22,848 research outputs found
Chiral Symmetry and the Residual Mass in Lattice QCD with the Optimal Domain-Wall Fermion
We derive the axial Ward identity for lattice QCD with domain-wall fermions,
and from which we obtain a formula for the residual mass (45)-(46), that can be
used to measure the chiral symmetry breaking due to the finite extension Ns in
the fifth dimension. Furthermore, we obtain an upper bound for the residual
mass in lattice QCD with the optimal domain-wall fermion.Comment: 27 pages, 3 figures, v3: new formula for the upper-bound of residual
mas
Exact Pseudofermion Action for Monte Carlo Simulation of Domain-Wall Fermion
We present an exact pseudofermion action for hybrid Monte Carlo simulation
(HMC) of one-flavor domain-wall fermion (DWF), with the effective 4-dimensional
Dirac operator equal to the optimal rational approximation of the overlap-Dirac
operator with kernel , where and are constants. Using this exact pseudofermion action, we perform HMC of
one-flavor QCD, and compare its characteristics with the widely used rational
hybrid Monte Carlo algorithm (RHMC). Moreover, to demonstrate the practicality
of the exact one-flavor algorithm (EOFA), we perform the first dynamical
simulation of the (1+1)-flavors QCD with DWF.Comment: 13 pages, 4 figures, v2: Simulation of (1+1)-flavors QCD with DWF,
and references added. To appear in Phys. Lett.
Testing Electroweak Baryogenesis with Future Colliders
Electroweak Baryogenesis (EWBG) is a compelling scenario for explaining the
matter-antimatter asymmetry in the universe. Its connection to the electroweak
phase transition makes it inherently testable. However, completely excluding
this scenario can seem difficult in practice, due to the sheer number of
proposed models. We investigate the possibility of postulating a "no-lose"
theorem for testing EWBG in future e+e- or hadron colliders. As a first step we
focus on a factorized picture of EWBG which separates the sources of a stronger
phase transition from those that provide new sources of CP violation. We then
construct a "nightmare scenario" that generates a strong first-order phase
transition as required by EWBG, but is very difficult to test experimentally.
We show that a 100 TeV hadron collider is both necessary and possibly
sufficient for testing the parameter space of the nightmare scenario that is
consistent with EWBG.Comment: 26 pages + references, 10 figures. Fixed minor typos, updated TLEP
and 100 TeV projections. Conclusions unchange
Extended Conformal Symmetry in : Conformal Symmetry of Abelian Gauge Theory in the Physical Sector
Abelian gauge theory in spacetime dimensions is an example of a
scale invariant theory which does not possess conformal symmetry -- the special
conformal transformation(SCT) explicitly breaks the gauge invariance of the
theory. In this work, we construct a non-local gauge-invariant extension of the
SCT, which is compatible with the BRST formalism and defines a new symmetry of
the physical Hilbert space of the Maxwell theory for any dimension . We prove the invariance of the Maxwell theory in by
explicitly showing that the gauge-invariant two-point correlation functions,
the action, and the classical equation of motion are unchanged under such a
transformation.Comment: 23 page
Tevatron Asymmetry of Tops in a W',Z' Model
Recent results from the CDF Collaboration indicate the the top-pair
forward-backward asymmetry is largest in regions of high rapidity difference
and invariant mass We show that experimental
observations can be explained by our previously proposed Asymmetric Left-Right
Model (ALRM). The gauge symmetry is broken by
a triplet Higgs in the primed sector. The boson has a right-handed
coupling and the boson has diagonal fermion couplings. We determine the
model parameters to be GeV, TeV, and charged current
coupling . The and total decay widths are of
GeV). The signals from and at the
LHC will test the model.Comment: 14 pages, 7 figures; typos corrected, references added. Version to
appear in PL
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