Bernardini, M.
nucl-ex
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Electroproduction of $\phi(1020)$ mesons at $1.4\leq Q^2\leq$ 3.8 GeV$^2$ measured with the CLAS spectrometer

The CLAS collaboration Santoro, J.P. ; Smith, E.S. ; Garc con, M. ; et al.
Phys.Rev.C 78 (2008) 025210, 2008.
Inspire Record 781974 DOI 10.17182/hepdata.50913

Electroproduction of exclusive $\phi$ vector mesons has been studied with the CLAS detector in the kinematical range $1.6\leq Q^2\leq 3.8$ GeV$^{2}$, $0.0\leq t^{\prime}\leq 3.6$ GeV$^{2}$, and $2.0\leq W\leq 3.0$ GeV. The scaling exponent for the total cross section as $1/(Q^2+M_{\phi}^2)^n$ was determined to be $n=2.49\pm 0.33$. The slope of the four-momentum transfer $t'$ distribution is $b_{\phi}=0.98 \pm 0.17$ GeV$^{-2}$. The data are consistent with the assumption of s-channel helicity conservation (SCHC). Under this assumption, we determine the ratio of longitudinal to transverse cross sections to be $R=0.86 \pm 0.24$. A 2-gluon exchange model is able to reproduce the main features of the data.

5 data tables
Table 1

Axis error includes +- 18.6/18.6 contribution.

Table 2

Axis error includes +- 18.6/18.6 contribution.

Table 3

Axis error includes +- 18.6/18.6 contribution.

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Cascade production in the reactions gamma p --> K+ K+ (X) and gamma p --> K^+ K^+ pi- (X)

Guo, L. ; Weygand, D.P. ; Battaglieri, M. ; et al.
Phys.Rev.C 76 (2007) 025208, 2007.
Inspire Record 744487 DOI 10.17182/hepdata.31494

Photoproduction of the cascade resonances has been investigated in the reactions $\gamma p \to K^+ K^+ (X)$ and $\gamma p \to K^+ K^+ \pi^- (X)$. The mass split of the $\Xi$ doublet is measured to be $5.4\pm 1.8$ MeV/c$^2$, consistent with existing measurements. The differential (total) cross sections for the $\Xi^{-}$ have been determined for photon beam energies from 2.75 to 3.85 (4.75) GeV, and are consistent with a possible production mechanism of $Y^*\to K^+\Xi^-$ through a $t$-channel process. The reaction $\gamma p \to K^+ K^+ \pi^-[\Xi^0]$ has also been investigated in search of excited cascade resonances. No significant signal of excited cascade states other than the $\Xi^-(1530)$ is observed. The cross section results of the $\Xi^-(1530)$ have also been obtained for photon beam energies from 3.35 to 4.75 GeV.

47 data tables
Table 1

Differential cross section for XI- production as a function of the invariant mass of the XI- with either of the K+ mesons for incident photon energy 2.79 Gev.

Table 2

Differential cross section for XI- production as a function of the invariant mass of the XI- with either of the K+ mesons for incident photon energy 2.89 Gev.

Table 3

Differential cross section for XI- production as a function of the invariant mass of the XI- with either of the K+ mesons for incident photon energy 2.99 Gev.

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Precision measurement of the quasi-free p n --> d Phi reaction close to threshold.

Maeda, Y. ; Hartmann, M. ; Keshelashvili, I. ; et al.
Phys.Rev.Lett. 97 (2006) 142301, 2006.
Inspire Record 720728 DOI 10.17182/hepdata.31513

The quasi-free pn->dphi reaction has been studied at the Cooler Synchrotron COSY-Juelich, using the internal proton beam incident on a deuterium cluster-jet target and detecting a fast deuteron in coincidence with the K+K- decay of the phi-meson. The energy dependence of the total and differential cross sections are extracted for excess energies up to 80 MeV by determining the Fermi momentum of the target neutron on an event-by-event basis. Though these cross sections are consistent with s-wave production, the kaon angular distributions show the presence of p waves at quite low energy. Production on the neutron is found to be stronger than on the proton but not by as much as for the eta-meson.

3 data tables
Table 1

Differential cross section dependence on the angle of the K+ from the PHI decay in the PHI rest frame.

Table 2

Differential cross section dependence on the polar angle of the PHI in the overall rest frame.

Table 3

Total cross section as a function of the excess energy.


A Precise Determination of the Electroweak Mixing Angle from Semileptonic Neutrino Scattering

The CHARM collaboration Allaby, J.V. ; Amaldi, U. ; Barbiellini, G. ; et al.
Z.Phys.C 36 (1987) 611, 1987.
Inspire Record 249672 DOI 10.17182/hepdata.15697

The cross-section ratio of neutral-current and charged-current semileptonic interactions of muon-neutrinos on isoscalar nuclei has been measured with the result:Rv=0.3093±0.0031 for hadronic energy larger than 4 GeV. From this ratio we determined the electroweak mixing angle sin2θW, wheremc is the charm-quark mass in GeV/c2. Comparison with direct measurements ofmw andmz determines the radiative shift of the intermediate boson mass Δr=0.077±0.025(exp.)±0.038(syst.), in agreement with the prediction. Assuming the validity of the electroweak standard theory we determined ϱ=0.990−0.013(mc−1.5)±0.009(exp.)±0.003(theor.).

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

STATISTICAL ERROR IN THE VALUE CITED IS REDUCING, WHEN CUT IS MORE STRINGENT?.