Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userTopological insights in many-flavor QCD on the lattice
63
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
LatKMI Collaboration discusses the topological insights in many-flavor QCD on the lattice. We explore walking/conformal/confining phase in $N_mathrm{f}$ = 4, 8 and 12 (in particular $N_mathrm{f}$ = 8) lattice QCD via the topological charge and susceptibility, eigenvalues and anomalous dimension.
rate research
Read More
In the search for a composite Higgs boson in walking technicolor models, many flavor QCD, in particular with $N_f=8$, is an attractive candidate, and has been found to have a composite flavor-singlet scalar as light as the pion. Based on lattice simulations of this theory with the HISQ action, we will present our preliminary results on the scalar decay constant using the fermionic bilinear operator, and on the mass of the lightest baryon state which could be a dark matter candidate. Combining these two results, implications for dark matter direct detection are also discussed.
We determine the topological susceptibility chi_t in the topologically-trivial sector generated by lattice simulations of N_f = 2+1 QCD with overlap Dirac fermion, on a 16^3 x 48 lattice with lattice spacing ~ 0.11 fm, for five sea quark masses m_q ranging from m_s/6 to m_s (where m_s is the physical strange quark mass). The chi_t is extracted from the plateau (at large time separation) of the 2-point and 4-point time-correlation functions of the flavor-singlet pseudoscalar meson eta, which arises from the finite size effect due to fixed topology. In the small m_q regime, our result of chi_t agrees with the chiral effective theory. Using the formula chi_t = Sigma(m_u^{-1} + m_d^{-1} + m_s^{-1})^{-1} by Leutwyler-Smilga, we obtain the chiral condensate Sigma^{MSbar}(2 GeV) = [249(4)(2) MeV]^3.
Based on lattice simulations using highly improved staggered quarks for twelve-flavor QCD with several bare fermion masses, we observe a flavor-singlet scalar state lighter than the pion in the correlators of fermionic interpolating operators. The same state is also investigated using correlators of gluonic interpolating operators. Combined with our previous study, that showed twelve-flavor QCD to be consistent with being in the conformal window, we infer that the lightness of the scalar state is due to infrared conformality. This result shed some light on the possibility of a light composite Higgs boson (technidilaton) in walking technicolor theories.
We present the first observation of a flavor-singlet scalar meson as light as the pion in $N_f=8$ 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.
In the search for a realistic walking technicolor model, QCD with many flavors is an attractive candidate. From the series of studies by the LatKMI collaboration, we present updated results of the scaling properties of various hadron spectra, including the (pseudo)scalar, vector, and baryon channels, for $N_f=8$ QCD analyzed with the HISQ action. By comparing these with $N_f=12$ QCD, which has properties consistent with conformality, possible signals of walking dynamics are discussed. We also present a preliminary result of the flavor-singlet pseudoscalar mass in many-flavor QCD.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
