Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userHadronic Structure Functions of the Photon Measured at LEP
82
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
The measurements of hadronic structure functions of the photon based on the reaction ee --> ee gamma^(*)(P^2) gamma^*(Q^2)--> ee hadrons are discussed.
rate research
Read More
The mean charge multiplicity in hadronic three-jet Z decays has been measured with the DELPHI detector as a function of the event topology and compared with recent theoretical calculations. The QCD colour factor ratio C_A/C_F was determined, and the gluon contribution to this multiplicity was extracted giving a measurement of the mean charge multiplicity of a two-gluon colour-singlet system as a function of the effective c.m. energy covering the range from 16 to 52 GeV.
A new phenomenological approach is suggested to determine the strangeness contents of light-flavour isoscalars. This approach is based on phenomenological laws of hadron production related to the spin, isospin, strangeness content and mass of the particles. The ``effective numbers of s and bar{s} quarks in the isoscalar partners i_1 and i_2 are given by the nonstrange-strange mixing angle phi: k(i_1)=2sin^2phi and k(i_2)=2cos^2phi. From the total production rates per hadronic Z decay of all light-flavour hadrons measured so far at LEP the values for k are found to be: k(eta) equiv 2-k(eta^{prime}) = 0.91 pm 0.12, k(phi) equiv 2-k(omega) = 1.94 pm 0.09, k(f_2^{prime}) equiv 2-k(f_2) = 1.84 pm 0.21 and k(f_0) = 0.09 pm 0.13. Our results on the eta--eta^{prime}, omega--phi and f_2--f_2^{prime} isoscalar mixing are consistent with the present experimental evidence. Quite remarkably, our value for k(eta) corresponds to the singlet-octet mixing angle theta_P = -12.4^{circ} pm 3.5^{circ}. The obtained strangeness content of the f_0(980) scalar/isoscalar is not consistent with the values supported by different model studies. However, taking the f_0(980) in our analysis with the mass of the bare state (K-matrix pole) f_0^{bare}(720 pm 100), the mixing angle is found to be: |phi_S^{bare}| = 73^{circ} pm 7^{circ} pm 24^{circ}, in good agreement with the prediction of the K-matrix analysis.
The four LEP experiments ALEPH, DELPHI, L3 and OPAL successfully recorded e+e- collision data during the years 1989 to 2000. As part of the ordinary evolution in High Energy Physics, these experiments can not be repeated and their data is therefore unique. This article briefly reviews the data preservation efforts undertaken by the four experiments beyond the end of data taking. The current status of the preserved data and associated tools is summarised.
A new phenomenological approach is suggested for determining the strangeness content of light-flavour isoscalars. This approach is based on phenomenological laws of hadron production related to the spin, isospin, strangeness content and mass of the particles. From the total production rates per hadronic Z decay of all light-flavour hadrons, measured so far at LEP, the values of the nonstrange-strange mixing angles are found to be |phi_P| = 42.3^{circ} pm 3.5^{circ}, |phi_V| = 10^{circ} pm 8^{circ}, |phi_T| = 16^{circ} pm 11^{circ} and |phi_S| = 13^{circ} pm 9^{circ}. Our results on the eta-eta^{prime}, omega-phi and f_2-f_2^{prime} isoscalar mixing are consistent with the present experimental evidence. The strangeness content obtained for the f_0(980) scalar/isoscalar is not consistent with the values supported by recent model studies and is discussed further in the framework of our approach and the K-matrix analysis.
A study of the inclusive charged hadron production in two-photon collisions is described. The data were collected with the DELPHI detector at LEP II. Results on the inclusive single-particle p_T distribution and the differential charged hadrons dsigma/dp_T cross-section are presented and compared to the predictions of perturbative NLO QCD calculations and to published results.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
