14615477
Exact 1/4 BPS loop- : Chiral primary correlator
Abstract 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. Leading loop corrections to the sum are shown to vanish. The correlation functions are also computed in the strong-coupling limit by examining the supergravity dual of the loop–loop correlator. The strong coupling result is found to agree with the extrapolation of the planar ladders. The result is related to known correlators of 1 / 2 BPS Wilson loops and 1 / 2 BPS chiral primaries by a simple re-scaling of the coupling constant, similar to an observation of Drukker [N. Drukker, hep-th/0605151] for the case of the 1 / 4 BPS loop vacuum expectation value.
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.
55184082
Chiral primary one-point functions in the D3-D7 defect conformal field theory
A bstractWe compute the one-point functions of chiral primary operators in the non-supersymmetric defect conformal field theory that is dual to the IIB string theory on AdS5 × S5 background with a probe D7 brane with internal gauge field flux, both in perturbative Yang-Mills theory and in the string theory dual. The former is expected to be accurate at weak coupling whereas the latter should be accurate in the planar strong coupling limit of the gauge theory. We consider the distinct cases where the D7 brane has geometry AdS4 × S4 with an instanton bundle of the worldvolume gauge fields on S4 and AdS4 × S2 × S2 with Dirac monopole bundles on each S2. The gauge theory computation and the string theory computation can be compared directly in the planar limit and then a subsequent limit where the worldvolume flux is large. We find that there is exact agreement between the two in the leading order.
48341289
Holographic dual of the Eguchi-Kawai mechanism
A bstractThe holographic dual of $ \mathcal{N} $ = 2*, D = 4 supersymmetric Yang-Mills theory has many features common to 5d CFT. We interpret this as a manifestation of Eguchi-Kawai mechanism.
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.
119284900
Dressed Wilson Loops on S^2
We present a new, two-parameter family of string solutions corresponding to the holographic duals of specic 1/8-BPS Wilson loops on S 2 inN = 4 supersymmetric Yang-Mills theory. The solutions are obtained using the dressing method on the known longitude solution in the context of the auxiliary -model on S 3 put forth in arXiv:0905.0665[hep-th]. We verify that the regularized area of the world-sheets are consistent with expectations.
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.
111257994
RF Perturbation Measurements in Long Linac Cavities
Equipment and procedures have been developed for measuring the axial accelerating electric field in proton linear accelerator cavities. The method used is the usual one of measuring the change in resonant frequency caused by a small perturbing sphere on the axis of the cavity. The frequency change is determined at millimeter intervals along the axis by measuring the corresponding period length using an on-line digital computer. The computation is carried out on the computer so that the derived fields can be obtained, integrated, plotted, and compared. The method is rapid and the increased precision of the measurement allows better knowledge of the fields in operating linear accelerators. This equipment has been used on the 50-MeV linac injector for the Zero Gradient Synchrotron at Argonne National Laboratory.1 It has also been used to measure the axial field in a cavity with fields which can be calculated using a field computational program.2 The measured and calculated field values have been compared.
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.)
123057920
Magnetic Guide Field Measurements and Corrections in the MURA 50‐MeV Electron Accelerator. VI
Methods of measurement and correction of the magnetic fields of the MURA 50‐MeV electron accelerator are described. Measurements of the vertical and horizontal field components were made and the field errors corrected. Correction coils, iron shims, and adjustment of magnet positions were used to produce fields within the required tolerances. Computer methods were used to calculate needed corrections and to evaluate the quality of the corrections achieved.