V.L. Telegdi

Nuclear effects on the nucleon structure functions in hadronic high-mass dimuon production

We compare the differential cross sections of high-mass muon pair production on deuterium and tungsten by incident negative pions of 140 and 286 GeV. We find an indication of a nuclear effect on the nucleon quark distributions comparable in magnitude to what is observed in muon-iron deep inelastic scattering, whereas the pion-quark distribution is unaffected, compatibly with QCD factorization.

Observation of a Nuclear Dependence of the Transverse Momentum Distribution of Massive Muon Pairs Produced in Hadronic Collisions

Abstract We present the first clear evidence for a nuclear dependence of the transverse momentum distribution of massive muon pairs produced in hadronic interactions. Comparing the cross sections for high-mass dimuon production by incident negative pions (140 and 286 GeV) off tungsten and deuterium, we find that their ratio increases with the dimuon transverse momentum. The resulting difference in the mean transverse momentum squared amounts to 0.15±0.03 (syst.) GeV 2 / c 2 and is shown to be independent of the dimuon mass and longitudinal momentum.

On the interpretation of the redshift in a static gravitational field

The classical phenomenon of the redshift of light in a static gravitational potential, usually called the gravitational redshift, is described in the literature essentially in two ways: On the one hand, the phenomenon is explained through the behavior of clocks which run faster the higher they are located in the potential, whereas the energy and frequency of the propagating photon do not change with height. The light thus appears to be redshifted relative to the frequency of the clock. On the other hand, the phenomenon is alternatively discussed (even in some authoritative texts) in terms of an energy loss of a photon as it overcomes the gravitational attraction of the massive body. This second approach operates with notions such as the “gravitational mass” or the “potential energy” of a photon and we assert that it is misleading. We do not claim to present any original ideas or to give a comprehensive review of the subject, our goal being essentially a pedagogical one.

A high resolution spectrometer for the study of high mass muon pairs produced by intense hadron beams

Abstract We describe the design, construction and performance of a high-resolution spectrometer used at CERN to study the production of high-mass muon pairs by intense hadron beams. We also discuss the on- and off-line software used with this spectrometer.

A high-statistics study of ϒ-meson production in π-W reactions at 286 GeV/c

Abstract With a sample of about 2000( γ + γ ′+ γ ″) events observed in π-W interactions at 286GeV/ c , the ratio ( γ ′+ γ ″)/ γ =0.51±0.07, the branching ratio times the inclusive total cross section Bσ =(386±17±85) pb per W nucleus, as well as the differential cross sections in χ F and p T have been measured. These results are compared with previous data obtained with the same apparatus at a lower beam momentum (194 GeV/ c ). Both data sets are compared with a theoretical calculation (“duality model”) which also allows one to extract the shape parameter β g of the gluon distribution in the pion. β g is found to be 2.3 −0.3 +0.4 (stat.) −0.5 +0.1 (syst.).