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Study of Phi and f2'(1525) meson production in anti-p p annihilation at rest.

The OBELIX collaboration Alberico, A. ; Bertin, A. ; Bruschi, M. ; et al.
Phys.Lett.B 438 (1998) 430-440, 1998.
Inspire Record 481232 DOI 10.17182/hepdata.28160

The reaction p ̄ p→K + K − π 0 was analysed for antiproton annihilations at rest at three hydrogen target densities. A strong dependence of the p ̄ p→φπ 0 yield on the quantum numbers of the initial state is observed. The branching ratio of the φπ 0 channel from the 3 S 1 initial state is more than 15 times larger than the one from the 1 P 1 state. A large apparent violation of the OZI rule for tensor meson production from p ̄ p -annihilations from the P -waves (1 ++ +2 ++ ) is observed: R exp ( f ′ 2 π 0 / f 2 π 0 )=(149±20)·10 −3 , significantly exceeding the OZI-rule prediction R =16·10 −3 .

4 data tables
Table 1

Three densities (LH2, NTP, and LP) of the hydrogen target.

Table 2

S- and P-wave in the initial PBAR P system.

Table 3

S- and P-wave in the initial PBAR P system.

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New data on OZI rule violation in anti-p p annihilation at rest.

The OBELIX collaboration Bertin, A. ; Bruschi, M. ; De Castro, S. ; et al.
Phys.Lett.B 388 (1996) 450-456, 1996.
Inspire Record 420512 DOI 10.17182/hepdata.41681

The results of a measurement of the ratio R = Y(phi pi+ pi-) / Y(omega pi+ pi-) for antiproton annihilation at rest in a gaseous and in a liquid hydrogen target are presented. It was found that the value of this ratio increases with the decreasing of the dipion mass, which demonstrates the difference in the phi and omega production mechanisms. An indication on the momentum transfer dependence of the apparent OZI rule violation for phi production from the 3S1 initial state was found.

1 data table
Table 1

(C=CORRECTED) the ratio with phase space correctio. The annihilation in liquid hydrogen (C=LIQUID) and in hydrogen at 3 atm (C=P).


Protonium annihilation into K(S) K(L) at three different target densities

The OBELIX collaboration Bertin, A. ; Bruschi, M. ; Capponi, M. ; et al.
Phys.Lett.B 386 (1996) 486-494, 1996.
Inspire Record 431933 DOI 10.17182/hepdata.28347

The frequency of the protonium annihilation channel p p → K S K L has been measured at three different target densities: liquid hydrogen ( LH ), gaseous hydrogen at NTP conditions and gaseous hydrogen at low pressure (5 mbar). The obtained results are: f( p p → K S K L , LH) = (7.8 ± 0.7 stat ± 0.3 sys ) × 10 −4 , f( p p → K S K L , NTP) = (3.5 ± 0.5 stat ± 0.2 sys ) × 10 −4 and f( p p → K S K L , 5 mbar ) = (1.0 ± 0.3 stat ± 0.1 sys ) × 10 −4 . Since the K S K L final stat and be originated only from the 3 S 1 initial state, these values give direct information on the scaling of the protonium spin-triplet S-wave annihilation probability with the density.

1 data table
Table 1

Three different target densities: liquid hydrogen (LH), gaseous hydrogen atstandard temperature and pressure conditions (NTP), and gaseous hydrogen at 5 m bar pressure (LP). The annihilation proceeds only from 3S1 initial state.