2,547 research outputs found
An absorption tube for the investigation of gases in the photographic infrared
An absorption cell of novel design is described, which combines the advantages of long path and relatively small volume
The Principles of Command and Logistics
When I was a student here in 1936, there was very little consideration given to the subject of logistics. At that time we in the Navy had, as we have now, a fine supply corps. Our supply officers were men who had a good knowledge of how to get things, when to get them, and how to distribute them, but the average line offiÂcer took very little active part in such matters and in fact there was a tendency to avoid them if possible
Problems of Command and Logistics
I am glad that we in the higher echelons of all our Military Services have finally come to realize that a knowledge of the principles of logistics is a necesÂsary qualification for command of military forces
On-shell recursion relations for all Born QCD amplitudes
We consider on-shell recursion relations for all Born QCD amplitudes. This
includes amplitudes with several pairs of quarks and massive quarks. We give a
detailed description on how to shift the external particles in spinor space and
clarify the allowed helicities of the shifted legs. We proof that the
corresponding meromorphic functions vanish at z --> infinity. As an application
we obtain compact expressions for helicity amplitudes including a pair of
massive quarks, one negative helicity gluon and an arbitrary number of positive
helicity gluons.Comment: 30 pages, minor change
SUSY Ward identities for multi-gluon helicity amplitudes with massive quarks
We use supersymmetric Ward identities to relate multi-gluon helicity
amplitudes involving a pair of massive quarks to amplitudes with massive
scalars. This allows to use the recent results for scalar amplitudes with an
arbitrary number of gluons obtained by on-shell recursion relations to obtain
scattering amplitudes involving top quarks.Comment: 22 pages, references adde
The pure rotation spectrum of ammonia
New experimental means for the study of absorption spectra in the extreme infra-red are described. These have been used in extending our knowledge of the pure rotation spectra to the case of a polyatomic molecule. The absorption spectrum of ammonia has been investigated in the region between 55μ and 130μ, and a very simple structure was found. Six lines were observed which belong to a pure rotation spectrum and are apparently due to changes in the energy of rotation of the ammonia molecule about an axis normal to the line of symmetry, that is, to transitions in which the quantum number j increases by unity. Other lines due to transitions with a change also of τ, the quantum number connected with rotations about the axis of symmetry, are absent. These facts are briefly discussed in connection with the predictions of the wave mechanics with which they are shown to be in accord. The moment of inertia of the ammonia molecule about an axis normal to the line of symmetry is estimated to be 2.77×10^(-40) gm cm^2
Multigluon tree amplitudes with a pair of massive fermions
We consider the calculation of n-point multigluon tree amplitudes with a pair
of massive fermions in QCD. We give the explicit transformation rules of this
kind of massive fermion-pair amplitudes with respect to different reference
momenta and check the correctness of them by SUSY Ward identities. Using these
rules and onshell BCFW recursion relation, we calculate the analytic results of
several n-point multigluon amplitudes.Comment: 15page
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