12,589 research outputs found

### CP Violation, an experimental perspective

I present a review of current and near-future experimental investigations of
CP violation. In this review, I cover limits on particle electric dipole
moments (EDMs) and CP violation studies in the K and B systems. The wealth of
results from the new B factories provide impressive constraints on the CKM
quark mixing matrix elements. Current and future measurements are focusing on
processes dominated by loop diagrams, which probe physics at high mass scales
in low-energy experiments.Comment: Invited plenary talk, DPF meeting, August 200

### Brief Resume of Seiberg-Witten Theory

Talk presented by the second author at the Inaugural Coference of the Asia
Pacific Center for Theoretical Physics, Seoul, June 1996. The purpose of this
note is to give a resume of the Seiberg-Witten theory in the simplest possible
mathematical terms.Comment: 10 pages, LaTe

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### Evidence for a regulatory idiotypic network in the in vivo response to H-2 antigens.

Treatment of BALB/c mice with purified pig antiidiotype to 11-4.1 (anti-H-2Kk) monoclonal antibody has been found previously to induce the appearance of idiotype-bearing molecules (Id') in the serum of these mice, in the absence of detectable antigen-binding activity. In the present study we examined the effect of subsequent immunization of such antiidiotype-primed mice with the original H-2Kk antigen. Skin grafting of virgin BALB/c mice with BALB.K skin did not generate any detectable Id' antibodies when tested by enzyme-linked immunosorbent assay (ELISA). In contrast, grafting of antiidiotype-primed mice with BALB.K skin specifically boosted ther serum level of Id' molecules. Challenge of antiidiotype-primed mice with either B10.D2 or rat skin had no effect on the production of such Id' molecules. Absorption studies demonstrated that the majority of Id' molecules induced by H-2Kk antigenic stimulus and detected in ELISA are antigen-nonbinding molecules, thus indicating specific restimulation by the original H-2Kk antigen of nonbinding idiotype-positive B cell clones. The relevance of these findings to the existence of network interactions in the immune response to H-2 antigens is discussed

### Complex stamp forming of advanced thermoplastic composites

The inherent advantages of thermoplastics over the traditional thermoset composite systems are well recognized in the aeronautics community. The main advantages are the much faster processing and the higher toughness. The current advanced thermoplastic material systems provide excellent mechanical performance but their main disadvantage is the difficult processing. Ideally, future aircraft subcomponents with complex shapes can be readily formed on the basis of pre-consolidated tailored laminates based on uni-directional plies. However, to exploit the full potential of thermoplastic composites models are to be developed in order to predict the process feasibility and product performance in an early stage of development. This paper addresses a number of steps to increase the accuracy of stamp forming simulations and highlights promising results for identifying intra-ply shear and tool-ply behavior of thermoplastic composites. A comparison of the forming behavior of a doubly curved reference part with simulations will be presented. The paper concludes with remarks on necessary future researc

### Normal frames for non-Riemannian connections

The principal properties of geodesic normal coordinates are the vanishing of
the connection components and first derivatives of the metric components at
some point. It is well-known that these hold only at points where the
connection has vanishing torsion and non-metricity. However, it is shown that
normal frames, possessing the essential features of normal coordinates, can
still be constructed when the connection is non-Riemannian.Comment: 4 pages, plain TeX. To appear in Class. Quantum Gra

### Scaling tests with dynamical overlap and rooted staggered fermions

We present a scaling analysis in the 1-flavor Schwinger model with the full
overlap and the rooted staggered determinant. In the latter case the chiral and
continuum limit of the scalar condensate do not commute, while for overlap
fermions they do. For the topological susceptibility a universal continuum
limit is suggested, as is for the partition function and the Leutwyler-Smilga
sum rule. In the heavy-quark force no difference is visible even at finite
coupling. Finally, a direct comparison between the complete overlap and the
rooted staggered determinant yields evidence that their ratio is constant up to
$O(a^2)$ effects.Comment: 28 pages, 20 figures containg 37 graphs. v2: 6 new references, 2 new
footnotes (to match published version

### CP Violation and Arrows of Time Evolution of a Neutral $K$ or $B$ Meson from an Incoherent to a Coherent State

We study the evolution of a neutral $K$ meson prepared as an incoherent equal
mixture of $K^0$ and $\bar{K^0}$. Denoting the density matrix by \rho(t) =
{1/2} N(t) [\1 + \vec{\zeta}(t) \cdot \vec{\sigma} ] , the norm of the state
$N(t)$ is found to decrease monotonically from one to zero, while the magnitude
of the Stokes vector $|\vec{\zeta}(t)|$ increases monotonically from zero to
one. This property qualifies these observables as arrows of time. Requiring
monotonic behaviour of $N(t)$ for arbitrary values of $\gamma_L, \gamma_S$ and
$\Delta m$ yields a bound on the CP-violating overlap $\delta =
\braket{K_L}{K_S}$, which is similar to, but weaker than, the known unitarity
bound. A similar requirement on $|\vec{\zeta}(t)|$ yields a new bound,
$\delta^2 < {1/2} (\frac{\Delta \gamma}{\Delta m}) \sinh (\frac{3\pi}{4}
\frac{\Delta \gamma}{\Delta m})$ which is particularly effective in limiting
the CP-violating overlap in the $B^0$-$\bar{B^0}$ system. We obtain the Stokes
parameter $\zeta_3(t)$ which shows how the average strangeness of the beam
evolves from zero to $\delta$. The evolution of the Stokes vector from
$|\vec{\zeta}| = 0$ to $|\vec{\zeta}| = 1$ has a resemblance to an order
parameter of a system undergoing spontaneous symmetry breaking.Comment: 13 pages, 6 figures. Inserted conon "." in title; minor change in
text. To appear in Physical review

### Complete null data for a black hole collision

We present an algorithm for calculating the complete data on an event horizon
which constitute the necessary input for characteristic evolution of the
exterior spacetime. We apply this algorithm to study the intrinsic and
extrinsic geometry of a binary black hole event horizon, constructing a
sequence of binary black hole event horizons which approaches a single
Schwarzschild black hole horizon as a limiting case. The linear perturbation of
the Schwarzschild horizon provides global insight into the close limit for
binary black holes, in which the individual holes have joined in the infinite
past. In general there is a division of the horizon into interior and exterior
regions, analogous to the division of the Schwarzschild horizon by the r=2M
bifurcation sphere. In passing from the perturbative to the strongly nonlinear
regime there is a transition in which the individual black holes persist in the
exterior portion of the horizon. The algorithm is intended to provide the data
sets for production of a catalog of nonlinear post-merger wave forms using the
PITT null code.Comment: Revised version, to appear in Phys. Rev. D. July 15 (2001), 41 pages,
11 figures, RevTeX/epsf/psfi

### Finding Principal Null Direction for Numerical Relativists

We present a new method for finding principal null directions (PNDs). Because
our method assumes as input the intrinsic metric and extrinsic curvature of a
spacelike hypersurface, it should be particularly useful to numerical
relativists. We illustrate our method by finding the PNDs of the
Kastor-Traschen spacetimes, which contain arbitrarily many $Q=M$ black holes in
a de Sitter back-ground.Comment: 10 pages, LaTeX style, WU-AP/38/93. Figures are available (hard
copies) upon requests [[email protected] (H.Shinkai)

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