Measurement of CP violating asymmetries in B0 decays to CP eigenstates

The BaBar collaboration Aubert, Bernard ; Boutigny, D. ; De Bonis, I. ; et al.
Phys.Rev.Lett. 86 (2001) 2515-2522, 2001.
Inspire Record 553002 DOI 10.17182/hepdata.50471

We present measurements of time-dependent CP-violating asymmetries in neutral B decays to several CP eigenstates. The measurement uses a data sample of 23 million Upsilon(4S)-->B-anti-B decays collected by the BABAR detector at the PEP-II asymmetric B Factory at SLAC. In this sample, we find events where one neutral B meson is fully reconstructed in a CP eigenstate containing charmonium and the flavor of the other neutral B meson is determined from its decay products. The amplitude of the CP-violating asymmetry, which in the Standard Model is proportional to sin2beta, is derived from the decay time distributions in such events. The result is sin2beta=0.34 +/- 0.20 (stat) +/- 0.05 (syst).

1 data table

Standard Model predicts the time-dependent rate asymmetry as follows: A(t) = (B0(t)-BBAR0(t))/(B0(t)+BBAR0(t)) = SIN(2*BETA)*SIN(Delta(M)*t), where Delta(M) is the mass difference between the two B0 mass eigenstates. The total systematic error equals +0.50 -0.46.


MEASUREMENT OF THE ASYMMETRY PARAMETER A IN PI- P ELASTIC AND CHARGE EXCHANGE SCATTERING AT PION ENERGIES T (PI) = 98-MEV, 238-MEV, 292-MEV, AND 310-MEV

Alder, J.c. ; Joseph, C. ; Perroud, J.p. ; et al.
Phys.Rev.D 27 (1983) 1040-1055, 1983.
Inspire Record 192365 DOI 10.17182/hepdata.23839

The asymmetry parameter A in π−p elastic scattering at incident pion laboratory kinetic energies Tπ of 98, 238, and 2922 MeV and in π−p charge-exchange scattering π−p→π0n at Tπ=238, 292, and 310 MeV have been measured over a wide range of scattering angles (typically from about 60° to 130° c.m.) with a polarized proton target. The data have been used in an energy-independent phase-shift analysis to improve the precision of the pion-nucleon phase shifts, to set new limits on violation of isospin conservation in the pion-nucleon S wave, and to confirm significant charge dependence in the P32 wave.

6 data tables

Axis error includes +- 0.0/0.0 contribution (?////BACKGROUND SUBTRACTION SMALL).

Axis error includes +- 0.0/0.0 contribution (?////BACKGROUND SUBTRACTION SMALL).

Axis error includes +- 0.0/0.0 contribution (?////BACKGROUND SUBTRACTION SMALL).

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Measurement of Cross-sections and Asymmetry Parameters for the Production of Charged Pions From Various Nuclei by 585-{MeV} Protons

Crawford, J.F. ; Daum, M. ; Eaton, G.H. ; et al.
Phys.Rev.C 22 (1980) 1184-1196, 1980.
Inspire Record 143030 DOI 10.17182/hepdata.26362

We have measured the differential cross section d2σdΩdTπ and the polarization parameter P for the production of π+ and π− in various target nuclei (H1, H2, Be, C, O, Al, Ni, Cu, Mo, and Pb) by protons with a kinetic energy of 585 MeV, for production angles θπ=22.5°, 45°, 60°, 90°, and 135°, and for pion kinetic energies Tπ of 24, 35, 46, 88, 151, 192, and 254 MeV (all quantities in the laboratory system). Our data disagree strongly with recent data for 580-MeV protons. On the other hand, for pion energies up to 150 MeV, our cross sections differ little from those measured for a proton energy of 730 MeV. For nuclei with A>20, the total production cross sections σ(π+) and σ(π−) show the Z13 and N23 proportionality expected from theoretical arguments. There is evidence in our data of a shift of the π+ energy distributions compared to the π− distributions due to the effects of the Coulomb field of the nuclear protons on the emitted pions. NUCLEAR REACTIONS H1, H2, Be, C, O, Al, Ni, Cu, Mo, Pb p, π±, Tp=585 MeV; measured σ(Tπ, θπ) and asymmetry parameter P(Tπ, θπ).

3 data tables

No description provided.

No description provided.

No description provided.


Measurement of the Polarization Parameter in $\pi^- p$ Scattering at 291.5-{MeV} and 308-{MeV}

Alder, J.C. ; Perroud, J.P. ; Tran, M.T. ; et al.
Lett.Nuovo Cim. 23 (1978) 381, 1978.
Inspire Record 130236 DOI 10.17182/hepdata.37401

None

2 data tables

No description provided.

No description provided.


Precision Measurement of the Muon Momentum in Pion Decay at Rest

Daum, M. ; Eaton, G.H. ; Frosch, R. ; et al.
Phys.Lett.B 74 (1978) 126-129, 1978.
Inspire Record 122405 DOI 10.17182/hepdata.27473

A precision measurement of the μ + momentum in π + decay at rest has been made with a magnetic spectrometer. The result is p μ + = (29.7873 ± 0.0014) MeV/c. The consequences of thisresult for the rest masses of the muon neutrino and of the positive pion are discussed.

2 data tables

DECAY AT REST WAS STUDIED.

No description provided.


New Determination of the Upper Limit for the Muon Neutrino Mass

Daum, M. ; Dubal, L. ; Eaton, G.H. ; et al.
Phys.Lett.B 60 (1976) 380-384, 1976.
Inspire Record 112895 DOI 10.17182/hepdata.27715

We have measured the muon momentum in pion decay at rest using a magnetic spectrometer. From the result, p μ + = (29.787±0.005) MeV/ c , we deduce a squared muon neutrino mass of (0.23±0.54) MeV 2 / c 4 .

1 data table

No description provided.