Richard Blankenbecler

Large Transverse Momentum Processes

Abstract We present a comprehensive survey of experimental and theoretical work on large transverse momentum processes. Exclusive data and single particle inclusive measurements are summarized and some discussion of multiparticle inclusive data is included. We review many of the predictions of nonparton models including the geometrical, statistical, eikonal and bootstrap approaches. A more detailed discussion is given of the structure of models based on the hard scattering of constituents. The predictions for hadronic and electromagnetic processes based on quark counting rules and the constituent interchange model (CIM) are summarized. We present numerous comparisons with experiment and indicate the framework for the comparison with new experimental data. Recent theoretical progress in the problem of relating short distance structure of hadrons with the asymptotic behavior of form factors and fixed angle amplitudes is also reviewed. We include a brief discussion of the possible influence of new hadronic degrees of freedom on large- p T phenomena. Finally, we attempt to anticipate the type of experiments which will prove decisive in the understanding of this subject.

BOUNDS ON SCATTERING AMPLITUDES.

Abstract The method of Lagrange multipliers, generalized to include inequality constraints, is used to derive bounds on scattering amplitudes based on unitarity and polynomial behavior. Various physical quantities associated with two-body scattering processes are treated, such as the total cross section, elastic cross section, absorptive part and real part of the scattering amplitude. Using these new mathematical techniques, several familiar problems are trated and generalized. In addition, a number of new results are presented. Both asymptotically large energy bounds and finite energy bounds with no arbitrary constants will be given.

Composite Theory of Large Angle Scattering and New Tests of Parton Concepts

Abstract A formalism for handling the scattering of composite systems is presented. Using this formalism, the contribution to bound state scattering at large energy and angle from the interchange force is calculated. This force leads to elastic cross sections which behave at fixed angle like the sixth power of the form factor and for which ( d σ d t ) ( d σ d t ) 90° is an energy independent function of z. Comparison with p-p and π-p data shows excellent agreement. A new test of the existence of a pointlike coupling of the photon to partons is suggested.

Matching protein structures with fuzzy alignments

Unraveling functional and ancestral relationships between proteins as well as structure-prediction procedures require powerful protein-alignment methods. A structure-alignment method is presented where the problem is mapped onto a cost function containing both fuzzy (Potts) assignment variables and atomic coordinates. The cost function is minimized by using an iterative scheme, where at each step mean field theory methods at finite “temperatures” are used for determining fuzzy assignment variables followed by exact translation and rotation of atomic coordinates weighted by their corresponding fuzzy assignment variables. The approach performs very well when compared with other methods, requires modest central processing unit consumption, and is robust with respect to choice of iteration parameters for a wide range of proteins.

Unusual shadowing effects in particle production off nuclei

Abstract Some consequences of the AKG cutting rules for particle production off nuclei at low transverse momentum are examined. The condition for an arbitrarily defined cross section to be shadowed only by itself is given. Some physical examples and experimental consequences are discussed. Many new tests of certain general features of reggeon field theory follow from our results.

INCLUSIVE PROCESSES AT HIGH TRANSVERSE MOMENTUM.

Abstract The interchange theory for inclusive scattering at large transverse momentum is extended into kinematic regions where Regge effects are important. Hadronic bremsstrahlung is shown to lead inevitably to Reggeization of the fundamental production process as s goes to infinity for fixed, large, P T . The cross sections are shown to rise to their ultimate scaling limit. This transition zone connects smoothly with the Feynman scaling region at low p T , and the deep scale-invariant region at large p T ∼ O(√ s ). The inclusive results of the interchange theory have the form of the standard fragmentation, triple Regge, and pionization formulae in their respective regions, but in addition predict the behavior of the associated residues and trajectories at large t or p 2 T .

Fundamentals of macro axial gradient index optical design and engineering

Homogeneous lens material is characterized by an index of refraction and a point on the glass map nd5f(y d). Gradient refractive index (GRIN) lenses have a spatially varying index and dispersion and are represented by a line on the glass map. GRIN lenses open the door to a wide variety of optical design applications incorporating entire lenses of axial gradient refractive material (macro-AGRIN). Axial gradient mate- rial essentially gives biaspheric behavior to lenses with spherical sur- faces and exhibits a controlled gradient in both index and dispersion. Thus, the applications for this material range from simple singlet lens used for imaging laser light, in which spherical aberration is eliminated, to complex multielement lens systems, where improved overall perfor- mance is desired. The fusion/diffusion process that produces this mate- rial is surprisingly simple, repeatable, and applicable to mass production. The advantages of AGRIN technology coupled with the recent advances in material development and its accessibility in commercially available lens design programs provides optical designers with the opportunity to push the performance of optical systems farther than with conventional optics.

Diquark contributions to scaling violations and to σLσT

Abstract Arguments for significant dynamical diquark substructure in baryons are reviewed. If present, integer-spin diquarks will absorb longitudinally polarized currents resulting in a relatively large value of R = σ L / σ T in certain kinematic regions of deep-inelastic reactions. We provide simple parametrizations for this higher-twist contribution to structure functions and to R . We present fits to the x and Q 2 dependences of SLAC-MIT data on electroproduction. Further tests are suggested, and implications are discussed for the interpretation of R in perturbative QCD.

Low-dose Pretreatment for Radiation Therapy

In radiotherapy, a large radiation dose must be applied to both cancer and neighboring healthy cells. Recent experiments have shown that a low dose of ionizing radiation turns on certain protective mechanisms that allow a cell to better survive a subsequent high dose of radiation. This adaptive response can have important and positive consequences for radiotherapy. This paper describes a simple change in treatment procedures to make use of these beneficial effects. A low dose applied only to the healthy cells will probably produce some damage. However, it will also start the adaptive response which will yield increased protection when the large therapeutic dose is applied. The resultant immediate damage will be thereby reduced as well as the probability that the high dose therapy itself will induce a subsequent secondary cancer. After a brief historical review, the effects of a low radiation dose on a canine cancer cell line will be discussed as well as trials of the suggested pre-dose therapy on canine cancer patients undergoing standard radiation therapy.

The Reason Project

Reason is a software package to allow one to do physics analysis with the look and feel of the Apple Macintosh. It was implemented on a NeXT computer which does not yet support the standard HEP packages for graphics and histogramming. This paper will review our experiences and the program.