Abstract: We investigate the potential for detecting pion-like dark matter within the framework of a Strongly Interacting Massive Particle (SIMP) model using the MoEDAL Apparatus for Penetrating Particles (MAPP) at the LHC. The model, motivated by Chiral Perturbation Theory, features milli-charged dark pions that couple to Standard Model particles via kinetic mixing with a dark photon. Production channels considered include Drell-Yan pair production and photon fusion via the Wess-Zumino-Witten term, the latter providing a distinctive three-body final state signature. Cross-sections are computed using MadGraph and WHIZARD for a range of dark pion masses, decay constants, and dark Z boson masses. Sensitivity projections for MAPP-1 during the High-Luminosity LHC phase are presented under a background-free assumption, showing competitive reach into previously unexplored parameter space for milli-charged dark pseudoscalars. These results highlight the complementary role of MoEDAL-MAPP in probing dark sector models and motivate further detector-level simulations to refine exclusion limits.

Abstract: We study the decay of a heavy CP-even neutral Higgs into an on-shell Standard Model-like Higgs boson and two photons, H -> h gamma gamma, in the two-Higgs doublet model. We argue that the decay channel H -> h gamma gamma, followed by the decay of the Standard Model Higgs h -> bb, could be observed at the 5 sigma level at the High-Luminosity LHC for masses of the heavy Higgs up to 950 GeV for the type-II, 650 GeV for the Lepton Specific and the Flipped 2HDMs, and 350 GeV for the type-I. We also discuss the possible role of the decay H -> h gamma gamma in discriminating among different types of 2HDMs and in enhancing the total number of events in the final state H -> bb gamma gamma compared to the cascade decay H -> hh followed by h -> gamma gamma h -> bb with identical final state (although with different kinematical distributions).

Abstract: Extensions of the Standard Model typically contain “flaton fields” defined as fields with large vacuum expectation values and almost flat potentials where scalar self-coupling is small or vanishes at tree level. Such potentials have been used to drive a secondary inflationary epoch after a primary phase of inflation, in what are called thermal inflation models. Although the primordial, high-scale inflationary epoch can solve the horizon and flatness problems, it does not always resolve difficulties associated with late-time relics produced in extensions of the Standard Model. These relics typically decay too late, injecting entropy and energetic particles that spoil successful predictions like Big Bang Nucleosynthesis. It is here that thermal inflation plays a crucial role: diluting unwanted relics by many orders of magnitude without erasing the baryon asymmetry or the large-scale structure set up by the earlier phase of inflation. The preferred scale for this phenomenon is in the range 106 – 108 GeV if one considers supergravity, but without it, any scale above the EW scale is valid. We investigate a typical form of these potentials and determine what are the conditions for the potentials to develop a barrier such that when the flatons settle to the true minimum, the associated Gravitational Waves can be observed, focusing on first-order phase transitions from spontaneous lepton number breaking.

Abstract: Baryon number is an accidental symmetry of the Standard Model at the Lagrangian level. Its violation is arguably one of the most compelling phenomena predicted by physics beyond the Standard Model. Furthermore, there is a large experimental effort to search for it including the Hyper-K, DUNE, JUNO, and THEIA experiments. Therefore, an agnostic, model-independent, analysis of baryon number violation using the power of Effective Field Theory is very timely. In particular, in this work we study the contribution of dimension six and seven effective operators to |triangle(B – L)| = 0, 2 nucleon decays taking into account the effects of Renormalisation Group Evolution. We obtain lower limits on the energy scale of each operator and study the correlations between different decay modes. We find that for some operators the effect of running is very significant.

Abstract: We consider the phenomenological signatures of Simplified Models of Flavourful Leptoquarks, whose Beyond-the-Standard Model (SM) couplings to fermion generations occur via textures that are well motivated from a broad class of ultraviolet flavour models (which we briefly review). We place particular emphasis on the study of the vector leptoquark Delta(mu) with assignments (3, 1, 2/3) under the SM's gauge symmetry, SU(3)(C) x SU(2)(L) x U(1)(Y), which has the tantalising possibility of explaining both R-K(*) and R-D(*) anomalies. Upon performing global likelihood scans of the leptoquark's coupling parameter space, focusing in particular on models with tree-level couplings to a single charged lepton species, we then provide confidence intervals and benchmark points preferred by low(er)-energy flavour data. Finally, we use these constraints to further evaluate the (promising) Large Hadron Collider (LHC) detection prospects of pairs of tau-flavoured Delta(mu), through their distinct (a)symmetric decay channels. Namely, we consider direct third-generation leptoquark and jets plus missing-energy searches at the LHC, which we find to be complementary. Depending on the simplified model under consideration, the direct searches constrain the Delta(mu), mass up to 1500-1770 GeV when the branching fraction of Delta(mu), is entirely to third-generation quarks (but are significantly reduced with decreased branching ratios to the third generation), whereas the missing-energy searches constrain the mass up to 1150-1700 GeV while being largely insensitive to the third-generation branching fraction.