Pieces of the Higgsaw

The discovery of a 125 GeV scalar boson at the Large Hadron Collider in 2012 sparked at least as many questions as it answered. The Higgs boson is unique in being the only known fundamental scalar particle, which makes it compelling in a variety of contexts. As the field of Higgs physics has developed and aged, this era-defining boson has crept into relevance throughout all areas of high-energy physics. This thesis looks at the Higgs boson and its potential properties in three different regimes: The first focuses on how measurements of Higgs interactions at particle colliders can be used to discern and identify signs of new physics. A novel analysis method is presented, which uses differential observables to constrain the effects of higher-energy physics within the Standard Model Effective Field Theory framework. This approach takes advantage of expected angular structures in the matrix elements to maximise sensitivity and obtain competitive bounds on the anomalous Higgs-gauge couplings. The second takes a more theoretical approach and looks at the potential high-energy high-multiplicity behaviour of the Higgs. Multiparticle scalar production is considered in an idealised non-perturbative limit by employing a semiclassical treatment. Previous calculations of the semiclassical rate are consolidated and extended. The third investigates the potential role of the Higgs in the dynamics of the early universe. A unified model is presented in which minimal additional field content leads to the solution of five problems in fundamental physics. The available parameter space for this model is within the reach of proposed future experiments. These three areas of research all have the same physics at their core but are fuelled by techniques and ideas from different fields. Together they form three small distant-yet-connected pieces of the ever-growing network of Higgs-related investigations, or Higgsaw

A3_4 King of the Swingers

The idea of swinging on a vine as a means of travel within a jungle is one that has been used in a variety of contexts; while the physical act may be difficult to do, modelling the action and calculating some value for the average horizontal ground velocity can be done with relative ease. Within films and books it has been used for many years; the chase scene from the movie 'Indiana Jones and the Kingdom of the Crystal Skull' is one such film. From investigating this scene the average horizontal ground velocity of Shia la Beouf is found to be 15.3 ms^-1

All-in-one relaxion: A unified solution to five particle-physics puzzles

We present a unified relaxion solution to the five major outstanding issues in particle physics: Higgs mass naturalness, dark matter, matter-antimatter asymmetry, neutrino masses and the strong CP problem. The only additional field content in our construction with respect to standard relaxion models is an up-type vectorlike fermion pair and three right-handed neutrinos charged under the relaxion shift symmetry. The observed dark matter abundance is generated automatically by oscillations of the relaxion field that begin once it is misaligned from its original stopping point after reheating. The matter-antimatter asymmetry arises from spontaneous baryogenesis induced by the CPT violation due to the rolling of the relaxion after reheating. The CPT violation is communicated to the baryons and leptons via an operator, ∂μϕJμ, where Jμ consists of right-handed neutrino currents arising naturally from a simple neutrino mass model. Finally, the strong CP problem is solved via the Nelson-Barr mechanism, i.e., by imposing CP as a symmetry of the Lagrangian that is broken only spontaneously by the relaxion. The CP breaking is such that although an Oð1Þ strong Cabibbo-Kobayashi-Maskawa (CKM) phase is generated, the induced strong CP phase is much smaller, i.e., within experimental bounds

A3_1 Simple Harmonic Rex

Artistic licence often tests fundamental physical laws in contemporary cinema, allowing for unrealistic yet creative scenes. Nevertheless, these improbable scenarios can be valuable exercises in applying our physical knowledge to unique situations. From the 1999 movie Toy Story 2, we calculated the spring constant of Slinky the Dog's spring and the friction coefficient between his paws and the rooftop he was standing on. The value for the spring constant was found to vary between 9.04 N/m and 2.63 N/m and the friction coefficient was found to vary between 1.69 and 4.90. These are then compared to typically used values to assess the scenario's plausibility

A3_5 Oh Buoy

As always, films are a great place to look for physical inaccuracies and impossibilities. One such film is Disney's 'Pirates of the Caribbean', where they walk underwater within a capsized row boat. From resolving the buoyancy and weight forces, the resultant force is 13230 N opposing the force of weight, which will act to push the boat up to the surface. From this we conclude that it is not possible for them to be able to traverse underwater in this fashion

A3_3 This Time Next Year, We'll be Millionaires!

The path to ‘getting rich quick’ is one fraught with instability and conjecture. In the British sitcom Only Fools and Horses, stock marketer Del Boy Trotter notoriously claims that “This time next year, we’ll be millionaires”. In this article we utilise the special relativistic phenomenon that is time dilation to calculate the conditions under which this feat would be possible. We found that by investing $3000 in three companies in the 1980s, travelling at 0.999c for 12 ly and instantaneously turning around to undergo a return journey, Del Boy Trotter could have become a millionaire in only a year.

A3_2 It's Snow Problem

Falling into a pile of snow can sometimes feel like falling into a cold, wet and slightly uncomfortable cushion. Although it may not be the most enjoyable way to break a fall, the fact remains that snow can dampen the force you experience and subsequently make the fall less painful (but unfortunately, no less embarrassing). In this article we calculate how much snow it would take to make a deadly fall, survivable. For a 70kg body falling at terminal velocity, the height of snow required to reduce the deceleration to a survivable 10 g was found to be 17.8 m