55291989
Low energy improvements to the Fermilab 400-MeV linear accelerator
Improvements in the Fermilab operating 400-MeV linear accelerator injector are required to achieve the beam intensity and emittance requirement of the Proton Driver design study. It has been determined that these requirements can be achieved by replacing the components in the linac below 10 MeV. An improved H/sup -/ ion source with an electrostatic transport to a two-section radio-frequency quadrupole (RFQ) accelerator, with the RFQ sections separated by a magnetic five-dimensional phase-space imaging system as used in an earlier Fermilab/SAIC PET Project, and a new 10-MeV drift-tube linac cavity have been studied. It appears possible that an H/sup -/ intensity of 4.5/spl times/10/sup 13/ ions per pulse with an improvement in beam emittance from the present system can be achieved with the proposed changes.
55868408
400-MeV upgrade for the Fermilab linac
Fermilab plans to upgrade the Tevatron to expand the physics research program in both the fixed target and the collider operating modes. The first phase of this program is to increase the energy of the H{sup -} linac from 200 to 400 MeV in order to reduce the incoherent space change tuneshift at injection into the Booster which can limit either the brightness or the total intensity of the beam. The linac upgrade will be achieved by replacing the last four 201 MeV, with seven 805 MHz side-coupled cavity modules operating at an average axial field of about 8 MV/m. This will allow acceleration to 400 MeV in the existing Linac enclosure. 4 refs., 3 figs., 1 tab.
118976170
Operating experience with the NAL 200-MeV linac.
117804340
DESIGN OF PROTON LINEAR ACCELERATORS FOR ENERGIES UP TO 300 Mev
Extension of the conventional 2 pi structure for particle acceleration to 200 Mev or higher requires minimization of power losses by optimizing cavity and drift-tube parameters. Using a previously developed method, an optimization of the cavity drift-tube dimensions was made at 200 Mc and at energies of 50, 100, 150, and 200 Mev to give minimum power losses for cylindrical tubes. Drift tubes of other shapes may reduce observed high-energy power losses due to currents in the drift-tube surface. Ellipsoidal tubes appear more efficient than the cylindrical tubes. (D.C.W.)
199476454
Wilson Loops in N = 2 Superconformal Yang-Mills Theory
119103237
ABJ(M) chiral primary three-point function at two-loops
A bstractWe compute the leading correction to the structure constant for the threepoint function of three length-two chiral primary operators in planar ABJ(M) theory at weak ’t Hooft coupling.
119106209
Holographic three-point functions of giant gravitons
Working within the AdS/CFT correspondence we calculate the three-point function of two giant gravitons and one pointlike graviton using methods of semi classical string theory and considering both the case where the giant gravitons wrap an S3 ⊂ S5 and the case where the giant gravitons wrap an S3 ⊂ AdS5. We likewise calculate the correlation function in $ \mathcal{N} = 4 $ SYM using two Schur polynomials and a single trace chiral primary. We find that the gauge and string theory results have structural similarities but do not match perfectly, and interpret this in terms of the Schur polynomials’ inability to interpolate between dual giant and pointlike gravitons.
15171358
The AdS/CFT correspondence : classical, quantum, and thermodynamical aspects
Certain aspects of the AdS/CFT correspondence are studied in detail. We investigate the one-loop mass shift to certain two-impurity string states in light-cone string field theory on a plane wave background. We find that there exist logarithmic divergences in the sums over intermediate mode numbers which cancel between the cubic Hamiltonian and quartic "contact term". We argue that generically, every order in intermediate state impurities contributes to the mass shift at leading perturbative order. The same mass shift is also computed using an improved 3-string vertex proposed by Dobashi and Yoneya. The result is found to agree with gauge theory at leading order and is close but not quite in agreement at subleading order. We extend the analysis to include discrete light-cone quantization, considering states with up to three units of p+. We study the (apparently) first-order phase transition in the weakly coupled plane-wave matrix model at finite temperature. We analyze the effect of interactions by computing the relevant parts of the effective potential for the Polyakov loop operator to three loop order. We show that the phase transition is indeed of first order. We also compute the 2-loop correction to the Hagedorn temperature. Finally, correlation functions of 1/4 BPS Wilson loops with the infinite family of 1/2 BPS chiral primary operators are computed in N=4 super Yang-Mills theory by summing planar ladder diagrams. The correlation functions are also computed in the strong-coupling limit using string theory; the result is found to agree with the extrapolation of the planar ladders. The result is related to similar correlators of 1/2 BPS loops by a simple re-scaling of the coupling constant, discovered by Drukker for the case of the 1/4 BPS loop VEV.
119241526
Form factors of chiral primary operators at two loops in ABJ(M)
A bstractWe calculate the colour-ordered form factor for chiral primary operators built from J scalar fields of ABJ(M) theory to J scalar final states. We work in the ’t Hooft limit and show that the leading quantum correction is $ \mathcal{O}\left( {{\lambda^2}} \right) $, where λ is the ’t Hooft coupling. We evaluate this leading correction using standard Feynman diagrams and dimensional regularization, and find that the leading divergence is 1/ϵ2 where the spacetime dimension is d = 3 − 2ϵ. We further find that the result respects maximal transcendentality.