Version 2
Reaction plane correlated triangular flow in Au+Au collisions at $\mathbf{\sqrt{s_{\textrm{NN}}}=3}$ GeV

The STAR Collaboration 19 & STAR collaborations Abdulhamid, Muhammad ; Aboona, Bassam ; Adam, Jaroslav ; et al.
Phys.Rev.C 109 (2024) 044914, 2024.
Inspire Record 2702151 DOI 10.17182/hepdata.144480

We measure triangular flow relative to the reaction plane at 3 GeV center-of-mass energy in Au+Au collisions at the BNL Relativistic Heavy Ion Collider. A significant $v_3$ signal for protons is observed, which increases for higher rapidity, higher transverse momentum, and more peripheral collisions. The triangular flow is essentially rapidity-odd with a slope at mid-rapidity, $dv_3/dy|_{(y=0)}$, opposite in sign compared to the slope for directed flow. No significant $v_3$ signal is observed for charged pions and kaons. Comparisons with models suggest that a mean field potential is required to describe these results, and that the triangular shape of the participant nucleons is the result of stopping and nuclear geometry.

12 data tables

Event plane resolutions for calculating $v_3\{\Psi_1\}$ as a function of centrality from $\sqrt{s_{\textrm{NN}}}=3$ GeV Au+Au collisions at STAR.

Event plane resolutions for calculating $v_3\{\Psi_1\}$ as a function of centrality from $\sqrt{s_{\textrm{NN}}}=3$ GeV Au+Au collisions at STAR.

$v_3\{\Psi_1\}$ vs. centrality for $\pi^+$, $\pi^-$, and protons using the event plane method in $\sqrt{s_{\textrm{NN}}}=3$ GeV Au+Au collisions at STAR.

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First Observation of Directed Flow of Hypernuclei $^3_{\Lambda}$H and $^4_{\Lambda}$H in $\sqrt{s_{\rm NN}}$ = 3 GeV Au+Au Collisions at RHIC

The STAR collaboration Aboona, Bassam ; Adam, Jaroslav ; Adams, Joseph ; et al.
Phys.Rev.Lett. 130 (2023) 212301, 2023.
Inspire Record 2605845 DOI 10.17182/hepdata.136028

We report here the first observation of directed flow ($v_1$) of the hypernuclei $^3_{\Lambda}$H and $^4_{\Lambda}$H in mid-central Au+Au collisions at $\sqrt{s_{\rm NN}}$ = 3 GeV at RHIC. These data are taken as part of the beam energy scan program carried out by the STAR experiment. From 165 $\times$ 10$^{6}$ events in 5%-40% centrality, about 8400 $^3_{\Lambda}$H and 5200 $^4_{\Lambda}$H candidates are reconstructed through two- and three-body decay channels. We observe that these hypernuclei exhibit significant directed flow. Comparing to that of light nuclei, it is found that the midrapidity $v_1$ slopes of $^3_{\Lambda}$H and $^4_{\Lambda}$H follow baryon number scaling, implying that the coalescence is the dominant mechanism for these hypernuclei production in such collisions.

8 data tables

$\Lambda$ hyperon and hypernuclei directed flow $v_1$, shown as a function of rapidity, from the $\sqrt{s_{NN}}$ = 3 GeV 5-40% mid-central Au+Au collisions. In the case of $^{3}_{\Lambda}$H $v_1$, both two-body (dots) and three-body (triangles) decays are used. The linear terms of the fitting for $#Lambda$, $^{3}_{\Lambda}$H and $^{4}_{\Lambda}$H are shown as the yellow-red lines. The rapidity dependence of $v_1$ for $p$, $d$, $t$, $^3$He, and $^4$He are also shown as open markers (circles, diamonds, up-triangles, down-triangles and squares), and the linear terms of the fitting results are shown as dashed lines in the positive rapidity region.

$\Lambda$ hyperon and hypernuclei directed flow $v_1$, shown as a function of rapidity, from the $\sqrt{s_{NN}}$ = 3 GeV 5-40% mid-central Au+Au collisions. In the case of $^{3}_{\Lambda}$H $v_1$, both two-body (dots) and three-body (triangles) decays are used. The linear terms of the fitting for $#Lambda$, $^{3}_{\Lambda}$H and $^{4}_{\Lambda}$H are shown as the yellow-red lines. The rapidity dependence of $v_1$ for $p$, $d$, $t$, $^3$He, and $^4$He are also shown as open markers (circles, diamonds, up-triangles, down-triangles and squares), and the linear terms of the fitting results are shown as dashed lines in the positive rapidity region.

$\Lambda$ hyperon and hypernuclei directed flow $v_1$, shown as a function of rapidity, from the $\sqrt{s_{NN}}$ = 3 GeV 5-40% mid-central Au+Au collisions. In the case of $^{3}_{\Lambda}$H $v_1$, both two-body (dots) and three-body (triangles) decays are used. The linear terms of the fitting for $#Lambda$, $^{3}_{\Lambda}$H and $^{4}_{\Lambda}$H are shown as the yellow-red lines. The rapidity dependence of $v_1$ for $p$, $d$, $t$, $^3$He, and $^4$He are also shown as open markers (circles, diamonds, up-triangles, down-triangles and squares), and the linear terms of the fitting results are shown as dashed lines in the positive rapidity region.

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Higher-Order Cumulants and Correlation Functions of Proton Multiplicity Distributions in $\sqrt{s_{\mathrm{NN}}}$ = 3 GeV Au+Au Collisions at the STAR Experiment

The STAR collaboration Abdallah, Mohamed ; Aboona, Bassam ; Adam, Jaroslav ; et al.
Phys.Rev.C 107 (2023) 024908, 2023.
Inspire Record 2631860 DOI 10.17182/hepdata.134023

We report a measurement of cumulants and correlation functions of event-by-event proton multiplicity distributions from fixed-target Au+Au collisions at $\sqrt{s_{\rm NN}}$ = 3 GeV measured by the STAR experiment. Protons are identified within the rapidity ($y$) and transverse momentum ($p_{\rm T}$) region $-0.9 < y<0$ and $0.4 < p_{\rm T} <2.0 $ GeV/$c$ in the center-of-mass frame. A systematic analysis of the proton cumulants and correlation functions up to sixth-order as well as the corresponding ratios as a function of the collision centrality, $p_{\rm T}$, and $y$ are presented. The effect of pileup and initial volume fluctuations on these observables and the respective corrections are discussed in detail. The results are compared to calculations from the hadronic transport UrQMD model as well as a hydrodynamic model. In the most central 5% collisions, the value of proton cumulant ratio $C_4/C_2$ is negative, drastically different from the values observed in Au+Au collisions at higher energies. Compared to model calculations including Lattice QCD, a hadronic transport model, and a hydrodynamic model, the strong suppression in the ratio of $C_4/C_2$ at 3 GeV Au+Au collisions indicates an energy regime dominated by hadronic interactions.

41 data tables

The uncorrected number of charged particles except protons ($N_{\rm ch}$) within the pseudorapidity $−2<\eta<0$ used for the centrality selection for Au+Au collisions at $\sqrt{s_{\rm NN}}$ = 3 GeV. The centrality classes are expressed in % of the total cross section. The lower boundary of the particle multiplicity ($N_{\rm ch}$) is included for each centrality class. Values are provided for the average number of participants ($\langle N_{\rm part}\rangle$) and pileup fraction. The fraction of pileup for each centrality bin is also shown in the last column. The averaged pileup fraction from the minimum biased collisions is determined to be 0.46%. Values in the parentheses are systematic uncertainty.

The centrality definition determined by $N_{\rm part}$ in Au+Au collisions at $\sqrt{s_{\rm NN}}$ = 3 GeV from the UrQMD model. The centrality definition is only used in the UrQMD calculation.

Main contributors to systematic uncertainty to the proton cumulant ratios: $C_2/C_1$, $C_3/C_2$,and $C_4/C_2$ from 0–5% central 3 GeV Au+Au collisions. The first row shows the values and statistical uncertainties of those ratios. The corresponding values of these ratios along with the statistical uncertainties are listed in the table. The final total value is the quadratic sum of uncertainties from centrality, pileup, and the dominant contribution from TPC hits, DCA, TOF $m^2$, and detector efficiency. Clearly, this analysis is systematically dominant.

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Light Nuclei Collectivity from $\sqrt{s_{\rm NN}}$ = 3 GeV Au+Au Collisions at RHIC

The STAR collaboration Abdallah, M.S. ; Aboona, B.E. ; Adam, J. ; et al.
Phys.Lett.B 827 (2022) 136941, 2022.
Inspire Record 1986611 DOI 10.17182/hepdata.115569

In high-energy heavy-ion collisions, partonic collectivity is evidenced by the constituent quark number scaling of elliptic flow anisotropy for identified hadrons. A breaking of this scaling and dominance of baryonic interactions is found for identified hadron collective flow measurements in $\sqrt{s_{\rm NN}}$ = 3 GeV Au+Au collisions. In this paper, we report measurements of the first- and second-order azimuthal anisotropic parameters, $v_1$ and $v_2$, of light nuclei ($d$, $t$, $^{3}$He, $^{4}$He) produced in $\sqrt{s_{\rm NN}}$ = 3 GeV Au+Au collisions at the STAR experiment. An atomic mass number scaling is found in the measured $v_1$ slopes of light nuclei at mid-rapidity. For the measured $v_2$ magnitude, a strong rapidity dependence is observed. Unlike $v_2$ at higher collision energies, the $v_2$ values at mid-rapidity for all light nuclei are negative and no scaling is observed with the atomic mass number. Calculations by the Jet AA Microscopic Transport Model (JAM), with baryonic mean-field plus nucleon coalescence, are in good agreement with our observations, implying baryonic interactions dominate the collective dynamics in 3 GeV Au+Au collisions at RHIC.

22 data tables

The rapidity and $p_{T}$ dependencies of $v_{1}$ for $p$ in 10-40% mid-central Au+Au collisions at 3 GeV.

The rapidity and $p_{T}$ dependencies of $v_{1}$ for $d$ in 10-40% mid-central Au+Au collisions at 3 GeV.

The $p_{T}$ dependencies of $v_{1}$ within $-0.1<y<0$ for $t$ in 10-40% mid-central Au+Au collisions at 3 GeV.

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Measurements of Proton High Order Cumulants in 3 GeV Au+Au Collisions and Implications for the QCD Critical Point

The STAR collaboration Abdallah, M.S. ; Aboona, B.E. ; Adam, J. ; et al.
Phys.Rev.Lett. 128 (2022) 202303, 2022.
Inspire Record 1981670 DOI 10.17182/hepdata.115559

We report cumulants of the proton multiplicity distribution from dedicated fixed-target Au+Au collisions at 3.0 GeV, measured by the STAR experiment in the kinematic acceptance of rapidity ($y$) and transverse momentum ($p_{\rm T}$) within $-0.5 < y<0$ and $0.4 < p_{\rm T} <2.0 $ GeV/$c$. In the most central 0--5% collisions, a proton cumulant ratio is measured to be $C_4/C_2=-0.85 \pm 0.09 ~(\rm stat.) \pm 0.82 ~(\rm syst.)$, which is less than unity, the Poisson baseline. The hadronic transport UrQMD model reproduces our $C_4/C_2$ in the measured acceptance. Compared to higher energy results and the transport model calculations, the suppression in $C_4/C_2$ is consistent with fluctuations driven by baryon number conservation and indicates an energy regime dominated by hadronic interactions. These data imply that the QCD critical region, if created in heavy-ion collisions, could only exist at energies higher than 3 GeV.

10 data tables

$\sqrt{s_{NN}}$ = 3.0 GeV data (black markers), GM (red histogram), and single and pile-up contributions from unfolding. Vertical lines on markers represent statistical uncertainties. Single, pile-up and single+pile-up collisions are shown in solid blue markers, dashed green and dashed magenta curves, respectively. Analysis is performed on 0–5% central events, indicated by a black arrow.

$\sqrt{s_{NN}}$ = 3.0 GeV data (black markers), GM (red histogram), and single and pile-up contributions from unfolding. Vertical lines on markers represent statistical uncertainties. Single, pile-up and single+pile-up collisions are shown in solid blue markers, dashed green and dashed magenta curves, respectively. Analysis is performed on 0–5% central events, indicated by a black arrow.

Centrality dependence of the proton cumulant ratios for Au+Au collisions at $\sqrt{s_{NN}}$ = 3.0 GeV. Protons are from $-0.5 < y < 0$ and $0.4 < p_{T} < 2.0$ GeV/$c$. Systematic uncertainties are represented by gray bars. Statistical uncertainties are smaller than marker size. CBWC is applied to all cumulant ratios. While open squares represent the data without the VFC correction, blue triangles and red circles are the results with VFC using the $\langle N_{\rm{part}} \rangle$ distributions from the UrQMD and Glauber models, respectively. UrQMD model results are represented as gold dashed line.

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Probing Strangeness Canonical Ensemble with $K^{-}$, $\phi(1020)$ and $\Xi^{-}$ Production in Au+Au Collisions at ${\sqrt{s_{NN}} = {3\,GeV}}$

The STAR collaboration Abdallah, M.S. ; Aboona, B.E. ; Adam, J. ; et al.
Phys.Lett.B 831 (2022) 137152, 2022.
Inspire Record 1897327 DOI 10.17182/hepdata.110657

We report the first multi-differential measurements of strange hadrons of $K^{-}$, $\phi$ and $\Xi^{-}$ yields as well as the ratios of $\phi/K^-$ and $\phi/\Xi^-$ in Au+Au collisions at ${\sqrt{s_{\rm NN}} = \rm{3\,GeV}}$ with the STAR experiment fixed target configuration at RHIC. The $\phi$ mesons and $\Xi^{-}$ hyperons are measured through hadronic decay channels, $\phi\rightarrow K^+K^-$ and $\Xi^-\rightarrow \Lambda\pi^-$. Collision centrality and rapidity dependence of the transverse momentum spectra for these strange hadrons are presented. The $4\pi$ yields and ratios are compared to thermal model and hadronic transport model predictions. At this collision energy, thermal model with grand canonical ensemble (GCE) under-predicts the $\phi/K^-$ and $\phi/\Xi^-$ ratios while the result of canonical ensemble (CE) calculations reproduce $\phi/K^-$, with the correlation length $r_c \sim 2.7$ fm, and $\phi/\Xi^-$, $r_c \sim 4.2$ fm, for the 0-10% central collisions. Hadronic transport models including high mass resonance decays could also describe the ratios. While thermal calculations with GCE work well for strangeness production in high energy collisions, the change to CE at $\rm{3\,GeV}$ implies a rather different medium property at high baryon density.

12 data tables

$K^-$ (a), invariant yields as a function of $m_T-m_0$ for various rapidity regions in 0--10\% central Au+Au collisions at ${\sqrt{s_{\mathrm{NN}}} = \mathrm{3\,GeV}}$. Statistics and systematic uncertainties are added quadratic here for plotting. Solid and dashed black lines depict $m_T$ exponential function fits to the measured data points with arbitrate scaling factors in each rapidity windows.

$\phi$ meson (b) invariant yields as a function of $m_T-m_0$ for various rapidity regions in 0--10\% central Au+Au collisions at ${\sqrt{s_{\mathrm{NN}}} = \mathrm{3\,GeV}}$. Statistics and systematic uncertainties are added quadratic here for plotting. Solid and dashed black lines depict $m_T$ exponential function fits to the measured data points with arbitrate scaling factors in each rapidity windows.

$\Xi^-$ (c) invariant yields as a function of $m_T-m_0$ for various rapidity regions in 0--10\% central Au+Au collisions at ${\sqrt{s_{\mathrm{NN}}} = \mathrm{3\,GeV}}$. Statistics and systematic uncertainties are added quadratic here for plotting. Solid and dashed black lines depict $m_T$ exponential function fits to the measured data points with arbitrate scaling factors in each rapidity windows.

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Disappearance of partonic collectivity in $\sqrt{s_{NN}}$ = 3 GeV Au+Au collisions at RHIC

The STAR collaboration Abdallah, M.S. ; Aboona, B.E. ; Adam, J. ; et al.
Phys.Lett.B 827 (2022) 137003, 2022.
Inspire Record 1897294 DOI 10.17182/hepdata.110656

We report on the measurements of directed flow $v_1$ and elliptic flow $v_2$ for hadrons ($\pi^{\pm}$, $K^{\pm}$, $K_{S}^0$, $p$, $\phi$, $\Lambda$ and $\Xi^{-}$) from Au+Au collisions at $\sqrt{s_{NN}}$ = 3 GeV and $v_{2}$ for ($\pi^{\pm}$, $K^{\pm}$, $p$ and $\overline{p}$) at 27 and 54.4 GeV with the STAR experiment. While at the two higher energy midcentral collisions the number-of-constituent-quark (NCQ) scaling holds, at 3 GeV the $v_{2}$ at midrapidity is negative for all hadrons and the NCQ scaling is absent. In addition, the $v_1$ slopes at midrapidity for almost all observed hadrons are found to be positive, implying dominant repulsive baryonic interactions. The features of negative $v_2$ and positive $v_1$ slope at 3 GeV can be reproduced with a baryonic mean-field in transport model calculations. These results imply that the medium in such collisions is likely characterized by baryonic interactions.

32 data tables

Event plane resolution as a function of collision centrality from Au+Au collisions at $\sqrt{s_{NN}}$=3 (a), 27 and 54.4 GeV (b). In case of the 3 GeV collisions, $\Psi_{1}$ is used to determine the event plane resolutions for the first and second harmonic coefficients shown as $R_{11}$ and $R_{12}$ in left panel. In the 27 and 54.4 GeV collisions, $\Psi_{2}$ is used to evaluate the second order event plane resolution, see right panel. In all cases, the statistic uncertainties are smaller than symbol sizes.

Rapidity($y$) dependence of $v_1$ (top panels) and $v_2$ (bottom panels) of proton and $\Lambda$ baryons (left panels), pions (middle panels) and kaons (right panels) in 10-40% centrality for the $\sqrt{s_{NN}}$ = 3GeV Au+Au collisions. Statistical and systematic uncertainties are shown as bars and gray bands, respectively. Some uncertainties are smaller than the data points. The UrQMD and JAM results are shown as bands:golden, red and blue bands stand for JAM mean-field, UrQMD mean-field and UrQMD cascade mode, respectively. The value of the incompressibility $\kappa$ = 380 MeV is used in the mean-field option. More detailed model descriptions and data comparisons can be found in Supplemental Material.

Rapidity($y$) dependence of $v_1$ (top panels) and $v_2$ (bottom panels) of proton and $\Lambda$ baryons (left panels), pions (middle panels) and kaons (right panels) in 10-40% centrality for the $\sqrt{s_{NN}}$ = 3GeV Au+Au collisions. Statistical and systematic uncertainties are shown as bars and gray bands, respectively. Some uncertainties are smaller than the data points. The UrQMD and JAM results are shown as bands:golden, red and blue bands stand for JAM mean-field, UrQMD mean-field and UrQMD cascade mode, respectively. The value of the incompressibility $\kappa$ = 380 MeV is used in the mean-field option. More detailed model descriptions and data comparisons can be found in Supplemental Material.

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Global $\Lambda$-hyperon polarization in Au+Au collisions at $\sqrt{s_\mathrm{NN}}=3$ GeV

The STAR collaboration Abdallah, M.S. ; Aboona, B.E. ; Adam, J. ; et al.
Phys.Rev.C 104 (2021) L061901, 2021.
Inspire Record 1897216 DOI 10.17182/hepdata.110658

Global hyperon polarization, $\overline{P}_\mathrm{H}$, in Au+Au collisions over a large range of collision energy, $\sqrt{s_\mathrm{NN}}$, was recently measured and successfully reproduced by hydrodynamic and transport models with intense fluid vorticity of the quark-gluon plasma. While naïve extrapolation of data trends suggests a large $\overline{P}_\mathrm{H}$ as the collision energy is reduced, the behavior of $\overline{P}_\mathrm{H}$ at small $\sqrt{s_\mathrm{NN}}<7.7$ GeV is unknown. Operating the STAR experiment in fixed-target mode, we measured the polarization of $\Lambda$ hyperons along the direction of global angular momentum in Au+Au collisions at $\sqrt{s_\mathrm{NN}}=3$ GeV. The observation of substantial polarization of $4.91\pm0.81(\rm stat.)\pm0.15(\rm syst.)$% in these collisions may require a reexamination of the viscosity of any fluid created in the collision, of the thermalization timescale of rotational modes, and of hadronic mechanisms to produce global polarization.

6 data tables

The measured invariant-mass distributions of two classes of $\Lambda$-hyperon decays. The decay classes are defined using the scalar triple product $\left(\vec{p}_\Lambda\times\vec{p}_p^*\right)\cdot \vec{B}_{\rm STAR}$, which is positive for right decays and negative for left decays. The right decay class has a notably sharper invariant-mass distribution than the left decay class, and this is due to the effects of daughter tracks crossing in the STAR TPC with the STAR magnetic field anti-parallel to the lab frame's z direction. The opposite pattern is obtained by flipping the sign of the STAR magnetic field or by reconstructing $\bar{\Lambda}$ hyperons.

The signal polarizations extracted according to the restricted invariant-mass method as a function of $\phi_\Lambda - \phi_p^*$, for positive-rapidity $\Lambda$ hyperons. The sinusoidal behavior is driven by non-zero net $v_1$. The vertical shift corresponds to the vorticity-driven polarization; in collider mode, where the net $v_1$ is zero, this dependence on $\phi_\Lambda - \phi_p^*$ does not exist.

The integrated Global $\Lambda$-hyperon Polarization in mid-central collisions at $\sqrt{s_{\rm NN}}=3$ GeV. The trend of increasing $\overline{P}_{\rm H}$ with decreasing $\sqrt{s_{\rm NN}}$ is maintained at this low collision energy. Previous experimental results are scaled by the updated $\Lambda$-hyperon decay parameter $\alpha_\Lambda=0.732$ for comparison with this result. Recent model calculations extended to low collision energy show disagreement between our data and AMPT and rough agreement with the 3-Fluid Dynamics (3FD) model. Previous measurements shown alongside our data can be found at: https://www.hepdata.net/record/ins750410?version=2; https://www.hepdata.net/record/ins1510474?version=1; https://www.hepdata.net/record/ins1672785?version=2; https://www.hepdata.net/record/ins1752507?version=2.

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Flow and interferometry results from Au+Au collisions at $\sqrt{\textit{s}_{NN}}$ = 4.5 GeV

The STAR collaboration Adam, J. ; Adamczyk, L. ; Adams, J.R. ; et al.
Phys.Rev.C 103 (2021) 034908, 2021.
Inspire Record 1809043 DOI 10.17182/hepdata.95903

The Beam Energy Scan (BES) program at the Relativistic Heavy Ion Collider (RHIC) was extended to energies below $\sqrt{\textit{s}_{NN}}$ = 7.7 GeV in 2015 by successful implementation of the fixed-target mode of operation in the STAR (Solenoidal Track At RHIC) experiment. In the fixed-target mode, ions circulate in one ring of the collider and interact with a stationary target at the entrance of the STAR Time Projection Chamber. The first results for Au+Au collisions at $\sqrt{\textit{s}_{NN}}$ = 4.5 GeV are presented, including directed and elliptic flow of identified hadrons, and radii from pion femtoscopy. The proton flow and pion femtoscopy results agree quantitatively with earlier measurements by Alternating Gradient Synchrotron experiments at similar energies. This validates running the STAR experiment in the fixed-target configuration. Pion directed and elliptic flow are presented for the first time at this beam energy. Pion and proton elliptic flow show behavior which hints at constituent quark scaling, but large error bars preclude reliable conclusions. The ongoing second phase of BES (BES-II) will provide fixed-target data sets with 100 times more events at each of several energies down to $\sqrt{\textit{s}_{NN}}$ = 3.0 GeV.

12 data tables

Centrality selection for STAR FXT sqrt(sNN) = 4.5 GeV Au+Au collisions

Rapidity dependence of directed flow, v1(y), for protons with transverse momentum 0.4 < pT < 2.0 GeV/c from events with 10-25% centrality.

Rapidity dependence of directed flow, v1(y), for negative pions with transverse momentum pT > 0.2 GeV/c and total momentum magnitude |p| < 1.6 GeV/c from events within 10-30% centrality. Here, the BBC-based Event Plane method is used. Plotted error bars are statistical only, and systematic errors are of comparable size.

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Study of the process $e^+e^-\to\omega\eta\pi^0$ in the energy range $\sqrt{s} <2$ GeV with the SND detector

Achasov, M.N. ; Aulchenko, V.M. ; Barnyakov, A.Yu. ; et al.
Phys.Rev.D 94 (2016) 032010, 2016.
Inspire Record 1471515 DOI 10.17182/hepdata.82577

The process $e^+e^-\to\omega\eta\pi^0$ is studied in the energy range $1.45-2.00$ GeV using data with an integrated luminosity of 33 pb$^{-1}$ accumulated by the SND detector at the $e^+e^-$ collider VEPP-2000. The $e^+e^-\to\omega\eta\pi^0$ cross section is measured for the first time. The cross section has a threshold near 1.75 GeV. Its value is about 2 nb in the energy range $1.8-2.0$ GeV. The dominant intermediate state for the process $e^+e^- \to \omega\eta\pi^0$ is found to be $\omega a_0(980)$.

1 data table

The energy interval, integrated luminosity ($L$), number of selected events ($N$), estimated number of background events ($N_{bkg}$), detection efficiency for $e^+e^-\to\omega\eta\pi^0\to 7\gamma$ events ($\epsilon$), radiative correction ($\delta+1$), and $e^+e^-\to\omega\eta\pi^0$ Born cross section ($\sigma$). The shown cross-section errors are statistical. The systematic error is 4.2%. The 90% confidence level upper limits are listed for the first two energy intervals.


Measurement of the $e^+e^- \to K^+K^-\pi^+\pi^-$ cross section with the CMD-3 detector at the VEPP-2000 collider

Shemyakin, D.N. ; Fedotovich, G.V. ; Akhmetshin, R.R. ; et al.
Phys.Lett.B 756 (2016) 153-160, 2016.
Inspire Record 1395968 DOI 10.17182/hepdata.76553

The process $e^+e^- \to K^+K^-\pi^+\pi^-$ has been studied in the center-of-mass energy range from 1500 to 2000\,MeV using a data sample of 23 pb$^{-1}$ collected with the CMD-3 detector at the VEPP-2000 $e^+e^-$ collider. Using about 24000 selected events, the $e^+e^- \to K^+K^-\pi^+\pi^-$ cross section has been measured with a systematic uncertainty decreasing from 11.7\% at 1500-1600\,MeV to 6.1\% above 1800\,MeV. A preliminary study of $K^+K^-\pi^+\pi^-$ production dynamics has been performed.

1 data table

Center-of-mass energy, integrated luminosity, number of four-track events, number of three-track events, detection efficiency, radiative correction and Born cross section of the process $e^{+}e^{-} \to K^{+} K^{-} \pi^{+} \pi^{-}$. Errors are statistical only.


Interaction of 9-BeV protons with free and quasifree nucleons in photographic emulsinos

Bogachev, N.P. ; Bunyatov, S.A. ; Gramenitskii, I.M. ; et al.
Sov.Phys.JETP 10 (1960) 872-877, 1960.
Inspire Record 1392948 DOI 10.17182/hepdata.39967

None

1 data table

No description provided.


Inelastic Interaction of Protons and Nucleons at an Energy of 9 BeV

Visky, T. ; Gramenitskii, I.M. ; Korbel, Z. ; et al.
Sov.Phys.JETP 14 (1962) 763-767, 1962.
Inspire Record 1388049 DOI 10.17182/hepdata.17008

The multiplicity dependence of the angular and energy characteristics of secondary particles in proton-nucleon collisions at 9 Bevis studied. A comparison is made with results of calculations based on the single-meson scheme.

9 data tables

No description provided.

No description provided.

No description provided.

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Study of the $e^+e^-\to K^+K^-$ reaction in the energy range from 2.6 to 8.0 GeV

The BaBar collaboration Lees, J.P. ; Poireau, V. ; Tisserand, V. ; et al.
Phys.Rev.D 92 (2015) 072008, 2015.
Inspire Record 1383130 DOI 10.17182/hepdata.73784

The $e^+e^-\to K^+K^-$ cross section and charged-kaon electromagnetic form factor are measured in the $e^+e^-$ center-of-mass energy range ($E$) from 2.6 to 8.0 GeV using the initial-state radiation technique with an undetected photon. The study is performed using 469 fb$^{-1}$ of data collected with the BABAR detector at the PEP-II $e^+e^-$ collider at center-of-mass energies near 10.6 GeV. The form factor is found to decrease with energy faster than $1/E^2$, and approaches the asymptotic QCD prediction. Production of the $K^+K^-$ final state through the $J/\psi$ and $\psi(2S)$ intermediate states is observed. The results for the kaon form factor are used together with data from other experiments to perform a model-independent determination of the relative phases between single-photon and strong amplitudes in $J/\psi$ and $\psi(2S)\to K^+K^-$ decays. The values of the branching fractions measured in the reaction $e^+e^- \to K^+K^-$ are shifted relative to their true values due to interference between resonant and nonresonant amplitudes. The values of these shifts are determined to be about $\pm5\%$ for the $J/\psi$ meson and $\pm15\%$ for the $\psi(2S)$ meson.

1 data table

The $K^+K^-$ invariant-mass interval ($M_{K^+K^-}$), number of selected events ($N_{\rm sig}$) after background subtraction, detection efficiency ($\varepsilon$), ISR luminosity ($L$), measured $e^+e^-\to K^+K^-$ cross section ($\sigma_{K^+K^-}$), and the charged-kaon form factor ($|F_K|$). For the number of events and cross section. For the form factor, we quote the combined uncertainty. For the mass interval 7.5 - 8.0 GeV/$c^2$, the 90$\%$ CL upper limits for the cross section and form factor are listed.


Cross sections for the reactions $e^+ e^-\to K_S^0 K_L^0$, $K_S^0 K_L^0 \pi^+\pi^-$, $K_S^0 K_S^0 \pi^+\pi^-$, and $K_S^0 K_S^0 K^+K^-$ from events with initial-state radiation

The BaBar collaboration Lees, J.P. ; Poireau, V. ; Tisserand, V. ; et al.
Phys.Rev.D 89 (2014) 092002, 2014.
Inspire Record 1287920 DOI 10.17182/hepdata.64506

We study the processes $e^+ e^-\to K_S^0 K_L^0 \gamma$, $K_S^0 K_L^0 \pi^+\pi^-\gamma$, $K_S^0 K_S^0 \pi^+\pi^-\gamma$, and $K_S^0 K_S^0 K^+K^-\gamma$, where the photon is radiated from the initial state, providing cross section measurements for the hadronic states over a continuum of center-of-mass energies. The results are based on 469 fb$^{-1}$ of data collected with the BaBar detector at SLAC. We observe the $\phi(1020)$ resonance in the $K_S^0 K_L^0$ final state and measure the product of its electronic width and branching fraction with about 3% uncertainty. We present a measurement of the $e^+ e^-\to K_S^0 K_L^0 $ cross section in the energy range from 1.06 to 2.2 GeV and observe the production of a resonance at 1.67 GeV. We present the first measurements of the $e^+ e^-\to K_S^0 K_L^0 \pi^+\pi^-$, $K_S^0 K_S^0 \pi^+\pi^-$, and $K_S^0 K_S^0 K^+K^-$ cross sections, and study the intermediate resonance structures. We obtain the first observations of \jpsi decay to the $K_S^0 K_L^0 \pi^+\pi^-$, $K_S^0 K_S^0 \pi^+\pi^-$, and $K_S^0 K_S^0 K^+K^-$ final states.

22 data tables

Cross section measurement for PHI(1020).

Mass measurement for PHI(1020).

Measurement of the PHI(1020) width.

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Study of e+e- --> omega pi0 --> pi0 pi0 gamma in the energy range 1.05--2.00 GeV with SND

Achasov, M.N. ; Aulchenko, V.M. ; Barnyakov, A.Yu. ; et al.
Phys.Rev.D 88 (2013) 054013, 2013.
Inspire Record 1224801 DOI 10.17182/hepdata.62287

The cross section for the process e+e- --> omega pi0 --> pi0 pi0 gamma has been measured in the energy range 1.05--2.00 GeV. The experiment has been performed at the e+e- collider VEPP-2000 with the SND detector. The measured e+e- --> omega pi0 cross section above 1.4 GeV is the most accurate to date. Below 1.4 GeV our data are in good agreement with the previous SND and CMD-2 measurements. Data on the e+e- --> omega pi0 cross section are well described by the VMD model with two excited rho-like states. From the measured cross section we have extracted the gamma^* --> omega pi0 transition form factor. It has been found that the VDM model cannot describe simultaneously our data and data obtained from the omega --> pi0 mu+ mu- decay. We have also tested CVC hypothesis comparing our results on the e+e- --> omega pi0 cross section with data on the tau- --> omega pi- nu_{tau} decay.

1 data table

The c.m. energy(E) and measured Born cross section(SIG). For the cross section, the first error is statistical, the second is systematic.


Study of e+e- --> p anti-p via initial-state radiation at BABAR

The BaBar collaboration Lees, J.P. ; Poireau, V. ; Tisserand, V. ; et al.
Phys.Rev.D 87 (2013) 092005, 2013.
Inspire Record 1217421 DOI 10.17182/hepdata.62678

The process e+e- --> p anti-p gamma is studied using 469 fb-1 of integrated luminosity collected with the BABAR detector at the PEP-II collider, at an e+e- center-of-mass energy of 10.6 GeV. From the analysis of the p anti-p invariant mass spectrum, the energy dependence of the cross section for e+e- --> p anti-p is measured from threshold to 4.5 GeV. The energy dependence of the ratio of electric and magnetic form factors, |G_E/G_M|, and the asymmetry in the proton angular distribution are measured for p anti-p masses below 3 GeV. We also measure the branching fractions for the decays J/psi --> p anti-p and psi(2S) --> p anti p.

1 data table

Measurement of the cross section as a function of the invariant mass of the PBAR-P system and the effective form factor for the reaction E+ E- --> PBAR P. The contributions from J/PSI and PSI(25) decaying to PBAR-P have been subtracted. The form factor error is the combined statistical and systematic.


Cross Sections for the Reactions e+e- --> K+ K- pi+pi-, K+ K- pi0pi0, and K+ K- K+ K- Measured Using Initial-State Radiation Events

The BaBar collaboration Lees, J.P. ; Poireau, V. ; Prencipe, E. ; et al.
Phys.Rev.D 86 (2012) 012008, 2012.
Inspire Record 892684 DOI 10.17182/hepdata.62222

We study the processes e+e- --> K+ K- pi+pi-gamma, K+ K- pi0pi0gamma, and K+ K- K+ K-gamma, where the photon is radiated from the initial state. About 84000, 8000, and 4200 fully reconstructed events, respectively, are selected from 454 fb-1 of BaBar data. The invariant mass of the hadronic final state defines the \epem center-of-mass energy, so that the K+ K- pi+pi- data can be compared with direct measurements of the e+e- --> K+ K- pi+pi- reaction. No direct measurements exist for the e+e- --> K+ K-pi0pi0 or e+e- --> K+ K-K+ K- reactions, and we present an update of our previous result with doubled statistics. Studying the structure of these events, we find contributions from a number of intermediate states, and extract their cross sections. In particular, we perform a more detailed study of the e+e- --> phi(1020)pipigamma reaction, and confirm the presence of the Y(2175) resonance in the phi(1020) f0(980) and K+K-f0(980) modes. In the charmonium region, we observe the J/psi in all three final states and in several intermediate states, as well as the psi(2S) in some modes, and measure the corresponding product of branching fraction and electron width.

8 data tables

The cross section for the reaction E+ E- --> K+ K- PI+ PI- measured with ISR data. Statistical errors only.

Cross section measurements for the reaction E+ E- --> K*(892)0 K- PI+. Statistical errors only.

Cross section measurements for the reaction E+ E- --> PHI PI+ PI-. Statistical errors only.

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Measurements of e+ e- ---> K+ K- eta, K+ K- pi0 and K0(s) K+- pi-+ cross- sections using initial state radiation events

The BaBar collaboration Aubert, Bernard ; Bona, M. ; Boutigny, D. ; et al.
Phys.Rev.D 77 (2008) 092002, 2008.
Inspire Record 765258 DOI 10.17182/hepdata.50372

This paper reports measurements of processes: e+e- -> gamma KsK+pi-, e+e- -> gamma K+K-pi0, e+e- -> gamma phi eta, and e+e- -> gamma phi pi0. The initial state radiated photon allows to cover the hadronic final state in the energy range from thresholds up to ~4.6 GeV. The overall size of the data sample analyzed is 232 fb-1, collected by the BaBar detector running at the PEP-II e+e- storage ring. From the Dalitz plot analysis of the KsK+pi- final state, moduli and relative phase of the isoscalar and the isovector components of the e+e- -> K K*(892) cross section are determined. Parameters of phi and rho recurrences are also measured, using a global fitting procedure which exploits the interconnection among amplitudes, moduli and phases of the e+e- -> KsK+pi-, K+K-pi0, phi eta final states. The cross section for the OZI-forbidden process e+e- -> phi pi0, and the J/psi branching fractions to KK*(892) and K+K-eta are also measured.

9 data tables

The cross section for E+ E- --> K0S K+ PI- + CC with statistical errors only.

The cross section for E+ E- --> K+ K- PI0 with statistical errors only.

The cross section for E+ E- --> PHI PI0 with statistical errors only.

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The $e^+ e^-\to 2(\pi^+\pi^-)\pi^0$, 2(\pi^+\pi^-)\eta$, $K^+ K^-\pi^+\pi^-\pi^0$ and $K^+ K^-\pi^+\pi^-\eta$ Cross Sections Measured with Initial-State Radiation

The BaBar collaboration Aubert, Bernard ; Bona, M. ; Boutigny, D. ; et al.
Phys.Rev.D 76 (2007) 092005, 2007.
Inspire Record 758568 DOI 10.17182/hepdata.51824

We study the processes $e^+ e^-\to 2(\pi^+\pi^-)\pi^0\gamma$, $2(\pi^+\pi^-)\eta\gamma$, $K^+ K^-\pi^+\pi^-\pi^0\gamma$ and $K^+ K^-\pi^+\pi^-\eta\gamma$ with the hard photon radiated from the initial state. About 20000, 4300, 5500 and 375 fully reconstructed events, respectively, are selected from 232 fb$^{-1}$ of BaBar data. The invariant mass of the hadronic final state defines the effective $e^+ e^-$ center-of-mass energy, so that the obtained cross sections from the threshold to about 5 GeV can be compared with corresponding direct \epem measurements, currently available only for the $\eta\pi^+\pi^-$ and $\omega\pi^+\pi^-$ submodes of the $e^+ e^-\to 2(\pi^+\pi^-)\pi^0$ channel. Studying the structure of these events, we find contributions from a number of intermediate states, and we extract their cross sections where possible. In particular, we isolate the contribution from $e^+ e^-\to\omega(782)\pi^+\pi^-$ and study the $\omega(1420)$ and $\omega(1650)$ resonances. In the charmonium region, we observe the $J/\psi$ in all these final states and several intermediate states, as well as the $\psi(2S)$ in some modes, and we measure the corresponding branching fractions.

11 data tables

Measured cross section for E+ E- --> 2(PI+ PI-) PI0 with statistical errorsonly.

Measured cross section for E+ E- --> ETA PI+ PI- with statistical errors only.

Measured cross section for E+ E- --> OMEGA PI+ PI- with statistical errors only.

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The $e^+ e^-\to K^+ K^- \pi^+\pi^-$, $K^+ K^- \pi^0\pi^0$ and $K^+ K^- K^+ K^-$ Cross Sections Measured with Initial-State Radiation

The BaBar collaboration Aubert, Bernard ; Bona, M. ; Boutigny, D. ; et al.
Phys.Rev.D 76 (2007) 012008, 2007.
Inspire Record 747875 DOI 10.17182/hepdata.50373

We study the processes $e^+ e^-\to K^+ K^- \pi^+\pi^-\gamma$, $K^+K^-\pi^0\pi^0\gamma$ and $K^+ K^- K^+ K^-\gamma$, where the photon is radiated from the initial state. About 34600, 4400 and 2300 fully reconstructed events, respectively, are selected from 232 \invfb of \babar data. The invariant mass of the hadronic final state defines the effective \epem center-of-mass energy, so that the $K^+ K^- \pi^+\pi^-\gamma$ data can be compared with direct measurements of the $e^+ e^-\to K^+K^- \pipi$ reaction/ no direct measurements exist for the $e^+ e^-\to K^+ K^- \pi^0\pi^0$ or $\epem\to K^+ K^- K^+ K^-$ reactions. Studying the structure of these events, we find contributions from a number of intermediate states, and we extract their cross sections where possible. In particular, we isolate the contribution from $e^+ e^-\to\phi(1020) f_{0}(980)$ and study its structure near threshold. In the charmonium region, we observe the $J/\psi$ in all three final states and several intermediate states, as well as the $\psi(2S)$ in some modes, and measure the corresponding branching fractions. We see no signal for the Y(4260) and obtain an upper limit of $\BR_{Y(4260)\to\phi\pi^+\pi^-}\cdot\Gamma^{Y}_{ee}<0.4 \ev$ at 90% C.L.

7 data tables

Measurement of the E+ E- --> K+ K- PI+ PI- cross section. Statistical errors only.

Measurement of the E+ E- --> K(892)0 K PI cross section. Statistical errors only.

Measurement of the E+ E- --> PHI PI+ PI- cross section. Statistical errors only.

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Evidence of a broad structure at an invariant mass of 4.32- GeV/c**2 in the reaction e+ e- ---> pi+ pi- psi(2S) measured at BaBar

The BaBar collaboration Aubert, Bernard ; Barate, R. ; Bona, M. ; et al.
Phys.Rev.Lett. 98 (2007) 212001, 2007.
Inspire Record 729388 DOI 10.17182/hepdata.19344

We present a measurement of the cross section of the process $e^+e^-\to\pi^+pi^-\psi(2S)$ from threshold up to 8 GeV center-of-mass energy using events containing initial-state radiation, produced at the PEP-II $e^+e^-$ storage rings. The study is based on 298 fb$^{-1}$ of data recorded with the BaBar detector. A structure is observed in the cross-section not far above threshold, near 4.32 GeV. We also investigate the compatibility of this structure with the Y(4260) previously reported by this experiment.

1 data table

The measured c.m. energy dependence of the cross section with statistical errors only.. Bins with no recorded data are shown as a 'dash'.


The e+ e- ---> 3(pi+ pi-), 2(pi+ pi- pi0) and K+ K- 2(pi+ pi-) cross sections at center-of-mass energies from production threshold to 4.5-GeV measured with initial-state radiation

The BaBar collaboration Aubert, Bernard ; Barate, R. ; Boutigny, D. ; et al.
Phys.Rev.D 73 (2006) 052003, 2006.
Inspire Record 709730 DOI 10.17182/hepdata.41843

We study the processes e+ e- --> 3(pi+pi-)gamma, 2(pi+pi-pi0)gamma and K+ K- 2(pi+pi-)gamma, with the photon radiated from the initial state. About 20,000, 33,000 and 4,000 fully reconstructed events, respectively, have been selected from 232 fb-1 of BaBar data. The invariant mass of the hadronic final state defines the effective e+e- center-of-mass energy, so that these data can be compared with the corresponding direct e+e- measurements. From the 3(pi+pi-), 2(pi+pi-pi0) and K+ K- 2(pi+pi-) mass spectra, the cross sections for the processes e+ e- --> 3(pi+pi-), e+ e- --> 2(pi+pi-pi0) and e+ e- --> K+ K- 2(pi+pi-) are measured for center-of-mass energies from production threshold to 4.5 GeV. The uncertainty in the cross section measurement is typically 6-15%. We observe the J/psi in all these final states and measure the corresponding branching fractions.

3 data tables

The cross section for E+ E- --> 3PI+ 3PI- as measured with the ISR data. Errors are statistical only.

The cross section for E+ E- --> 2PI+ 2PI- 2PI0 as measured with the ISR data. Errors are statistical only.

The cross section for E+ E- --> K+ K- 2PI+ 2PI- as measured with the ISR data. Errors are statistical only.


Multiplicity and pseudorapidity distributions of charged particles and photons at forward pseudorapidity in Au + Au collisions at s(NN)**(1/2) = 62.4-GeV.

The STAR collaboration Adams, J. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.C 73 (2006) 034906, 2006.
Inspire Record 697905 DOI 10.17182/hepdata.98930

We present the centrality dependent measurement of multiplicity and pseudorapidity distributions of charged particles and photons in Au + Au collisions at sqrt{s_NN} = 62.4 GeV. The charged particles and photons are measured in the pseudorapidity region 2.9 < eta < 3.9 and 2.3 < eta < 3.7, respectively. We have studied the scaling of particle production with the number of participating nucleons and the number of binary collisions. The photon and charged particle production in the measured pseudorapidity range has been shown to be consistent with energy independent limiting fragmentation behavior. The photons are observed to follow a centrality independent limiting fragmentation behavior while for the charged particles it is centrality dependent. We have carried out a comparative study of the pseudorapidity distributions of positively charged hadrons, negatively charged hadrons, photons, pions, net protons in nucleus--nucleus collisions and pseudorapidity distributions from p+p collisions. From these comparisons we conclude that baryons in the inclusive charged particle distribution are responsible for the observed centrality dependence of limiting fragmentation. The mesons are found to follow an energy independent behavior of limiting fragmentation while the behavior of baryons seems to be energy dependent.

11 data tables

(Color Online) Variation of $N_{ch}$ normalized to the number of participating nucleon pair in the FTPC coverage $(2.9 \leq \eta \leq 3.9)$ and $N_{\gamma}$ normalized to the number of participating nucleon pair in the PMD acceptance $(2.3 \leq \eta \leq 3.7)$ as a function of $N_{part}$. The lower band shows the uncertainty in the ratio due to uncertainties in $N_{part}$ calculations.

(Color Online) Variation of $N_{ch}$ normalized to the number of participating nucleon pair in the FTPC coverage $(2.9 \leq \eta \leq 3.9)$ and $N_{\gamma}$ normalized to the number of participating nucleon pair in the PMD acceptance $(2.3 \leq \eta \leq 3.7)$ as a function of $N_{part}$. The lower band shows the uncertainty in the ratio due to uncertainties in $N_{part}$ calculations.

(Color Online) Variation of $N_{ch}$ normalized to the number of collisions in the FTPC coverage $(2.9 \leq \eta \leq 3.9)$ and $N_{\gamma}$ normalized to number of collisions, in the PMD coverage $(2.3 \leq \eta \leq 3.7)$ as a function of $N_{coll}$. The lower band shows the uncertainty in the ratio due to uncertainties in $N_{coll}$ calculations.

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The e+ e- ---> pi+ pi- pi+ pi-, K+ K- pi+ pi-, and K+ K- K+ K- cross sections at center-of-mass energies 0.5-GeV to 4.5-GeV measured with initial-state radiation

The BaBar collaboration Aubert, Bernard ; Barate, R. ; Boutigny, D. ; et al.
Phys.Rev.D 71 (2005) 052001, 2005.
Inspire Record 676691 DOI 10.17182/hepdata.22111

We study the process $e^+e^-\to\pi^+\pi^-\pi^+\pi^-\gamma$, with a hard photon radiated from the initial state. About 60,000 fully reconstructed events have been selected from 89 $fb^{-1}$ of BaBar data. The invariant mass of the hadronic final state defines the effective \epem center-of-mass energy, so that these data can be compared with the corresponding direct $e^+e^-$ measurements. From the $4\pi$-mass spectrum, the cross section for the process $e^+e^-\to\pi^+\pi^-\pi^+\pi^-$ is measured for center-of-mass energies from 0.6 to 4.5 $GeV/c^2$. The uncertainty in the cross section measurement is typically 5%. We also measure the cross sections for the final states $K^+ K^- \pi^+\pi^-$ and $K^+ K^- K^+ K^-$. We observe the $J/\psi$ in all three final states and measure the corresponding branching fractions. We search for X(3872) in $J/\psi (\to\mu^+\mu^-) \pi^+\pi^-$ and obtain an upper limit on the product of the $e^+e^-$ width of the X(3872) and the branching fraction for $X(3872) \to J/\psi\pi^+\pi^-$.

3 data tables

Measured PI+ PI- PI+ PI- cross sections. The errors are statistical only.

Measured K+ K- PI+ PI- cross sections. The errors are statistical only.

Measured K+ K- K+ K- cross sections. The errors are statistical only.