Search results for "nuclear physics"

Energy and range focusing of in-flight separated exotic nuclei – A study for the energy-buncher stage of the low-energy branch of the Super-FRS

2003

Abstract The relative momentum spread of in-flight separated exotic nuclear beams produced in fragmentation and/or fission reactions is of the order of a few percent. A new technique is presented, which reduces the momentum spread significantly, and first experimental results obtained with relativistic projectile fragments are shown. This technique is the key to experiments with slowed-down and stopped beams, in particular for the efficient stopping of relativistic exotic nuclei in gas-filled stopping cells. It will be employed at the energy-buncher stage of the low-energy branch of the Super-FRS facility. The ion-optical design of the energy buncher is presented and a brief outlook to the …

Measurement of ππ Scattering Lengths from and Decays

2011

In the last few years it has become possible to study low energy ππ scattering with high precision in kaon decays, thanks to the high statistics measurements of K ± → π ± π 0 π 0 ( K 3 π ) and K ± → π + π − e ± ν ( K e 4 ) decays performed by the NA48/2 experiment at the CERN SPS. In K ± → π ± π 0 π 0 , at the π + π − threshold, the π 0 π 0 mass spectrum exhibits a Wigner-cusp, from which the scattering lengths a 0 and a 2 are extracted. From the study of K e 4 decays a similar precision, but quite independent measurement of a 0 and a 2 can be obtained. The combination of both measurements provides one of the most stringent tests of Chiral Perturbation Theory.

Manifestation of fine structures in the fission fragment mass-energy distribution of the reaction

2002

Methods of identifying structure peculiarities in two-dimensional distributions of experimental observables are discussed. Structures different from that produced by proton odd-even staggering were revealed for the first time in the mass-energy distribution of fission fragments in the 233 Uðnth; fÞ reaction. The new structures could presumably be linked with fission modes and collective vibrations of the fissioning system. r 2002 Elsevier Science B.V. All rights reserved.

Untersuchung der beiden ersten angeregten Zustände des Li6-Kernes durch Elektronenstreuung

1969

Inelastic electron cross sections for Li6 were measured using the facilities at the 300 MeV linear accelerator of the Institut fur Kernphysik in Mainz. The form factor for theC 2 transition to the 2.184 MeV level is given in the region of momentum transfer 0.4 fm−1<q<1.9 fm−1. It was possible to determine the form factor for the 3.562 MeVM 1 transition up toq=1.2 fm−1.

Dalitz plot analyses ofB0→D−D0K+andB+→D¯0D0K+decays

2015

We present Dalitz plot analyses for the decays of B mesons to D^−D^0K^+ and D^0D^0K^+. We report the observation of the D^∗_(s1)(2700)^+ resonance in these two channels and obtain measurements of the mass M(D^∗_(s1)(2700)+)=2699^(+14)_(−7)  MeV/c^2 and of the width Γ(D^∗_(s1)(2700)+)=127^(+24)_(−19)  MeV, including statistical and systematic uncertainties. In addition, we observe an enhancement in the D^0K^+ invariant mass around 2350–2500  MeV/c^2 in both decays B^0→D^−D^0K^+ and B^+→D^0D^0K^+, which we are not able to interpret. The results are based on 429  fb^(−1) of data containing 471×10^6BB pairs collected at the Υ(4S) resonance with the BABAR detector at the SLAC National Accelerato…

Precise measurement of the K±→π±e+e− decay

2009

Abstract A sample of 7253 K ± → π ± e + e − ( γ ) decay candidates with 1.0% background contamination has been collected by the NA48/2 experiment at the CERN SPS, which allowed a precise measurement of the decay properties. The branching ratio in the full kinematic range was measured to be BR = ( 3.11 ± 0.12 ) × 10 − 7 , where the uncertainty includes also the model dependence. The shape of the form factor W ( z ) , where z = ( M e e / M K ) 2 , was parameterized according to several models, and, in particular, the slope δ of the linear form factor W ( z ) = W 0 ( 1 + δ z ) was determined to be δ = 2.32 ± 0.18 . A possible CP violating asymmetry of K + and K − decay widths was investigated,…

Microsecond isomers in 187Tl and 188Pb

2000

Lifetime measurements of states in nuclei with A=187 and 188 have been performed, using reactions between 155Gd and 36Ar and following the transport of evaporation residues to the focal plane of a gas-filled recoil separator. In a separate experiment using the 159Tb(32S, 4n) reaction the γ-decay of isomeric levels in 187Tl has been studied using delayed γ-γ coincidence measurements. From observation of their subsequent γ decay, the mean lifetimes were measured to be 1000 ± 55 ns and 1600 ± 100 ns. Although it was not possible to characterize the isomers completely, they are proposed as candidates for one-proton, two-neutron excitations. In the course of this study, the decay of an isomer in…

The reliability of nuclear model predictions of?-decay properties of nuclei far from stability

1983

The longitudinal muon polarization in KL → μ+μ-

1991

17 páginas, 3 figuras, 1 tabla.-- CERN-TH-6035-91 ; UWTHPH-1991-9.

Underground multimuon experiment in the Pyhäsalmi mine

2006

An experiment to observe simultaneous, multiple muon events originating from extensive air showers is under preparation. The experiment will be situated in shallow depths in the Pyhasalmi mine in Finland, where the existing free caverns will be used. The aim is to cover an area of about 200 - 300 m(2). The detection of the multimuon events is motivated by partly unknown composition of the primary cosmic rays in the energy region of 10(15) - 10(16) eV, i.e. the 'knee' region. A prototype detector is under construction and is expected to be running at the spring 2005.