Strange particle production inp+pcollisions ats=200GeV

Abstract

We present strange particle spectra and yields measured at midrapidity in √ s = 200 GeV proton-proton (p + p) collisions at the BNL Relativistic Heavy Ion Collider (RHIC). We find that the previously observed universal transverse mass (m T ≡ p T 2 + m 2 ) scaling of hadron production in p + p collisions seems to break down at higher m T and that there is a difference in the shape of the m T spectrum between baryons and mesons. We observe midrapidity antibaryon to baryon ratios near unity for and baryons and no dependence of the ratio on transverse momentum, indicating that our data do not yet reach the quark-jet dominated region. We show the dependence of the mean transverse momentum p T on measured charged particle multiplicity and on particle mass and infer that these trends are consistent with gluon-jet dominated particle production. The data are compared with previous measurements made at the CERN Super Proton Synchrotron and Intersecting Storage Rings and in Fermilab experiments and with leading-order and next-to-leading-order string fragmentation model predictions. We infer from these comparisons that the spectral shapes and particle yields from p + p collisions at RHIC energies have large contributions from gluon jets rather than from quark jets.

Inclusiveπ0,η, and direct photon production at high transverse momentum inp+pAbelev1, Aggarwal2, Ahammed3 et al. 2010Phys. Rev. CSelf Cite393130View full textAdd to dashboardCite

“…The dashed curves in Fig. 24 show the prediction based on m T scaling [25,[59][60][61]. It is seen that the data are consistent with such scaling behavior.…”

“…The normalization is irrelevant because it cancels in the ratio γ decay /π 0 . To estimate the yields of the η and ω(782), we used the fact that these scale with the π 0 yields when expressed in terms of the transverse mass m T ≡ m 2 + p 2 T instead of p T [25,[59][60][61]. For the η spectra, we used the scaling ratios R η/π = 0.46 ± 0.05 for p + p and 0.44 ± 0.08 for d + Au data, as followed from our measurement of η production.…”

Antimatter production in proton-proton and heavy-ion collisions at ultrarelativistic energies

“…The increase of the antimatter-to-matter ratio in heavy-ion collisions with the increase of center-of-mass energy has been observed by the NA49 [38,39] and STAR [40] Collaborations. Figure 1 shows changes of the p/p ratio with collision energy at mid-rapidity in central heavy-ion and in p + p collisions.…”

Applicability of transverse mass scaling in hadronic collisions at energies available at the CERN Large Hadron Collider

“…This parameter was originally identified as the highest possible temperature for hadronic matter. Indeed, it was found that the m T spectra of different particle species (e.g., π − , K 0 , , ρ 0 , and ω) produced in hadronic collisions at center-of-mass energies of [8][9][10][11][12][13][14][15][16] GeV are reasonably well described by an exponential or Bose-Einstein distribution with the inverse slope parameter being independent of the particle mass [2,3]. Subsequently, the effect was called "m T -scaling" [4].…”