A phenomenological analysis on γp → π+n, πOp below 1.2 GeV

A phenomenological partial-wave analysis on γp → π⁺n and π^Op reactions has been performed in the energy range 0.25–1.2 GeV with available data, laying special emphasis on the polarization and asymmetry data. A good fit has been obtained.     

A convergent series for the QED effective action

The one-loop effective action of QED obtained by Heisenberg and Euler and by Schwinger has been expressed by an asymptotic perturbative series which is divergent. In this Letter we present a nonperturbative but convergent series of the effective action. With the convergent series we establish the existence of the manifest electric-magnetic duality in the one-loop effective action of QED.     

Charged-particle pseudorapidity density distributions from Au+Au collisions at sqrt[s(NN)]=130 GeV

The charged-particle pseudorapidity density dN(ch)/d eta has been measured for Au+Au collisions at sqrt[s(NN)] = 130 GeV at RHIC, using the PHOBOS apparatus. The total number of charged particles produced for the 3% most-central Au+Au collisions for /eta/相似文献   

General formalism in collinear regime for pseudoscalar meson production in NN collisions

The spin structure of the matrix element for the pseudoscalar meson production processes in nucleon-nucleon collisions is established in the collinear kinematical regime in terms of 3 independent scalar amplitudes. This result is valid for any reaction mechanism and for any energy of the colliding and the produced particles. The complete experiment for the full reconstruction of all 3 complex amplitudes must contain two different classes of polarization experiments. The polarization transfer coefficients can be used to determine the moduli of all 3 amplitudes, whereas the spin correlation coefficients for + collisions are sensitive to the relative phases of different amplitudes. Received: 13 August 2001 / Accepted: 20 September 2001     

The formation and decay of radicals in potassium nitrate

The buildup kinetics of the radicals produced by irradiation of potassium nitrate at 77 K over a wide dose range and the postradiation transformations of paramagnetic centers over the temperature range 38-401 K were studied. The low-temperature limit for the radical decay rate was determined. The specific features of the radical buildup kinetics were associated with the two factors, the restrictions for hole and electron trapping sites and the set of recombination reactions including tunneling recombination of trapped charges. The parameters of tunneling reactions of radical recombination were evaluated, which appeared to be of the same order of magnitude as those for glassy materials     

Random walk on upper triangular matrices mixes rapidly

We present an upper bound O(n ² ) for the mixing time of a simple random walk on upper triangular matrices. We show that this bound is sharp up to a constant, and find tight bounds on the eigenvalue gap. We conclude by applying our results to indicate that the asymmetric exclusion process on a circle indeed mixes more rapidly than the corresponding symmetric process. Received: 25 January 1999 / Revised version: 17 September 1999 / Published online: 14 June 2000     

QR-Submanifolds of (p - 1) QR-Dimension in a Quaternionic Projective Space QP (n+p)/4

The purpose of this paper is to study n-dimensional QR-submanifolds of (p - 1) QR-dimension isometrically immersed in a quaternionic projective space QP ^(n+p)/4 and to give sufficient conditions in order for such a submanifold to be a tube over a quaternionic invariant submanifold.