Measurement of direct photon production at Tevatron fixed target energies

Measurements of the production of high transverse momentum direct photons by a 515 GeV/c piminus beam and 530 and 800 GeV/c proton beams in interactions with beryllium and hydrogen targets are presented. The data span the kinematic ranges of 3.5 < p_T < 12 GeV/c in transverse momentum and 1.5 units in rapidity. The inclusive direct-photon cross sections are compared with next-to-leading-order perturbative QCD calculations and expectations based on a phenomenological parton-k_T model.Comment: RevTeX4, 23 pages, 32 figures, submitted to Phys. Rev.

Muon (g-2) Technical Design Report

The Muon (g-2) Experiment, E989 at Fermilab, will measure the muon anomalous magnetic moment a factor-of-four more precisely than was done in E821 at the Brookhaven National Laboratory AGS. The E821 result appears to be greater than the Standard-Model prediction by more than three standard deviations. When combined with expected improvement in the Standard-Model hadronic contributions, E989 should be able to determine definitively whether or not the E821 result is evidence for physics beyond the Standard Model. After a review of the physics motivation and the basic technique, which will use the muon storage ring built at BNL and now relocated to Fermilab, the design of the new experiment is presented. This document was created in partial fulfillment of the requirements necessary to obtain DOE CD-2/3 approval

Measurement of the Positive Muon Anomalous Magnetic Moment to 0.20 ppm

We present a new measurement of the positive muon magnetic anomaly, a_{μ}≡(g_{μ}-2)/2, from the Fermilab Muon g-2 Experiment using data collected in 2019 and 2020. We have analyzed more than 4 times the number of positrons from muon decay than in our previous result from 2018 data. The systematic error is reduced by more than a factor of 2 due to better running conditions, a more stable beam, and improved knowledge of the magnetic field weighted by the muon distribution, ω[over ˜]_{p}^{'}, and of the anomalous precession frequency corrected for beam dynamics effects, ω_{a}. From the ratio ω_{a}/ω[over ˜]_{p}^{'}, together with precisely determined external parameters, we determine a_{μ}=116 592 057(25)×10^{-11} (0.21 ppm). Combining this result with our previous result from the 2018 data, we obtain a_{μ}(FNAL)=116 592 055(24)×10^{-11} (0.20 ppm). The new experimental world average is a_{μ}(exp)=116 592 059(22)×10^{-11} (0.19 ppm), which represents a factor of 2 improvement in precision

The 2010 Interim Report of the Long-Baseline Neutrino Experiment Collaboration Physics Working Groups

Corresponding author R.J.Wilson ([email protected]); 113 pages, 90 figuresCorresponding author R.J.Wilson ([email protected]); 113 pages, 90 figuresIn early 2010, the Long-Baseline Neutrino Experiment (LBNE) science collaboration initiated a study to investigate the physics potential of the experiment with a broad set of different beam, near- and far-detector configurations. Nine initial topics were identified as scientific areas that motivate construction of a long-baseline neutrino experiment with a very large far detector. We summarize the scientific justification for each topic and the estimated performance for a set of far detector reference configurations. We report also on a study of optimized beam parameters and the physics capability of proposed Near Detector configurations. This document was presented to the collaboration in fall 2010 and updated with minor modifications in early 2011

The 2010 Interim Report of the Long-Baseline Neutrino Experiment Collaboration Physics Working Groups

In early 2010, the Long-Baseline Neutrino Experiment (LBNE) science collaboration initiated a study to investigate the physics potential of the experiment with a broad set of different beam, near- and far-detector configurations. Nine initial topics were identified as scientific areas that motivate construction of a long-baseline neutrino experiment with a very large far detector. We summarize the scientific justification for each topic and the estimated performance for a set of far detector reference configurations. We report also on a study of optimized beam parameters and the physics capability of proposed Near Detector configurations. This document was presented to the collaboration in fall 2010 and updated with minor modifications in early 2011.Comment: Corresponding author R.J.Wilson ([email protected]); 113 pages, 90 figure

The criminal justice voluntary sector: concepts and an agenda for an emerging field

This is the peer reviewed version of the following article: Tomczak, P. & Buck, G. (2019). The criminal justice voluntary sector: concepts and an agenda for an emerging field. Howard Journal of Crime and Justice, 58(3), which has been published in final form at https://doi.org/10.1111/hojo.12326. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.Volunteers and voluntary organisations play significant roles pervading criminal justice. They are key actors, with unrecognised potential to shore up criminal justice and/or collaboratively reshape social justice. Unlike public and for-profit agents, criminal justice volunteers and voluntary organisations (CJVVOs) have been neglected by scholars. We call for analyses of diverse CJVVOs, in national and comparative contexts. We provide three categories to highlight distinctive organising auspices, which hold across criminal justice: statutory volunteers, quasi-statutory volunteers and voluntary organisations. The unknown implications of these different forms of non-state, non-profit justice involvement deserve far greater attention from academics, policymakers and practitioners

Measurement of the Positive Muon Anomalous Magnetic Moment to 0.46 ppm

We present the first results of the Fermilab Muon g-2 Experiment for the positive muon magnetic anomaly $a_\mu \equiv (g_\mu-2)/2$. The anomaly is determined from the precision measurements of two angular frequencies. Intensity variation of high-energy positrons from muon decays directly encodes the difference frequency $\omega_a$ between the spin-precession and cyclotron frequencies for polarized muons in a magnetic storage ring. The storage ring magnetic field is measured using nuclear magnetic resonance probes calibrated in terms of the equivalent proton spin precession frequency ${\tilde{\omega}'^{}_p}$ in a spherical water sample at 34.7$^{\circ}$C. The ratio $\omega_a / {\tilde{\omega}'^{}_p}$, together with known fundamental constants, determines $a_\mu({\rm FNAL}) = 116\,592\,040(54)\times 10^{-11}$ (0.46\,ppm). The result is 3.3 standard deviations greater than the standard model prediction and is in excellent agreement with the previous Brookhaven National Laboratory (BNL) E821 measurement. After combination with previous measurements of both $\mu^+$ and $\mu^-$, the new experimental average of $a_\mu({\rm Exp}) = 116\,592\,061(41)\times 10^{-11}$ (0.35\,ppm) increases the tension between experiment and theory to 4.2 standard deviationsComment: 10 pages; 4 figure

The E760 Jet Target: Measurements of Performance at 77K THEE760JETTARGET: MEASUREMENTS OFPERFORMANCE at 77K

Introduction In this report we describe the measurements performed on the E760 hydrogen Jet Target in order to investigate some of the basic parameters of the system. These measurements were performed in the context of the upgrade program of the target for the successor experiment E835. Fermilab experiment E760 studied charmonium states formed in antiproton-proton annihilations [1, The results from E760 have shown that an increase in integrated luminosity by a factor of more than 5 is needed to complete the study of the channonium spectrum. The E835 experiment is designed to achieve this by increasing the intensity of the antiproton beam and the density of the hydrogen-cluster-jet. This report is concerned with preparations for the work needed to increase the density of the hydrogencluster-jet. The average density (atoms/cm3) of the cluster-jet is given by (1) where Bjd is the cluster-jet flux (atoms/s), A jet is the cluster-jet cross section in the interaction area and v,, is the speed of the clusters. The experiment luminosity is directly proportional to the product of this density and the current of antiprotons ; one wants therefore to maximize Ojti and minimize vCl. (Since the cluster-jet has cylindrical symmetry, the quantity A je, is essentially set by the height of the antiproton beam and is not a free parameter). For reference, we show a schematic of the gas-jet target system as b) Improving the pumping speed in the first chamber of the gas-jet system to reduce interaction between background gas in the chamber and the cluster-jet. c) Control of the x-y position of the nozzle and its angle ( The work undertaken in the summer of 1993 was to build and test the apparatus and instrumentation to determine the important parameters of the gas-jet system performance prior to implementing the upgrades described above. The gas-jet target system was installed in the Proton Assembly Building at Fermilab and the following is a short report of the measurements at To=77 K and their interpretation. The jet target density measured is in the range of 1013 atoms/cms.A complete report with a full description of our testing and results can be found in Our cluster-jet is produced by letting hydrogen gas expand through a converging-diverging nozzle with a small diameter throat (20-100 l.trn) and an opening angle of about 7 degrees (see 3 If we treat the expansion as an adiabatic process in a continuum flow regime, we can find an expression for the nozzle mass flow, assuming that the speed at the nozzle throat is equal to the local speed of sound at the stagnation condition (pressure PO and temperature TO) and the nozzle geometry [5]: where W is the gas molecular weight, Ati is the cross section of the nozzle throat and y = cP/cV ( y = 5 for molecular hydrogen at low temperature). We have found this relation in good agreement with our experimental data at both liquid nitrogen temperature and room temperature using two different nozzles, both trumpet-shaped, with throat diameters of 37 pm and 56 pm. l Measurements of Cluster-jet flow and background gas The gas throughput Q (usually expressed in torr liter/set) inside a chamber can be evaluated knowing the pumping speed S and the pressure P by means of the relation: Q=SP. (3) The molecular flux (molecules/second) is then related to the throughput measured through the equation 1 torrliter/sec = 3.21.1019 molecules/set = 6.42.10*9 atoms/set, which applies at 300K, the temperature -of the gas in the region of the ion gauges. Details of the calibration of the vacuum instruments used for the pressure measurement, a procedure which is especially important for the hot filament ionization We have verified that the method used to introduce the calibrated leak into any chamber allows us to assume that the pressure increment produced at the pressure gauge for a given flow rate (number of atoms per unit time) into the chamber is the same whether the hydrogen is introduced through the calibrated leak or with the cluster-jet stream. The &quot;background&quot; gas throughput is calculated from the pressure in the Antiproton Accumulator and the measured pumping speed S,,. l Dependence of the gas jet throughput on pressure To determine the throughput into Rlwe multiply the pressure increment inside the Rl chamber i.e. the pressure difference with the hydrogen jet on and off, by the Rl pumping speed. This is shown in fig6a for two nozzle aperture sizes. Once the &quot;clusterization&quot; begins, the cluster-jet throughput grows almost linearly with the stagnation pressure. This clusterization begins at a lower pressure for the 56 pm nozzle than for the 37 pm nozzle (see als