E. -M. Kabu\ss

Publications (2)0 Total impact

• Source

  Available from: ArXiv

  Article: Measurement of Strange Quark Contributions to the Vector Form Factors of the Proton at Q**2=0.22 (GeV/c)**2

  S. Baunack, K. Aulenbacher, D. Balaguer Ríos, L. Capozza, J. Diefenbach, B. Gläser, D. v. Harrach, Y. Imai, E. -M. Kabu\ss, R. Kothe, [......], J. Arvieux, M. A. El-Yakoubi, R. Kunne, F. E. Maas, M. Morlet, S. Ong, J. Van de Wiele, S. Kowalski, Y Prok, S Taylor
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  ABSTRACT: A new measurement of the parity violating asymmetry in elastic electron scattering on hydrogen at backward angles and at a four momentum transfer of Q^2=0.22 (GeV/c)^2 is reported here. The measured asymmetry is A_LR=(-17.23 +- 0.82_stat +-0.89_syst) ppm. The Standard Model prediction assuming no strangeness is A_0=(-15.87 +- 1.22) ppm. In combination with previous results from measurements at forward angles, it it possible to disentangle for the first time the strange electric and magnetic form factors at this momentum transfer, G_E^s(0.22)=0.050 +- 0.038 +- 0.019 and G_M^s(0.22)=-0.14 +- 0.11 +- 0.11. Comment: Submitted to Physical Review Letters
  03/2009;
• Source

  Available from: Igor Altarev

  Article: Evidence for Strange Quark Contributions to the Nucleon's Form Factors at $Q^2$ = 0.108 (GeV/c)$^2$

  F. E. Maas, K. Aulenbacher, S. Baunack, L. Capozza, J. Diefenbach, B. Gläser, T. Hammel, D Von Harrach, Y. Imai, E. -M. Kabu\ss, [......], M. El-Yakoubi, R. Frascaria, R. Kunne, M. Morlet, S. Ong, J. Van de Wiele, S. Kowalski, B. Plaster, R Suleiman, S Taylor
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  ABSTRACT: We report on a measurement of the parity violating asymmetry in the elastic scattering of polarized electrons off unpolarized protons with the A4 apparatus at MAMI in Mainz at a four momentum transfer value of $Q^2$ = \Qsquare (GeV/c)$^2$ and at a forward electron scattering angle of 30$^\circ < \theta_e < 40^\circ$. The measured asymmetry is $A_{LR}(\vec{e}p)$ = (\Aphys $\pm$ \Deltastat$_{stat}$ $\pm$ \Deltasyst$_{syst}$) $\times$ 10$^{-6}$. The expectation from the Standard Model assuming no strangeness contribution to the vector current is A$_0$ = (\Azero $\pm$ \DeltaAzero) $\times$ 10$^{-6}$. We have improved the statistical accuracy by a factor of 3 as compared to our previous measurements at a higher $Q^2$. We have extracted the strangeness contribution to the electromagnetic form factors from our data to be $G_E^s$ + \FakGMs $G_M^s$ = \GEsGMs $\pm $ \DeltaGEsGMs at $Q^2$ = \Qsquare (GeV/c)$^2$. As in our previous measurement at higher momentum transfer for $G_E^s$ + 0.230 $G_M^s$, we again find the value for $G_E^s$ + \FakGMs $G_M^s$ to be positive, this time at an improved significance level of 2 $\sigma$.
  01/2005;