y scaling in electron-nucleus scattering

Data on inclusive electron scattering from A = 4, 12, 27, 56, 197 nuclei at large momentum transfer are presented and analyzed in terms of y scaling. We find that the data do scale for y 1), and we study the convergence of the scaling function with the momentum transfer Q^2 and A

Experimental Studies of Light Emission Phenomena in Superconducting RF Cavitites

Experimental studies of light emission phenomena in superconducting RF cavities, which we categorize under the general heading of cavity lights, are described. The cavity lights data, which were obtained using a small CCD video camera, were collected in a series of nine experimental runs ranging from {approx} 1/2 to {approx} 2 h in duration. The video data were recorded on a standard VHS tape. As the runs progressed, additional instrumentation was added. For the last three runs a LabVIEW controlled data acquisition system was included. These runs furnish evidence for several, possibly related, light emission phenomena. The most intriguing of these is what appear to be small luminous objects {le} 1.5 mm in size, freely moving about in the vacuum space, generally without wall contact, as verified by reflections of the tracks in the cavity walls. In addition, on a number of occasions, these objects were observed to bounce off of the cavity walls. The wall-bounce aspect of most of these events was clearly confirmed by pre-bounce and post-bounce reflections concurrent with the tracks. In one of the later runs, a mode of behavior was observed that was qualitatively different from anything observed in the earlier runs. Perhaps the most perplexing aspect of this new mode was the observation of as many as seven luminous objects arrayed in what might be described as a macromolecular formation, coherently moving about in the interior of the cavity for extended periods of time, evidently without any wall contact. It is suggested that these mobile luminous objects are without explanation within the realm of established physics. Some remarks about more exotic theoretical possibilities are made, and future plans are discussed

Evidence of High Harmonics from Echo-Enabled Harmonic Generation for Seeding X-Ray Free Electron Lasers

Echo-enabled harmonic generation free electron lasers hold great promise for the generation of fully coherent radiation in x-ray wavelengths. Here we report the first evidence of high harmonics from the echo-enabled harmonic generation technique in the realistic scenario where the laser energy modulation is comparable to the beam slice energy spread. In this experiment, coherent radiation at the seventh harmonic of the second seed laser is generated when the energy modulation amplitude is about 2-3 times the slice energy spread. The experiment confirms the underlying physics of echo-enabled harmonic generation and may have a strong impact on emerging seeded x-ray free electron lasers that are capable of generating laserlike x rays which will advance many areas of science

Magnetic measurements and simulations for a 4-magnet dipole chicane for the International Linear Collider

T-474 at SLAC is a prototype BPM-based energy spectrometer for the ILC. We describe magnetic measurements and simulations for the 4-magnet chicane used in T-474

Precision Measurement of the Weak Mixing Angle in Moller Scattering

We report on a precision measurement of the parity-violating asymmetry in fixed target electron-electron (Moller) scattering: A_PV = -131 +/- 14 (stat.) +/- 10 (syst.) parts per billion, leading to the determination of the weak mixing angle \sin^2\theta_W^eff = 0.2397 +/- 0.0010 (stat.) +/- 0.0008 (syst.), evaluated at Q^2 = 0.026 GeV^2. Combining this result with the measurements of \sin^2\theta_W^eff at the Z^0 pole, the running of the weak mixing angle is observed with over 6 sigma significance. The measurement sets constraints on new physics effects at the TeV scale.Comment: 4 pages, 2 postscript figues, submitted to Physical Review Letter

Nuclear structure functions at x > 1

Nuclear structure functions are extracted for high-energy electron scattering from nuclei at large values of the kinematic variable x and Q^2 in the range 1–4 (GeV/c)^2. At the highest Q^2, the data for x>1 begin to display a scaling indicative of local duality

Cavity BPM System Tests for the ILC Spectrometer

The main physics programme of the International Linear Collider (ILC) requires a measurement of the beam energy at the interaction point with an accuracy of $10^{-4}$ or better. To achieve this goal a magnetic spectrometer using high resolution beam position monitors (BPMs) has been proposed. This paper reports on the cavity BPM system that was deployed to test this proposal. We demonstrate sub-micron resolution and micron level stability over 20 hours for a 1\m long BPM triplet. We find micron-level stability over 1 hour for 3 BPM stations distributed over a 30\m long baseline. The understanding of the behaviour and response of the BPMs gained from this work has allowed full spectrometer tests to be carried out.Comment: Paper submitted to Nuclear Instruments and Methods. 35 pages, 23 figure

Inclusive electron-nucleus scattering at high momentum transfer

The response function of nuclei in the quasielastic region at large momentum transfer (q≤10 fm^-1) is measured for a series of nuclei, 4He, 12C, 27Al, 56Fe, and 197Au, up to large values of the Bjorken scaling variables x<2.5

A proof-of-principle echo-enabled harmonic generation experiment at SLAC

In this paper we describe the technical design of an ongoing proof-of-principle echo-enabled harmonic generation (EEHG) experiment at the Next Linear Collider Test Accelerator (NLCTA) at SLAC. We present the design considerations and the technical details of the experiment

Nuclear matter response function

The response function of nuclear matter is determined from experimental data on inclusive electron scattering from finite nuclei