Search results for "antimatter"
showing 10 items of 64 documents
Status of the analysis for the search of polarization in the antiproton production process
2016
The P-349 experiment aims to test whether for antiprotons the production process itself can be a source of polarization in view of the preparation of a polarized antiproton beam. In this article we present the details of performed measurements and report on the status of the ongoing analysis.
Positron annihilation studies of binary Ni-based alloys
1987
Positron annihilation studies of Ni–1 at. % X (X = Pb, In and Zn) alloys have been performed. The experimentally observed changes in the parameters connecting the shape of angular correlation curve with the kind and concentration of crystal lattice defects are correlated with the values of the vacancy-solute binding energy calculated from the vacancy model of melting.
Nonlinear density dependence of the positron decay rate in helium
1980
The decay rate of thermalized positrons in helium is calculated as a function of the fluid density, incorporating the multiple scattering of the positron off the atoms. The obtained nonlinearity agrees with experimental data outside the self-trapping region.
ATRAP antihydrogen experiments
2007
Antihydrogen (Hbar) was first produced at CERN in 1996. Over the past decade our ATRAP collaboration has made massive progress toward our goal of producing large numbers of cold Hbar atoms that will be captured in a magnetic gradient trap for precise comparison between the atomic spectra of matter and antimatter. The AD at CERN provides bunches of 3 × 107 low energy Pbars every 100 seconds. We capture and cool to 4 K, 0.1% of these in a cryogenic Penning trap. By stacking many bunches we are able to do experiments with 3 × 105 Pbars. ∼100 e+/sec from a 22Na radioactive source are captured and cooled in the trap, with 5 × 106 available experiments.We have developed 2 ways to make Hbar from t…
Centrifugal Separation of Antiprotons and Electrons
2010
Centrifugal separation of antiprotons and electrons is observed, the first such demonstration with particles that cannot be laser cooled or optically imaged. The spatial separation takes place during the electron cooling of trapped antiprotons, the only method available to produce cryogenic antiprotons for precision tests of fundamental symmetries and for cold antihydrogen studies. The centrifugal separation suggests a new approach for isolating low energy antiprotons and for producing a controlled mixture of antiprotons and electrons.
First Capture of Antiprotons in a Penning Trap: A Kiloelectronvolt Source
1986
Antiprotons from the Low Energy Antiproton Ring of CERN are slowed from 21 MeV to below 3 keV by being passed through 3 mm of material, mostly Be. While still in flight, the kiloelectronvolt antiprotons are captured in a Penning trap created by the sudden application of a 3-kV potential. Antiprotons are held for 100 s and more. Prospects are now excellent for much longer trapping times under better vacuum conditions. This demonstrates the feasibility of a greatly improved measurement of the inertial mass of the antiproton and opens the way to other intriguing experiments.
Search for Muon Neutrino and Antineutrino Disappearance in MiniBooNE
2009
The MiniBooNE Collaboration reports a search for nu(mu) and nu(mu) disappearance in the Delta m(2) region of 0.5-40 eV(2). These measurements are important for constraining models with extra types of neutrinos, extra dimensions, and CPT violation. Fits to the shape of the nu(mu) and nu(mu) energy spectra reveal no evidence for disappearance at the 90% confidence level (C.L.) in either mode. The test of nu(mu) disappearance probes a region below Delta m(2)=40 eV(2) never explored before.
High-precision comparison of the antiproton-to-proton charge-to-mass ratio
2015
Invariance under the charge, parity, time-reversal (CPT) transformation$^{1}$ is one of the fundamental symmetries of the standard model of particle physics. This CPT invariance implies that the fundamental properties of antiparticles and their matter-conjugates are identical, apart from signs. There is a deep link between CPT invariance and Lorentz symmetry—that is, the laws of nature seem to be invariant under the symmetry transformation of spacetime—although it is model dependent$^{2}$. A number of high-precision CPT and Lorentz invariance tests—using a co-magnetometer, a torsion pendulum and a maser, among others—have been performed$^{3}$, but only a few direct high-precision CPT tests …
GHOSTLY BEACONS OF NEW PHYSICS
2013
The article discusses the elementary particle of the neutrino, with information on research regarding its fundamental properties and how it differs from other particles. Topics include the connection between neutrinos and their antiparticles, the observation of the particles' activity during nuclear beta decay and their interactions, and the possible implications that an asymmetric relationship between neutrinos and their antimatter would suggest regarding the composition of the universe with a majority of matter.
Constraints on Exotic Spin-Dependent Interactions Between Matter and Antimatter from Antiprotonic Helium Spectroscopy.
2018
Heretofore undiscovered spin-0 or spin-1 bosons can mediate exotic spin-dependent interactions between standard-model particles. Here we carry out the first search for semileptonic spin-dependent interactions between matter and antimatter. We compare theoretical calculations and spectroscopic measurements of the hyperfine structure of antiprotonic helium to constrain exotic spin- and velocity-dependent interactions between electrons and antiprotons.