UCL HEP Seminars
Seminars are generally held at 4pm on Fridays in room A1 on the top floor of the physics department
A calendar of all seminars in the Physics Department
is available on the Physics Events Calendar page.
If you use Google Calendar or similar, such as Apple iCal, it is possible to subscribe to this calendar via: XML, ICAL or HTML.
Please send suggestions for topics and/or speakers to Andreas Korn and Patrick Motylinski.
09/10/2015 Linda Cremonesi (UCL)
Neutrino interactions at the T2K near detector complex
The T2K long-baseline neutrino oscillation experiment observed electron neutrino appearance in 2011 and reported the first results of a search for electron anti-neutrino appearance in 2015. Systematic uncertainties relating to the models of neutrino interactions on atomic nuclei are increasingly problematic as the precision of oscillation measurements improves. Interaction cross-section measurements are therefore vital for the correct interpretation of neutrino data, and consequently reducing the uncertainties on the oscillation measurements. The near detector complex of T2K, with scintillating tracking detectors on-axis (INGRID) and a magnetised fine-grained tracking system off-axis (ND280), offers a unique opportunity to study neutrino interactions in the region of 0.6~1GeV. In this seminar I will report the latest cross-section measurements performed at ND280 and INGRID, which include muon neutrino charged current interactions on different targets (scintillator or water) and with various final states (inclusive, zero pion, one pion and coherent pion production). I will illustrate the value of this data and the difficulties that still remain.
16/10/2015 Louis Lyons (Oxford/Imperial)
“Statistical Issues in Searches for New Physics
Given the cost, both financial and even more importantly in terms of human effort, in building High Energy Physics accelerators and detectors and running them, it is important to use good statistical techniques in analysing data. This talk covers some of the statistical issues that arise in searches for New Physics. They include topics such as:
- Blind analyses
- Should we insist on the 5 sigma criterion for discovery claims?
- $P(A|B)$ is not the same as $P(B|A)$.
- The meaning of $p$-values.
- Example of a problematic likelihood.
- What is Wilks' Theorem and when does it not apply?
- How should we deal with the `Look Elsewhere Effect'?
- Dealing with systematics such as background parametrisation.
- Coverage: What is it and does my method have the correct coverage?
- Combining results, and combining $p$-values
- The use of $p_0$ v $p_1$ plots.
23/10/2015 Sarah Malik (Imperial)
Review of the status and future prospects of dark matter searches at colliders
Understanding the nature of dark matter is one of the most compelling, long standing questions in physics. Reports of possible dark matter signals from several direct detection experiments have further highlighted the need for independent verification from non-astrophysical experiments, such as colliders. I will review the results of searches for dark matter at CMS in Run 1 of the LHC, what we can expect in Run 2 and beyond, as well as recent developments in dark matter phenomenology.
30/10/2015 Doug Cowen (Penn State)
High Energy Atmospheric Neutrino Appearance and Disappearance with IceCube
The IceCube neutrino observatory, buried deep in the ice at the South Pole, has detected neutrinos that span over five orders of magnitude in energy. Fulfilling one of its original stated goals of discovering cosmological ultrahigh energy neutrinos, its large instrumented volume also provides us with a surprisingly powerful instrument for studying neutrino oscillations with an unprecedented statistical sample of energetic atmospheric neutrinos. In this presentation we will describe the IceCube detector and focus on its current and future atmospheric neutrino oscillation measurements with DeepCore, IceCube's low-energy in-fill array. We will also describe a new proposed low-energy extension, the Precision IceCube Next Generation Upgrade (PINGU), highlighting its ability to measure one of the remaining fundamental unknowns in particle physics, the neutrino mass hierarchy.