Forward and midrapidity like-particle ratios from p + p collisions at √s = 200 GeV

I. G. Bearden, D. Beavis, C. Besliu, B. Budick, H. Bøggild, C. Chasman, C. H. Christensen, P. Christiansen, J. Cibor, R. Debbe, E. Enger, J. J. Gaardhøje, M. Germinario, K. Hagel, A. Holm, A. K. Holme, H. Ito, E. Jakobsen, A. Jipa, F. JundtJ. I. Jørdre, C. E. Jørgensen, R. Karabowicz, T. Keutgen, E. J. Kim, T. Kozik, T. M. Larsen, J. H. Lee, Y. K. Lee, G. Løvhøiden, Z. Majka, A. Makeev, M. Mikelsen, M. J. Murray, J. Natowitz, B. S. Nielsen, J. Norris, K. Olchanski, D. Ouerdane, R. Płaneta, F. Rami, C. Ristea, D. Röhrich, B. H. Samset, D. Sandberg, S. J. Sanders, R. A. Scheetz, P. Staszel, T. S. Tveter, F. Videbæk, R. Wada, A. Wieloch, Z. Yin, I. S. Zgura

    Research output: Contribution to journalArticlepeer-review


    We present a measurement of π-/π+, K-/K+ and p̄/p from p+p collisions at s=200 GeV over the rapidity range 0<y<3.4. For pT<2.0 GeV/c we see no significant transverse momentum dependence of the ratios. All three ratios are independent of rapidity for y≲1.5 and then steadily decline from y∼1.5 to y∼3. The π-/π+ ratio is below unity for y>2.0. The p̄/p ratio is very similar for p+p and 20% central Au + Au collisions at all rapidities. In the fragmentation region the three ratios seem to be independent of beam energy when viewed from the rest frame of one of the protons. Theoretical models based on quark-diquark breaking mechanisms overestimate the p̄/p ratio up to y≲3. Including additional mechanisms for baryon number transport such as baryon junctions leads to a better description of the data.

    Original languageEnglish (US)
    Pages (from-to)42-50
    Number of pages9
    JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
    Issue number1-2
    StatePublished - Feb 3 2005


    • Baryon junctions
    • Forward rapidity
    • Limiting fragmentation
    • Particle ratios
    • Proton collisions

    ASJC Scopus subject areas

    • Nuclear and High Energy Physics


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