11 research outputs found
Classical Simulation of Quantum Fields II
We consider the classical time evolution of a real scalar field in 2
dimensional Minkowski space with a interaction. We compute the
spatial and temporal two-point correlation functions and extract the
renormalized mass of the interacting theory. We find our results are consistent
with the one- and two-loop quantum computation. We also perform Monte Carlo
simulations of the quantum theory and conclude that the classical scheme is
able to produce more accurate results with a fraction of the CPU time.Comment: 16 pages, 8 figures, now matches published versio
The Little Higgs from a Simple Group
We present a model of electroweak symmetry breaking in which the Higgs boson
is a pseudo-Nambu-Goldstone boson. By embedding the standard model SU(2) x U(1)
into an SU(4) x U(1) gauge group, one-loop quadratic divergences to the Higgs
mass from gauge and top loops are canceled automatically with the minimal
particle content. The potential contains a Higgs quartic coupling which does
not introduce one-loop quadratic divergences. Our theory is weakly coupled at
the electroweak scale, it has new weakly coupled particles at the TeV scale and
a cutoff above 10 TeV, all without fine tuning. We discuss the spectrum of the
model and estimate the constraints from electroweak precision measurements.Comment: 29 pages, referencing error corrected after death threats, dude
remove
Top quark associated production of the neutral top-pion at high energy colliders
In the context of topcolor-assisted technicolor (TC2) models, we calculate
the associated production of the neutral top-pion with a pair of
top quarks via the process . We
find that the production cross section is larger than that of the process both in the standard model (SM) and in the
minimal supersymmetric SM. With reasonable values of the parameters in TC2
models, the cross section can reach . The neutral top-pion
may be direct observed via this process.Comment: Latex files, 10 pages and 3 figure
Applicability of perturbative QCD to decays
We develop perturbative QCD factorization theorem for the semileptonic heavy
baryon decay , whose form factors are
expressed as the convolutions of hard quark decay amplitudes with universal
and baryon wave functions. Large logarithmic
corrections are organized to all orders by the Sudakov resummation, which
renders perturbative expansions more reliable. It is observed that perturbative
QCD is applicable to decays for velocity transfer
greater than 1.2. Under requirement of heavy quark symmetry, we predict the
branching ratio , and determine
the and baryon wave functions.Comment: 12 pages in Latex file, 3 figures in postscript files, some results
are changed, but the conclusion is the sam
Neutral top-pion and lepton flavor violating processes
In the context of topcolor-assisted techicolor(TC2) models, we study the
contributions of the neutral top-pion to the lepton flavor
violating(LFV) processes and .
We find that the present experimental bound on gives severe
constraints on the free parameters of models. Taking into account these
constraints, we consider the processes generated by
top-pion exchange at the tree-level and the one loop level, and obtain
, , in most of
the parameter space.Comment: latex files,16 pages, 6 figures. Submitted to Phys. Rev.
Neutral currents and strangeness of the nucleon from the NuTeV experiment
The NuTeV neutrino experiment ran in 1997-1998 at Fermilab and accumulated the world’s highest statistics samples of high energy (20-300 GeV) separated neutrino and anti-neutrino interactions. The NuTeV collaboration has used this data to extract the electroweak parameter, sin2θW, from the measurement of the ratios of neutral current to charged current neutrino and antineutrino deep inelastic scattering cross sections. This result, though consistent with previous neutrino electroweak measurements, is not consistent with predictions. One interpretation involves the possibility that the strange quark sea carries significantly more momentum in the nucleon than the anti-strange sea. We report on the direct study of this possibility from measurements of charged-current interactions on strange quarks in our neutrino and anti-neutrino beams.PACS: 12.15.Mn Neutral Currents – 13.60.Hb Cross-sections in inelastic lepton-hadron scatterin