# Theoretical Particle Physics Research

Lead Research Organisation: University of Oxford
Department Name: Oxford Physics

### Abstract

Our overall aim is to elucidate the nature of matter and its fundamental interactions via a variety of phenomenological and theoretical studies. Of crucial importance will be the new results coming from the Large Hadron Collider (LHC) at CERN. The proposed research will improve our ability to predict the effects of the strong interactions (QCD) on the processes that will be studied at the LHC and develop efficient methods to determine the properties of any new states of matter discovered there. Both analytical and numerical methods will be used to study the properties of hadrons, strongly interacting bound states of quarks. Our research will seek to determine what lies beyond the Standard Model of the strong, weak and electromagnetic interactions, with the ultimate goal of providing a fully unified theory, including gravity. The most promising candidate theories will be studied, including Grand and superstring unification and theories with additional space dimensions. Laboratory, astrophysical and cosmological implications will be analysed to determine the most sensitive experimental tests of these theories. We hope these studies will lead to a complete understanding of the origin of mass, including an understanding of the quark, charged lepton and neutrino masses, mixing angles and CP violation, as well as of the nature of dark matter. In addition to having direct relevance to the LHC program, our research will have relevance to present and future neutrino and astroparticle experiments and to astrophysical and cosmological studies. In particular a concerted effort will be made to understand the nature of the dark matter and optimise strategies for detecting both direct and indirect signals. The implications of particle physics models for early universe processes such as inflation will also be studied, with reference to forthcoming data from Planck concerning possible non-gaussianity in the CMB anisotropy and spectral features which provide new probes of the dynamics. The physics potential of the IceCube detector (in particular the PINGU sub-array) for studying oscillations of atmospheric neutrinos will be investigated.

### Planned Impact

Particle physics underlies the workings of the material world, being concerned with the architecture of the fundamental physical interactions at the highest energies i.e. on the smallest distance scales. This naturally provides a link to the birth and evolution of the universe as a whole since the laws that governed the dynamics of space-time and matter at very early epochs close to the Big Bang are precisely those that we seek to unravel today through studies of elementary particles in both terrestrial accelerators, as well as through studies of high energy cosmic radiation. This research is truly fundamental in nature, seeking to obtain a mathematically rigorous and physically meaningful description of the laws that govern the universe - from gravity and electromagnetism on the largest scales to the weak and strong forces on the smallest. The Particle Theory Group at Oxford is active in most of the frontier areas of the subject - from particle phenomenology relevant to understanding the data pouring out of the Large Hadron Collider at CERN, as well as astroparticle experiments like IceCube and Auger, to mathematical studies aimed at constructing a consistent quantum description of gravity, e.g. superstring theory, which can resolve the mystery of the initial singularity at the Big Bang where all physical laws that we know today become inapplicable. We use analytic techniques as well as innovative numerical approaches using fast computers to study a wide range of problems which bear on the key science questions in the STFC roadmap.

We participate in a wide range of outreach activities ranging from talks to local schools and the public, consultation by national media, and extensive interactions with undergraduate audiences both in the UK and elsewhere. We participate in our University's programme to promote science by contributing to Open Days, Masterclasses and Access schemes. An innovative website http://whystringtheory.com/ set up with the help of summer students has received over 34,000 visits since Sep 2012.

### Publications

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Aartsen M (2017) THE CONTRIBUTION OF -2LAC BLAZARS TO DIFFUSE TEV-PEV NEUTRINO FLUX in The Astrophysical Journal

Aartsen M (2014) Search for neutrino-induced particle showers with IceCube-40 in Physical Review D

Aartsen M (2017) Measurement of the $$\nu _{\mu }$$ ? µ energy spectrum with IceCube-79 in The European Physical Journal C

Aartsen M (2016) Characterization of the atmospheric muon flux in IceCube in Astroparticle Physics

Aartsen M (2015) Search for dark matter annihilation in the Galactic Center with IceCube-79 in The European Physical Journal C

Aartsen M (2016) Neutrino oscillation studies with IceCube-DeepCore in Nuclear Physics B

Aartsen M (2015) Measurement of the Atmospheric ? e Spectrum with IceCube in Physical Review D

Aartsen M (2017) The IceCube realtime alert system in Astroparticle Physics

Aartsen M (2017) The IceCube Neutrino Observatory: instrumentation and online systems in Journal of Instrumentation

Aartsen M (2014) Improvement in fast particle track reconstruction with robust statistics in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

Aartsen M (2015) SEARCH FOR PROMPT NEUTRINO EMISSION FROM GAMMA-RAY BURSTS WITH ICECUBE in The Astrophysical Journal

Aartsen M (2014) Search for non-relativistic magnetic monopoles with IceCube in The European Physical Journal C

Aartsen M (2016) Searches for relativistic magnetic monopoles in IceCube in The European Physical Journal C

Aartsen M (2017) PINGU: a vision for neutrino and particle physics at the South Pole in Journal of Physics G: Nuclear and Particle Physics

Aartsen M (2017) Search for annihilating dark matter in the Sun with 3 years of IceCube data in The European Physical Journal C

Aartsen M (2017) First search for dark matter annihilations in the Earth with the IceCube detector in The European Physical Journal C

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Exploitation Route Will be reported on at end of grant
Sectors Education

Description Will be reported on at end of grant

Description AMVA4NewPhysics Marie Curie Initial Training Network of the European Comission
Organisation European Commission
Country European Union (EU)
Sector Public
PI Contribution Exploitation of advanced multivariate techniques for the search for New Physics at the Large Hadron Collider
Collaborator Contribution General organisation of the network and research activities.
Impact .
Start Year 2015