HEPData Search

Showing 10 of 10000 results

SEARCH FOR THE S MESON IN ANTI-PROTON PROTON INTERACTIONS

Fickinger, W. ; Marino, R. ; Robinson, D.K. ; et al.

Phys.Rev.D 34 (1986) 3332-3342, 1986.

Inspire Record 239036 DOI 10.17182/hepdata.26472

The interaction between antiprotons and protons has been studied in the range 1910 to 1990 MeV center-of-mass energy in a drift-chamber experiment at the Brookhaven Alternating Gradient Synchrotron. The total cross section has been determined at eleven different incident momenta, and the elastic cross section between 8 and 30 deg in the laboratory has been measured with an energy resolution of about 5 MeV. The cross section for annihilation into charged mesons has also been measured, with the same resolution. There is no evidence in any of these channels for the existence of a narrow resonance.

3 data tables

Table 1

Data are for total sample with nuclear physics calculation as described in the paper.

Table 2

Partial elastic cross sections.

Table 3

Partial annihilation cross sections.

Atomic Beam Measurement of Parity Nonconservation in Cesium

Gilbert, S.L. ; Wieman, Carl E. ;

Phys.Rev.A 34 (1986) 792-803, 1986.

Inspire Record 237319 DOI 10.17182/hepdata.26392

We present a new measurement of parity nonconservation in cesium. In this experiment, a laser excited the 6S→7S transition in an atomic beam in a region of static electric and magnetic fields. The quantity measured was the component of the transition rate arising from the interference between the parity nonconserving amplitude, scrEPNC, and the Stark amplitude, βE. Our results are ImscrEPNC/β=−1.65±0.13 mV/cm and C2p=-2±2, where C2p is the proton-axial-vector–electron-vector neutral-current coupling constant. These results are in agreement with previous less precise measurements in cesium and with the predictions of the electroweak standard model. We give a detailed discussion of the experiment with particular emphasis on the treatment and elimination of systematic errors. This experimental technique will allow future measurements of significantly higher precision.

3 data tables

Table 1

Axis error includes +- 0.0/0.0 contribution (?////THE UNCERTAINTY IS DOMINATED BY THE PURELY STATISTICAL CONTRIBUTION).

Table 2

Axis error includes +- 0.0/0.0 contribution (?////THE UNCERTAINTY IS DOMINATED BY THE PURELY STATISTICAL CONTRIBUTION).

Table 3

Axis error includes +- 0.0/0.0 contribution (?////THE UNCERTAINTY IS DOMINATED BY THE PURELY STATISTICAL CONTRIBUTION).

Lepton and pion pair production in γγ collisions measured near the threshold at DCI

Courau, A. ; Falvard, A. ; Haissinski, J. ; et al.

Nucl.Phys.B 271 (1986) 86800013 1-20, 1986.

Inspire Record 232808 DOI 10.17182/hepdata.38240

This paper reports a complete analysis of data taken at DCI to measure lepton and pion pair production close to the threshold in two-photon processes: e+e− → e+e−(e+e−, μ+μ−, π+π−). Preliminary results have been previously published including one-half of the total statistics. Final results presented here are in good agreement with QED for lepton pair production. The measured cross section for pion pair production is twice as large as that expected from Born terms only — a two standard deviation effect.

1 data table

Table 1

Normalised to number of observed electron pairs. Fully corrected for acceptance, radiative effects etc.

ATOMIC PARITY VIOLATION MEASUREMENTS IN THE HIGHLY FORBIDDEN (6)S(1/2) - (7)S(1/2) CESIUM TRANSITION. 3. DATA ACQUISITION AND PROCESSING. RESULTS AND IMPLICATIONS

Bouchiat, M.A. ; Guena, J. ; Pottier, L. ; et al.

J.Phys.(France) 47 (1986) 1709-1730, 1986.

Inspire Record 232798 DOI 10.17182/hepdata.38588

This paper completes the detailed presentation of our PV experiment on the 6S1/2 - 7S1/2 transition in Cs. A detailed description of the data acquisition and processing is given. The results of two independent measurements made on ΔF = 0 and ΔF =1 hfs components agree, providing an important cross-check. After a complete reanalysis of systematics and calibration, the precision is slightly improved, leading to the weighted average Im Epv 1/β = - 1.52 ± 0.18 mV/cm. Later results from an independent group agree quite well. With the semi-empirical value β = (26.8 ± 0.8) a30, our result yields Epv1 = (- 0.79 ± 0.10) x 10-11 i |e|a0. Coupled with the atomic calculations, this implies that the weak nuclear charge of Cs is Qw = -68 ± 9. This value agrees with the standard electroweak theory and leads to a weak interaction angle sin2 θ W = 0.21 ± 0.04. The complementarity of these measurements with high energy experiments is illustrated.

3 data tables

Table 1

Revision of the earlier experiment PL 117B, 358. (7s)2S1/2:F=4 --> (6s)2S1/2:F=4 transition.

Table 2

Revision of the earlier experiment PL 134B, 463. (7s)2S1/2:F=3 --> (6s)2S1/2:F=4 transition.

Table 3

Combined of the two above measurements following the philosophy: quadratic sum of the statistical and systematic uncertainties and weighting each result by the squared reciprocal of that uncertainty. (7s)2S1/2 --> (6s)2S1/2 transitions.