Stop near threshold

tt̄ Near Threshold

Near Threshold Graphs

A conjecture of Grone and Merris states that for any graph G, its Laplacian spectrum, Λ(G), is majorized by its conjugate degree sequence, D∗(G). That conjecture prompts an investigation of the relationship between Λ(G) and D∗(G), and Merris has characterized the graphs G for which the multisets Λ(G) and D∗(G) are equal. In this paper, we provide a constructive characterization of the graphs G ...

0 η ′ photoproduction near threshold

In this work, the η meson photoproduction near threshold is studied in the quark model framework. A pseudovector effective Lagrangian is introduced for the ηNN coupling and the newly published data from the SAPHIR Collaboration provide good constraints to this parameter. Corrections of order O(1/m2q) for the electromagnetic interaction vertex are taken into account, which produce corrections of...

PHOTOFISSION OF 232Th NEAR THRESHOLD

Measurements are presented of the photofission cross section and the mean number fi of neutrons per fission for 232Th made using bremsstrahlung from the Harwell electron linear accelerator HELIOS and a high efficiency neutron detector to record neutron multiplicity distributions. The cross section is interpreted in terms of a fission barrier with shallow wells in two separate outer barriers. In...

Near-threshold fatigue: a review

Interest in extending the high cycle fatigue life of structures has increased in the last decade of the 20th century. Since a long fatigue life depends on keeping cyclic loads near or below the fatigue threshold, understanding near-threshold behavior is now all the more important. This paper reviews the status of the ‘threshold of fatigue’ and to a lesser extent its relation to the ‘fatigue lim...