YTF 21

Session

Full-length talks

16 Dec 2021, 15:30

Zoom (Centre for Particle Theory, Durham)

Conveners

Full-length talks: Thursday afternoon session 2

• Arpit Das (Durham University)

Full-length talks: Thursday afternoon session 1

• Connor Armstrong (Durham University)

Full-length talks: Thursday evening session 2

• Richie Dadhley

Full-length talks: Thursday evening session 1

• Dorian Amaral (IPPP)

Full-length talks: Friday morning session 2

• Ryan Moodie (Durham University)

Full-length talks: Friday morning session 1

• Guillaume Rostagni (IPPP, Durham University)

Full-length talks: Friday afternoon session 1

• Hitham Hassan (Durham University (1st year PhD student))

Full-length talks: Friday afternoon session 2

• Jack Shergold (Durham University)

Full-length talks: Friday evening session 1

• Richie Dadhley

Full-length talks: Friday evening session 2

• Oscar Braun-White (IPPP Durham University)

Description

20 minutes talks + 5 minutes questions

122. $Hb\overline{b}$ production as an example of modern amplitudes calculations

Jakub Krys (IPPP Durham)

16/12/2021, 15:30

20 minutes talk

In this talk, I present some of the modern techniques used in computation of scattering amplitudes. Using $Hb\overline{b}$ production as an example, I give an overview of the method and describe how computational bottlenecks can be overcome by using finite field reconstruction to obtain analytic expressions from numerical evaluations. I also show how the method of differential equations allows us...

143. Fifth forces in scalar-tensor theories and how to avoid them

Sergio Sevillano Muñoz (University of Nottingham)

16/12/2021, 15:30

20 minutes talk

The Einstein-Hilbert action is well known as the standard choice when model-building theories of gravity. However, couplings between scalar fields and the space-time curvature regularly arise in string theory and cannot be avoided when RG running standard theories of gravity in the presence of additional scalar fields. The resulting theories are usually referred to as scalar-tensor theories...

138. A Good and Fun way to lift Supergravity Moduli

George Smith (Imperial College London)

16/12/2021, 16:00

20 minutes talk

Moduli in Supergravity compactifications are fields which parameterise properties of the compactificaiton space such as its volume or the size of its cycles. If the effective field theory potential is degenerate in the moduli directions then these moduli appear as massless scalars in the effective theory for which there is no experimental evidence. More seriously if the moduli have no VEV...

150. Three-loop helicity amplitudes for diphoton production in gluon fusion

Piotr Bargiela (University of Oxford)

16/12/2021, 16:00

20 minutes talk

We present a calculation of the helicity amplitudes for the process gg→γγ in three-loop massless QCD. We employ a recently proposed method to calculate scattering amplitudes in the 't Hooft-Veltman scheme that reduces the amount of spurious non-physical information needed at intermediate stages of the computation. Our analytic results for the three-loop helicity amplitudes are remarkably...

140. Cosmological and quantum gravity applications of quantum Riemannian geometry on polygons

Julio Narciso Argota Quiroz (Queen Mary University of London)

16/12/2021, 16:30

20 minutes talk

The idea that space-time could be better modeled due to quantum gravity effects by non-commutative coordinates or ‘quantum spacetime’ is widely accepted as a possibility and is a cornerstone of the formalism of Quantum Riemmanian Geometry (QRG). This formalism allows to address issues related to unification of quantum theory and gravity in a systematic way. Using the QRG approach we fully...

157. Decomposition of Triple Collinear Splitting Functions

Oscar Braun-White (IPPP Durham University)

16/12/2021, 16:30

20 minutes talk

In the kinematic region where three particles are collinear, the multi-parton scattering amplitudes factorise into a product of a triple collinear splitting function and a multi-parton scattering amplitude with two fewer particles. These triple collinear splitting functions contain both iterated single unresolved contributions, and genuine double unresolved contributions. We make this...

123. Chiral models of composite axions and accidental Peccei-Quinn symmetry

Filippo Revello (University of Oxford)

16/12/2021, 17:30

20 minutes talk

The QCD axion, based on the existence of the anomalous Peccei-Quinn (PQ) symmetry, realizes a remarkably simple and elegant solution to the strong CP problem, and is also a well-motivated dark matter candidate. However, hiding behind the apparent simplicity, explicit realizations are extremely sensitive to PQ-violating effects in the UV, which can destabilize the axion potential and spoil the...

153. Holomorphic Modular Bootstrap

Arpit Das (Durham University)

16/12/2021, 17:30

20 minutes talk

In this talk, we shall discuss a classification scheme, called holomorphic modular bootstrap, for classifying Rational Conformal Field Theories (RCFTs) using the Modular Linear Differential Equations (MLDEs) their characters (which are the holomorphic factors of their torus partition functions) satisfy. This is a classification scheme based on two parameters (n,l) where n is the number of...

125. A stochastic approach to scalar correlators in cosmological de Sitter

Archie Cable (Imperial College London)

16/12/2021, 18:00

20 minutes talk

The study of scalar correlation functions in de Sitter spacetime is important to develop our understanding of the inflationary epoch. However, the standard procedure of QFT in a curved spacetime can only be used in a regime where the fields are sufficiently massive. This is because light self-interacting scalar fields cause perturbation theory to break down due to infrared divergences. This...

141. Hilbert series techniques in quantum field theory

Mohammad Akhond (Swansea University)

16/12/2021, 18:00

20 minutes talk

I will say some general things about the Hilbert series associated to the moduli space of a supersymmetric QFT. I will then discuss the physical information one can extract from the Hilbert series.

144. Cosmology of a new class of massive vector fields

VICTOR POZSGAY (Imperial College London)

16/12/2021, 18:30

20 minutes talk

I will start by presenting existing classes of massive vector fields before moving on to the new Extended Proca-Nuevo, a non-linear theory of a massive spin-1 field that enjoys a non-linearly realized constraint that distinguishes it among other generalized vector models. I will show how this theory builds a (partial) bridge between the equivalent Generalized Proca and Proca Nuevo while...

134. Gravity at the Tip of the Throat

Bruno Bento (University of Liverpool)

16/12/2021, 18:30

20 minutes talk

Warped throats have been a major tool in trying to connect string theories with our 4d Universe, in particular for their ability to suppress high energy scales.
An explicit description of such a throat (the deformed conifold) can be used to perform explicit computations to determine how the throat affects gravity in 4d.
In this talk I will briefly show how a tower of massive graviton modes...

160. Introduction to the Cosmic Neutrino Background

Jack Shergold (Durham University)

17/12/2021, 09:15

20 minutes talk

In the early universe, neutrinos are produced in equilibrium with the Standard Model plasma. As the universe cools these neutrinos freeze-out, and exist today as a thermal relic that we call the Cosmic Neutrino Background (CnuB). In this talk I will attempt to introduce the CnuB and derive its important properties, before giving a brief introduction to CnuB detection proposals.

132. Primordial black hole formation with full numerical relativity

Eloy de Jong (King's College London)

17/12/2021, 09:15

20 minutes talk

I will talk about studying the formation of black holes from subhorizon and superhorizon perturbations in a matter dominated universe with 3+1D numerical relativity simulations. We find that there are two primary mechanisms of formation depending on the initial perturbation's mass and geometry -- via direct collapse of the initial overdensity and via post-collapse accretion of the ambient dark...

162. Energy transport by dark matter scattering in the Sun

Hannah Banks

17/12/2021, 09:45

20 minutes talk

Asymmetric dark matter (ADM) that is captured in the Sun can act as an efficient conductor of heat, causing observable modifications to properties of the Solar interior. The two formalisms commonly used to parametrise this phenomenon were developed over 30 years ago, and calibrated on single set of simulations. In this talk, I will present the results of new state-of-the-art Monte Carlo...

124. Quantum computing approaches for simulating parton showers in high energy collisions

Simon Williams (Imperial College London)

17/12/2021, 09:45

20 minutes talk

The interpretation of measurements from high energy collisions at experiments like the Large Hadron Collider (LHC) relies heavily on the performance of full event generators, specifically their accuracy and speed in simulating complex multi-particle final states. With the rapid and continuous improvement in quantum computers, these devices present an exciting opportunity for high energy...

155. Precision Calculation in Theoretical Predictions

Mr Hang Yu (University of Liverpool-Theoretical Physics)

17/12/2021, 10:15

20 minutes talk

The precision-imporved theoretical prediction plays a crucial rules in matching with the experiment result and test new physics. Our project is currently computing the 3-loop QCD correction to neutral kaon oscillation $\overline{s}d\to s\overline{d}$ amplitude, which helps with testing the CP violation about in kaon decays. The process and some techniques (e.g. tetrahedron symmetries) are...

149. Searching for dark-matter waves with pulsar polarimetry

Jorge Terol Calvo (Instituo de Astrofísica de Canarias (IAC))

17/12/2021, 10:15

20 minutes talk

In this talk I will explain how the polarization of photons emitted by astrophysical sources might be altered as they travel through a medium of dark matter composed of ultra light axion-like particles (ALPs). I will describe a new, more robust, analysis we delevoped to search for this effect. Afterwards, I will show the resulting strong limits on the axion-photon coupling for a wide range of ...

133. EW Sudakov logarithms and their implementation in OpenLoops

Lorenzo Mai

17/12/2021, 13:30

20 minutes talk

In the energy range above the electroweak (EW) scale the leading contributions coming from EW radiative corrections have a logarithmic nature: they can be both double (DL) or single (SL) logs and they are generally known as Sudakov logarithms. These terms increase with energy and they can provide corrections of order 10% or larger for scales of 1 TeV and beyond; therefore, it is crucial to...

146. Fueling the search for light dark matter-electron scattering

Louis Hamaide

17/12/2021, 13:30

20 minutes talk

Dark matter (DM) detectors employing a Spherical Proportional Counter (SPC) have demonstrated a single-electron detection threshold and are projected to have small background rates. We explore the sensitivity to DM-electron scattering with SPC detectors in the context of DarkSphere, a proposal for a 300 cm diameter fully-electroformed SPC. SPCs can run with different gases, so we investigate...

135. Light inflaton model in a metastable Universe

Ms Abigail Keats (University of Manchester)

17/12/2021, 14:00

20 minutes talk

We minimally extend the Standard Model (SM) with a Z${}_2$ symmetric potential containing a single scalar field, serving as our inflaton with a quartic self-coupling. In the model we have symmetry breaking in both sectors, and with the addition of an inflaton-Higgs portal, the Universe is able to efficiently reheat via 2-2 inflaton-Higgs scattering. Assuming that the Universe with a positive...

156. Theoretical Frontiers in Neutrinoless Double-Beta Decay

Graham Van Goffrier (University College London)

17/12/2021, 14:00

20 minutes talk

Neutrinoless double beta (0νββ) decay is a hypothetical process of crucial interest due to its sensitivity both to the neutrino mass scale and to lepton-number violation. The precision of searches for the decay is largely constrained by disagreement between different many-body models for their nuclear matrix elements (NMEs), due in part to the large nuclei involved and the presence of...

158. Improved Constraints on Effective Top Quark Interactions using Edge Convolution Networks

Panagiotis Stylianou (University of Glasgow)

17/12/2021, 14:30

20 minutes talk

Reinterpreting the LHC results as bounds on the Wilson Coefficients (WCs) of the Standard Model Effective Field Theory (SMEFT) allows studying new-physics effects in a model-independent way. However the large number of effective interactions along with theoretical and experimental uncertainties often result in poor constraints on WCs that motivate the use of alternative techniques with more...

130. Indirect detection of long-lived particles via a less-simplified dark Higgs portal

Krzysztof Jodlowski (National Centre for Nuclear Research)

17/12/2021, 14:30

20 minutes talk

Simplified models of light new physics are an important theoretical and experimental benchmark. Models that extend minimal scenarios by introducing other degrees of freedom are well motivated ways to go beyond the Standard Model (SM). In this talk, I will focus on the light dark Higgs portal that connects the dark sector consisting of, e.g., TeV-scale secluded dark matter (DM) with the SM. I...

163. Lattice simulations of early universe first order deconfinement phase transitions

David Mason (University of Swansea)

17/12/2021, 15:15

20 minutes talk

The detection of gravitational waves has opened an entirely new route to constrain new physics beyond the standard model. A promising direction of investigation is the analysis of gravitational waves produced by first order phase transitions in the early universe. The determination of the expected signatures requires precise measurements of the thermodynamic observables of the transition, such...

151. Unoriented dualities from brane tiling

Salvatore Mancani (Università di Roma La Sapienza)

17/12/2021, 15:15

20 minutes talk

In the context of AdS/CFT, brane tiling allows us to construct the dual gauge theories associated with toric geometries. Studying the orientifold projection of such gauge theories and their conformal points via a-maximization, we show that for three infinite families of theories the projection reduces the degrees of freedom by more than a half and that these families are related by a web of dualities.

136. A comparison of spectral reconstruction methods applied to non-zero temperature NRQCD meson correlation functions

Mr Thomas Spriggs (Department of Physics, Swansea University)

17/12/2021, 15:45

20 minutes talk

We present results from the fastsum collaboration's programme to determine the spectrum of the bottomonium system as a function of temperature. Three different methods of extracting spectral information are discussed: a Maximum Likelihood approach using a Gaussian spectral function for the ground state, the Backus Gilbert method, and the Kernel Ridge Regression machine learning procedure. We...

139. Type II Calabi-Yau compactifications in general spacetime signature

Maxime Médevielle (University of Liverpool)

17/12/2021, 15:45

20 minutes talk

String Theory is a web of perturbatively defined 10 dimensional theories related to each other by various dualities such as "T-duality". When considering a "timelike" T-duality we uncover theories that realize all spacetime signatures.

In this talk, I will motivate the study of dynamic spacetime signature in a quantum gravity context and present the theories obtained in 4 dimensions when...

126. Constructing The Standard Model from String Theory

Thomas Harvey (University of Oxford)

17/12/2021, 16:15

20 minutes talk

The oldest, and one of the most promising, attempts of connecting string theory to low energy physics has been the compactification of $E_8\times E_8$ Heterotic string theory on Calabi-Yau 3-folds.

In this talk I will (attempt to) give a pedagogical overview of such constructions, and string model building in general. The talk will then finish with a discussion of recent work, where modern...

142. Scheme Dependence in pQCD at the Four Loop Level

Robert Mason

17/12/2021, 16:15

20 minutes talk

Explaining data from particle colliders relies on understanding the underlying quantum field theories, such as Quantum Chromodynamics (QCD) for processes involving the strong force. Measurable quantities in perturbative QCD are represented by series in the interaction coupling constant. The renormalization process introduces an ambiguity into calculations leading to multiple schemes for...