A conference that brings together students from many SEPnet nodes to discuss recent developments in the fields of particle theory, phenomenology and experiment
Welcome from the organisers in the Stag's pub on campus (across from the student's union)
This talk will present a study of diffractive scattering of high-energy protons at the LHC. Hadronic diffraction is not well-understood and many alternative approaches exist. The Monte Carlo event generator Pythia follows a Pomeron-based approach, where the invariant mass of the diffractive system and the squared momentum transfer of the system is set up according to a phenomenological Pomeron flux parameterization. Simulated single diffractive events with a fast detector response simulation of the ATLAS and ALFA detectors have been compared to 13 TeV Run 2 data.
The High Level Trigger (HLT) system used in the ATLAS detector at the
Large Hadron Collider provides high efficiency selection of a wide range of
signals. Very important targeted signatures are those where we identify single
or multiple electron candidate events in the data. This is because they
have a very wide application in many type of physics searches, like Higgs
searches, searches of physics Beyond the Standard Model (BSM), as well as
Standard Model physics.
Understanding the differences in the efficiencies for the selection of such triggers
in ATLAS data compared to Monte Carlo simulation is a key preliminary
to any measurement (Standard Model as well as BSM).
the full Run II ATLAS data collected between 2015 and 2018. The differences
in efficiency between data and Monte Carlo are studied using pure electron
samples obtained from Z --> ee Monte Carlo and data. From these differences,
correction factors have been calculated and will be applied in ATLAS
by a large number of analyses.
The LHC has yet to achieve a discovery more exciting than the Higgs boson
in 2012, but the collaboration has not given up hope of one. In the quest to
observe physics Beyond the Standard Model (BSM) we probe higher luminoci-
ties, and employ new techniques to access previously elusive areas of phase space.
One aspect of the phenomenology that is under active development is the iden-
tification of quark flavour from jets, known as jet tagging. A jet is a shot-gun
like spray of particles caused by the hadronisation of a quark. If jet tagging was
more robust for collimated jets, that is jets that overlap due to their low angle,
it would be a boon to many searches.
This challenge is a approached using machine learning techniques, in partic-
ular deep neural networks.
In this talk we consider aspects of beyond the standard model phenomenology involving b-jet classification. In particular, we consider events involving an extended Higgs sector from 2HDMs, which decay into final states of multiple b-jets. We review how these jets are identified and tagged both at the LHC and in Monte Carlo simulation, including so called jet clustering algorithms, and pose the question of whether certain parameters and techniques can be optimised for particular LHC searches. Finally we hint at birthing a new way of performing this analysis for future use in looking for BSM physics at experiments.
Colored and colorless particles that are stable on collider scales and carry exotic electric charges, so-called MCHSPs, exist in extensions of the Standard Model, and can include the top partner(s) in solutions of the hierarchy problem. In this talk I will present a recast of two production channels of MCHSPs: the “open” channel – where the particles are pair-produced above threshold, and are detectable in dedicated LHC searches for stable multiply charged leptons, and the “closed” channel – where a particle-antiparticle pair is produced as a bound state, detectable in searches for a diphoton resonance. We obtain current and projected bounds on the masses of MCHSPs with different quantum numbers. In all cases there is a crossover between dominance by open and closed searches at some charge. Moreover, we show that a joint observation in the open and the closed channels allows to determine the mass, spin, color, and electric charge of the particle.
The SNO+ experiment is a multi-purpose liquid scintillator neutrino experiment, with a main goal to search for neutrino less double beta decay of 130Te. In preparation for the liquid scintillator phase, the detector has been running with pure water as a detection medium for the past year. During this time, measurements of solar neutrinos with very low backgrounds have been made as well as new limits being placed on invisible modes of nucleon decay. In the future, as well as searching for neutrino less double beta decay, SNO+ will be able search for other physics including reactor antineutrinos, geoneutrinos and supernovae neutrinos. This poster will present existing SNO+ results and discuss planned measurements and their potential impact.
B mesons are ideally suited to test the Standard Model Flavour Sector through experimental measurements of the CKM matrix elements |V_ub| and |V_cb|. Theoretical calculations of these matrix elements are also required, which is where lattice QCD steps in. However, heavy quarks cannot be placed on the lattice in the same manner as light quarks. The lattice introduces discretisation errors that are proportional to ma, the product of the quark mass and lattice spacing. If this product is of order unity or above, as is the case for heavy quarks on current lattices, the discretisation errors become uncontrolled. This talk will primarily discuss how an anisotropic fermion action (the Relativistic Heavy Quark action) can be used to circumvent this discretisation problem, and enable simulations of semi-leptonic B meson decays to calculate theoretical values for |V_ub| and |V_cb|.
I will give an introduction to modular symmetries and how
they can be interpreted as a family symmetry. Afterwards, I
will focus on an SU(5) model in 6d where the two extra dimensions are
compactified on a T_2/Z_2 orbifold, with a twist angle of \omega=ei2pi/3. Such construction suggests an underlying modular A_4 symmetry,leading to an effective \mu-\tau reflection symmetry at low energies.
This implies maximal atmospheric mixing and maximal leptonic CP violation.
The LHC has found a Higgs boson compatible with the Standard Model Higgs but no other particles despite intesive searches. Also dark matter direct detection experiments have reached the sensitivity to test WIMP candidates. I shall give a short introduction of left-right supersymmetry and then discuss what have we learned from (i) Higgs measurements, (ii) BSM searches and (iii) direct detection experiments.
This talk will focus on how holography can be applied to condensed matter physics. I will review the physics of zero sound in Fermi liquids, an excitation which resembles hydrodynamic sound but exists at low temperature. I will then discuss a class of holographic models which exhibit a phenomenon similar to zero sound. These holographic models describe systems which are most definitely not Fermi liquids, so the fact that they possess a zero sound-like excitation raises the question of whether other materials, in particular strange metals, may exhibit zero sound.
In this brief talk I discuss two aspects of a novel approach to quantum gravity, the first of these is the construction of evanescent operators of the dilaton which provides an initial direction to finding solutions to the inherent problems of non-renormalizability of quantum gravity. The second is the use of the Batalin-Vilkovisky anti-field technique and how this can be used with cohomological techniques to restrict the terms in our action. Following this I present a brief review of present and future work.
Recent developments in scattering amplitudes have illuminated new mathematical structures in quantum field theory. Most notably research in N=4 Super Yang-Mills has led to the development of the cluster bootstrap program in which scattering amplitudes have a geometric interpretation through cluster algebras. In my talk I will discuss one new facet of this program - cluster adjacency - and what this means for the analytic properties of scattering amplitudes.