Conveners
Particle physics beyond the Standard Model: Particle physics beyond the Standard Model I
- Oliver Witzel (Uni Siegen)
Particle physics beyond the Standard Model: Particle physics beyond the Standard Model II
- Georg Bergner (University of Jena)
Particle physics beyond the Standard Model: Particle physics beyond the Standard Model III
- David Schaich (University of Liverpool)
Particle physics beyond the Standard Model: Particle physics beyond the Standard Model IV
- Benjamin Jaeger (University of Southern Denmark)
We show that a recently discovered non-perturbative field-theoretical mechanism giving mass to elementary fermions, is also capable of generating a mass for the electro-weak bosons and can thus be used as a viable alternative to the Higgs scenario. A detailed analysis of this remarkable feature shows that the non-perturbatively generated fermion and $W$ masses have the parametric form...
We present an update of our results for the ongoing work on the four-supercharge two-dimensional Yang–Mills theory discretized on a Euclidean torus using thermal boundary conditions. Although the theory under consideration does not have a gravity dual, we investigate whether it has features qualitatively similar to its sixteen-supercharge counterpart. Our investigation hints at a possible...
We present an update of our ongoing study of the SU(2) gauge theory with one flavor of Dirac fermion in the adjoint representation. Compared to our previous results we now have data at larger lattice volumes, smaller values of the fermion mass, and also larger values of $\beta$. We present data for the spectrum of mesons, baryons, glueballs, and the hybrid fermion-glue state, as well as new...
In this work we present perturbative results for the renormalization of the supercurrent operator, $S_\mu$, in ${\cal{N}}=1$ Supersymmetric Yang-Mills theory. At the quantum level, this operator mixes with both gauge invariant and noninvariant operators, which have the same global transformation properties. In total, there are 13 linearly independent mixing operators of the same and lower...
Supersymmetry on the lattice is explicitly broken by the gluino mass and lattice artifacts. However, it can be restored in the continuum limit by fine tuning the parameters based on the renormalized Ward identities. On the renormalization step not only the mass but also the renormalization of the supercurrent needs to be addressed. Here we present a lattice investigation to obtain the...
Vector Boson scattering (VBS) is a central process in the search for physics beyond the SM at collider experiments. To correctly identify SM and BSM physics, such as composite Higgs scenarios, at these experiments, it is crucial to gain a clear picture of VBS-like processes.
In our study we therefore analyse this process in a reduced SM-setup for different physical scenarios. To this end we...
We use one-flavour QCD ($N_c=3$) as a proxy to understand $\mathcal{N}=1$ SYM. For our simulations, we use tree-level improved Wilson fermions and Symmanzik improved gauge action. The hadron spectrum is obtained using LapH for different masses and simulation volumes. We find that the ratio of pseudo-scalar over scalar is smaller than one, which is in line with expectations from theory. We also...
Composite Higgs models are a popular solution to the Naturalness problem in the Higgs sector, where the mass of the Higgs bosons is explained in terms of Goldstone dynamics. We address a composite model described by a $SU(4)$ gauge group with fermions in the fundamental and two index anti-symmetric representations of the gauge group. We will show results from lattice simulations investigating...
We present ongoing investigations of maximally supersymmetric Yang--Mills ($Q = 16$ SYM) theory in three space-time dimensions. This theory is conjectured to be holographically dual to higher-dimensional quantum gravity. Previous results focused on the homogeneous "D2" phase. The work in progress concerns phase transitions between this "D2" phase and a localized "D0" phase.
Maximally supersymmetric Yang--Mills theory ($\mathcal N = 4$ SYM) is conformal for any value of the coupling. Lattice regularization breaks conformality through the introduction of a non-zero lattice spacing and a finite lattice volume. I will present ongoing computations of conformal scaling dimensions in lattice $\mathcal N = 4$ SYM, based on a lattice formulation that exactly preserves a...
On behalf of the Lattice Strong Dynamics (LSD) collaboration, we present first results of the SU(4) Gauge theory Stealth Dark Matter hadron spectrum using stochastic Laplacian Heaviside (sLapH) smearing. We compare our results to previous work in the context of our Stealth Dark Matter baryon scattering project.
In the context of Strongly Interacting Dark Matter theories dark isosinglet mesons might play an important role in the low-energy dynamics and might provide crucial signatures in collider and direct detection searches. We present first results in $Sp(4)$ gauge theory with $N_f=2$ fundamental Dirac flavours on the dark isosinglet pseudoscalar $\eta'$ and the isosinglet contribution to the dark...
The renormalization group (RG) $\beta$ function describes the running of the renormalized coupling and connects the ultraviolet and infrared regimes of quantum field theories. Focusing at systems with SU(3) gauge group and fermions in the fundamental representation, we study how the RG $\beta$ function changes from a QCD-like system with $N_f=2$ flavors to a conformal system with $N_f=12$...
We report on numerical results of masses and decay constants of the lightest pseudoscalar, vector and axial vector mesons in $Sp(4)$ lattice gauge theory with three Dirac flavours of fermions in the antisymmetric representation. In addition, we measure the masses of other flavoured mesons in the spin-0 and spin-1 channels, as well as the first excited state of the vector meson. Using the...
Chimera baryons are an important feature of composite Higgs models, since they play role of top partner in partial top compositeness. In the realisation of the mechanism provided by $Sp(4)$ gauge theory, such exotic objects are composed of two fundamental and one antisymmetric fermion constituents. We perform lattice computations for the chimera baryon spectrum both in the quenched...
Many models of composite dark matter feature a first-order confinement transition in the early universe, which would produce a stochastic background of gravitational waves that will be searched for by future gravitational-wave observatories. I will present work in progress using lattice field theory to predict the properties of such first-order transitions and the resulting spectrum of...
In the Holographic Model, the two-point function of Energy-Momentum Tensor (EMT) of the dual QFT can be mapped into the power spectrum of the Cosmic Microwave Background in the gravitational theory. However, the presence of divergent contact terms poses challenges in extracting a renormalized EMT two-point function on the lattice. Using a $\phi^4$ theory of adjoint scalars valued in the su(N)...
The infrared effective theory of adjoint QCD with one Dirac
flavour is still under debate. The theory could be confining, conformal,
or fermionic fields could become the lightest fields in the IR. Chiral
symmetry seems to be important to answer this question. Previous
investigations have considered Wilson fermions breaking chiral symmetry.
We present here the first results for this theory...
Gradient flow can be used to describe a Wilsonian renormalization group transformation. In this talk, we use gradient flow to extract running mesonic and baryonic anomalous dimensions for an SU(3) gauge system with $N_f = 10$ fundamental flavors. Our results are important for constructing theories beyond the Standard Model describing fermion mass generation either by partial compositeness or...
The IKKT matrix model in the large-$N$ limit is conjectured to be a non-perturbative definition of the ten-dimensional type IIB superstring theory. Due to the Pfaffian's inherently complex nature upon Euclideanization, the model has a severe sign problem. The phase of the Pfaffian plays a critical role in determining the correct vacuum of the model. In recent years, the complex Langevin method...
Past lattice simulations tentatively suggested that the spectrum of observable particles in BSM theories is qualitatively different than perturbatively expected. We expand on this using a GUT-like toy theory, SU(3) Yang-Mills coupled to a scalar `Higgs' in the fundamental representation. We show the most comprehensive spectroscopy to date, including all channels up to spin 2., and find it...
Beyond the standard model theories involving early universe first order phase transitions can lead to a gravitational wave background that may be measurable with improved detectors. Thermodynamic observables of the transition, such as the latent heat, determined through lattice simulations can be used to predict the expected signatures from a given theory and constrain physical models....
Computing CP-violating nucleonic matrix elements on the lattice allows one to place theoretical constraints on the couplings of effective interactions related to BSM sources of CP-violation. These interactions are related to local operators that mix under renormalization. Typically, this mixing is parametrized by the only scale available, the lattice spacing, and induces local divergences...
