We report a measurement of the positive muon lifetime to a precision of 1.0 ppm; it is the most precise particle lifetime ever measured. The experiment used a time-structured, low-energy muon beam ...and a segmented plastic scintillator array to record more than 2×10(12) decays. Two different stopping target configurations were employed in independent data-taking periods. The combined results give τ(μ(+)) (MuLan)=2 196 980.3(2.2) ps, more than 15 times as precise as any previous experiment. The muon lifetime gives the most precise value for the Fermi constant: G(F) (MuLan)=1.166 378 8(7)×10(-5) GeV(-2) (0.6 ppm). It is also used to extract the μ(-)p singlet capture rate, which determines the proton's weak induced pseudoscalar coupling g(P).
Question of Lorentz violation in muon decay Noordmans, J. P.; Onderwater, C. J. G.; Wilschut, H. W. ...
Physical review. D,
06/2016, Letnik:
93, Številka:
11
Journal Article
Recenzirano
Odprti dostop
Possibilities to test the Lorentz invariance of the weak interaction in muon decay are considered. We derive the direction-dependent muon-decay rate with a general Lorentz-violating addition to the ...W-boson propagator. We discuss measurements of the directional and boost dependence of the Michel parameters and of the muon lifetime as a function of absolute velocity. The total muon-decay rate in the Lorentz-violating standard model extension is addressed. Suggestions are made for dedicated (re)analyses of the pertinent data and for future experiments.
The mean life of the positive muon has been measured to a precision of 11 ppm using a low-energy, pulsed muon beam stopped in a ferromagnetic target, which was surrounded by a scintillator detector ...array. The result, tau(micro)=2.197 013(24) micros, is in excellent agreement with the previous world average. The new world average tau(micro)=2.197 019(21) micros determines the Fermi constant G(F)=1.166 371(6)x10(-5) GeV-2 (5 ppm). Additionally, the precision measurement of the positive-muon lifetime is needed to determine the nucleon pseudoscalar coupling g(P).
This paper reports deuteron vector and tensor beam polarization measurements taken to investigate the systematic variations due to geometric beam misalignments and high data rates. The experiments ...used the In-Beam Polarimeter at the KVI-Groningen and the EDDA detector at the Cooler Synchrotron COSY at Jülich. By measuring with very high statistical precision, the contributions that are second-order in the systematic errors become apparent. By calibrating the sensitivity of the polarimeter to such errors, it becomes possible to obtain information from the raw count rate values on the size of the errors and to use this information to correct the polarization measurements. During the experiment, it was possible to demonstrate that corrections were satisfactory at the level of 10
−5 for deliberately large errors. This may facilitate the real time observation of vector polarization changes smaller than 10
−6 in a search for an electric dipole moment using a storage ring.
Search for EDMs using Storage Rings Onderwater, C J G
Journal of physics. Conference series,
05/2011, Letnik:
295, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Permanent electric dipole moments (EDMs) violate parity and time-reversal symmetry. Within the Standard Model (SM), they require CP violation and are many orders of magnitude below present ...experimental sensitivity. Many extensions of the SM predict much larger EDMs, which are therefore an excellent probe for the existence of new physics. Until recently it was believed that only electrically neutral systems could be used for sensitive searches of EDMs. With the introduction of a novel experimental method, high precision for charged systems will be within reach as well. The features of this method and its possibilities and status are discussed.
A single Ra
+
ion stored in a Paul radio frequency ion trap has excellent potential for a precision measurement of the electroweak mixing angle at low momentum transfer and as the most stable optical ...clock. The effective transport and cooling of singly charged ions of the isotopes
209
Ra to
214
Ra in a gas filled radio frequency quadrupole device is reported. The absolute frequencies of the transition 7s
2
S
1/2
–7d
2
D
3/2
at wavelength 828 nm have been determined in
212–214
Ra
+
with ≤19 MHz uncertainty using laser spectroscopy on small samples of ions trapped in a linear Paul trap at the online facility Trapped Radioactive Isotopes: µicrolaboratories for fundamental Physics (TRIµP) of the Kernfysisch Versneller Instituut.
A single trapped Ra
+
(
Z
= 88) ion provides a very promising route towards a most precise measurement of Atomic Parity Violation (APV), since APV effects grow faster than
Z
3
. This experiment ...promises the best determination of the electroweak coupling constant at the lowest accessible energies. Such a measurement provides a sensitive test of the Standard Model in particle physics. At the present stage of the experiment, we focus on trapping and laser cooling stable Ba
+
ions as a precursor for radioactive Ra
+
. Online laser spectroscopy of the isotopes
209 − 214
Ra
+
in a linear Paul trap has provided information on transition wavelengths, fine and hyperfine structures and excited state lifetimes as test of atomic structure calculations. Additionaly, a single trapped Ra
+
ion could function as a very stable clock.
A gas cell for stopping, storing and polarizing radioactive particles Sytema, A.; van den Berg, J.E.; Böll, O. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
06/2016, Letnik:
822
Journal Article
Recenzirano
Odprti dostop
A radioactive beam of 20Na is stopped in a gas cell filled with Ne gas. The stopped particles are polarized by optical pumping. The degree of polarization that can be achieved is studied. A maximum ...polarization of 50% was found. The dynamic processes in the cell are described with a phenomenological model.
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