Enrico Rinaldi

Light composite scalar in eight-flavor QCD on the lattice

We present the first observation of a flavor-singlet scalar meson as light as the pion in

Glueball masses in the large N limit

N_f=8

Strongly interacting dynamics and the search for new physics at the LHC

QCD on the lattice, using the Highly Improved Staggered Quark action. Such a light scalar meson can be regarded as a composite Higgs with mass 125 GeV. In accord with our previous lattice results showing that the theory exhibits walking behavior, the light scalar may be a technidilaton, a pseudo Nambu-Goldstone boson of the approximate scale symmetry in walking technicolor.

Lattice QCD input for axion cosmology

The lowest-lying glueball masses are computed in SU(N) gauge theory on a spacetime lattice for constant value of the lattice spacing a and for N ranging from 3 to 8. The lattice spacing is fixed using the deconfinement temperature at temporal extension of the lattice NT = 6. The calculation is conducted employing in each channel a variational ansatz performed on a large basis of operators that includes also torelon and (for the lightest states) scattering trial functions. This basis is constructed using an automatic algorithm that allows us to build operators of any size and shape in any irreducible representation of the cubic group. A good signal is extracted for the ground state and the first excitation in several symmetry channels. It is shown that all the observed states are well described by their large N values, with modest

Two-Nucleon Higher Partial-Wave Scattering from Lattice QCD

\mathcal{O}\left( {{{1} \left/ {{{N^2}}} \right.}} \right)

Lattice simulations with eight flavors of domain wall fermions in SU(3) gauge theory

corrections. In addition spurious states are identified that couple to torelon and scattering operators. As a byproduct of our calculation, the critical couplings for the deconfinement phase transition for N = 5 and N = 7 and temporal extension of the lattice NT = 6 are determined.

SU(Nc) gauge theories at deconfinement

We present results for the spectrum of a strongly interacting SU(3) gauge theory with Nf = 8 light fermions in the fundamental representation. Carrying out nonperturbative lattice calculations at the lightest masses and largest volumes considered to date, we confirm the existence of a remarkably light singlet scalar particle. We explore the rich resonance spectrum of the 8-flavor theory in the context of the search for new physics beyond the standard model at the Large Hadron Collider (LHC). Lastly, connecting our results to models of dynamical electroweak symmetry breaking, we estimate the vector resonance mass to be about 2 TeV with a width of roughly 450 GeV, and predict additional resonances with masses below ~3 TeV.

Composite bosonic baryon dark matter on the lattice: SU(4) baryon spectrum and the effective Higgs interaction

One intriguing BSM particle is the QCD axion, which could simultaneously provide a solution to the Strong CP problem and account for some, if not all, of the dark matter density in the universe. This particle is a pNGB of the conjectured Peccei-Quinn (PQ) symmetry of the Standard Model. Its mass and interactions are suppressed by a heavy symmetry breaking scale,

Light scalars in strongly-coupled extra-dimensional theories

f_a

Maximum-likelihood approach to topological charge fluctuations in lattice gauge theory

, whose value is roughly greater than