Conveners
Physics Beyond the Standard Model
- Yasumichi Aoki (RIKEN)
Physics Beyond the Standard Model
- Issaku Kanamori (R-CCS, RIKEN)
Physics Beyond the Standard Model
- Oliver Witzel (University of Colorado Boulder)
Physics Beyond the Standard Model
- LIN DAVID (National Chiao-Tung University)
Physics Beyond the Standard Model
- Vincent Drach (Plymouth University)
The holographic principle allows us to study the physics of the early universe in terms of three-dimensional boundary quantum field theories. For instance, the power spectrum of the CMB at high multipoles has in this way been post-dicted successfully in terms of calculations for 2pt functions of the energy-momentum tensor (EMT) in perturbation theory. The lower end of the power spectrum maps...
In holographic cosmology, cosmological observables are described in terms of correlators of a three-dimensional boundary quantum field theory. In this talk, we study the renormalisation of the energy-momentum tensor 2 point function for 3D massless $SU(N)$ scalar matrix field theory. We present a non-perturbative procedure to remove divergences resulting from the loss of translational...
Higgs particles in the adjoint representation of a non-Abelian gauge theory play an important role in many scenarios beyond the standard model, especially grand-unified theories, partial compositeness models, and (broken) supersymmetric theories. However, recently new analytic results based on gauge-invariant perturbation theory have arisen, which require a reevaluation of the observable,...
I will present ongoing investigations into the finite-temperature dynamics of stealth dark matter, which adds to the standard model a new SU(4) gauge sector with four moderately heavy fundamental fermions. The lightest scalar SU(4) `baryon' is the composite dark matter candidate. With the Lattice Strong Dynamics Collaboration, I am building on our past studies of direct detection and...
We summarize the latest results from our numerical simulations of supersymmetric Yang-Mills theory with two and three colors. For gauge group SU(2) we use an optimized variational method with an extended operator basis to extract the masses of groundstates and excited states in the scalar, pseudoscalar and spin 1/2 sector. The extrapolations to the chiral and continuum limits indicate the...
In this presentation I will provide an overview of our investigations of supersymmetric gauge theories. I summarize our final results of SU(3) $\mathcal{N}=1$ supersymmetric Yang-Mills theory that allow for the first time an extrapolation to the continuum limit. This result shows that the symmetry is recovered in the continuum limit. I will review our recent approaches towards a simulation of...
We investigate the pure gauge sector of Super-QCD, i.e. Super-Yang-Mills (SYM) theory, with focus on the bound states. To improve chiral symmetry as well as supersymmetry at finite lattice spacing, we use a deformed SYM lattice action. It contains a twist term, similar to the lattice formulation of twisted mass QCD. We present the status of our theoretical and numerical investigation.
SU(2) 8 fundamental flavor system with naive staggered fermion has a phase transition or crossover at strong coupling, which seems to be a bulk transition.
By using chiral random matrix model we analyse the chiral condensate of this sytem.
We also report the chiral susceptibility and its volume dependence near the transition point.
We compare the absence of the conformal fixed point in the near-conformal gauge theory paradigm with the alternate hypothesis where a complex conjugate pair of conformal fixed points drives the slow scale-dependence (walking) of the renormalized gauge coupling. The complex conformal fixed points would control the scale-dependent anomalous dimensions and the EFT of Goldstone pions coupled to...
After developing the full implementation of the Implicit Maximum Likelihood Method, we discuss new tests of the dilaton low-energy effective field theory in the near-conformal paradigm with emergent light scalars in the sextet and eight-flavor models.
We give an update on our lattice studies of the beta-function for near-conformal and conformal gauge theories. These include 10, 12 and 13 flavors in the fundamental representation, and 2 flavors in the sextet representation of SU(3). We discuss the overall trends and new developments.
The dimensionless ratio $m_\varrho / f_\pi$ is computed in the continuum and chiral limit for SU(3) gauge theory coupled to $N_f = 2,3,4,5,6$ fundamental fermions. All systematics (finite volume, finite fermion mass, finite cut-off) are controlled and the final results show no statistically significant $N_f$-dependence.
Experimentally a light 125 GeV Higgs boson has been observed but so far no other heavier resonances. Viable models to describe the Higgs boson as composite particle require hence to exhibit a large separation of scales which e.g. occurs in systems located near a conformal fixed point.
First I present our nonperturbative gradient flow step-scaling calculation of the renormalization group beta...
The Lattice Strong Dynamics (LSD) collaboration has been studying SU(3) Yang-Mills with eight light flavors of Dirac fermions. This theory has accumulating numerical evidence for near conformal dynamics and a light composite isosinglet scalar meson. It could serve as a prototype of a composite Higgs sector if a reliable low-energy Effective Field Theory (EFT) could be identified. Several...
We report on fits of the SU(3) N_f=8 LSD spectral data to chiral
perturbation theory with a dilatonic meson. These fits confirm that
current simulations are in the ``large-mass'' regime, with approximate
hyperscaling as the leading mass dependence. We find that the
leading-order effective field theory describes the data well. In
particular, the effective field theory allows us to...
In recent years, gradient flows of Yang-Mills and spinor fields have opened new possibilities in lattice simulations. I will focus on two applications of this method. Firstly, it has been shown that flowed composite local operators, like condensates and currents, are renormalised independently of the regularisation scheme. This facilitates the study of thermal phase transitions, e.g. in...
Composite Higgs models are very promising candidate models to address
the long-standing naturalness problem in the Standard Model.
Among them, the most minimal one is the SU(2) with 2 flavours of
fermions in the fundamental representation of the gauge group.
An important prediction in these models is the existence of resonance
spectrum in vector boson scattering. In this talk I will describe...
We calculate the meson spectrum of Sp(4) lattice gauge theory coupled to two fundamental flavors of dynamical Dirac fermions, where we focus on the lowest (flavored) spin-0 and spin-1 states. Such theories are often considered in the phenomenological models of composite Higgs and self-interacting dark matter. We carry out continuum extrapolations using four different values of lattice...
Owing to their importance for BSM model building, understanding the non-perturbative physics of Sp(2N) gauge theories is of high importance due to their large-N extrapolations. In this talk, we examine the glueball spectrum of Yang-Mills theories based on symplectic groups. Glueball masses are calculated numerically with a variational method from Monte Carlo generated gauge configurations....
We have calculated quantities of interest to a theory of compositeness. The lattice model, approximating the candidate theory, is the SU(4) gauge theory coupled to fermions in two color representations. For the composite Higgs, a current correlator gives one of the ingredients of the effective Higgs potential. For the partially composite top quark, we have hyperbaryon matrix elements that...
We consider the lattice formulation of the SO(10) chiral gauge theory with left-handed Weyl fermions in the sixteen dimensional spinor representation (16)/the Standard Model in the framework of the Overlap fermion/the Ginsparg-Wilson relation. We define a manifestly gauge-invariant path-integral measure for the left-handed Weyl field using all the components of the Dirac field, but the...
We study the bound states of three gluinos in $N=1$ supersymmetric Yang-Mills theory (SYM) on the lattice, we call these states as baryonic states analogous to baryons in QCD. The gluino is a spin 1/2 Majorana particle in the adjoint representation of the gauge group, it is the superpartner of the gluon. The correlation functions of the corresponding baryonic operators contain a contribution...
We present lattice calculation results for the proton decay matrix elements along with preliminary result of non-perturbative renormalization. The computation is done by using 2+1 flavor dynamic domain wall fermions at the physical point on the $24^3 \times 64$ lattice with lattice spacing $a^{-1}$ = 1GeV. The matrix element computations was done with 121 gauge configurations and...
