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Hyperfine splitting in light-flavour hadron production at LEP

Author: P.V. Chliapnikov
Chliapnikov P V
Publication venue
Publication date: 01/01/1999
Field of study

The production rates of light-flavour hadrons at LEP~1 are set by their masses, spins, strangeness suppression, and strongly influenced by the spin-spin interactions of their quarks. Similarities in production of pseudoscalar mesons and octet baryons, vector mesons and decuplet baryons are observed and explained by the relative spin configurations of their quarks. Similarity in production of tensor mesons and

\Lambda(1520)

is also seen. The vector-to-pseudoscalar meson and decuplet-to-octet baryon suppressions are the same and explained by the hyperfine mass splitting. The strangeness suppression factor,

\lambda = 0.295 \pm 0.006

, is the same for mesons and baryons. It is related to the difference in the constituent quark masses,

\lambda = e^{-(m_s-\hat{m})/T}

, where

\hat{m} = m_u = m_d

, at the temperature,

T = 142.4 \pm 1.8

~MeV/

c^2

. No evidence for additional suppression of strange baryons is observed. The LEP~1 data are compared with hadronic reactions and heavy nuclear collisions

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Relating production and masses of the vector and P-wave mesons for light and heavy flavours al LEP

Author: Chliapnikov P V
Chliapnikov P.V.
Publication venue
Publication date: 05/12/2001
Field of study

The production rates of primary vector and P-wave mesons in Z hadronic decays are analysed. The mass dependence of production rates for the bottom, charm, strange charm and three families of the light-flavour mesons is found to be very similar, allowing to relate the relative production rates for mesons with different flavours and, possibly, their masses. The strange axial mesons K_1(1273) and K_1(1402) might be assigned to the 1^+(1/2) and 1^+(3/2) levels degenerate with the 0^+(1/2) and 2^+(3/2) levels of the K^*_0(1430) and K^*_2(1430), respectively, if the observed K^*_0(1430) mass is replaced by its ``bare'' q\bar{q} mass corresponding to the K-matrix pole and close to the K_1(1273) mass. Then the 0^+(1/2) and 1^+(1/2) levels are below the 1^+(3/2) and 2^+(3/2) levels for the strange, charm and bottom mesons

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