The ratios of yields of anti-baryons to baryons probes the mechanisms of baryon-number transport. Results for $\bar{\rm p}/{\rm p}$, $\bar{\rm \Lambda}/{\rm \Lambda}$, $\rm\bar{\Xi}$$^{+}/{\rm \Xi}^{-}$ and $\rm\bar{\Omega}$$^{+}/{\rm \Omega}^{-}$ in pp collisions at $\sqrt{s} = 0.9$, 2.76 and 7 TeV, measured with the ALICE detector at the LHC, are reported. Within the experimental uncertainties and ranges covered by our measurement, these ratios are independent of rapidity, transverse momentum and multiplicity for all measured energies. The results are compared to expectations from event generators, such as PYTHIA and HIJING-B, that are used to model the particle production in pp collisions. The energy dependence of $\bar{\rm p}/{\rm p}$, $\bar{\rm \Lambda}/{\rm \Lambda}$, $\rm\bar{\Xi}$$^{+}/{\rm \Xi^{-}}$ and $\rm\bar{\Omega}$$^{+}/{\rm \Omega^{-}}$, reaching values compatible with unity for $\sqrt{s} = 7$ TeV, complement the earlier $\bar{\rm p}/{\rm p}$ measurement of ALICE. These dependencies can be described by exchanges with the Regge-trajectory intercept of $\alpha_{\rm {J}} \approx 0.5$, which are suppressed with increasing rapidity interval ${\rm \Delta} y$. Any significant contribution of an exchange not suppressed at large ${\rm \Delta} y$ (reached at LHC energies) is disfavoured.
The pbar/p ratio at sqrt(s) = 2.76 TeV as a function of pT.
The pbar/p ratio at sqrt(s) = 2.76 TeV as a function of rapidity.
The LambdaBar/Lambda ratio at sqrt(s) = 0.9 TeV as a function of pT.
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THE MOMENTUM OF EACH INCIDENT PION WAS DETERMINED WITH AN ACCURACY 0.2 PCT.
THE MOMENTUM OF EACH INCIDENT PION WAS DETERMINED WITH AN ACCURACY 0.2 PCT.
THE MOMENTUM OF EACH INCIDENT PION WAS DETERMINED WITH AN ACCURACY 0.2 PCT.
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NUCLEUS IS P, C, AL.
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CHARGED IS CUMULATIVE PI+-, OR K+-, OR P+-.
CHARGED IS CUMULATIVE PI+-, OR K+-, OR P+-.
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A search for baryonia with negative and positive strangeness decaying respectively into\(\Lambda+ \bar p + pions\) and\(\bar \Lambda+ p + pions\) has been carried out in a neutron beam with a mean momentum of ≅40 GeV/c in an experiment performed at the Serpukhov accelerator. There is a strong indication of the existence of these baryonia. The following four charge states are observed for negative and positive strangeness: neutral, negative, positive and doubly charged. Their mean mass is 3055±25 MeV/c2 and the width Γ≦36±15 MeV/c2. The data show that the isotopic spin of the baryonia is ≧3/2. The baryonia production cross sections in the acceptable kinematic regionXF≧0.2 andPT≦1 GeV/c times the branching ratios of the observed decays are of the order of 1 μb per nucleon.
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AVERAGE OVER ALL TARGETS.
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