Beta decays have been instrumental in establishing the Standard Model as the theory of the electroweak interactions. In the era of the Large Hadron Collider, beta decays still provide very sensitive probes of physics beyond the Standard Model, which are highly competitive and complementary to searches at the energy frontier.For example, recent tensions in tests of the unitarity of the first row of the Cabibbo-Kobayashi-Maskawa quark mixing matrix might point to new physics at scales of about 10 TeV, still beyond the reach of the LHC.Because of the increasing experimental accuracy, advances in hadronic and nuclear theory are crucial to fully exploit beta decays as probes of new physics. In this talk, I will discuss the advantages of organizing various contributions to beta decays using effective field theories (EFTs). After discussing the EFT setup, I will review its application to neutron decay and to the calculation of the beta spectrum in the decay of 6He.

Historically it was both a surprise and a theoretical triumph to find out that anti-matter exists at all. As we learnt more about the Universe, we are surprised by something very different - why do we almost exclusively see matter. The fact that throughout most of human history, we were oblivious to the existence of anti-matter is a testament to the dominance of matter over anti-matter. Looking at the earliest light and earliest elements in the Universe, we find that this imbalance goes back to at least when the Universe was a mere second old. However, inflation would wipe out any difference between matter and anti-matter and all processes we know of cannot create such an asymmetry. I will review the three main answers physicists have given to this fundamental question and what challenges face the community trying to shed light on this issue.

 Recent suggestion that SU(3) gauge theories with fundamental quarks generate a phase with IR scale invariant glue leads to interesting consequences materializing in very unusual ways. In this talk I will discuss these developments, including those featured in the Title.

I will review recent results, and list outstanding challenges, of deriving an emergent spacetime from a non-perturbative proposal of String Theory -- namely, the BFSS matrix model. I will show how a metric can be coarse-grained from abstract matrix degrees of freedom, and how one naturally gets a scale-invariant spectrum of primordial perturbations in this model without introducing arbitrary tunable parameters. Furthermore, I will highlight distinct cosmological signatures of this model which have the potential of distinguishing it from other early-universe paradigms.
 

The advent of quantum computation presents the opportunity to solve questions in high energy theory which are inaccessible to classical computation such as real-time evolution and the equation of state at finite density. In order to take advantage of this new resource, a number of theoretical and computational hurdles will need to be addressed.  In this talk, I will discuss the state of the art research being performed in HEP and outstanding questions that require our attention going forward, focusing on digitization of lattice gauge theories and extracting physical results that demonstrate practical quantum advantage.

The ~4σ discrepancy between the experiment and the data-driven theory prediction of the anomalous magnetic moment of the muon is one of the crucial benchmarks to verify the correctness of the standard model. On the lattice QCD side, the Budapest-Marseille-Wuppertal collaboration (BMWc) has a precise full calculation that favors the experimental prediction. Various independent lattice QCD calculations have been done to verify their findings, especially on well-defined ``window quantities'' which suffer fewer lattice artifacts. I will present our lattice calculation of the leading order (LO) hadronic vacuum polarization (HVP) contribution to the muon anomalous magnetic moment for the connected light and strange quarks in the widely used window t0 = 0.4 fm, t1 = 1.0 fm, ∆ = 0.15 fm, and also in the short distance region. We use the overlap fermions on 4 physical-point ensembles. Two 2+1 flavor RBC/UKQCD ensembles use the domain wall fermion (DWF) and Iwasaki gauge actions at a = 0.084 and 0.114 fm, and two 2+1+1 flavor MILC ensembles use the highly improved staggered quark (HISQ) and Symanzik gauge actions at a = 0.088 and 0.121 fm. They have incorporated infinite volume corrections from 3 additional DWF ensembles at L = 4.8, 6.4, and 9.6 fm and physical pion mass. Eventually, our results on the connected light and strange quarks in the widely used window agree with the BMWc findings and other most recent lattice calculations which deviate from the data-driven theory prediction.

Unitarity of the Cabibbo-Kobayashi-Maskawa quark mixing matrix is a measure 

of completeness of the Standard Model, and a good tool for looking for its extensions.

In the past few years there have been major new developments in the extraction 

of the CKM matrix elements Vud and Vus from the experimental data. At present, a 

3-sigma unitarity deficit is observed, known as the Cabibbo angle anomaly (CAA). 

I review the main ingredients of CAA across hadronic and nuclear-structure dependent 

radiative corrections, and give an outlook to future developments in theory and experiment.

Dark matter self interactions can leave distinctive signatures on the properties of satellite galaxies around Milky Way-like hosts. By analyzing a number of Milky Way dwarf galaxies, we were able to place new constraints on models of self-interacting dark matter which interact via a Yukawa potential. The results push the theory into a parameter space with a very specific prediction: self-interactions within satellite galaxies can be either very large (so large that new dynamical effects become important), or very small (so small that such models are usually thought of as collisionless), but not intermediate. Specifically, if self-interactions are large, some dwarfs of the Milky Way must be undergoing a process of gravothermal collapse, and this process has a number of distinct observational predictions which can be searched for in current and upcoming data.

In principle, quantum computers can simulate gauge theory phenomena inaccessible to classical computers or analytic treatment. For the foreseeable future, however, quantum computers will be sharply limited by noise and memory constraints. To make the most of near-term hardware and develop simulation techniques, it is interesting to benchmark simpler theories that capture some essential physics of gauge theories, to test different platforms and encodings, and to explore hybrid classical/quantum algorithms. This talk will summarize work on digital quantum simulations of the ``femtouniverse," a quantum mechanical multi-matrix model derived from the dimensional reduction of Yang-Mills theory on a small spatial torus. Using the hybrid variational quantum eigensolver and quantum subspace expansion techniques, we obtain the low-lying spectrum and string tension / glueball mass ratio at couplings near the large-small volume transition. Limitations and directions for future development are described.

I will present a classification of all unitary, rational conformal field theories with two primaries, central charge c < 25, and arbitrary Wronskian index. These are shown to be either certain level-1 WZW models or cosets of meromorphic theories by such models. By leveraging the existing classification of  meromorphic CFTs of central charge c ≤ 24, all the relevant cosets are enumerated and their characters computed. This leads to 123 theories, most of which are new. It will be emphasised that this is a classification of RCFTs and not just consistent characters. Work in collaboration with Brandon Rayhaun.

This is a joint Theory Seminar/Strings Seminar