Constraints on the Higgs boson mass from direct searches and precision measurements

We combine, within the framework of the standard model, the results of Higgs search experiments with the information coming from an accurate theoretical calculation and precision measurements to provide a probability density function for the Higgs mass, from which all numbers of interest can be derived. The expected value is around 160–170 GeV, with an expectation uncertainty, quantified by the standard deviation of the distribution, of about 60–80 GeV. The median of the distribution is 150 GeV, while 75% of the probability is concentrated in the region GeV. The 95% probability upper limit turns out to be around 300 GeV. Received: 18 February 1999 / Published online: 28 September 1999     

High precision hyperfine structure measurements in185Re and187Re

The hyperfine structure of the atomic levels 5d ⁵ 6s ^{2 6} S _5/2 and⁴ P _5/2 in¹⁸⁵Re and¹⁸⁷Re has been studied with high precision by atomic-beam magnetic-resonance. Additional measurements were performed in the 5d ⁵ 6s ^{2 4} G _5/2 and 5d ⁶ 6s ⁶ D _9/2 states of¹⁸⁷Re. For the interpretation of the results eigenvectors in intermediate coupling have been derived by a least squares fit of all known levels of the configurations (5d+6s)⁷. The ratioB(¹⁸⁵Re)/B(¹⁸⁷Re) is the same for the⁶ S _5/2 and the⁴ P _5/2 state within the error limits of 6 parts in 10⁵. Combining the present results with the known hyperfine structure data of¹⁸⁶Re and¹⁸⁸Re we find the magnetic-dipole hyperfine anomalies for the isotopic series^185?188Re.     

High precision measurements of the pion proton elastic scattering and kaon-lambda production in the EPECUR experiment

Study of the pion-nucleon scattering can produce a rich information on the dynamics of the strong interaction and baryon spectroscopy. The EPECUR collaboration is aimed at the research of baryon resonances in the second resonance region in s-channel via pion-proton elastic scattering and kaon-lambda production.     

Constraints on non-standard effects from present and futureg μ−2 measurements

Motivated by the expected high accuracy of the next AGS measurement of the muong?2 we have computed several types of contributions arising from new particles and interactions. Results are first given for individual terms where limits on new parameters, coming fromg _μ?2 are compared to those expected from future colliders. Combined effects due to different contributions are then considered and this reveals that constrained models with a low effective scale could still be allowed.     

Optical methods for precision measurements

Contactless measuring techniques are becoming increasingly important for industrial applications. The use of a laser, solid-state detector arrays and powerful small computers leads to a very efficient fringe analysis in holography as well as in Moiré and speckle techniques. Due to the computer analysis, much more information can be extracted from interferograms, leading to higher sensitivities and accuracies. The application of different fringe analysis procedures is discussed, together with some potentials of the application of interferometry, holography, and speckle and Moiré techniques.     

Fundamental symmetries and precision measurements on trapped particles

The tests of fundamental symmetries (CPT symmetry and the equivalence principle for antiparticles) that can be deduced from high-precision frequency measurements on trapped particles are reviewed.     

Limitations on the precision of atomic meanlife measurements

Uncertainty estimates in atomic meanlife measurements are usually obtained by statistical inference based on the hypothesis that the exponential decay law is exact and the distribution of random errors about it is Gaussian. At some level of precision these parameter evaluation methods must be accompanied by additional hypothesis testing. Possible limitations on these accuracies are examined in the light of recent measurements and calculations, and are quantitatively studied through the simulation and fitting of several alternative models.     

A comparison of high statistics measurements of the proton and deuteron structure functions

We present a detailed comparison of high statistics measurements of the structure functionF ₂(x, Q ²) from deep inelastic scattering of charged leptons on hydrogen and deuterium targets. It is found that the CERN results from the EMC and BCDMS Collaborations are both compatible with the lowQ ² electron scattering results from SLAC after an adjustment of the relative normalizations. We discuss the residual discrepancy between EMC and BCDMS which persists after this renormalization and find that the SLAC data are in better agreement with the steeperx dependence of the BCDMS results. A phenomenological parametrization ofF ₂(x, Q ²) is given.     

Progress of precision measurements at JYFLTRAP

This review compiles the results obtained since 2006 by use of the JYFLTRAP Penning trap mass spectrometer. Almost 300 atomic masses of ground or isomeric states of exotic nuclei have been measured. Some of the measurements required the development of new techniques which are briefly mentioned. In addition, JYFLTRAP was applied to a variety of spectroscopic studies and to the production of isobarically or isomerically pure beams.     

Constraints in estimating the proton density fat fraction

The study evaluates four physically motivated constraints in the estimation of the proton density fat fraction (PDFF). Least squares approaches were developed for constraining the parameters in PDFF quantification based on the physics of magnetic resonance imaging. These were smooth fieldmap, smooth initial phase, nonnegative proton density and moderate R₂¹ values. The constraints were evaluated in terms of their influence on the bias and standard deviation of the estimated parameters using numerical simulations and in vivo data acquired at 0.35 T. Results show that unconstrained least squares estimation is noisy and biased and that constraints can be effective at reducing both the standard deviation and bias.     

Once more on extra quark-lepton generations and precision measurements

Precisionmeasurements of Z-boson parameters andW-boson and t-quark masses put strong constraints on non SU(2) × U(1) singlet New Physics.We demonstrate that one extra generation passes electroweak constraints even when all new particle masses are well above their direct mass bounds.     

Beam-halo measurements in high-current proton beams

We present results from an experimental study of the beam halo in a high-current 6.7-MeV proton beam propagating through a 52-quadrupole periodic-focusing channel. The gradients of the first four quadrupoles were independently adjusted to match or mismatch the injected beam. Emittances and beamwidths were obtained from measured profiles for comparisons with maximum emittance-growth predictions of a free-energy model and maximum halo-amplitude predictions of a particle-core model. The experimental results support both models and the present theoretical picture of halo formation.