arXiv subjects
Publications and source records attributed to C. Hodd.
We present data on pbar-p -> eta-eta-pizero at beam momenta of 600, 900, 1050, and 1200 MeV/c. At the higher three momenta, a signal is clearly visible due to pbar-p -> f_0(1770)-pizero, f_0(1770) -> eta-eta. It has mass 1770+-12 MeV and width 220+-40 MeV, where errors cover systematic uncertainties as well as statistics.
Data are presented on the reaction pbar-p -> omega-omega-pizero at rest from the Crystal Barrel detector. These data identify a strong signal due to f2(1565) -> omega-omega. The relative production from initial pbar-p states 3P2, 3P1 and 1S0 is well determined from omega-omega decay angular correlations; P-state annihilation dominates strongly. A combined fit is made with data on pbar-p -> 3pizero at rest, where f2(1565) -> pizero-pizero is observed.
Data on pbar-p -> etaprime(958)-pizero-pizero are presented at nine pbar momenta from 600 to 1940 MeV/c. Strong S-wave production of f_2(1270)-etaprime is observed, requiring a J^{PC} = 2^{-+} resonance with mass M = 2248+-20 MeV, Gamma = 280+-20 MeV.
Data on pbar-b annihilation in flight into pizero-pizero-eta are presented for nine beam momenta 600 to 1940 MeV/c. The strongest four intermediate states are found to be f_2(1270)-eta, a_2(1320)-pi, sigma-eta and a_0(980)-pi. Partial wave analysis is performed mainly to look for resonances formed by pbar-p and decaying into pizero-pizero-eta through these intermediate states. There is evidence for the following s-channel I = 0 resonances : two 4^{++} resonances with mass and width (M,Gamma) at (2044, 208) MeV and (2320+-30, 220+-30) MeV; three 2^{++} resonances at (2020+-50, 200+-70) MeV, (2240+-40, 170+-50) MeV and (2370+-50, 320+-50) MeV; two 3^{++} resonances at (2000+-40, 250+-40) MeV and (2280+-30, 210+-30) MeV; a 1^{++} resonance at (2340+-40, 340+-40) MeV; and two 2^{-+} resonances at (2040+-40, 190+-40) MeV and (2300+-40, 270+-40) MeV.
A partial wave analysis is presented of Crystal Barrel data on pbar-p -> pizero-pizero, eta-eta and eta-etaprime from 600 to 1940 MeV/c, combined with earlier data on d\sigma /d\Omega and P for pbar-p->piminus-piplus. The following s-channel I=0 resonances are identified: (i) J^{PC} = 5^{--} with mass and width (M,\Gamma) at (2295+-30,235^{+65}_{-40}) MeV, (ii) J^{PC} = 4^{++} at (2020+-12, 170+-15) MeV and (2300+-25, 270+-50) MeV, (iii) 3D3 JPC = 3^{--} at (1960+-15, 150+-25) MeV and (2210+-4$, 360+-55) MeV, and a 3G3 state at (2300 ^{+50}_{-80}, 340+-150) MeV, (iv) JPC = 2^{++} at (1910+-30, 260+-40) MeV, (2020+-30, 275+-35) MeV, (2230+-30, 245+-45) MeV, and (2300+-35, 290+-50) MeV, (v) JPC = 1^{--} at (2005+-40, 275+-75) MeV, and (2165+-40, 160 ^{+140}_{-70}) MeV, and (vi) JPC = 0^{++} at (2005+-30, 305+-50) MeV, (2105+-15, 200+-25) MeV, and (2320+-30, 175+-45) MeV. In addition, there is a less well defined 6^{++} resonance at 2485+-40 MeV, with Gamma = 410+-90 MeV. For every JP, almost all these resonances lie on well defined linear trajectories of mass squared v. excitation number. The slope is 1.10+-0.03 Gev^2 per excitation. The f_0(2105) has strong coupling to eta-\eta, but much weaker coupling to pizero-pizero. Its flavour mixing angle between q-qbar and s-sbar is (59-71.6)deg, i.e. dominant decays to s-sbar. Such decays and its strong production in pbar-p interactions strongly suggest exotic character.
A combined fit is presented to data on pbar-p annihilation in flight to final states eta-pizero-pizero, pizero-pizero, eta-eta, eta-etaprime and piminus-piplus. The emphasis lies in improving an earlier study of eta-pizero-pizero by fitting data at nine pbar momenta simultaneously and with parameters consistent with the two-body channels. There is evidence for all of the I=0, C=+ q-qbar states expected in this mass range. New resonances are reported with masses and widths M,Gamma as follows: JPC = 4^{-+} (2328+-38, Gamma=240+-90) MeV, 1^{++} (1971+-15, 240+-45) MeV, 0^{-+} (2285+-20, 325+-30) MeV, and 0^{-+} (2010 ^{+35}_{-60}, 270+-60) MeV. Errors on the masses and widths of other resonances are also reduced substantially. All states lie close to parallel straight line trajectories of excitation number v. mass squared.