None
No description provided.
No description provided.
None
No description provided.
No description provided.
No description provided.
A narrow meson which decays into ηη is observed in 38 GeV/ c π − p collisions at large momentum transfer. The experiment has been performed at the Serpukhov accelerator with the GAMS-2000 spectrometer. The mass of this new meson is (1755 ± 8) MeV, its width is less than 50 MeV. Its spin-parity is J PC =0 ++ or less probably 2 ++ .
No description provided.
A comparison is made between the properties of the final state hadrons produced in 280 GeV μp interactions and ine+e− annihilation. The Lund model of hadroproduction is used as an aid in understanding the differences observed. The hadron distributions from μp ande+e− interactions are consistent with the quark parton model assumption of environmental independence, provided that the differences in heavy quark production and hard QCD effects in the two processes are taken into account. A comparison with aK+p experiment is also made. Values are also determined for the Lund model parameters σq = 0.410 ± 0.002 ± 0.020 GeV and σ′ = 0.29−0.15 −0.13+0.09+0.10 GeV, controlling the transverse momenta in fragmentation and intrinsic transverse momenta of the struck quark respectively.
With respect to the virtual photon axis.
With respect to the sphericity axis.
With respect to the thrust axis.
A search for stableH-dibaryon ofI=0,Y=0,JP=0+ was undertaken in negative pion-, neutron-,12C-nucleus- and proton-propane interactions at 4.0, 7.0, 50.4 and 10 GeV/c, respectively, using 55 cm and 2 m propane bubble chambers. This technique permite one to examine the whole range of possibleH-mass value. In the range ofMH>2MΛ=2231.2 MeV/c2 an enhancement ofMΛΛ=(2365.3±9.6) MeV/c2, ΓΛΛ=(47.2±15.1) MeV/c2 with production cross section σ=(24.2±7.0) μb per carbon nucleus was found. The mass rangeMΣ−p<MH<2MΛ was explored via the search for a weak decay modeH→Σ−+p. AV0-particle was found pointing to a two-prong interaction and satisfying the kinematics of the above two-body decay mode with a high confidence level. The possibility of imitation of the observed event by background processes was investigated for a series of two-step strong reactions and weak decays. We succeeded to show the significance of theH-production hypothesis on a deuteron-mass nuclear fluctuon via thepd→HpK+K0 reaction. The mass of the event treated as aH→Σ−+p weak decay appeared to be (2173.94±1.32) MeV/c2, its life-time being 0.668·10−10 s. Both are in agreement with predictions of the MIT Bag Model for the so-calledH-dihyperon. The formally determined production cross section of theH in proton-propane interactions at 10 GeV/c is estimated to be 40 nb. Perhaps, this event can be considered as a first evidence for a six-quark bound state-H-dihyperon. An independent way for the search for theH-particle, based on a specific conversion processHN→YYN, peculiar to its intranuclear strong interactions was proposed and tried. For this purpose all events with two Λ-hyperons and identified protons were tested for the hypothesesHp→ΛΛp at three fixed masses:MH=1880.00, 2173.94 MeV/c2 and the ΛΛ invariant mass for the event in question. The kinematics of this reaction fits successfully only one event and only atMH=2173.94 MeV/c2. It seems worthy of note that the final state ΛΛ invariant massMΛΛ=2344 MeV/c2 is rather close to the observed peak at 2365 MeV/c2. It is shown that the intranuclear conversion processes Ξ−p→ΛΛ and Ξ0n→ΛΛ fail to imitate the observed event. The ΛΛp invariant mass of this event equal to 3363 MeV/c2 is out of a 3568 MeV/c2 peak region of the ΛΛp invariant mass spectrum observed earlier. TheH conversion cross section exceeds the production one. Thus, we consider this event as providing a new evidence for the stableH-dibaryon ofMH=(2173.94±1.32) MeV/c2.
Claime of DIBARYON(S=-2) with mass M=(2365.3+-9.6) MeV and width G=(47.2+-15.1) MeV.
New data are presented on charged particle pseudorapidity distributions for inelastic events produced at c.m. energies\(\sqrt s \)=200 and 900 GeV. The data were obtained at the CERN antiproton-proton Collider operated in a new pulsed mode. The rise of the central density ρ(0) at energies up to\(\sqrt s \)=900 GeV has been studied. A new form of central region scaling is found involving the densityρn(0) for charged multiplicityn, namely that the scaled central densityρn(0)/ρ(0) expressed as a function ofz=n/〈n〉 is independent ofs. Scaling in the fragmentation region holds to 10–20%, and the small amount of scalebreaking observed here could be accommodated within the framework suggested by Wdowcyk and Wolfendale to account for both accelerator and cosmic ray data.
.
.
.
Inclusive Ξ− production in e+e− annihilation at 29 GeV has been measured with the Mark II detector. From an integrated luminosity of 207 pb−1, we determine a production rate of 0.017±0.004±0.004 Ξ−+Ξ¯+ per hadronic event. A search for Ξ*0(1530)→Ξ−π+ leads to an upper limit of N(Ξ*0)/N(Ξ−)<0.35 at a 90% confidence level.
Numerical values supplied by S. Klein.
Extrapolation over full x range using LUND Monte Carlo.
We report a measurement of the inclusive D/D̄ production cross section in 800 GeV/ c proton-proton interactions. The experiment used the high resolution bubble chamber LEBC exposed to an 800 GeV/ c proton beam at the Fermilab MPS. We obtain σ( D/ D ̄ )=59 −15 +22 μ b (statistical errors), having analysed 25% of the total data sample. Comparison with 400 GeV/ c pp dat a obtained with LEBC at CERN shows a D/D̄ cross section increase by a factor of 1.7 −0.5 +0.7 . This is in good agreement with fusion model calculations.
No description provided.
No description provided.
PAGE FROM PREPRINT.
None
Errors are statistical plus point-to-point systematics.
A forward-backward asymmetry A , consistent with that expected from the γ − Z 0 interference term in the process e + e − → q q , is observed in the laboratory production angular distribution of high-momentum ∧ baryons. The data were collected with the High Resolution Spectrometer at PEP. The asymmetry for ∧ baryons with fractional energy z= 2E s greater than 0.3 is A = (−23± 8 plusmn ; 2)%.
No description provided.
Data read from graph.
Forum