The MUSE experiment Downie, E. J.
EPJ Web of conferences,
2014, Letnik:
73
Journal Article
Recenzirano
Odprti dostop
The proton radius puzzle is the difference between the proton radius as measured with electron scattering and in the excitation spectrum of atomic hydrogen, and that measured with muonic hydrogen ...spectroscopy. The MUSE experiment seeks to resolve this puzzle by simultaneously measuring elastic electron and muon scattering on the proton, in both charge states, thereby providing new information to the puzzle. MUSE addresses issues of two-photon effects, lepton universality and, possibly, new physics, while providing simultaneous form factor, and therefore radius, measurements with both muons and electrons.
OBJECTIVE To compare circulating concentrations of N terminal pro-brain natriuretic peptide (N-BNP) and cardiotrophin 1 in stable and unstable angina. DESIGN AND SETTING Observational study in a ...teaching hospital. PATIENTS 15 patients with unstable angina, 10 patients with stable angina, and 15 controls. MAIN OUTCOME MEASURES Resting plasma N-BNP and cardiotrophin 1 concentrations. RESULTS N-BNP concentration (median (range)) was 714 fmol/ml (177–3217 fmol/ml) in unstable angina, 169.5 fmol/ml (105.7–399.5 fmol/ml) in stable angina (p = 0.005v unstable angina), and 150.5 fmol/ml (104.7–236.9 fmol/ml) in controls (p < 0.0001v unstable angina; NSv stable angina). Cardiotrophin 1 concentration was 142.5 fmol/ml (42.2–527.4 fmol/ml) in unstable angina, 73.2 fmol/ml (41.5–102.1 fmol/ml) in stable angina (p < 0.05 v unstable angina), and 27 fmol/ml (6.9–54.1 fmol/ml) in controls (p < 0.0005v stable angina; p < 0.0001v unstable angina). Log cardiotrophin 1 correlated with log N-BNP in unstable angina (r = 0.93, p < 0.0001). CONCLUSIONS Both circulating N-BNP and cardiotrophin 1 are raised in unstable angina, while cardiotrophin 1 alone is raised in stable angina. The role of cardiotrophin 1 and the relation between cardiotrophin 1 and N-BNP in myocardial ischaemia remain to be defined.
The quest to understand the physics of any system cannot be said to be complete as long as one cannot predict and fully understand its resonance spectrum. Despite this, due to the experimental ...challenge of the required double polarization measurements and the difficulty in achieving unambiguous, model-independent extraction and interpretation of the nucleon resonance spectrum of many broad and overlapping resonances, understanding of the structure and dynamics of the nucleon has suffered. The recent improvement in statistical quality and kinematic range of the data made available by such full-solid-angle systems as the CB and TAPS constellation at MAMI, coupled with the high flux polarized photon beam provided by the Glasgow Photon Tagger, and the excellent properties of the Mainz Frozen Spin Target, when paired with new developments in Partial Wave Analysis (PWA) methodology make this a very exciting and fruitful time in nucleon resonance studies. Here the recent influx of data and PWA developments are summarized, and the requirements for a complete, unambiguous PWA solution over the first and second resonance region are briefly reviewed.
Although many bacteria contain only a single groE operon encoding the essential chaperones GroES and GroEL, examples of bacteria containing more than one groE operon are common. The root-nodulating ...bacterium Rhizobium leguminosarum contains at least three operons encoding homologues to Escherichia coli GroEL, referred to as Cpn60.1, Cpn60.2 and Cpn60.3, respectively. We report here a detailed analysis of the requirement for and relative levels of these three proteins. Cpn60.1 is present at higher levels than Cpn60.2, and Cpn60.3 protein could not be detected under any conditions although the cpn60.3 gene is transcribed under anaerobic conditions. Insertion mutations could not be constructed in cpn60.1 unless a complementing copy was present, showing that this gene is essential for growth under the conditions used here. Both cpn60.2 and cpn60.3 could be inactivated with no loss of viability, and a double cpn60.2 cpn60.3 mutant was also constructed which was fully viable. Thus only Cpn60.1 is required for growth of this organism.
The calorimeter project for the Mu2e experiment Budagov, J.; Carosi, R.; Cervelli, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2013, Letnik:
718
Journal Article
Recenzirano
The Mu2e experiment at Fermilab aims to measure the charged lepton flavor violating neutrinoless conversion of a negative muon into an electron. The conversion results in a monochromatic electron ...with an energy slightly below the rest mass of the muon (104.97MeV). We expect to set a limit of ∼ 6×10 −17 at 90% CL in three years of running, using an intense and clean pulsed μ− beam providing ∼ 10 18 stopped muons on target in three years of running. The experiment performs a strong suppression of potential background by gating off the prompts and performing precise momentum determination in conjunction with an highly efficient cosmic veto. The calorimeter should confirm that the candidates reconstructed by the tracker system are indeed conversion electrons and provide an independent trigger (or event reduction filter) for the experiment. It should also provide standalone muon to electron rejection. Moreover, it must be able to keep functionality in a high radiation dose environment inside a 10 −4torr vacuum enclosure and in a presence of 1T axial magnetic field. In order to accomplish all these tasks, a LYSO crystals calorimeter has been chosen. We show the proposed design and the experimental results obtained by exposing a small size calorimeter prototype to a tagged photon beam from 40 to 300MeV at the A2 photon facility of the Mainz Microton (MAMI), Germany.
The γ n → π 0 n differential cross section evaluated for 27 energy bins span the photon-energy range 290– 813 MeV (W = 1.195–1.553 GeV) and the pion c.m. polar production angles, ranging from 18° to ...162°, making use of model-dependent nuclear corrections to extract π0 production data on the neutron from measurements on the deuteron target. Additionally, the total photoabsorption cross section was measured. The tagged photon beam produced by the 883 MeV electron beam of the Mainz Microtron MAMI was used for the π0-meson production. Our accumulation of 3.6 × 106 γ n → π 0 n events allowed a detailed study of the reaction dynamics. Our data are in reasonable agreement with previous A2 measurements and extend them to lower energies. The data are compared with predictions of previous SAID, MAID, and BnGa partial-wave analyses and to the latest SAID fit MA19 that included our data. Selected photon-decay amplitudes N * → γ n at the resonance poles are determined for the first time.
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