92 research outputs found
Direct search for light gluinos
We present the results for a direct search for light gluinos through the appearance of with high transverse momentum in the vacuum tank of the NA48 experiment at CERN. We find one event within a lifetime range of s and another one between s. Both events are consistent with the expected background from neutrons in the beam, produced by 450 GeV protons impinging on the Be targets, which interact with the residual air in the tank. From these data we give limits on the production of the hypothetical bound state, the hadron, and its decay in the mass range between 1 and 5~GeV
New high statistics measurement of decay form factors and scattering phase shifts
We report results from a new measurement of the decay by the NA48/2 collaboration at the CERN SPS, based on a partial sample of more than 670000 decays in both charged modes collected in 2003. The form factors of the hadronic current (F, G, H) and phase difference () have been measured in ten independent bins of the mass spectrum to investigate the variation. A sizeable acceptance at large mass, a low background and a very good resolution contribute to an improved experimental accuracy, a factor two better than in the previous measurement, when extracting the scattering lengths and . Under the assumption of isospin symmetry and using numerical solutions of the Roy equations, the following values are obtained in the plane (. The presence of potentially large isospin effects is also considered and will allow comparison with precise predictions from Chiral Perturbation Theory
Search for direct CP violating charge asymmetries in and decays
A measurement of the direct CP violating charge asymmetries of the Dalitz
plot linear slopes in and
decays by the NA48/2 experiment at CERN SPS is
presented. A new technique of asymmetry measurement involving simultaneous
and beams and a large data sample collected allowed a result of an
unprecedented precision. The charge asymmetries were measured to be
with
decays, and with
decays. The precision of the
results is limited mainly by the size of the data sample.Comment: 29 pages, 9 figures. An updated version accepted by the EPJ
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