# 10ᵗʰ Anniversary Special Edition

Europe/London
Centre for Particle Theory, Durham

#### Centre for Particle Theory, Durham

IPPP & Dept. Mathematical Sciences Durham University South Road Durham DH1 3LE
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Description

Welcome to YTF 10!

YTF exists to bring together postgraduate students working in theoretical physics and encourage them to present their work to a sympathetic audience.  We hope to foster development of early-career researchers and encourage collaboration between students at different universities.

YTF 10 will be held at Durham University between the 10th and 12th of January, 2018.  It is being organised to be seamlessly compatible with YETI, which will be held at Durham earlier in the same week.  We encourage you to come to both!

Topics expected to be discussed include:

• Amplitudes
• Beyond-Standard-Model physics
• Cosmology
• Dark Matter
• Flavour physics
• Gravity
• Holography
• Neutrinos
• QCD
• Solitons
• Standard Model phenomenology
• String phenomenology
• String theory
• SUSY
• and much more!

Registration is now open!  You'll need to log in using your IPPP Indico account – if you don't have one, you'll need to create one and wait for it to be approved.  We'll do this as quickly as possible, and you'll then be able to register.  This will make it easier for you to upload the abstracts.  Registration is open until the 15th of December.

Abstract submission is open until the 15th of December.  We'll release a detailed schedule shortly after registration closes.

For more information, visit our website – and if you tweet, follow us at @Durham_YTF to keep up-to-date with the latest from the team.  If you have any questions, do get in touch at DurhamYTF@gmail.com and someone from the YTF 10 team will get back to you.

Participants
• Aaron O'Neill
• Alan Price
• Alan Reynolds
• Alastair Wickens
• Alex Jenkins
• Alexander Mitchell-Lister
• Alexander Titterton
• Amy Lloyd-Stubbs
• Andreas Pithis
• Andres Olivares del Campo
• Andrew Cheek
• Arianna Renzini
• Baptiste Ravina
• Benjamin Percival
• Bogdan Ganchev
• Boschi Tommaso
• Christos Vlahos
• Daniel Hatton
• Daniel Locke
• David Rodriguez
• Dries Seynaeve
• Dumitru Dan Smaranda
• Duncan Walker
• Elliott Reid
• Euan McLean
• Finn Kieran
• Francesco Buciuni
• Giuseppe De Laurentis
• Henry Day-Hall
• Hynek Paul
• Jack Holguin
• Jack Richings
• Jack Setford
• James Black
• James Cook
• James Edholm
• James Richings
• Jamie Rogers
• Jesse Liu
• Jiajia Qin
• Joey Reiness
• Jonathan Cullen
• Joseph Bullock
• Joseph Farrow
• Josu C. Aurrekoetxea
• Juan Cruz-Martinez
• Kareem Farrag Farrag
• Kevin Kwok
• Lasse Carsten Schmieding
• Leonora Donaldson Wood
• Luigi Marchese
• Maciej Matuszewski
• maria laura piscopo
• Marian Heil
• Marius Höfer
• Martin Daniel
• Matheus Hostert
• Matthew De Angelis
• Matthew Kirk
• Matthew Lim
• Matthew Mostert
• Matthew Russell
• Maybee Ben
• Nicola Rendell
• Olivier Lennon
• Patrick Bolton
• Patrick Tunney
• Ronald Rodgers
• Sam Rowley
• Sandra Kvedaraite
• Simon King
• Sonali Mohapatra
• Stav Zalel
• Stephanie Baines
• Stephen Brown
• Stephen Webster
• Tarso Franarin
• Tega Edo
• Thomas Helfer
• Tom Steudtner
• Ulserik Moldanazarova
• Vaios Ziogas
• Wei Liu
• Wendy Gray
• Ying-Rui Hou
Support
• Wednesday, 10 January
• 12:30 13:30
Lunch 1h Dining Hall (Collingwood College)

### Dining Hall

#### Collingwood College

• 13:30 14:30
Registration and check-in 1h Reception (Collingwood College)

### Reception

#### Collingwood College

Registration, welcome and accommodation check-in at Collingwood college

• 14:30 14:40
Welcome 10m
• 14:40 15:50
Session I: BSM
• 14:40
An Introduction to SMEFT 10m
In this talk I will discuss the Standard Model Effective Field Theory (SMEFT), a very general model to describe the interaction of the Standard Model with fields at masses far higher than those of the SM. I will discuss the necessity for, and techniques of using dimension-6 operators to compute decay rates and cross sections at next-to-leading order (NLO) and the phenomenological applications of such calculations.
Speaker: Jonathan Cullen (Durham University)
• 14:50
General Treatment of the Monopole Production Cross Sections by Drell-Yan and Photon Fusion for Three Spin Models 20m
Recently there is a revived interest in monopole searches with masses accessible at current colliders, due to several theoretical models predicting the existence of light monopoles. However all of such models predict monopoles with structure (solitons), whose production at colliders may be strongly suppressed. On the other hand, there is no theory up to now for point-like monopoles, viewed as sources of singular magnetic fields, of the type envisaged by Dirac. For the latter type, there are only effective descriptions, viewing the monopole as a matter field, which may carry spins 0, $\frac{1}{2}$ or 1 and all three cases are actively searched for in the MoEDAL detector at CERN. Theoretical expressions for kinematic distributions serve as guides to these searches. The cross section distributions in each case are presented, derived from a U(1) invariant gauge theory. The analytical expressions in the spin $\frac{1}{2}$ and 1 cases are defined completely generally through the inclusion of a magnetic moment term proportional to a parameter $\kappa$, related to the gyromagnetic ratio $g_R=1+\kappa$. This term does not exist in the spin 0 case. This original work proposes $\kappa$ as a new phenomenological parameter in monopole searches.
Speaker: Ms Stephanie Baines ((King's College London) on behalf of the MoEDAL collaboration)
• 15:10
Higgs assisted Q-balls from pseudo-Nambu-Goldstone bosons 20m
Motivated by recent constructions of TeV-scale strongly-coupled dynamics, either associated with the Higgs sector itself as in pseudo-Nambu-Goldstone boson (pNGB) Higgs models or in theories of asymmetric dark matter, I will discuss work where it was shown that stable solitonic Q-balls can be formed from light pion-like pNGB fields carrying a conserved global quantum number in the presence of the Higgs field. I will focus on the case of thick-wall Q-balls, where solutions satisfying all constraints are shown to exist over a range of parameter values. In the limit that our approximations hold, the Q-balls are weakly bound and parametrically large, and the form of the interactions of the light physical Higgs with the Q-ball is determined by the breaking of scale symmetry.
Speaker: Mr Olivier Lennon (University of Oxford)
• 15:30
Scherk Schwartz twists in GUT models 20m
The talk will give an overview of orbifold models in 5D and 6D and will revolve around the question of can non-trivial boundary conditions in the compactified dimensions (also known as Scherk-Schwartz twitsts) give a SM like low energy spectrum with a "naturaly" broken SUSY.
Speaker: Mr Dumitru Dan Smaranda (University of Glasgow)
• 15:50 16:00
Tea and Coffee 10m Department of Mathematical Sciences

#### Department of Mathematical Sciences

• 16:00 17:00
Session II: SUSY
• 16:00
Sneutrino Dark Matter in the BLSSM 20m
In the framework of the $B-L$ Supersymmetric Standard Model (BLSSM), we assess the ability of ground and space based experiments to establish the nature of its prevalent Dark Matter (DM) candidate, the sneutrino, which could either be CP-even or -odd. Firstly, by benchmarking this theory construct against the results obtained by the Planck spacecraft, we extract the portions of the BLSSM parameter space compliant with relic density data. Secondly, we show that, based on current sensitivities of the Fermi Large Area Telescope (FermiLAT) and their future projections, the study of high-energy gamma-ray spectra will eventually enable us to extract evidence of this DM candidate through its annihilations into $W^+W^-$ pairs (in turn emitting photons), in the form of both an integrated flux and a differential energy spectrum which cannot be reconciled with the assumption of DM being fermionic (like, e.g., a neutralino), although it should not be possible to distinguish between the scalar and pseudoscalar hypotheses. Thirdly, we show that, while underground direct detection experiments will have little scope in testing sneutrino DM, the Large Hadron Collider (LHC) may be able to do so in the well-studied tri-lepton (plus missing transverse energy) signal following data collection during Run 2 and 3.
Speaker: Mr Simon King (University of Southampton)
• 16:20
Searches for NMSSM Signatures with Low Missing Transverse Energy at the LHC 20m
We examine scenarios in the Next to Minimal Supersymmetric Standard Model where squarks and gluinos decay via various two cascades, each ending in a stable neutralino LSP and a standard model Higgs with the mass gaps in the decay such that the Missing Transverse Energy is very small. Performing two-dimensional parameter scans and focusing on the hadronic $h\rightarrow b\bar{b}$ decay giving a $b\bar{b}b\bar{b}$ + MET final state we then explore the sensitivity of a current CMS $\alpha_{\text{T}}$-based general-purpose jets+MET analysis to such scenarios with a view to developing novel search approaches in the near future.
Speaker: Mr Alexander Titterton (University of Bristol, University of Southampton, Rutherford Appleton Laboratory)
• 16:40
Opening unexplored frontiers for new physics at the LHC 20m
The smoking gun signals for new physics at the energy frontier elude us. What gaps remain under the lamppost? Where do we focus our next searches? I'll show striking opportunities to probe new and challenging signatures of supersymmetry and dark matter. These need dedicated experimental efforts such as custom triggers or soft leptons, and I'll highlight key synergies with theoretical input. Such trends drive ongoing and upcoming 13 TeV LHC searches, which open tantalising prospects for discoveries at the weak scale.
Speaker: Jesse Liu (Oxford University)
• 17:00 17:30
Tea and Coffee 30m Department of Mathematical Sciences

#### Department of Mathematical Sciences

• 17:30 19:00
YTF Invited Speaker I: Talk by Prof. John Ellis
• 19:00 21:00
Posters and Pizza Bransden Room (Department of Physics)

### Bransden Room

#### Department of Physics

• Thursday, 11 January
• 09:00 10:30
Session III: LHC and QCD
• 09:00
Measurement of top quark pair production in association with a vector boson at ATLAS 10m
We review the Run-1 @8 TeV and preliminary Run-2 @13 TeV measurements of the ttV cross-section with the ATLAS experiment. These processes play a crucial role both as Standard Model precision measurements (unique window into the coupling of the top quark to the Z boson) and to provide more accurate background estimations for many BSM searches (e.g. simplified SUSY models and Dark Matter searches). Rephrased in terms of EFT parameters, Run-1 of the LHC enabled the first direct constraints on a number of relevant operators. Future prospects and expectations from the full Run-2 dataset will be outlined.
Speaker: Mr Ravina Baptiste (University of Sheffield)
• 09:15
Quark mass determination from lattice QCD 20m
The ability of lattice QCD to calculate experimental observables, such as meson masses, from a small number of input parameters makes it a powerful tool for the accurate determination of those parameters. One method of determining quark masses relies on the tuning of the bare quark masses on the lattice and the calculation of the relevant mass renormalisation factors. This can be done nonperturbatively with momentum subtraction schemes such as RI-SMOM, which can be matched to $\overline{\mathrm{MS}}$ in the continuum to give high precision quark mass determinations.
Speaker: Mr Daniel Hatton (University of Glasgow)
• 09:35
Pion scattering and Lattice QCD 20m
Lattice QCD allows us to probe Low Energy physics by allowing us to make precise predictions of standard model properties. Now that Lattice predictions are reaching higher levels of precision, our ability to search for discrepancies between experiment results and standard model predictions is enhanced. I will discuss the methods used to make predictions in Lattice QCD and some of the challenges involved, through the example of pion scattering.
Speaker: Mr James Richings (University of Southampton)
• 10:00
QCD at NNLO using antenna subtraction 20m
Progress made by ATLAS and CMS in recent years has dramatically reduced the experimental uncertainty associated with many important measurements of hadronic processes. Any detection of BSM physics at the LHC will require theoretical SM predictions matching this precision, and thus the inclusion of NNLO QCD corrections. I will outline the challenges of such calculations, summarise the universal infrared structure of QCD, and introduce the antenna subtraction method, which exploits this structure to regulate the IR divergences of phase-space integrands. I will then walk through the assembly of an NNLO calculation for an example process.
Speaker: Mr James Whitehead (IPPP, Durham)
• 10:30 11:00
Tea and Coffee 30m Department of Mathematical Sciences

#### Department of Mathematical Sciences

• 11:00 12:30
Session IV: Non-perturbative physics
• 11:00
Tracking down quirks at the LHC 20m
Quirks - particles charged under a QCD-like confining force - are an interesting extension to the Standard Model. Pair-produced quirks can exhibit extremely unusual behaviour if produced at the LHC. Current track reconstruction algorithms at the LHC are mostly blind to the 'quirky' tracks these particles would leave in the detector, so a new search strategy is proposed that offers good prospects for detection across a broad region of the parameter space.
Speaker: Mr Jack Setford (University of Sussex)
• 11:20
Latest results in meson mixing and lifetimes 20m
Predictions of meson mixing observables and the lifetime ratios of heavy mesons provide an excellent way to test our theoretical tools against experiment. One of the main numerical inputs to these calculations are non-perturbative parameters - I will speak about the latest determinations of these inputs, and how they affect our understanding of the theory calculation, as well as briefly about how these observables constrain new physics that could explain some of the recent flavour anomalies.
Speaker: Mr Matthew Kirk (IPPP, Durham University)
• 11:40
AdS/CFT Simulations of Meson Decay Rates 20m
Recent work has show that the AdS/CFT correspondence can be used to successfully model mesons. In particular, the combination of this method and the instanton method shows particular promise in calculating meson decay rates. I will present the background of this technique, beginning with introducing a toy 2 dimensional model. I will then present my more recent work on a more realistic model using the Sakai-Sugimoto spacetime in for the string picture.
Speaker: Maciej Matuszewski (Durham University)
• 12:00
Detecting a Dark Sector Phase Transition in the Early Universe 10m
In this talk, I will be discussing the viability of a purely SU(N) dark sector that undergoes a confining phase transition at some energy scale in the early universe. We will explore the relationship between key parameters in this theory along with their effect on an observable gravitational wave signal from upcoming gravitational wave detection experiments.
Speaker: Mr Alastair Wickens (King's College London)
• 12:30 13:30
Lunch 1h Bransden Room (Physics Department)

### Bransden Room

#### Physics Department

• 13:30 15:00
Session V: Asymptotic Safety
• 13:30
UV conformal window for asymptotically safe gauge-Yukawa theories 20m
We investigate a class of strictly four-dimensional, renormalisible gauge-Yukawa theories which exhibit Asymptotic Safety - their UV behaviour is controlled by an interacting, ultraviolet fixed point. The conformal window introduced by this fixed point is studied in a systematic expansion, provided by the Veneziano limit. Constraints from the strong coupling limit, fixed point mergers and vacuum instability are formulated. We will show that the conformal window lies within a perturbative regime.
Speaker: Mr Tom Steudtner (University of Sussex)
• 13:50
An Introduction to Higgsplosion 20m
What is Higgsplosion? Why should you care? By adding literally nothing to the SM it can be argued that there is some physical minimum resolvable scale. Beyond this scale, particles 'Higgsplode' into a large number of soft quanta. This has interesting implications for the UV behaviour of the theory. My talk will be in three parts: 1. What is it? 2. Effect on RG running in phi4 theory [1709.08655] 3. Possibility of Higgsploding dark matter
Speaker: Mr Joey Reiness (IPPP)
• 14:10
Infrared divergences for quantum fields in cosmological spacetimes 20m
Our universe is believed to have experienced an inflationary period in its early stages of development. It is therefore of interest to understand the behaviour of the graviton two point function in an inflationary spacetime. We consider a background Friedman-Lemaitre- Robertson-Walker (FLRW) spacetime, which is a (slow roll) inflationary spacetime. The graviton two point function is known to be infrared divergent in such a spacetime. It has been previously found, in de Sitter spacetime, that a large coordinate gauge transformation can be used to remove the infrared divergence, and this suggests that the divergence should not lead to local physical effects. The next natural step appeared to be to see if this type of transformation could be used effectively in a FLRW spacetime. We found that this was indeed the case, and removed the leading order divergence of the graviton two point function. The correspondence between the gauge invariant part of the graviton two point function and the linearized Weyl tensor correlator gives a bound on the extent to which the divergence can be removed. This bound suggests that our transformation removes all unphysical infrared divergence, without affecting the physical behaviour of the two point function.
Speaker: Ms Nicola Rendell (University of York)
• 14:30
Quantum Gravity from Conformal Field Theory 20m
I will describe the problem of constructing perturbative loop corrections to AdS_5 supergravity amplitudes, which are dual to 4pt-correlators in N=4 super Yang-Mills theory. By using the consistency of the CFT's operator product expansion and known tree-level supergravity results, we are able to bootstrap loop corrections by imposing a consistent spectrum of exchanged double-trace operators.
Speaker: Mr Hynek Paul (University of Southampton)
• 15:00 15:30
Tea and Coffee 30m Department of Mathematical Sciences

#### Department of Mathematical Sciences

• 15:30 17:00
Session VI: Gravity
• 15:30
Infinite Derivative Gravity 20m
Infinite Derivative Gravity (IDG) provides a mechanism for resolving the singularity present in General Relativity as well as producing inflation. Here I will discuss how the weak-field limit can be made regular using IDG around both flat and curved backgrounds.
Speaker: Mr James Edholm (Lancaster University)
• 15:50
Gravitational Waves from Oscillaton Star Collisions 20m
I will talk about the GW signatures from the collisions of Oscillatons -- which are long-lived non-topological solutions of massive scalar fields. I will describe the technical challenges and present the GW wave forms of such collisions calculated using the numerical relativity code GRCHOMBO. I will show that for black hole end states, the total gravitational waves energy released in such collisions is more than that of BH-BH collisions of equal masses by a significant amount.
Speaker: Mr Thomas Helfer (Kings College London)
• 16:10
The double copy for scattering of Reissner-Nordström black holes 20m
The double copy is a direct duality between Yang-Mills theory and gravity that emerges from the modern scattering amplitudes programme. In this talk I will discuss how the double copy can be applied to the scattering of Reissner-Nordström black holes, deriving the classical perturbative result from charged scalar diagrams, and showing that a novel external axion mode also arises. Such calculations offer the tantalising possibility of greatly simplifying theoretical predictions for precision gravitational wave astronomy.
Speaker: Ben Maybee (University of Edinburgh)
• 16:30
Scalar hairy black holes in four dimensions are unstable 20m
We present a numerical analysis of the stability properties of the black holes with scalar hair constructed by Herdeiro and Radu. We prove the existence of a novel gauge where the scalar field perturbations decouple from the metric perturbations, and analyse the resulting quasinormal mode spectrum. We find unstable modes with characteristic growth rates which for uniformly small hair are almost identical to those of a massive scalar field on a fixed Kerr background, whereas for larger amplitudes of the scalar cloud can be up to a few times larger than in Kerr.
Speaker: Mr Bogdan Ganchev (University of Cambridge)
• 16:50
Full GR Cosmic String Dynamics 10m
In this talk I will give a very brief introduction to the field of Numerical Relativity and how it can be applied to get full GR Cosmic String simulations.
Speaker: Mr Josu C. Aurrekoetxea (King's College London)
• 17:00 17:30
Tea and Coffee 30m Department of Mathematical Sciences

#### Department of Mathematical Sciences

• 17:30 19:00
YTF Invited Speaker II: Talk by Dr. Silke Weinfurtner
• 17:30
Black hole physics in the laboratory: Rotational superradiant scattering in a vortex flow 20m
Wave scattering phenomena are ubiquitous to almost all Sciences, from Biology to Physics. When an incident wave scatters off of an obstacle, it is partially reflected and partially transmitted. Since the scatterer absorbs part of the incident energy, the reflected wave carries less energy than the incident one. However, if the obstacle is rotating, this process can be reversed and waves can be amplified, extracting energy from the scatterer. Even though this phenomenon, known as superradiance, has been thoroughly analysed in several theoretical scenarios (from eletromagnetic radiation scattering on a rotating cylinder to gravitational waves incident upon a rotating black hole), it has never been observed. Here we describe in detail the first laboratory detection of superradiance. We observed that plane waves propagating on the surface of water are amplified after being scattered by a draining vortex. The maximum amplification measured in the experiment was 14%± 8% obtained for 3.70 Hz waves, in a 6.25 cm deep fluid. Our results are consistent with superradiant scattering caused by rapid rotation. In particular, a draining fluid can transfer part of its rotational energy to incident low-frequency waves. Our experimental findings will shed new light on Black Hole Physics, since shallow water waves scattering on a draining fluid constitute an analogue of a black hole. We believe, especially in view of the recent observations of gravitational waves, that our results will motivate further research (both theoretical and experimental) on the observation of superradiance of gravitational waves. Reference: https://www.nature.com/nphys/journal/vaop/ncurrent/full/nphys4151.html
Speaker: Dr Silke Weinfurtner (Nottingham University)
• Friday, 12 January
• 09:00 10:30
Session VII: Cosmology
• 09:00
Horizon Feedback Inflation 10m
We consider the effect of the Gibbons-Hawking radiation on the inflaton in the situation where it is coupled to a large number of spectator fields. We argue that this will lead to two important effects - a thermal contribution to the potential and a gradual change in parameters in the Lagrangian which results from thermodynamic and energy conservation arguments. We present a scenario of hilltop inflation where the field starts trapped at the origin before slowly experiencing a phase transition during which the field extremely slowly moves towards its zero temperature expectation value. We show that it is possible to obtain enough e-folds of expansion as well as the correct spectrum of perturbations without hugely fine-tuned parameters in the potential (albeit with many spectator fields). We also comment on how initial conditions for inflation can arise naturally in this situation.
Speaker: Mr David Rodriguez (King's College London)
• 09:10
The Gravitational-Wave Background: Anisotropies and Cosmic Strings 10m
With gravitational-wave interferometry firmly established as a new field of astronomy, one of the most exciting targets for future observations is the *stochastic gravitational-wave background* (SGWB). Comprised of a large number of distant, unresolved sources, this background carries much information about the early universe, and will soon become a powerful cosmological probe. While the SGWB is commonly treated as isotropic, we relax this assumption and, by analogy with the CMB, develop a framework for computing analytical predictions of the full anisotropic background. As a concrete example, we consider the SGWB generated by a network of cosmic strings.
Speaker: Mr Alex Jenkins (King's College London)
• 09:20
Incoherent Mapping of the Gravitational Wave Background 20m
The Gravitational Wave Background (GWB) is a cornucopia of information, waiting to be unraveled and explored; to this end, we've constructed a mapper which reconstructs the GWB anisotropies on the sky. In this talk, I will first introduce the GWB and its unique features. I will then present what type of data we expect to work with, and explain the mapping algorithm. Finally, I will motivate the multiple baseline approach, in which lies the strength of our method.
Speaker: Ms Arianna Renzini (Imperial College London)
• 09:40
Evolution of Universes in Causal Set Cosmology 20m
The causal set approach to quantum gravity postulates that spacetime is fundamentally discrete. In this formalism spacetime is a causal set and each element in the set is a "spacetime atom" — a “here and now”, like a click of the fingers. The causal set spacetime grows through a stochastic process in which new elements are born into the set. We experience this birth process as the passage of time: the elements which are being born are the present, the elements that were born are the past, and the future has not yet come into being. Classical Sequential Growth (CSG) models (arXiv:gr-qc/9904062) are a class of physically motivated models for such spacetime growth. This talk will begin with an introduction to CSG models and the cosmologies they give rise to, and continue with a discussion of causal set models of spacetime singularities and how a renormalisation of dynamical parameters occurs in a CSG model over such structures (arXiv:1703.07556). We will conclude by speculating how this could realise aspects of evolutionary cosmologies (suggested by J.A. Wheeler and others) in which the parameters of nature are reprocessed as the universe ages.
Speaker: Ms Stav Zalel (Imperial College London)
• 10:00
Lattice Holographic Cosmology 20m
A cornerstone of modern cosmology is that the Big Bang was followed by a period of rapid expansion, a time we have come to call: inflation. This mechanism has been very successful in explaining a number of cosmological observations; flatness, isotropy, and structure formation in the universe we observe today, as well as the cosmic microwave background (CMB). Inflation, whilst being widely popular and successful, is still not well understood, and we do not have any fundamental theory to describe the mechanism underlying it. It is expected that this mechanism may originate from an unknown particle physics theory. In this 20 minute talk, we will introduce Holographic Cosmology, and the motivations behind the utilisation of lattice simulations to model this theory. We will then also look at the steps that the collaboration will take to achieve its goal: making falsifiable predictions against the power-spectrum and non-Gaussianities of the CMB (using data from the Planck satellite).
Speaker: Mr Matthew Mostert (University of Southampton)
• 10:20
Axion Structure Formation 10m
We explore structure formation in axion models, using full General Relativity, resulting in axion stars, blackholes, and no stable objects. This problem cannot be done analytically, and we use numerical methods.
Speaker: Mr James Cook (King's College London)
• 10:30 11:00
Tea and Coffee 30m Department of Mathematical Sciences

#### Department of Mathematical Sciences

• 11:00 12:30
Session VIII: Neutrinos
• 11:00
Baryons and Simulations 10m
Speaker: Mr Jack Richings (Durham University)
• 11:10
Long-lived Heavy Neutrinos from Higgs Decays 20m
We investigate the pair-production of low mass right handed neutrino and its possible decays in a gauged $B-L$ model. The right handed neutrino of mass few tens of GeV that generates viable light neutrino masses through seesaw can lead to displaced vertices and distinctive leptonic signatures at LHC and future lepton colliders. The production of such low mass right handed neutrino depends on the mixing between SM and gage singlet Higgs state, whereas the decay length depends on the active-sterile neutrino mixing. We focus on the semi-leptonic final states arising from such a decay, and analyze the sensitivity reach of LHC and future linear colliders in probing active-sterile neutrino mixing. We show that the active-sterile neutrino mixing as small as $V_{\mu N} \sim \mathcal{O}(10^{-7})$ can be probed at 13 TeV LHC with 100 $\rm{fb}^{-1}$ luminosity and at leptonic colliders with 5000 $\rm{fb}^{-1}$ luminosity. The high-luminosity run of LHC and future experiment MATHUSLA can further improve this reach by one more magnitude.
Speaker: Mr Wei Liu (UCL)
• 11:30
Lepton Number Violating Interactions and Neutrino Matter Oscillations 10m
Beyond the intriguing anomalies at reactor and short baseline experiments, the three-neutrino mixing paradigm has been highly successful in describing the neutrino oscillation data. In order to pin down the last components of this model, long baseline experiments will attempt to determine the Dirac CP violating phase and neutrinoless double beta decay experiments will put limits on the Dirac/Majorana nature and mass ordering of the active neutrinos. Regardless of these results, new physics must be behind the generation of at least two non-zero active neutrino masses. BSM models predict the violation of lepton number in this process, and effective operators can describe these effects at low energy in a model independent way. We explore the possibility that LNV interactions affect the propagation of neutrinos through matter, and hence could be constrained by the next generation of neutrino oscillation experiments.
Speaker: Mr Patrick Bolton (University College London)
• 11:45
Prospects for detecting eV-scale sterile neutrinos from a galactic supernova 20m
Future neutrino detectors will obtain high-statistics data from a nearby core-collapse supernova. We study the mixing with eV-mass sterile neutrinos in a supernova environment and its effects on the active neutrino fluxes as detected by Hyper-Kamiokande and IceCube.
Speaker: Mr Tarso Franarin (King's College London)
• 12:10
Predicting the Right-Handed Neutrino Masses From the Littlest Seesaw and Leptogenesis 20m
The Littlest Seesaw model based on two right-handed neutrinos with constrained Yukawa couplings provides a highly predictive description of neutrino masses and PMNS mixing parameters. If realised at high energies there will be renormalisation group corrections to the low energy predictions, which depend on the right-handed neutrino masses. We perform a $\chi^2$ analysis to determine the right-handed neutrino masses from a four-parameter fit to the low energy neutrino parameters, also eventually taking into account leptogenesis.
Speaker: Mr Sam Rowley (University of Southampton)