Date

Heavy Quark Production in p+p and Energy Loss and Flow of Heavy Quarks in Au+Au Collisions at sqrt(s_NN)=200 GeV

The PHENIX collaboration Adare, A. ; Afanasiev, S. ; Aidala, C. ; et al.
Phys.Rev.C 84 (2011) 044905, 2011.
Inspire Record 854475 DOI 10.17182/hepdata.142339

Transverse momentum (p^e_T) spectra of electrons from semileptonic weak decays of heavy flavor mesons in the range of 0.3 < p^e_T < 9.0 GeV/c have been measured at mid-rapidity (|eta| < 0.35) by the PHENIX experiment at the Relativistic Heavy Ion Collider in p+p and Au+Au collisions at sqrt(s_NN)=200 GeV. The nuclear modification factor R_AA with respect to p+p collisions indicates substantial energy loss of heavy quarks in the produced medium. In addition, the azimuthal anisotropy parameter v_2 has been measured for 0.3 < p^e_T < 5.0 GeV/c in Au+Au collisions. Comparisons of R_AA and v_2 are made to various model calculations.

0 data tables match query

Measurement of the anti-p p ---> anti-lambda Lambda and anti-p p ---> Antisigma0 Lambda + c.c. reactions at 1.726-GeV/c and 1.771-GeV/c

Barnes, P.D. ; Franklin, G. ; Quinn, B. ; et al.
Phys.Rev.C 54 (1996) 2831-2842, 1996.
Inspire Record 433023 DOI 10.17182/hepdata.25800

Interest in the production of hyperon-antihyperon pairs following antiproton-proton annihilation stems largely from attempts to understand the nature of flavor production. To date the major focus of both the experimental and the theoretical effort has been on the p¯p→Λ¯Λ reaction. In this paper, we present data on the complementary channels p¯p→Σ¯0Λ and p¯p→Λ¯Σ0. Events from the kinematically similar p¯p→Λ¯Λ reaction were obtained in parallel. The procedure to distinguish these three separate reactions is described and results for all channels are presented. These include the total and differential cross sections, hyperon polarizations, and spin correlation coefficients. Data were obtained at incident antiproton lab momenta of 1.726 and 1.771 GeV/c which correspond to excess kinetic energies in the p¯p→Λ¯Σ0+c.c. reaction of 26 and 40 MeV, respectively, above threshold. Comparisons are made to earlier work at similar excess energies in the p¯p→Λ¯Λ channel. The low-energy regime has been highlighted in this experiment to reduce the complexity in the theoretical analysis. © 1996 The American Physical Society.

7 data tables match query

No description provided.

Axis error includes +- 2.3/2.3 contribution.

Axis error includes +- 2.3/2.3 contribution.

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Pion Scattering From C and Ca at 800-{MeV}/$c$

Marlow, Daniel R. ; Barnes, P.D. ; Colella, N.J. ; et al.
Phys.Rev.C 30 (1984) 1662, 1984.
Inspire Record 15083 DOI 10.17182/hepdata.26285

Results from π± elastic and inelastic scattering from C12 and Ca40 are reported. The data were all taken at an incident momentum of 800 MeV/c over an angular range from 4° to 38°. The elastic data are compared to first-order optical model calculations in momentum space; qualitative agreement is obtained. The inelastic data (from C12 only) are compared to distorted-wave Born approximation calculations, and reasonable agreement is found if realistic inelastic transition densities are used.

8 data tables match query

No description provided.

THE C12* NUCLEUS IS IN THE STATE 2+ (4.4 MEV).

THE C12* NUCLEUS IS IN THE STATE 3- (9.6 MEV).

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KAON SCATTERING FROM C AND CA AT 800-MEV/C

Marlow, Daniel R. ; Barnes, P.D. ; Colella, N.J. ; et al.
Phys.Rev.C 25 (1982) 2619-2637, 1982.
Inspire Record 180999 DOI 10.17182/hepdata.26337

Results from K± elastic and inelastic scattering from C12 and Ca40 are reported. The data were all taken at an incident momentum of 800 MeV/c over an angular range from 2° to 38°. The elastic data are compared to first-order optical model calculations in coordinate and momentum space; good qualitative agreement is obtained. The inelastic data (from C12 only) are compared to distorted-wave Born approximation calculations, and good agreement is found if "realistic" inelastic transition densities are used. Although a first-order optical potential description does not describe the data fully, there are strong indications of the increased penetrability of K+ over K− in this energy range. NUCLEAR REACTIONS C12(K±,K±)C12, Ca40(K±,K±)Ca40, E=442 MeV (800 MeV/c), measured σ(θ) for elastic and inelastic scattering, compared to optical model and DWBA calculations, deduced optical potential parameters; θ=2°−38°, Δθ=1°.

4 data tables match query

X ERROR D(THETA) = 1.0100 DEG.

X ERROR D(THETA) = 1.0100 DEG.

X ERROR D(THETA) = 1.1000 DEG.

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Measurement of the anti-p p --> K(S) K(S) eta cross section at beam momenta in the regions of 1.45-GeV/c and 1.7-GeV/c.

Barnes, P.D. ; Bunker, B. ; Dennert, H. ; et al.
Phys.Lett.B 516 (2001) 257-263, 2001.
Inspire Record 559482 DOI 10.17182/hepdata.41678

The PS185 experiment at LEAR/CERN has investigated strangeness production in antiproton-proton collisions with final states such as $\overline{\Lambda} \Lambda$, $\overline{\Sigma}^0 \Lambda + c.c$, $\overline{\Sigma^+} \Sigma^+$, $\overline{\Sigma^-} \Sigma^-$ and $K_S K_S$. Results are presented from a study of about 32,000 {$K_S K_S X$} events obtained at several antiproton momenta in the regions of 1.45 and 1.7 GeV/c. The $\overline{p} p \to K_S K_S \eta$ cross sections extracted at these momenta constitute the first measurement of this reaction in flight and are broadly consistent with expectations of a phase-space extrapolation of branching ratios from annihilation at rest.

1 data table match query

No description provided.


Study of the reaction anti-p p ---> anti-Lambda Lambda at 1.546-GeV/c and 1.695-GeV/c

Barnes, P.D. ; Diebold, G. ; Franklin, G. ; et al.
Nucl.Phys.A 526 (1991) 575-601, 1991.
Inspire Record 301648 DOI 10.17182/hepdata.36756

The PS185 experiment at the CERN Low Energy Antiproton Ring (LEAR) has studied the reaction p ̄ p → \ ̄ gLΛ at several momenta. In this paper results from two runs with high statistics at 1.546 GeV/ c and 1.695 GeV/ c are described. Based on 4063 and 11362 analysed events, respectively, differential and integrated cross sections, polarizations and spin correlations are presented. The singlet fraction, extracted from the spin correlations, is consistent with zero at both momenta, showing that the \ ̄ gLΛ pairs are produced in a pure triplet state. A comparison of the decay asymmetry parameters of Λ and \ ̄ gL reduces the upper limits for the violation of the CP invariance for this system.

10 data tables match query

No description provided.

THE BESTFIT WITH LMAX=3, HI2=1.204.

THE BESTFIT WITH LMAX=6, HI2=0.547.

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Mid-rapidity neutral pion production in proton proton collisions at s**(1/2) = 200-GeV

The PHENIX collaboration Adler, S.S. ; Afanasiev, S. ; Aidala, C. ; et al.
Phys.Rev.Lett. 91 (2003) 241803, 2003.
Inspire Record 617784 DOI 10.17182/hepdata.41956

The invariant differential cross section for inclusive neutral pion production in p+p collisions at sqrt(s_NN) = 200 GeV has been measured at mid-rapidity |eta| < 0.35 over the range 1 < p_T <~ 14 GeV/c by the PHENIX experiment at RHIC. Predictions of next-to-leading order perturbative QCD calculations are consistent with these measurements. The precision of our result is sufficient to differentiate between prevailing gluon-to-pion fragmentation functions.

1 data table match query

The invariant differential cross section as a function of PT. The mean PT here is defined as the PT for which the cross section equals its average over thebin.


Measurement of the mid-rapidity transverse energy distribution from s(N N)**(1/2) = 130-GeV Au + Au collisions at RHIC.

The PHENIX collaboration Adcox, K. ; Adler, S.S. ; Ajitanand, N.N. ; et al.
Phys.Rev.Lett. 87 (2001) 052301, 2001.
Inspire Record 555603 DOI 10.17182/hepdata.31419

The first measurement of energy produced transverse to the beam direction at RHIC is presented. The mid-rapidity transverse energy density per participating nucleon rises steadily with the number of participants, closely paralleling the rise in charged-particle density, such that E_T / N_ch remains relatively constant as a function of centrality. The energy density calculated via Bjorken's prescription for the 2% most central Au+Au collisions at sqrt(s_NN)=130 GeV is at least epsilon_Bj = 4.6 GeV/fm^3 which is a factor of 1.6 larger than found at sqrt(s_NN)=17.2 GeV (Pb+Pb at CERN).

1 data table match query

130 GeV is sqrt(S) per nucleon-nucleon collision. The statistical errors are negligible and only systematic errors are quoted. COL(NAME=CENTRALITY) is centrality.


Search for double-Lambda hypernuclei and the H dibaryon in the (K-,K+) reaction on C-12.

The E885 collaboration Yamamoto, K. ; Alburger, D.E. ; Barnes, P.D. ; et al.
Phys.Lett.B 478 (2000) 401-407, 2000.
Inspire Record 528779 DOI 10.17182/hepdata.28030

A search for double- Λ hypernuclei ( 12 ΛΛ Be) and H -dibaryons using the 12 C( K − , K + ) reaction was performed at the BNL-AGS using a high-intensity 1.8 GeV/ c K − beam. A missing-mass analysis below the end point of the quasi-free Ξ − production was used to investigate these S =−2 systems. The upper limit obtained for the forward-angle cross section of 12 ΛΛ Be production is 6 to 10 nb/sr. This is the first search for the direct production of double- Λ hypernuclei to reach the sensitivity required to observe the signal predicted by theoretical calculations. For the H -production cross section, we have obtained an upper limit in the range of a few nb/sr to 10 nb/sr for the H mass below 2100 MeV/ c 2 . This upper limit is the most sensitive H search result to date for a tightly bound H .

2 data tables match query

Upper limit is given.

The production of the H-dibaryon could occur via the (K-, K+) reaction on two protons in a nucleus: K- (PP) --> K+ H-dibaryon. Upper limit is given.


Study of the reaction anti-p p ---> Anti-lambda Lambda below 6-MeV excess energy

Barnes, P.D. ; Birien, P. ; Breunlich, W.H. ; et al.
Phys.Lett.B 331 (1994) 203-210, 1994.
Inspire Record 382628 DOI 10.17182/hepdata.28665

The reaction p p → Λ Λ → p π + pπ − is studied in the experiment PS185 at the CERN Low Energy Antiproton Ring (LEAR). A precise measurement of the excitation function in the immediate threshold region below 6 MeV excess energy was achieved. The total cross section shows an unexpected behaviour around 1 MeV excess energy.

2 data tables match query

The values are calculated using M(p)=M(pbar) = 938.27231 Mev and M(lambda)=M(lambdabar) = 1115.63 MeV.

D(SIG)/D(OMEGA) as a function of COS(THETA(RF=CM)) for the nine intervals of the excess energy. Excess energy is SQRT(S)-M(lambda)-M(lambdabar).