Version 2
Global polarization measurement in Au+Au collisions

The STAR collaboration Abelev, B.I. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.C 76 (2007) 024915, 2007.
Inspire Record 750410 DOI 10.17182/hepdata.98581

The system created in non-central relativistic nucleus-nucleus collisions possesses large orbital angular momentum. Due to spin-orbit coupling, particles produced in such a system could become globally polarized along the direction of the system angular momentum. We present the results of Lambda and anti-Lambda hyperon global polarization measurements in Au+Au collisions at sqrt{s_NN}=62.4 GeV and 200 GeV performed with the STAR detector at RHIC. The observed global polarization of Lambda and anti-Lambda hyperons in the STAR acceptance is consistent with zero within the precision of the measurements. The obtained upper limit, |P_{Lambda,anti-Lambda}| <= 0.02, is compared to the theoretical values discussed recently in the literature.

0 data tables match query

Version 2
Long range rapidity correlations and jet production in high energy nuclear collisions

The STAR collaboration Abelev, B.I. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.C 80 (2009) 064912, 2009.
Inspire Record 830070 DOI 10.17182/hepdata.101345

The STAR Collaboration at RHIC presents a systematic study of high transverse momentum charged di-hadron correlations at small azimuthal pair separation \dphino, in d+Au and central Au+Au collisions at $\rts = 200$ GeV. Significant correlated yield for pairs with large longitudinal separation \deta is observed in central Au+Au, in contrast to d+Au collisions. The associated yield distribution in \detano$\times$\dphi can be decomposed into a narrow jet-like peak at small angular separation which has a similar shape to that found in d+Au collisions, and a component which is narrow in \dphi and \textcolor{black}{depends only weakly on} $\deta$, the 'ridge'. Using two systematically independent analyses, \textcolor{black}{finite ridge yield} is found to persist for trigger $\pt > 6$ \GeVc, indicating that it is correlated with jet production. The transverse momentum spectrum of hadrons comprising the ridge is found to be similar to that of bulk particle production in the measured range ($2 < \pt < 4 \GeVc$).

0 data tables match query

J / psi production from proton proton collisions at s**(1/2) = 200-GeV

The PHENIX collaboration Adler, S.S. ; Afanasiev, S. ; Aidala, C. ; et al.
Phys.Rev.Lett. 92 (2004) 051802, 2004.
Inspire Record 623000 DOI 10.17182/hepdata.57093

J/psi production has been measured in proton-proton collisions at sqrt(s)= 200 GeV over a wide rapidity and transverse momentum range by the PHENIX experiment at RHIC. Distributions of the rapidity and transverse momentum, along with measurements of the mean transverse momentum and total production cross section are presented and compared to available theoretical calculations. The total J/psi cross section is 3.99 +/- 0.61(stat) +/- 0.58(sys) +/- 0.40(abs) micro barns. The mean transverse momentum is 1.80 +/- 0.23(stat) +/- 0.16(sys) GeV/c.

0 data tables match query

Scaling Properties of Hyperon Production in Au+Au Collisions at sqrt(s_NN) = 200 GeV

The STAR collaboration Adams, J. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.Lett. 98 (2007) 062301, 2007.
Inspire Record 718755 DOI 10.17182/hepdata.98928

We present the scaling properties of Lambda, Xi, Omega and their anti-particles produced at mid-rapidity in Au+Au collisions at RHIC at sqrt(s_NN) = 200 GeV. The yield of multi-strange baryons per participant nucleon increases from peripheral to central collisions more rapidly than the Lambda yield, which appears to correspond to an increasing strange quark density of matter produced. The value of the strange phase space occupancy factor gamma_s, obtained from a thermal model fit to the data, approaches unity for the most central collisions. We also show that the nuclear modification factors, R_CP, of Lambda and Xi are consistent with each other and with that of protons in the transverse momentum range 2.0 < p_T < 5.0 GeV/c. This scaling behaviour is consistent with a scenario of hadron formation from constituent quark degrees of freedom through quark recombination or coalescence.

0 data tables match query

Observation of pi^+pi^-pi^+pi^- Photoproduction in Ultra-Peripheral Heavy Ion Collisions at STAR

The STAR collaboration Abelev, B.I. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.C 81 (2010) 044901, 2010.
Inspire Record 838875 DOI 10.17182/hepdata.98963

We present a measurement of pi^+pi^-pi^+pi^- photonuclear production in ultra-peripheral Au-Au collisions at sqrt(s_{NN}) = 200 GeV from the STAR experiment. The pi^+pi^-pi^+pi^- final states are observed at low transverse momentum and are accompanied by mutual nuclear excitation of the beam particles. The strong enhancement of the production cross section at low transverse momentum is consistent with coherent photoproduction. The pi^+pi^-pi^+pi^- invariant mass spectrum of the coherent events exhibits a broad peak around 1540 pm 40 MeV/c^2 with a width of 570 pm 60 MeV/c^2, in agreement with the photoproduction data for the rho^0(1700). We do not observe a corresponding peak in the pi^+pi^- final state and measure an upper limit for the ratio of the branching fractions of the rho^0(1700) to pi^+pi^- and pi^+pi^-pi^+pi^- of 2.5 % at 90 % confidence level. The ratio of rho^0(1700) and rho^0(770) coherent production cross sections is measured to be 13.4 pm 0.8 (stat.) pm 4.4 (syst.) %.

0 data tables match query

Production of light-flavor hadrons in pp collisions at $\sqrt{s}$ = 7 and $\sqrt{s}$ = 13 TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adler, Alexander ; et al.
Eur.Phys.J.C 81 (2021) 256, 2021.
Inspire Record 1797443 DOI 10.17182/hepdata.100303

The production of $\pi^{\pm}$, $\rm{K}^{\pm}$, $\rm{K}^{0}_{S}$, $\rm{K}^{*}(892)^{0}$, $\rm{p}$, $\phi(1020)$, $\Lambda$, $\Xi^{-}$, $\Omega^{-}$, and their antiparticles was measured in inelastic proton-proton (pp) collisions at a center-of-mass energy of $\sqrt{s}$ = 13 TeV at midrapidity ($|y|<0.5$) as a function of transverse momentum ($p_{\rm{T}}$) using the ALICE detector at the CERN LHC. Furthermore, the single-particle $p_{\rm{T}}$ distributions of $\rm{K}^{0}_{S}$, $\Lambda$, and $\overline{\Lambda}$ in inelastic pp collisions at $\sqrt{s}$ = 7 TeV are reported here for the first time. The $p_{\rm{T}}$ distributions are studied at midrapidity within the transverse momentum range $0\leq p_{\rm{T}}\leq20$ GeV/$c$, depending on the particle species. The $p_{\rm{T}}$ spectra, integrated yields, and particle yield ratios are discussed as a function of collision energy and compared with measurements at lower $\sqrt{s}$ and with results from various general-purpose QCD-inspired Monte Carlo models. A hardening of the spectra at high $p_{\rm{T}}$ with increasing collision energy is observed, which is similar for all particle species under study. The transverse mass and $x_{\rm{T}}\equiv2p_{\rm{T}}/\sqrt{s}$ scaling properties of hadron production are also studied. As the collision energy increases from $\sqrt{s}$ = 7 to 13 TeV, the yields of non- and single-strange hadrons normalized to the pion yields remain approximately constant as a function of $\sqrt{s}$, while ratios for multi-strange hadrons indicate enhancements. The $p_{\rm{T}}$-differential cross sections of $\pi^{\pm}$, $\rm{K}^{\pm}$ and $\rm{p}$ ($\overline{\rm{p}}$) are compared with next-to-leading order perturbative QCD calculations, which are found to overestimate the cross sections for $\pi^{\pm}$ and $\rm{p}$ ($\overline{\rm{p}}$) at high $p_{\rm{T}}$.

0 data tables match query

Multiplicity dependence of the average transverse momentum in pp, p-Pb, and Pb-Pb collisions at the LHC

The ALICE collaboration Abelev, Betty Bezverkhny ; Adam, Jaroslav ; Adamova, Dagmar ; et al.
Phys.Lett.B 727 (2013) 371-380, 2013.
Inspire Record 1241423 DOI 10.17182/hepdata.61692

The average transverse momentum $\langle p_{\rm T}\rangle$ versus the charged-particle multiplicity $N_{\rm ch}$ was measured in p-Pb collisions at a collision energy per nucleon-nucleon pair $\sqrt{s_{\rm NN}}=5.02$ TeV and in pp collisions at collision energies of $\sqrt{s}=0.9$, 2.76, and 7 TeV in the kinematic range $0.15<p_{\rm T}<10.0$ GeV/$c$ and $|\eta|<0.3$ with the ALICE apparatus at the LHC. These data are compared to results in Pb-Pb collisions at $\sqrt{s_{\rm NN}}=2.76$ TeV at similar charged-particle multiplicities. In pp and p-Pb collisions, a strong increase of $\langle p_{\rm T}\rangle$ with $N_{\rm ch}$ is observed, which is much stronger than that measured in Pb-Pb collisions. For pp collisions, this could be attributed, within a model of hadronizing strings, to multiple-parton interactions and to a final-state color reconnection mechanism. The data in p-Pb and Pb-Pb collisions cannot be described by an incoherent superposition of nucleon-nucleon collisions and pose a challenge to most of the event generators.

0 data tables match query

The Multiplicity dependence of inclusive p(t) spectra from p-p collisions at s**(1/2) = 200-GeV

The STAR collaboration Adams, J. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.D 74 (2006) 032006, 2006.
Inspire Record 719969 DOI 10.17182/hepdata.102084

We report measurements of transverse momentum $p_t$ spectra for ten event multiplicity classes of p-p collisions at $\sqrt{s} = 200$ GeV. By analyzing the multiplicity dependence we find that the spectrum shape can be decomposed into a part with amplitude proportional to multiplicity and described by a L\'evy distribution on transverse mass $m_t$, and a part with amplitude proportional to multiplicity squared and described by a gaussian distribution on transverse rapidity $y_t$. The functional forms of the two parts are nearly independent of event multiplicity. The two parts can be identified with the soft and hard components of a two-component model of p-p collisions. This analysis then provides the first isolation of the hard component of the $p_t$ spectrum as a distribution of simple form on $y_t$.

0 data tables match query

Effect of event selection on jetlike correlation measurement in $d$+Au collisions at $\sqrt{s_{\rm{NN}}}=200$ GeV

The STAR collaboration Adamczyk, L. ; Adkins, J.K. ; Agakishiev, G. ; et al.
Phys.Lett.B 743 (2015) 333-339, 2015.
Inspire Record 1335765 DOI 10.17182/hepdata.73235

Dihadron correlations are analyzed in $\sqrt{s_{_{\rm NN}}} = 200$ GeV $d$+Au collisions classified by forward charged particle multiplicity and zero-degree neutral energy in the Au-beam direction. It is found that the jetlike correlated yield increases with the event multiplicity. After taking into account this dependence, the non-jet contribution on the away side is minimal, leaving little room for a back-to-back ridge in these collisions.

0 data tables match query

K0(s) and Lambda0 production studies in p anti-p collisions at s**(1/2) = 1800 and 630-GeV

The CDF collaboration Acosta, D. ; Affolder, T. ; Albrow, M.G. ; et al.
Phys.Rev.D 72 (2005) 052001, 2005.
Inspire Record 681320 DOI 10.17182/hepdata.42774

We present a study of the production of K_s^0 and Lambda^0 in inelastic pbar-p collisions at sqrt(s)= 1800 and 630 GeV using data collected by the CDF experiment at the Fermilab Tevatron. Analyses of K_s^0 and Lambda^0 multiplicity and transverse momentum distributions, as well as of the dependencies of the average number and <p_T> of K_s^0 and Lambda^0 on charged particle multiplicity are reported. Systematic comparisons are performed for the full sample of inelastic collisions, and for the low and high momentum transfer subsamples, at the two energies. The p_T distributions extend above 8 GeV/c, showing a <p_T> higher than previous measurements. The dependence of the mean K_s^0(Lambda^0) p_T on the charged particle multiplicity for the three samples shows a behavior analogous to that of charged primary tracks.

0 data tables match query