14,682 research outputs found
Left-Right Asymmetry of Weak Interaction Mass of Polarized Fermions in Flight
The left-right polarization-dependent asymmetry of the weak interaction mass
is investigated. Based on the Standard Model, the calculation shows that the
weak interaction mass of left-handed polarized fermions is always greater than
that of right-handed polarized fermions in flight with the same velocity in any
inertial frame. The asymmetry of the weak interaction mass might be very
important to the investigation of neutrino mass and would have an important
significance for understanding the parity nonconservation in weak interactions.Comment: 8 pages, 2 figures, corrected calculatio
The T2K Indication of Relatively Large theta_13 and a Natural Perturbation to the Democratic Neutrino Mixing Pattern
The T2K Collaboration has recently reported a remarkable indication of the
\nu_\mu -> \nu_e oscillation which is consistent with a relatively large value
of \theta_{13} in the three-flavor neutrino mixing scheme. We show that it is
possible to account for such a result of \theta_{13} by introducing a natural
perturbation to the democratic neutrino mixing pattern, without or with CP
violation. A testable correlation between \theta_{13} and \theta_{23} is
predicted in this ansatz. We also discuss the Wolfenstein-like parametrization
of neutrino mixing, and comment on other possibilities of generating
sufficiently large \theta_{13} at the electroweak scale.Comment: RevTeX 8 page
Lattice QCD calculation of scattering length
We study s-wave pion-pion () scattering length in lattice QCD for
pion masses ranging from 330 MeV to 466 MeV. In the "Asqtad" improved staggered
fermion formulation, we calculate the four-point functions for isospin
I=0 and 2 channels, and use chiral perturbation theory at next-to-leading order
to extrapolate our simulation results. Extrapolating to the physical pion mass
gives the scattering lengths as and for isospin I=2 and 0 channels, respectively. Our lattice
simulation for scattering length in the I=0 channel is an exploratory
study, where we include the disconnected contribution, and our preliminary
result is near to its experimental value. These simulations are performed with
MILC 2+1 flavor gauge configurations at lattice spacing fm.Comment: Remove some typo
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