Naturalness of the Coleman-Glashow Mass Relation in the 1/N_c Expansion: an Update

A new measurement of the Xi^0 mass verifies the accuracy of the Coleman-Glashow relation at the level predicted by the 1/N_c expansion. Values for other baryon isospin mass splittings are updated, and continue to agree with the 1/N_c hierarchy.Comment: 6 pages, revte

1/N_c Expansion of the Heavy Baryon Isgur-Wise Functions

The 1/N_c expansion of the heavy baryon Isgur-Wise functions is discussed. Because of the contracted SU(2N_f) light quark spin-flavor symmetry, the universality relations among the Isgur-Wise functions of \Lambda_b to \Lambda_c and \Sigma_b^{(*)} to \Sigma_c^{(*)} are valid up to the order of 1/N_c^2.Comment: 7 pages, latex, no figures, to appear in Phys. Rev.

The Rare Top Decays t→bW+Zt \to b W^+ Z and t→cW+W−t \to c W^+ W^-

The large value of the top quark mass implies that the rare top decays $t \rightarrow b W^+ Z, s W^+ Z$ and $d W^+ Z$, and $t \rightarrow c W^+ W^-$ and $u W^+ W^-$, are kinematically allowed decays so long as $m_t \ge m_W + m_Z + m_{d_i} \approx 171.5 GeV + m_{d_i}$ or $m_t \ge 2m_W + m_{u,c} \approx 160.6 GeV + m_{u,c}$, respectively. The partial decay widths for these decay modes are calculated in the standard model. The partial widths depend sensitively on the precise value of the top quark mass. The branching ratio for $t\rightarrow b W^+ Z$ is as much as $2 \times 10^{-5}$ for $m_t = 200 GeV$, and could be observable at LHC. The rare decay modes $t \rightarrow c W^+ W^-$ and $u W^+ W^-$ are highly GIM-suppressed, and thus provide a means for testing the GIM mechanism for three generations of quarks in the u, c, t sector.Comment: 19 pages, latex, t->bWZ corrected, previous literature on t->bWZ cited, t->cWW unchange

Giant planets around two intermediate-mass evolved stars and confirmation of the planetary nature of HIP67851 c

Precision radial velocities are required to discover and characterize planets orbiting nearby stars. Optical and near infrared spectra that exhibit many hundreds of absorption lines can allow the m/s precision levels required for such work. However, this means that studies have generally focused on solar-type dwarf stars. After the main-sequence, intermediate-mass stars (former A-F stars) expand and rotate slower than their progenitors, thus thousands of narrow absorption lines appear in the optical region, permitting the search for planetary Doppler signals in the data for these types of stars. We present the discovery of two giant planets around the intermediate-mass evolved star HIP65891 and HIP107773. The best Keplerian fit to the HIP65891 and HIP107773 radial velocities leads to the following orbital parameters: P=1084.5 d; m$_b$sin$i$ = 6.0 M$_{jup}$; $e$=0.13 and P=144.3 d; m$_b$sin$i$ = 2.0 M$_{jup}$; $e$=0.09, respectively. In addition, we confirm the planetary nature of the outer object orbiting the giant star HIP67851. The orbital parameters of HIP67851c are: P=2131.8 d, m$_c$sin$i$ = 6.0 M$_{jup}$ and $e$=0.17. With masses of 2.5 M$_\odot$ and 2.4 M$_\odot$ HIP65891 and HIP107773 are two of the most massive stars known to host planets. Additionally, HIP67851 is one of five giant stars that are known to host a planetary system having a close-in planet ($a <$ 0.7 AU). Based on the evolutionary states of those five stars, we conclude that close-in planets do exist in multiple systems around subgiants and slightly evolved giants stars, but probably they are subsequently destroyed by the stellar envelope during the ascent of the red giant branch phase. As a consequence, planetary systems with close-in objects are not found around horizontal branch stars.Comment: Accepted for publication in A&

Insect pests and their control - The lucerne flea (Sminthurus viridus L.)

The lucerne flea or clover springtail is best know in this State as a pest of clover pastures, but various plants, including many types of vegetables, are also liable to attack. The insect is of European origin, being widely distributed over that continent. It occurs also on the north coast of Africa, in the Argentine, and in all the Australian States with the exception of Queensland

Insect pests and their control - Clothes moths, Carpet beetles and their control

Clothes moths and carpet beetles are among the most destructive of household pests, but because of their retiring habits their presence is often overlooked until an infestation has become well established, and extensive damage has been done. Both types of insect, however, may be kept in check by periodic attention and the same control measures are effective against both beetles and moths

Insect pests and their control - Cockroaches and their control

Several species of cockroaches are now general household pests. In this country some of the native varieties have become semi-domesticated and, in addition, two or three introduced forms are quite common

Insect pests and their control - The Reg-legged earth mite and the lucerne flea

For many years the red-legged earth mite (Halotydeus destructor (Tucker)) and the lucerne flea (Smynthurus viridis L.) have been serious pests of pastures and leguminous crops in Western Australia. Under certain seasonal conditions, damage has also been done to cereals such as oats and barley and every year some damage is done to vegetable and flower gardens. Until recently, the control of both the earth mite and the lucerne flea was uneconomic on large areas due to the cost of material and the heavy application rates which were necessary. Recent investigations with new insecticides, however, have completely changed the picture and have provided farmers with cheap and effective methods for controlling both pests

How to submit insect specimens for identification

From time to time most farmers and orchardists come across insects or other small creatures which they have not seen before and about which they would like some information. I get numerous queries about such creatures and am always glad to help, but sometimes the task is made unnecessarily difficult. The most detailed description of a caterpillar or a beetle given by letter is often quite useless as many of the most important features from the scientific point of view may be omitted

Insect pests and their control - The webworm (Talis pedionoma Mayr.)

The popular name webworm has been applied to a small caterpillar whose depredations in ploughed-in wheat crops have concerned farmers in this State for many years. The first record of the insect as a pest was made by Newman (1927) under the scientific name of Sclerobia tritialis Wlk. and it has been referred to as such in some subsequent Departmental publications. Recent investigations, however, suggest that either more than one species of insect is covered by the term webworm or that the true webworm is a Crambid moth known as Talis pedionoma Mayr