to a different sound with a different pitch/volume/timbre according to their momentum/position/type. The project, which was originally funded by an STFC small award in 2010, has caught the attention of the media and the general public. In 2013 Asquith was invited to give a TEDx talk in Zurich, and she gave a public talk at the Montreux Jazz Festival in the same year. In 2014 Asquith gave a public talk on the LHC Sound project at the "A Particle Physics Evening", held at UCL during the BOOST14 conference. Asquith and other Sussex physicists and engineers are currently collaborating with a blind Sussex undergraduate, Daniel Hajas, exploring the potential for incorporating sonification into a tactile event display for non-visual graphics. De Santo and Leming have collaborated with STFC-RAL and Surrey, on the investigation of Particle Physics Experimental Techniques Applied to Time-of-Flight Positron-Electron Tomography. The potential continuation of this project, and its future impact, is being explored with our IPS fellow, Hayhurst.