1. |
- Schael, S, et al.
(author)
-
Precision electroweak measurements on the Z resonance
- 2006
-
In: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 427:5-6, s. 257-454
-
Research review (peer-reviewed)abstract
- We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLID experiment using a polarised beam at SLC. The measurements include cross-sections, forward-backward asymmetries and polarised asymmetries. The mass and width of the Z boson, m(Z) and Gamma(Z), and its couplings to fermions, for example the p parameter and the effective electroweak mixing angle for leptons, are precisely measured: m(Z) = 91.1875 +/- 0.0021 GeV, Gamma(Z) = 2.4952 +/- 0.0023 GeV, rho(l) = 1.0050 +/- 0.0010, sin(2)theta(eff)(lept) = 0.23153 +/- 0.00016. The number of light neutrino species is determined to be 2.9840 +/- 0.0082, in agreement with the three observed generations of fundamental fermions. The results are compared to the predictions of the Standard Model (SM). At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. Of the many Z-pole measurements, the forward-backward asymmetry in b-quark production shows the largest difference with respect to its SM expectation, at the level of 2.8 standard deviations. Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark, m(t) = 173(+10)(+13) GeV, and the mass of the W boson, m(W) = 80.363 +/- 0.032 GeV. These indirect constraints are compared to the direct measurements, providing a stringent test of the SM. Using in addition the direct measurements of m(t) and m(W), the mass of the as yet unobserved SM Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than 285 GeV at 95% confidence level. (c) 2006 Elsevier B.V. All rights reserved.
|
|
2. |
- Augustyniak, W., et al.
(author)
-
Polarization of a stored beam by spin-filtering
- 2012
-
In: Physics Letters B. - : Elsevier. - 0370-2693 .- 1873-2445. ; 718:1, s. 64-69
-
Journal article (peer-reviewed)abstract
- The PAX Collaboration has successfully performed a spin-filtering experiment with protons at the COSY-ring. The measurement allowed the determination of the spin-dependent polarizing cross section, that compares well with the theoretical prediction from the nucleon-nucleon potential. The test confirms that spin-filtering can be adopted as a method to polarize a stored beam and that the present interpretation of the mechanism in terms of the proton-proton interaction is correct. The outcome of the experiment is of utmost importance in view of the possible application of the method to polarize a beam of stored antiprotons.
|
|
3. |
- Oellers, D., et al.
(author)
-
New experimental upper limit of the electron-proton spin-flip cross-section
- 2014
-
In: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 759, s. 6-9
-
Journal article (peer-reviewed)abstract
- In a previous publication, measurements of the depolarization of a stored proton beam by interaction with a co-propagating unpolarized electron beam at low relative energy have been presented and an upper limit of about 3 x 10(7) b for the electron-proton spin flip cross-section was determined. A refined analysis presented in this paper reduces the previous upper limit by a factor of three by the introduction of a new procedure that, also makes use of non-identified particles.
|
|
4. |
- Oellers, D., et al.
(author)
-
Polarizing a stored proton beam by spin flip?
- 2009
-
In: Physics Letters B. - : Elsevier. - 0370-2693 .- 1873-2445. ; 674:4-5, s. 269-275
-
Journal article (peer-reviewed)abstract
- We discuss polarizing a proton beam in a storage ring, either by selective removal or by spin flip of the stored ions. Prompted by recent, conflicting calculations, we have carried out a measurement of the spin-flip cross section in low-energy electron–proton scattering. The experiment uses the cooling electron beam at COSY as an electron target. The measured cross sections are too small for making spin flip a viable tool in polarizing a stored beam. This invalidates a recent proposal to use co-moving polarized positrons to polarize a stored antiproton beam.
|
|
5. |
- Eversmann, D., et al.
(author)
-
New Method for a Continuous Determination of the Spin Tune in Storage Rings and Implications for Precision Experiments
- 2015
-
In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 115:9
-
Journal article (peer-reviewed)abstract
- A new method to determine the spin tune is described and tested. In an ideal planar magnetic ring, the spin tune-defined as the number of spin precessions per turn-is given by nu(s) = gamma G (gamma is the Lorentz factor, G the gyromagnetic anomaly). At 970 MeV/c, the deuteron spins coherently process at a frequency of approximate to 120 kHz in the Cooler Synchrotron COSY. The spin tune is deduced from the up-down asymmetry of deuteron-carbon scattering. In a time interval of 2.6 s, the spin tune was determined with a precision of the order 10(-8), and to 1 x 10(-10) for a continuous 100 s accelerator cycle. This renders the presented method a new precision tool for accelerator physics; controlling the spin motion of particles to high precision is mandatory, in particular, for the measurement of electric dipole moments of charged particles in a storage ring.
|
|
6. |
- Guidoboni, G., et al.
(author)
-
How to Reach a Thousand-Second in-Plane Polarization Lifetime with 0.97-GeV/c Deuterons in a Storage Ring
- 2016
-
In: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 117:5
-
Journal article (peer-reviewed)abstract
- We observe a deuteron beam polarization lifetime near 1000 s in the horizontal plane of a magnetic storage ring (COSY). This long spin coherence time is maintained through a combination of beam bunching, electron cooling, sextupole field corrections, and the suppression of collective effects through beam current limits. This record lifetime is required for a storage ring search for an intrinsic electric dipole moment on the deuteron at a statistical sensitivity level approaching 10(-29) e cm.
|
|
7. |
- Rahnev, D, et al.
(author)
-
The Confidence Database
- 2020
-
In: Nature human behaviour. - : Springer Science and Business Media LLC. - 2397-3374. ; 4:3, s. 317-325
-
Journal article (peer-reviewed)
|
|
8. |
- Thörngren Engblom, Pia, et al.
(author)
-
Extensive high-precision studies of proton deuteron breakup reactions at COSY
- 2011
-
In: Proceedings of Science. - : Sissa Medialab Srl.
-
Conference paper (peer-reviewed)abstract
- We plan to measure the spin dependence of proton deuteron breakup at 30 and 49 MeV proton beam energy where previous measurements are few and limited. The physics objective is to test the predictive power of the chiral effective field theory in the three nucleon continuum by measuring analyzing powers and double spin observables with high precision over large areas of phase space at relevant energies for the theoretical interpretation. The experiment will be done at a newly installed and commissioned low-b section and interaction point in the COSY ring utilizing the PAX Multipurpose Detection System that is presently in the design stage.
|
|
9. |
- Guidoboni, G., et al.
(author)
-
Connection between zero chromaticity and long in-plane polarization lifetime in a magnetic storage ring
- 2018
-
In: Physical Review Accelerators and Beams. - : American Physical Society. - 2469-9888. ; 21:2
-
Journal article (peer-reviewed)abstract
- In this paper, we demonstrate the connection between a magnetic storage ring with additional sextupole fields set so that the x and y chromaticities vanish and the maximizing of the lifetime of in-plane polarization (IPP) for a 0.97-GeV/c deuteron beam. The IPP magnitude was measured by continuously monitoring the down-up scattering asymmetry (sensitive to sideways polarization) in an in-beam, carbontarget polarimeter and unfolding the precession of the IPP due to the magnetic anomaly of the deuteron. The optimum operating conditions for a long IPP lifetime were made by scanning the field of the storage ring sextupole magnet families while observing the rate of IPP loss during storage of the beam. The beam was bunched and electron cooled. The IPP losses appear to arise from the change of the orbit circumference, and consequently the particle speed and spin tune, due to the transverse betatron oscillations of individual particles in the beam. The effects of these changes are canceled by an appropriate sextupole field setting.
|
|
10. |
- Hempelmann, N., et al.
(author)
-
Locking the Spin Precession in a Storage Ring
- 2017
-
In: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 119:1
-
Journal article (peer-reviewed)abstract
- This Letter reports the successful use of feedback from a spin polarization measurement to the revolution frequency of a 0.97 GeV= c bunched and polarized deuteron beam in the Cooler Synchrotron (COSY) storage ring in order to control both the precession rate (approximate to 121 kHz) and the phase of the horizontal polarization component. Real time synchronization with a radio frequency (rf) solenoid made possible the rotation of the polarization out of the horizontal plane, yielding a demonstration of the feedback method to manipulate the polarization. In particular, the rotation rate shows a sinusoidal function of the horizontal polarization phase (relative to the rf solenoid), which was controlled to within a 1 standard deviation range of sigma= 0.21 rad. The minimum possible adjustment was 3.7 mHz out of a revolution frequency of 753 kHz, which changes the precession rate by 26 mrad/s. Such a capability meets a requirement for the use of storage rings to look for an intrinsic electric dipole moment of charged particles.
|
|
11. |
- Hempelmann, N., et al.
(author)
-
Phase measurement for driven spin oscillations in a storage ring
- 2018
-
In: Physical Review Accelerators and Beams. - : American Physical Society. - 2469-9888. ; 21:4
-
Journal article (peer-reviewed)abstract
- This paper reports the first simultaneous measurement of the horizontal and vertical components of the polarization vector in a storage ring under the influence of a radio frequency (rf) solenoid. The experiments were performed at the Cooler Synchrotron COSY in Julich using a vector polarized, bunched 0.97 GeV/c deuteron beam. Using the new spin feedback system, we set the initial phase difference between the solenoid field and the precession of the polarization vector to a predefined value. The feedback system was then switched off, allowing the phase difference to change over time, and the solenoid was switched on to rotate the polarization vector. We observed an oscillation of the vertical polarization component and the phase difference. The oscillations can be described using an analytical model. The results of this experiment also apply to other rf devices with horizontal magnetic fields, such as Wien filters. The precise manipulation of particle spins in storage rings is a prerequisite for measuring the electric dipole moment (EDM) of charged particles.
|
|
12. |
- Saleev, A., et al.
(author)
-
Spin tune mapping as a novel tool to probe the spin dynamics in storage rings
- 2017
-
In: Physical Review Accelerators and Beams. - : American Physical Society. - 2469-9888. ; 20:7
-
Journal article (peer-reviewed)abstract
- Precision experiments, such as the search for electric dipole moments of charged particles using storage rings, demand for an understanding of the spin dynamics with unprecedented accuracy. The ultimate aim is to measure the electric dipole moments with a sensitivity up to 15 orders in magnitude better than the magnetic dipole moment of the stored particles. This formidable task requires an understanding of the background to the signal of the electric dipole from rotations of the spins in the spurious magnetic fields of a storage ring. One of the observables, especially sensitive to the imperfection magnetic fields in the ring is the angular orientation of stable spin axis. Up to now, the stable spin axis has never been determined experimentally, and in addition, the JEDI collaboration for the first time succeeded to quantify the background signals that stem from false rotations of the magnetic dipole moments in the horizontal and longitudinal imperfection magnetic fields of the storage ring. To this end, we developed a new method based on the spin tune response of a machine to artificially applied longitudinal magnetic fields. This novel technique, called spin tune mapping, emerges as a very powerful tool to probe the spin dynamics in storage rings. The technique was experimentally tested in 2014 using polarized deuterons stored in the cooler synchrotron COSY, and for the first time, the angular orientation of the stable spin axis at two different locations in the ring has been determined to an unprecedented accuracy of better than 2.8 mu rad.
|
|
13. |
|
|
14. |
- Johansson, Veronica, et al.
(author)
-
Do Brain Machine Interfaces on Nano Scale Pose New Ethical Challenges?
- 2009
-
In: Size Matters: Ethical, Legal and Social Aspects of Nanobiotechnology and Nano-Medicine. - 9783825815943 ; , s. 75-100
-
Book chapter (other academic/artistic)abstract
- Nanoethics is one of many new fields that has surfaced as a consequence of the intense ongoing debate on new technology. The term attempts to cover a great span, from free floating nano particles in general to more specific areas such as nano medicine. An important question is in which areas nano ethics can justify its own existence, i. e. to what extent will the application of nano technology give rise to new ethical challenges? To avoid sweeping statements, there is a need to be specific. In the following, the field of Brain Machine Interface will be put to the test. Does the development and implementation of nano scaled electrodes pose a new ethical challenge to the field of Brain Machine Interface?
|
|
15. |
- Kalucka, J, et al.
(author)
-
Kidney injury is independent of endothelial HIF-1α
- 2015
-
In: Journal of molecular medicine (Berlin, Germany). - : Springer Science and Business Media LLC. - 1432-1440 .- 0946-2716. ; 93:8, s. 891-904
-
Journal article (peer-reviewed)
|
|
16. |
- Levine, Daniel C., et al.
(author)
-
NAD+ Controls Circadian Reprogramming through PER2 Nuclear Translocation to Counter Aging
- 2020
-
In: Molecular Cell. - : Elsevier BV. - 1097-2765 .- 1097-4164. ; 78:5, s. 835-
-
Journal article (peer-reviewed)abstract
- Disrupted sleep-wake and molecular circadian rhythms are a feature of aging associated with metabolic disease and reduced levels of NAD(+), yet whether changes in nucleotide metabolism control circadian behavioral and genomic rhythms remains unknown. Here, we reveal that supplementation with the NAD(+) precursor nicotinamide riboside (NR) markedly reprograms metabolic and stress-response pathways that decline with aging through inhibition of the clock repressor PER2. NR enhances BMAL1 chromatin binding genome-wide through PER2K680 deacetylation, which in turn primes PER2 phosphorylation within a domain that controls nuclear transport and stability and that is mutated in human advanced sleep phase syndrome. In old mice, dampened BMAL1 chromatin binding, transcriptional oscillations, mitochondrial respiration rhythms, and late evening activity are restored by NAD(+) repletion to youthful levels with NR. These results reveal effects of NAD(+) on metabolism and the circadian system with aging through the spatiotemporal control of the molecular clock.
|
|