Conveners
Parallel session: Cosmology and Dark Matter
- Jessica Turner (IPPP, Durham University)
Parallel session: Holography and Solitons
- Vaios Ziogas (Durham University)
Parallel session: QCD
- Robin Linten (IPPP Durham)
Parallel session: String Theory
- Felix Haehl (Durham University)
Parallel session: Gravity
- Alan Reynolds (Durham University)
Parallel session: Standard Model Phenomenology
- Simon Armstrong (IPPP)
Parallel session: BSM
- Andres Olivares del Campo (IPPP, Durham University)
Parallel session: Amplitudes
- There are no conveners in this block
Ms
Francesca Day
(University of Oxford)
14/01/2016, 14:30
Axion-like particles (ALPs) populating many decades in mass (an "axiverse") are generically predicted by string theory. Depending on their mass and production mechanism, these ALPs may contribute to dark matter, dark energy and dark radiation. Such ALPs are potentially observable via their interaction with electromagnetism, leading to ALP-photon conversion in an external magnetic field. I will...
Mr
William Woodhead
(University of Southampton)
14/01/2016, 14:30
Entanglement entropy is a quantity that has received a large amount of attention recently in the literature, especially after the holographic prescription from Ryu and Takayanagi. It is a well known fact that the entanglement entropy is a UV divergent quantity and therefore should be renormalized.
There have been attempts recently to define a renormalized version of the entanglement...
Mr
Matthew Kirk
(IPPP, Durham University)
14/01/2016, 14:55
Dark matter models are often studied using the _Minimal Flavour Violation_ framework which restricts the new physics in various flavour measurements (e.g. meson mixing, rare decays).
I will talk about an extension of minimal flavour violation that allows for sizeable contributions to flavour observables, and explain how neutral meson mixing can constrain certain dark matter models in this...
Mr
Alexander Peach
(Durham University)
14/01/2016, 14:55
Many beautiful, recent results in the field of holography have made manifest that poignant aspects of bulk geometry are encoded in the boundary theory as quantum information. In particular, Susskind's recently conjectured ER=EPR conjecture pertains to the view that there is an intimate connection between entanglement entropy in the boundary theory and connectedness of the dual, bulk geometry....
Mr
Sotirios Karamitsos
(University of Manchester)
14/01/2016, 15:20
Inflation has been a very successful generic explanation of the origin of cosmological anisotropies. However, the multitude of inflationary models, all with numerous different theoretical underpinnings, poses a challenge in determining the fundamental driving mechanism of inflation. With the aim of obtaining predictions from inflationary models in a concise and straightforward manner, we...
Mr
Stanislav Schmidt
(University of Southampton)
14/01/2016, 15:20
The gauge/gravity correspondence offers a unique tool for understanding strongly coupled quantum field theories and quantum gravity, which made it one of the leading research fields in theoretical physics in the last 15 years. Over the years the correspondence has been refined and many lessons have been learned. However, with the complexity of the duality there are still a huge number of...
Mr
Matthew Elliot-Ripley
(Durham University)
14/01/2016, 15:45
Studies in holographic contexts, such as holographic QCD and holographic superconductors, have motivated the investigation of solitons in AdS and AdS-like spacetimes. In this talk we will investigate the baby Skyrme model in a pure AdS background without a pion mass term, and numerically find soliton and multi-soliton solutions. We find that ring-like structures appear to be energetically...
Mr
Lukáš Gráf
(University College London)
14/01/2016, 15:45
The constraints on baryogenesis models obtained from an observation of neutrinoless double beta decay will be discussed. The lepton number violating processes, which can underlie neutrinoless double beta decay, would together with sphaleron processes, which are effective in a wide range of energies, wash out a primordial baryon asymmetry of the universe. Typically, if a mechanism of...
Mrs
Yihong Wang
(Stonybrook University)
14/01/2016, 16:40
Quantum entanglement is a has played an increasingly important role in string theory.In this presentation, I will talk about negativity, a measure of entanglement for tripartite systems. In particularly, the negativity of a 2 dimensional free fermion, which is still a open question. I will discuss the main difficulty and current knowledge of the free fermion negativity and introduce a path...
Mr
James Cockburn
(University of Edinburgh)
14/01/2016, 16:40
In its embryonic form, High Energy Jets (HEJ) is a perturbative framework which allows for the resummation of QCD processes to Leading Log (LL) accuracy. This talk will briefly outline how the framework is derived and the key features of the resummation technique. Following on from this, we present how the formalism could be improved to Next-to-Leading Log (NLL) accuracy. We focus specifically...
Mr
Johar Ashfaque
(University of Liverpool)
14/01/2016, 17:05
Attempts have been made at constructing D-brane GUT models which suffer from a number of difficulties like the lack of spinor representation for the SO(10) or the perturbative vanishing of the top quark Yukawa couplings for the SU(5) models. In fact, these difficulties arose as the past constructions relied heavily on local 7-branes. Such obstacles can be avoided by considering mutually...
Mr
Jim Talbert
(University of Oxford)
14/01/2016, 17:05
I will present an algorithm for the automated calculation of NNLO dijet soft functions, and show novel results for a variety of collider observables. I will also detail the extraction of the associated two-loop, non-cusp soft anomalous dimensions necessary for resummations at NNLL accuracy in the Soft Collinear Effective Theory (SCET).
Ms
Rebecca Simms
(University of Liverpool)
14/01/2016, 17:30
QCD and other asymptotically free field theories possess the unique characteristic of the beta-function having a non-trivial fixed point. This is known as the Banks-Zaks fixed point and is believed to have connections with the chiral symmetry phase transition. Using perturbative quantum field theory techniques we can construct higher dimensional extensions of scalar and gauge theories. These...
Mr
Richard Stewart
(University of Durham)
14/01/2016, 17:30
A feature of the low energy theories of certain string models is the existence of a
shift-symmetry in the Kähler potential at tree level. In this talk I will consider the fate of this shift-symmetry at one-loop and show that while it does not generally hold at this order, there is a certain limit of compactification where the symmetry is restored. I will then argue why we expect this...
Ms
Katy Clough
(Kings College London)
15/01/2016, 09:00
I introduce GRChombo: a new numerical relativity code which incorporates full adaptive mesh refinement (AMR). The AMR capability permits the study of a range of new physics which has previously been computationally infeasible in a full 3+1 setting, including the study of critical phenomena in the collapse of scalar field bubbles in asymmetric configurations. I will present some preliminary...
Mr
Felipe Contatto
(Department of Applied Maths and Theoretical Physics - Cambridge)
15/01/2016, 09:25
Given a pseudo-Riemannian manifold, there is a natural notion of geodesics defined by the Levi-Civita connection. But the geodesic equations can be written just in terms of the Christoffel symbols $\Gamma$:
\begin{equation}
\ddot x^a+\Gamma^a_{bc} \dot x^b\dot x^c=0,
\end{equation}
where $x^a$ are local coordinates. Therefore, geodesics can be defined for any symmetric affine connection...
Mr
Karl Nordstrom
(University of Glasgow)
15/01/2016, 09:25
Top pair production is one of the most widely studied interactions at the LHC and offers opportunities both to improve our understanding of Standard Model "parameters" like parton density functions and constrain or potentially discover new physics beyond the Standard Model.
An interesting family of observables in top pair production are angular correlations which can probe the spin...
Mr
Julio Leite
(King's College London)
15/01/2016, 09:50
We consider "classical" fermions and scalars coupled to a 4-d diffeomorphism breaking gravity
model, and we derive the one-loop Lorentz-violating effective dispersion relation for matter,
after integrating out gravitons. The modified gravity model is the z=3 non-projectable
Horava-Lifshitz gravity which, due to its improved UV behaviour, involves logarithmic divergences only. We find that...
Mr
Alex Keshavarzi
(University of Liverpool)
15/01/2016, 09:50
The anomalous magnetic moment of the muon, $a_{\mu}$, stands as an enduring precision test of the Standard Model. With the hadronic contribution providing the largest uncertainty to the standing $3.3\sigma$ discrepancy between theoretical and experimental estimates, the combination of $e^{+}e^{-} \rightarrow$ hadrons cross section data in the determination of $a_{\mu}^{\text{had, LOVP}}$ must...
Mr
Sebastian Cespedes
(DAMTP, University of Cambridge)
15/01/2016, 10:15
Higher derivative interactions might induce an effective speed of sound for the tensor modes. Such speed can be removed by a disformal transformation which is a change in the light cone slope. This transformation rescale the coordinates in such a way that the scalar modes get a effective speed. We study the effects of this transformation for CMB photons propagation. We find that by using this...
Ms
Emine Yildirim
(University of Southampton)
15/01/2016, 10:15
We discuss a composite two Higgs doublet model based on a symmetry breaking SO(6) × U (1)_x → SO(4) ×SO(2) × U (1)_x at a scale f, and explain how the effective kinetic terms and Yukawa interactions are obtained. The coupling of the Higgs boson as a pseudo Nambu-Goldstone boson to the standard model fields can deviate from that of the standard model Higgs boson due to the non-linear feature....
Mr
Andrés Luna-Godoy
(University of Glasgow)
15/01/2016, 11:10
The BCJ double copy relates scattering amplitudes of gauge and gravity theories. In an attempt to study this duality in a non-perturbative context, it was recently found that Kerr-Schild solutions in general relativity are somehow a double copy of linearised Yang-Mills solutions. In this talk I apply the solutions double copy procedure to bremsstrahlung systems and explain its relation to the...
Mr
Juri Fiaschi
(University of Southampton)
15/01/2016, 11:10
The Drell-Yan di-lepton production at hadron colliders is by far the preferred channel to search for new heavy spin-1 particles. Traditionally, such searches have exploited the Narrow Width Approximation (NWA) for the signal, thereby neglecting the effect of the interference between the additional Z'-bosons and the Standard Model Z and γ. Recently, it has been established that both finite...
Mr
Silvan Kuttimalai
(IPPP Durham)
15/01/2016, 11:35
We present a fully automated framework as part of the Sherpa event generator for the computation of tree-level cross sections in beyond Standard Model scenarios, making use of model information given in the Universal FeynRules Output format. Elementary vertices are implemented into C++ code automatically and provided to the matrix-element generator Comix at runtime. Widths and branching ratios...
Mr
Edward Hughes
(Queen Mary University of London)
15/01/2016, 11:35
Controlling infrared divergences in QFT cross-sections has been an important phenomenological problem for many decades. Recently, there has been renewed theoretical interest, with the observation that soft theorems emerge as the Ward identities of asymptotic symmetries, at least at tree level. I shall discuss recent work probing the one-loop corrections to subleading soft theorems in the...
Mr
Fredrik Björkeroth
(University of Southampton)
15/01/2016, 12:00
There are many open questions in high energy physics today, ranging from the origin of neutrino mass to the strong CP problem. In particular, there is no current frontrunner for a theory which explains the flavour mixing and mass hierarchies within the SM, though some of the most complete and realistic attempts are found among Flavour GUTs. I will review two such models, based on SU(5) and...
Mr
Gustav Mogull
(University of Edinburgh)
15/01/2016, 12:00
Colour-kinematics duality in tree-level Yang-Mills amplitudes (BCJ relations) invites new possibilities for loop-level computations. In this talk I shall briefly introduce the generalised unitarity approach at one loop. Then, in the context of a 5-gluon, 2-loop QCD amplitude, I will demonstrate how the BCJ relations can be applied to unitarity cuts. This allows leading colour information to...
Mr
Simon Armstrong
(IPPP)
15/01/2016, 12:25
I will give a short intro to the blackhat library which I have been working on, why we need efficient high multiplicity NLO amplitudes, how we can calculate them using generalised unitarity, BCFW and how to not need 6 or more dimensions.
Mr
Darren Scott
(IPPP, Durham University)
15/01/2016, 12:25
Standard Model Effective Field Theory (SMEFT) is a method to parametrise the impact of new physics which may become accessible at higher energies without specifying its UV origin. The new physics is said to be integrated out, leaving behind effective non-renormalisable operators. In this talk, we supplement the Standard Model with all (baryon number conserving) operators which appear at...
