Akar, Simon
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Multi-particle azimuthal correlations in p-Pb and Pb-Pb collisions at the LHC

The ALICE collaboration Abelev, Betty Bezverkhny ; Adam, Jaroslav ; Adamova, Dagmar ; et al.
Phys.Rev.C 90 (2014) 054901, 2014.
Inspire Record 1300038 DOI 10.17182/hepdata.65710

Measurements of multi-particle azimuthal correlations (cumulants) for charged particles in p-Pb and Pb-Pb collisions are presented. They help address the question of whether there is evidence for global, flow-like, azimuthal correlations in the p-Pb system. Comparisons are made to measurements from the larger Pb-Pb system, where such evidence is established. In particular, the second harmonic two-particle cumulants are found to decrease with multiplicity, characteristic of a dominance of few-particle correlations in p-Pb collisions. However, when a $|\Delta \eta|$ gap is placed to suppress such correlations, the two-particle cumulants begin to rise at high-multiplicity, indicating the presence of global azimuthal correlations. The Pb-Pb values are higher than the p-Pb values at similar multiplicities. In both systems, the second harmonic four-particle cumulants exhibit a transition from positive to negative values when the multiplicity increases. The negative values allow for a measurement of $v_{2}\{4\}$ to be made, which is found to be higher in Pb-Pb collisions at similar multiplicities. The second harmonic six-particle cumulants are also found to be higher in Pb-Pb collisions. In Pb-Pb collisions, we generally find $v_{2}\{4\} \simeq v_{2}\{6\}\neq 0$ which is indicative of a Bessel-Gaussian function for the $v_{2}$ distribution. For very high-multiplicity Pb-Pb collisions, we observe that the four- and six-particle cumulants become consistent with 0. Finally, third harmonic two-particle cumulants in p-Pb and Pb-Pb are measured. These are found to be similar for overlapping multiplicities, when a $|\Delta\eta| > 1.4$ gap is placed.

42 data tables
Table 1

No description provided.

Table 2

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Event-plane dependent dihadron correlations with harmonic $v_n$ subtraction in Au+Au Collisions at $\sqrt{s_{_{\rm NN}}}=200$ GeV

The STAR collaboration Agakishiev, H. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.C 89 (2014) 041901, 2014.
Inspire Record 1288534 DOI 10.17182/hepdata.97120

STAR measurements of dihadron azimuthal correlations ($\Delta\phi$) are reported in mid-central (20-60\%) Au+Au collisions at $\sqrt{s_{_{\rm NN}}}=200$ GeV as a function of the trigger particle's azimuthal angle relative to the event plane, $\phi_{s}=|\phi_{t}-\psi_{\rm EP}|$. The elliptic ($v_2$), triangular ($v_3$), and quadratic ($v_4$) flow harmonic backgrounds are subtracted using the Zero Yield At Minimum (ZYAM) method. The results are compared to minimum-bias d+Au collisions. It is found that a finite near-side ($|\Delta\phi|<\pi/2$) long-range pseudorapidity correlation (ridge) is present in the in-plane direction ($\phi_{s}\sim 0$). The away-side ($|\Delta\phi|>\pi/2$) correlation shows a modification from d+Au data, varying with $\phi_{s}$. The modification may be a consequence of pathlength-dependent jet-quenching and may lead to a better understanding of high-density QCD.

0 data tables

Measurements of Dihadron Correlations Relative to the Event Plane in Au+Au Collisions at $\sqrt{s_{NN}}=200$ GeV

The STAR collaboration Agakishiev, H. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Chin.Phys.C 45 (2021) 044002, 2021.
Inspire Record 872067 DOI 10.17182/hepdata.102351

Dihadron azimuthal correlations containing a high transverse momentum ($p_T$) trigger particle are sensitive to the properties of the nuclear medium created at RHIC through the strong interactions occurring between the traversing parton and the medium, i.e. jet-quenching. Previous measurements revealed a strong modification to dihadron azimuthal correlations in Au+Au collisions with respect to p+p and d+Au collisions. The modification increases with the collision centrality, suggesting a path-length or energy density dependence to the jet-quenching effect. This paper reports STAR measurements of dihadron azimuthal correlations in mid-central (20-60%) Au+Au collisions at $\sqrt{s_{_{\rm NN}}}=200$ GeV as a function of the trigger particle's azimuthal angle relative to the event plane, $\phi_s=|\phi_t-\psi_{\rm EP}|$. The azimuthal correlation is studied as a function of both the trigger and associated particle $p_T$. The subtractions of the combinatorial background and anisotropic flow, assuming Zero Yield At Minimum (ZYAM), are described. The correlation results are first discussed with subtraction of the even harmonic (elliptic and quadrangular) flow backgrounds. The away-side correlation is strongly modified, and the modification varies with $\phi_s$, with a double-peak structure for out-of-plane trigger particles. The near-side ridge (long range pseudo-rapidity $\Delta\eta$ correlation) appears to drop with increasing $\phi_s$ while the jet-like component remains approximately constant. The correlation functions are further studied with subtraction of odd harmonic triangular flow background arising from fluctuations. It is found that the triangular flow, while responsible for the majority of the amplitudes, is not sufficient to explain the $\phi_s$-dependence of the ridge or the away-side double-peak structure. ...

879 data tables
data table 583

flow background with lower flow systematic uncertainty Au+Au 20-60%, 4<p_{\text{T}}^{(t)}<6 GeV/c, slice 5

data table 584

flow background with lower flow systematic uncertainty Au+Au 20-60%, 4<p_{\text{T}}^{(t)}<6 GeV/c, slice 0

data table 585

flow background with lower flow systematic uncertainty Au+Au 20-60%, 4<p_{\text{T}}^{(t)}<6 GeV/c, slice 1

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K*0 production in Cu+Cu and Au+Au collisions at \sqrt{s_NN} = 62.4 GeV and 200 GeV

The STAR collaboration Aggarwal, M.M. ; Ahammed, Z. ; Alakhverdyants, A.V. ; et al.
Phys.Rev.C 84 (2011) 034909, 2011.
Inspire Record 857694 DOI 10.17182/hepdata.102405

We report on K*0 production at mid-rapidity in Au+Au and Cu+Cu collisions at \sqrt{s_{NN}} = 62.4 and 200 GeV collected by the Solenoid Tracker at RHIC (STAR) detector. The K*0 is reconstructed via the hadronic decays K*0 \to K+ pi- and \bar{K*0} \to K-pi+. Transverse momentum, pT, spectra are measured over a range of pT extending from 0.2 GeV/c to 5 GeV/c. The center of mass energy and system size dependence of the rapidity density, dN/dy, and the average transverse momentum, <pT>, are presented. The measured N(K*0)/N(K) and N(\phi)/N(K*0) ratios favor the dominance of re-scattering of decay daughters of K*0 over the hadronic regeneration for the K*0 production. In the intermediate pT region (2.0 < pT < 4.0 GeV/c), the elliptic flow parameter, v2, and the nuclear modification factor, RCP, agree with the expectations from the quark coalescence model of particle production.

64 data tables
Table 1

The K$\pi$ pair invariant mass distribution integrated over the $K^{*0}$ $p_T$ for minimum bias Au+Au collisions at $\sqrt{s_{NN}}$ =200 GeV after mixed-event background subtraction.

Table 2

The K$\pi$ pair invariant mass distribution integrated over the $K^{*0}$ $p_T$ for minimum bias Au+Au collisions at $\sqrt{s_{NN}}$ =62.4 GeV after mixed-event background subtraction.

Table 3

The K$\pi$ pair invariant mass distribution integrated over the $K^{*0}$ $p_T$ for minimum bias Cu+Cu collisions at $\sqrt{s_{NN}}$ =200 GeV after mixed-event background subtraction.

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Higher Moments of Net-proton Multiplicity Distributions at RHIC

The STAR collaboration Aggarwal, M.M. ; Ahammed, Z. ; Alakhverdyants, A.V. ; et al.
Phys.Rev.Lett. 105 (2010) 022302, 2010.
Inspire Record 853304 DOI 10.17182/hepdata.73344

We report the first measurements of the kurtosis (\kappa), skewness (S) and variance (\sigma^2) of net-proton multiplicity (N_p - N_pbar) distributions at midrapidity for Au+Au collisions at \sqrt(s_NN) = 19.6, 62.4, and 200 GeV corresponding to baryon chemical potentials (\mu_B) between 200 - 20 MeV. Our measurements of the products \kappa \sigma^2 and S \sigma, which can be related to theoretical calculations sensitive to baryon number susceptibilities and long range correlations, are constant as functions of collision centrality. We compare these products with results from lattice QCD and various models without a critical point and study the \sqrt(s_NN) dependence of \kappa \sigma^2. From the measurements at the three beam energies, we find no evidence for a critical point in the QCD phase diagram for \mu_B below 200 MeV.

0 data tables

Electromagnetic Form-Factors of the Proton at Low Four-Momentum Transfer

Borkowski, F. ; Peuser, P. ; Simon, G.G. ; et al.
Nucl.Phys.B 93 (1975) 461-478, 1975.
Inspire Record 850 DOI 10.17182/hepdata.31992

The 300 MeV electron linear accelerator of Mainz has been used to measure the angular dependence of the electron-proton elastic scattering cross sections at seven different energies for squared four-momentum transfers between 0.13 and 4.7 fm −2 . The proton form factors have been extracted from the cross sections by means of Rosenbluth plots and by fitting parametrized analytical functions directly to the cross sections. The best fit is compared to the data of other laboratories. The previously reported deviations from the dipole fit have been confirmed. From the form factors at q 2 <0.9 fm 2 the proton r.m.s. radius has been determined. A determination of the spectral function of the nucleon isovector form factor G E V in the time-like is obtained using a realistic ϱ resonance.

9 data tables
Table 1

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Electromagnetic form-factors of the proton at low four-momentum transfer

Borkowski, F. ; Peuser, P. ; Simon, G.G. ; et al.
Nucl.Phys.A 222 (1974) 269-275, 1974.
Inspire Record 94754 DOI 10.17182/hepdata.37116

Electron-proton elastic scattering cross sections were measured at low four-momentum transfers squared ( q 2 from 0.13 to 2.15 fm −2 ) at six different energies between 150 and 275 MeV. The electric ( G E ) and magnetic ( G M ) form factors of the proton have been determined by Rosenbluth plots and independently by using analytical functions for the form factors to fit the cross sections. The electric form factor is found to deviate significantly from the dipole fit. From the slope of the form factor functions at q 2 = 0 the rms radii of the charge and the magnetic moment distribution were determined. The charge rms radius is found to be more than 10% larger than the value given by the dipole fit.

6 data tables
Table 1

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Table 3

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