Based on the experience from the production of anti-Lambda Lambda and
anti-Sigma Sigma pairs at LEAR (experiment PS185) it is suggested to continue
the investigations towards the heavier antihyperon--hyperon pairs anti-Xi Xi
and anti-Omega Omega in view of: (1) the production dynamics of the heavier
antihyperon--hyperon out of the anti-p p annihilation (2) a comparison of the
(3s 3anti-s quark system) anti-Omega Omega to the (3 (anti-s s)) 3 phi meson
production, where both systems have similar masses (3.345 and 3.057,
respectively) and identical valence quark content. A systematic study of the
antihyperon--hyperon production with increasing strangeness content is
interesting for the following reasons: The anti-Omega Omega production is the
creation of two spin 3/2 objects out of the two spin 1/2 anti-p p particles.
Results of the PS185 experiments prove a clear dominance of the spin triplet
anti-s s dissociation. In the Omega anti-Omega the three s-quarks (three anti-s
quarks) are aligned to spin 3/2 each. If the three anti-s s pairs are now all
in spin triplet configurations when created out of the gluonic interaction they
should have spin parity quantum number as 3^- as long as Omega anti-Omega is
created with relative L=0 angular momentum. The comparison of the Omega
anti-Omega baryon pair to the phi phi phi three meson production (where the
three anti-s s quark pairs might not but can be produced without relative
correlation) would provide a unique determination of the intermediate matter
state. Measurements of excitation functions and polarization transfers should
be used to examine these gluon rich anti-p p --> anti-Omega Omega and anti-p p
--> phi phi phi reaction channels. Such experiments should be performed at the
PANDA detector at the FAIR facility of the GSI.Comment: 4 pages, 2 figures, Presented at LEAP05: International Conference on
  Low Energy Antiproton Physics, Bonn - Juelich, Germany, May 16-22, 200

Grzonka, D.

Jarczyk, L.

Kilian, K.

Moskal, P.

Oelert, W.

Winter, P.

English

arXiv

W. Oelert

Crossref

Heavy Hyperon-Antihyperon Production

Based on the experience from the production of anti-Lambda Lambda and anti-Sigma Sigma pairs at LEAR (experiment PS185) it is suggested to continue the investigations towards the heavier antihyperon--hyperon pairs anti-Xi Xi and anti-Omega Omega in view of: (1) the production dynamics of the heavier antihyperon--hyperon out of the anti-p p annihilation (2) a comparison of the (3s 3anti-s quark system) anti-Omega Omega to the (3 (anti-s s)) 3 phi meson production, where both systems have similar masses (3.345 and 3.057, respectively) and identical valence quark content. A systematic study of the antihyperon--hyperon production with increasing strangeness content is interesting for the following reasons: The anti-Omega Omega production is the creation of two spin 3/2 objects out of the two spin 1/2 anti-p p particles. Results of the PS185 experiments prove a clear dominance of the spin triplet anti-s s dissociation. In the Omega anti-Omega the three s-quarks (three anti-s quarks) are aligned to spin 3/2 each. If the three anti-s s pairs are now all in spin triplet configurations when created out of the gluonic interaction they should have spin parity quantum number as 3^- as long as Omega anti-Omega is created with relative L=0 angular momentum. The comparison of the Omega anti-Omega baryon pair to the phi phi phi three meson production (where the three anti-s s quark pairs might not but can be produced without relative correlation) would provide a unique determination of the intermediate matter state. Measurements of excitation functions and polarization transfers should be used to examine these gluon rich anti-p p --> anti-Omega Omega and anti-p p --> phi phi phi reaction channels. Such experiments should be performed at the PANDA detector at the FAIR facility of the GSI.Based on the experience from the production of anti-Lambda Lambda and anti-Sigma Sigma pairs at LEAR (experiment PS185) it is suggested to continue the investigations towards the heavier antihyperon--hyperon pairs anti-Xi Xi and anti-Omega Omega in view of: (1) the production dynamics of the heavier antihyperon--hyperon out of the anti-p p annihilation (2) a comparison of the (3s 3anti-s quark system) anti-Omega Omega to the (3 (anti-s s)) 3 phi meson production, where both systems have similar masses (3.345 and 3.057, respectively) and identical valence quark content. A systematic study of the antihyperon--hyperon production with increasing strangeness content is interesting for the following reasons: The anti-Omega Omega production is the creation of two spin 3/2 objects out of the two spin 1/2 anti-p p particles. Results of the PS185 experiments prove a clear dominance of the spin triplet anti-s s dissociation. In the Omega anti-Omega the three s-quarks (three anti-s quarks) are aligned to spin 3/2 each. If the three anti-s s pairs are now all in spin triplet configurations when created out of the gluonic interaction they should have spin parity quantum number as 3^- as long as Omega anti-Omega is created with relative L=0 angular momentum. The comparison of the Omega anti-Omega baryon pair to the phi phi phi three meson production (where the three anti-s s quark pairs might not but can be produced without relative correlation) would provide a unique determination of the intermediate matter state. Measurements of excitation functions and polarization transfers should be used to examine these gluon rich anti-p p --> anti-Omega Omega and anti-p p --> phi phi phi reaction channels. Such experiments should be performed at the PANDA detector at the FAIR facility of the GSI.Based on the experience from the production of anti-Lambda Lambda and anti-Sigma Sigma pairs at LEAR (experiment PS185) it is suggested to continue the investigations towards the heavier antihyperon--hyperon pairs anti-Xi Xi and anti-Omega Omega in view of: (1) the production dynamics of the heavier antihyperon--hyperon out of the anti-p p annihilation (2) a comparison of the (3s 3anti-s quark system) anti-Omega Omega to the (3 (anti-s s)) 3 phi meson production, where both systems have similar masses (3.345 and 3.057, respectively) and identical valence quark content. A systematic study of the antihyperon--hyperon production with increasing strangeness content is interesting for the following reasons: The anti-Omega Omega production is the creation of two spin 3/2 objects out of the two spin 1/2 anti-p p particles. Results of the PS185 experiments prove a clear dominance of the spin triplet anti-s s dissociation. In the Omega anti-Omega the three s-quarks (three anti-s quarks) are aligned to spin 3/2 each. If the three anti-s s pairs are now all in spin triplet configurations when created out of the gluonic interaction they should have spin parity quantum number as 3^- as long as Omega anti-Omega is created with relative L=0 angular momentum. The comparison of the Omega anti-Omega baryon pair to the phi phi phi three meson production (where the three anti-s s quark pairs might not but can be produced without relative correlation) would provide a unique determination of the intermediate matter state. Measurements of excitation functions and polarization transfers should be used to examine these gluon rich anti-p p --> anti-Omega Omega and anti-p p --> phi phi phi reaction channels. Such experiments should be performed at the PANDA detector at the FAIR facility of the GSI.Such experiments should be performed at the PANDA detector at the FAIR facility of the GSI

Jarczyk, Lucjan

CERN Document Server

Juelich Shared Electronic Resources

Based on the experience from the production of anti-Lambda Lambda and anti-Sigma Sigma pairs at LEAR (experiment PS185) it is suggested to continue the investigations towards the heavier antihyperon--hyperon pairs anti-Xi Xi and anti-Omega Omega in view of: (1) the production dynamics of the heavier antihyperon--hyperon out of the anti-p p annihilation (2) a comparison of the (3s 3anti-s quark system) anti-Omega Omega to the (3 (anti-s s)) 3 phi meson production, where both systems have similar masses (3.345 and 3.057, respectively) and identical valence quark content. A systematic study of the antihyperon--hyperon production with increasing strangeness content is interesting for the following reasons: The anti-Omega Omega production is the creation of two spin 3/2 objects out of the two spin 1/2 anti-p p particles. Results of the PS185 experiments prove a clear dominance of the spin triplet anti-s s dissociation. In the Omega anti-Omega the three s-quarks (three anti-s quarks) are aligned to spin 3/2 each. If the three anti-s s pairs are now all in spin triplet configurations when created out of the gluonic interaction they should have spin parity quantum number as 3^- as long as Omega anti-Omega is created with relative L=0 angular momentum. The comparison of the Omega anti-Omega baryon pair to the phi phi phi three meson production (where the three anti-s s quark pairs might not but can be produced without relative correlation) would provide a unique determination of the intermediate matter state. Measurements of excitation functions and polarization transfers should be used to examine these gluon rich anti-p p --> anti-Omega Omega and anti-p p --> phi phi phi reaction channels. Such experiments should be performed at the PANDA detector at the FAIR facility of the GSI

arXiv:hep-ex/0508006v1  1 Aug 2005Heavy Hyperon–Antihyperon ProductionW. Oelert∗, D. Grzonka∗, L. Jarczyk†, K. Kilian∗, P. Moskal† and P. Winter∗∗IKP – Research Centre Jülich, D–52425 Jülich, Germany†Institute of Physics, Jagellonian University, PL–30–059 Cracow, PolandAbstract. Based on the experience from the production of light antihyperon–hyperon ( ¯ΛΛ, ¯ΣΣ)pairs at LEAR (experiment PS185) it is suggested to continue the investigations towards the heavierantihyperon–hyperon pairs ¯ΞΞ and ¯ΩΩ in view of:1. the production dynamics of the heavier antihyperon–hyperon out of the p¯p annihilation2. a comparison of the ”(3 s) (3 s¯)”– quark system ¯ΩΩto the 3 (s¯s) = 3 φ meson production,where both systems the ¯ΩΩ and the 3 φ have similar masses(3.345 and 3.057, respectively) and identical valence quark content.A systematic study of the antihyperon–hyperon production with increasing strangeness content isinteresting for the following reasons: The ¯ΩΩ production is the creation of two spin 3/2 objectsout of the two spin 1/2 p¯p particles. Results of the PS185 experiments prove a clear dominanceof the spin triplet s¯s dissociation. In the Ω( ¯Ω) the three s-quarks (three s¯-quarks) are aligned tospin 3/2 each. If the three s¯s pairs are now all in spin triplet configurations when created out of thegluonic interaction they should have spin parity quantum number as 3− as long as Ω ¯Ω is createdwith relative L = 0 angular momentum.The comparison of the Ω ¯Ω baryon pair to the φφφ three meson production (where the three s¯squark pairs might not but can be produced without relative correlation) would provide a uniquedetermination of the intermediate matter state.Measurements of excitation functions and polarization transfers should be used to examine thesegluon rich p¯p→ ¯ΩΩ and p¯p→ φφφ reaction channels.Such experiments should be performed at the PANDA detector at the FAIR facility of the GSI.INTRODUCTIONInterest for studying the production of hyperon–antihyperon pairs following antiproton–proton annihilations is based largely on the aim to understand the nature of flavourproduction and its dynamics. There is a large amount of data from the PS185 [1]collaboration as reported during the LEAP-05 conference by T. Johansson [2] andJ.M. Richard [3]. The goal of those PS185 experiments is to establish the definitivep¯p→ ¯YY data set in the low–energy regime. From the theoretical analysis of the data,one hopes to gain insight into the behaviour of hadron interactions at intermediateenergies, i.e. in an energy regime where perturbative QCD is inappropriate and bothquark–gluon and meson degrees of freedom are believed to be important.Heavy hyperon–antihyperon production studies are relevant since i) rather little isknown about heavy flavour hyperons, even down to the final proof of their existence;ii) different hyperon–antihyperon pairs are produced in distinct but specific hadronicenvironments; iii) threshold production studies keep the interpretation as simple aspossible and iv) quark dynamic effects can be observed. The special interest for theinvestigation of ¯ΩΩ production will be discussed in this contribution.RESULTS FROM THE PS185 EXPERIMENTResults of the PS185–collaboration studies – as far as relevant for the recent discussion –are shown in figure 1 (left) and (right), demonstrating that the differential cross sectionsfor the hyperon–antihyperon pair production following the p¯p annihilation feature theonset of higher partial waves already at very low excess energies and that the singletfraction for the p¯p→ ¯ΛΛ reaction is largely consistent with zero, respectively.101001000-1.4 -1.2 -1 -0.8 -0.6 -0.4 -0.2 0  14 MeV  25 MeV  39 MeV  73 MeV  92 MeV118 MeV141 MeV170 MeV196 MeV       t’ [(Gev/c) 2]cos θ cm  > -.8dσ/dt’ [µ b / (GeV/c)   ]2p p       Λ  Λ-0,500,511,50 50 100 150 200Singlet FractionExcess energy [MeV]S = 0S = 1pp    Λ  Λ  FIGURE 1. Left: PS185 results of differential cross sections at various energies, shown as a function ofmomentum transfer. Right: PS185 results of the singlet fractions for the reaction: p¯p→ ¯ΛΛ at variousenergies, shown as a function of the excess energyFROM LIGHT TO HEAVY HYPERONSBased on the experimental and theoretical experience from the production of lightantihyperon–hyperon pairs at LEAR it is suggested to measure the production of bothheavy antihyperon–hyperon pairs and the three φ -meson system at the future facilityFAIR at GSI. The foreseen momentum range [4] of the p¯–beam at the HESR/FAIRallows to study hyperons with one, two and three valence s-quarks or one valence c-quark up to the Ξc with its mass of M = 2.47 GeV/c2 in the p¯p interaction, see table 1.The common special feature of the hyperons is their weak (flavour changing) decaywith cτ values of a few centimeters, as presented in table 2. Typical decay schemesof the lighter hyperons might be represented in two categories. The charged hyperons(antihyperons) decay mainly (see figure 2) delayed into a charged meson and a Λ ( ¯Λ)which then decays to the two charged particles pi− and p (pi+ and p¯). The neutralhyperons (antihyperons) decay via Λ+pi0 ( ¯Λ+pi0) into the two charged particle systemTABLE 1. Relevant parameters for the production of hyperons in p¯p annihilationHyperon Mass(MeV/c2)√s(MeV)BeamMomentum(GeV/c)Λ 1115.57± 0.06 2231.14 1.435Σ+ 1189.37± 0.06 2378.74 1.854Σ0 1192.55± 0.10 2385.1 1.871Σ− 1197.50± 0.05 2395.0 1.900Ξ0 1314.80± 0.8 2629.60 2.582Ξ− 1321.34± 0.14 2642.68 2.621Ω− 1672.43± 0.14 3344.86 4.936Λ+c 2285.2 ± 1.2 4570.4 10.150Σ0c 2452.7 ± 1.3 4905.4 11.848Σ++c 2453.0 ± 1.2 4906.0 11.851Σ+c 2453.2 ± 1.2 4906.4 11.853Ξ+c 2466.5 ± 2.5 4933.0 11.993Ξ0c 2473.1 ± 2.0 4945.2 12.063Ω0c 2740. ± 2.0 5480. 15.1pi− and p (pi+ and p¯) and γ–quanta. The rather simple decay features allow an effectiveneutral or charge-multiplicity–step trigger. It is understood, however, that the hyperonswith quarks heavier than the strange quark do not have a unique decay scheme any moreand the restriction to particular decay channels seems to be appropriate.p100 %  x (64 %) 68 %  x (64 %)FIGURE 2. Decay scheme of the two hyperons Ξ0 and Ω−THE SYSTEM: 3 ×S AND 3 × ¯S QUARKSA systematic study of antihyperon-hyperon production with increasing strangeness(charm) content is certainly interesting due to the change of the quark dynamics in thedifferent flavour environment of hadronic matter.Besides the general interest of this research the production of the six–quark systemwith three s–quarks and three s¯–quarks in the final state (i.e. the observation of the¯ΩΩ baryon pair and the φφφ three meson system) should be stressed. The angulardistribution of ¯Ω (or Ω) would be symmetric to 900 c.m. if the intermediate state isa compound like system state of gluonic matter with definite quantum numbers. If,TABLE 2. Some properties of hyperons [5]Hyperon Quark-content I JpiMass(MeV/c2)Mean life(s ×10−13)cτ(cm) αMainΛ uds 0 12+ 1115.57± 0.06 2632 ± 20 7.89 + 0.642± 0.013Σ+ uus 1 12+ 1189.37± 0.06 799 ± 4 2.40 - 0.980± 0.015Σ0 uds 1 12+ 1192.55± 0.10 7.4 ×10 −7Σ− dds 1 12+ 1197.50± 0.05 1479 ± 11 4.40 - 0.068± 0.008Ξ0 uss 1212+ 1314.80± 0.8 2900 ± 90 8.69 - 0.411± 0.022Ξ− dss 1212+ 1321.34± 0.14 1639 ± 15 4.91 - 0.456± 0.014Ω− sss 0 32+ 1672.43± 0.14 822 ± 12 2.46 - 0.026± 0.026Λ+c udc 0 12+ 2285.2 ± 1.2 1.91 ±0.15 0.006Σ0c ddc 1 12+ 2452.7 ± 1.3Σ++c uuc 1 12+ 2453.0 ± 1.2Σ+c udc 1 12+ 2453.2 ± 1.2Ξ+c usc 1212+(?) 2466.5 ± 2.5 3.0 ± 1.0 0.009Ξ0c dsc 1212+(?) 2473.1 ± 2.0 0.82 ± 0.6 0.002Ω0c ssc 1212+(?) 2740. ± 2.0however, other production mechanisms as boson exchange probabilities are relevant,the symmetry via a pure intermediate gluonic matter state will be broken. It would be aninteresting and important result to see whether there is a correlation between the initialp¯ (p) and the final ¯ΩΩ.Since the asymmetry parameter α of the Ω decay is very small (see table 2), its po-larization features cannot be measured via the weak decay directly. The determinationof the polarization of the weakly decaying daughter hyperons allows to extract spinobservables for the Ω particle.A distinct feature of the ¯ΩΩ production is the creation of two spin 3/2 objects out ofthe p¯p interaction. Results from the PS185 experiment proove a clear dominance of thetriplet s¯s production at threshold. Since in the ¯Ω(Ω) the three s–quarks (s¯–quarks) areoriented parallel, the three s¯s pairs created out of the gluonic intermediate state shouldhave spin quantum number as 3− if the ¯Ω(Ω) is created with relative L = 0 angularmomentum.The comparison of the ¯Ω(Ω) baryon pair to the φφφ three meson production (wherethe three IG (JPC) = 0− (1−−) s¯s mesons may not but can be produced with norelative correlation) would give valuable information for a unique determination of theintermediate matter state.REFERENCES1. B. Bassalleck et al., Phys. Rev. Lett. 89 (2002) 212302 and references therein.2. T. Johansson, see contribution to the LEAP-05 conference in these proceedings.3. J.M. Richard, see contribution to the LEAP-05 conference in these proceedings.4. C. Schwarz et al., Physica Scripta T104 (2003) 147,see also http://www.gsi.de/fair/index.html.5. S. Eidelman et al., Phys. Lett. B 592 (2004) 1.

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