REVIEW
Evidence from d+Au measurements for final-state suppression of high $p_T$ hadrons in Au+Au collisions at RHIC
Nuclear Experiment · Submitted 17 Jun 2003 · 27 references
Pith's verdict: The d+Au control that made the Au+Au suppression story credible; the data are solid, but the abstract's 'demonstrate' does more work than a d+Au control can carry, and the body knows it.
T0 · AI review
Why Pith says this
Highlight any text to comment on it.
Referee report
The paper
The paper claims
By colliding deuterons with gold nuclei, the STAR experiment argues that the loss of high-momentum particles in central gold-gold collisions comes from the dense medium produced in the collision, not from the incoming nuclei.
The reading
What carries the argument
The argument rests on two measured quantities and one control. The first is the nuclear modification ratio $$R_{AB}(p_T) = rac{$d^{2}$N/dp_T d extbackslash eta}{T_{AB} $d^{2}$ extbackslash sigma_{pp}/dp_T d extbackslash eta},$$ where $T_{AB} = extbackslash langle N_{ extbackslash rm bin} extbackslash rangle / extbackslash sigma_{pp}^{ extbackslash rm inel}$ converts the p+p cross section into a binary-collision-scaled expectation; $R_{AB}=1$ means hard processes scale with the number of nucleon-nucleon collisions, $R_{AB}>1$ is enhancement, and $R_{AB}<1$ is suppression. The second is the two-particle azimuthal distribution $D( extbackslash Delta extbackslash phi)$, the per-trigger yield of associated particles relative to a high-$p_T$ trigger, fitted as a near-side Gaussian, a back-to-back Gaussian at $ extbackslash Delta extbackslash phi = extbackslash pi$, and a constant pedestal. The control is d+Au, where initial-state nuclear effects can act but a large Au+Au-like medium is not expected; the Glauber calculation supplies $ extbackslash langle N_{ extbackslash rm bin} extbackslash rangle = 15.0 extbackslash pm 1.1$ for the 20% highest-multiplicity d+Au events and sets the baseline.
Extended reading notes
Core claim
In minimum-bias and the 20% most central d+Au collisions, the nuclear modification ratio $R_{AB}(p_T)$ exceeds 1 for $2 < p_T < 7$ GeV/$c$, with a peak in the range $2.5 < p_T < 4$ GeV/$c$, while the two-particle azimuthal distribution keeps both a near-side jet peak and a back-to-back peak. The back-to-back peak broadens only slightly and is not strongly suppressed; the main change from p+p is a growing constant pedestal. The authors argue that this is the signature of initial-state multiple scattering, the Cronin effect, together with shadowing, not of the strong suppression seen in central Au+Au. Because the initial-state control does not show the suppression, they conclude that the Au+Au loss of inclusive yield and away-side pairs is due to final-state interactions with the dense medium generated in those collisions.
Load-bearing premise
The load-bearing premise is that d+Au is an adequate control for initial-state effects in Au+Au: any shadowing, multiple scattering, or saturation mechanism capable of producing the Au+Au suppression would also show up, at the measured centralities, as suppression in d+Au.
Editorial extensions
If this is right
- Initial-state gluon saturation alone cannot be the explanation for the central Au+Au high-$p_T$ suppression; any successful model must include final-state parton energy loss in the produced medium.
- The d+Au data establish a Cronin-type enhancement of charged hadrons in the $2$-$7$ GeV/$c$ range at RHIC, which constrains nuclear shadowing and multiple-scattering models of the gold nucleus.
- Away-side jet correlations survive in d+Au with only modest broadening, so the strong away-side loss is specific to the larger Au+Au system rather than to nuclear collisions in general.
- The centrality dependence in d+Au separates initial-state enhancement from final-state suppression: more central d+Au events show a larger yield enhancement but no corresponding disappearance of back-to-back pairs.
- The same deuteron-gold control strategy can be used at other collision energies and with other projectiles to test whether high-$p_T$ suppression tracks the size of the produced medium.
Reading between the lines
- A sharper test than d+Au versus Au+Au is a system scan at matched $ extbackslash langle N_{ extbackslash rm bin} extbackslash rangle$ or matched path length: if the suppression tracks produced energy density rather than the number of binary collisions, the final-state interpretation gains a quantitative handle.
- The pedestal grows with centrality but not in proportion to $ extbackslash langle N_{ extbackslash rm bin} extbackslash rangle$; that nonlinearity may encode trigger bias or correlated soft-particle production and could be checked by varying the trigger $p_T$ threshold.
- The height and position of the Cronin peak in d+Au could be used to extract an effective transport coefficient only if the same energy-loss calculation reproduces both the d+Au enhancement and the Au+Au suppression; a joint fit would be a useful next step.
- If the medium is short-lived in d+Au, one would expect no away-side suppression but perhaps a small broadening; measuring the broadening versus system size would test whether the away-side loss turns on gradually or abruptly.
Original abstract
We report measurements of single-particle inclusive spectra and two-particle azimuthal distributions of charged hadrons at high transverse momentum (high $p_T$) in minimum bias and central d+Au collisions at $\sqrt{s_{NN}}$=200 GeV. The inclusive yield is enhanced in d+Au collisions relative to binary-scaled p+p collisions, while the two-particle azimuthal distributions are very similar to those observed in p+p collisions. These results demonstrate that the strong suppression of the inclusive yield and back-to-back correlations at high $p_T$ previously observed in central Au+Au collisions are due to final-state interactions with the dense medium generated in such collisions.
The compiled record
The paper's own sentences, arranged, kept beside the review and separate from it. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.
The abstract, sentence by sentence
We report measurements of single-particle inclusive spectra and two-particle azimuthal distributions of charged hadrons at high transverse momentum (high $p_T$) in minimum bias and central d+Au collisions at $\sqrt{s_{NN}}$=200 GeV. The inclusive yield is enhanced in d+Au collisions relative to binary-scaled p+p collisions, while the two-particle azimuthal distributions are very similar to those observed in p+p collisions. These results demonstrate that the strong suppression of the inclusive yield and back-to-back correlations at high $p_T$ previously observed in central Au+Au collisions are due to final-state interactions with the dense medium generated in such collisions.
background contribution method result interpretation main claim
| # | sentence | role | the authors' own work | states the main conclusion | strength |
|---|---|---|---|---|---|
| s0 | We report measurements of single-particle inclusive spectra and two-particle azimuthal distributions of charged hadrons at high transverse momentum (high $p_T$) in minimum bias and central d+Au collisions at $\sqrt{s_{NN}}$=200 GeV. | contribution 0.97 | 0.97 | 0.02 | asserted 0.99 |
| s1 | The inclusive yield is enhanced in d+Au collisions relative to binary-scaled p+p collisions, while the two-particle azimuthal distributions are very similar to those observed in p+p collisions. | result 1.00 | 0.93 | 0.08 | asserted 1.00 |
| s2 | These results demonstrate that the strong suppression of the inclusive yield and back-to-back correlations at high $p_T$ previously observed in central Au+Au collisions are due to final-state interactions with the dense medium generated in such collisions. | interpretation 1.00 | 0.55 | 0.96 | asserted 1.00 |
What was examined, and what was not
- arXiv listing abstract v3
- full text
- figures and tables
- references and citing sentences
- relations to other papers
- P abstract
- S sections
- T body sentences
- C citations
- R cross-paper relations
Figures
Showing 3 of the paper's 4 figures. See all figures in the PDF ↗ Figures reproduced from arXiv:nucl-ex/0306024 by the authors.
References
How the literature uses it
76 arXiv papers cite this in 92 sentences
Papers whose main result relates to this one's
States the same result 3 papers
-
These measurements suggest a large energy loss of the high-$p_{T}$ particles in the highly interacting medium created in the central Au + Au collisions.
-
Comparison of the nuclear modification factors, $R_{dAu}(pT)$ and $R_{AA}(pT)$, demonstrates that the large suppression in central Au+Au collisions is due to strong final-state effects.
-
The large suppression of inclusive hadron production and absence of the away-side jet-like correlations in central Au+Au collisions are shown to be due to interactions of the jets with the very dense medium produced in these collisions.
Jets and high $p_T$ hadrons in dense matter: recent results from STAR · 0.80
Papers citing it · 71 sentences without a confident label
Uses its method or tool 2 papers
-
This is analogous to the experimental procedure of removing the pedestal [ref] .
Rapidity and centrality dependence of azimuthal correlations in high energy d+Au collisions · Correlations at $|y_T-y_A|≲1$ · 0.84
-
This is analogous to the experimental procedure of removing the pedestal [ref] .
Unveiling the nuclear structure at small x using azimuthal correlations in dA collisions · Correlations at $|y_T-y_A|≲1$ · 0.81
Uses its data or values 1 paper
-
One of the most important findings of the Relativistic Heavy Ion Collider (RHIC) was a roughly factor of five suppression of leading light hadrons with $p_T≳5$ GeV/c in central $Au+Au$ collisions [ref] .
Inconsistencies in, and short pathlength correction to, $R_{AA}(p_T)$ in $\mathrm{A}+\mathrm{A}$ and $\mathrm{p} + \mathrm{A}$ collisions · Introduction · 0.82
Compares with it 1 paper
-
Previous analyses of the charged hadron spectra by [ref] and the other RHIC experiments [ref] have demonstrated that this enhancement stands in stark contrast to the observed suppression of high $$ hadrons in the (central) collision system at $= 200$ [ref] .
Nucleon-Gold Collisions at 200 AGeV Using Tagged d+Au Interactions in PHOBOS · Introduction · 0.86
Cites it as background 16 papers
-
The ratio of the fragmentation functions in AA over collisions, , is used to study the jet modifications induced by the QGP, for example, in jet or di-hadron azimuthal correlation measurements [ref] .
Measurement of isolated-prompt photon$-$hadron correlations in Pb$-$Pb collisions at $\mathbf{\sqrt{\textit{s}_{\rm NN}} = 5.02}$ TeV · Introduction · 0.80
-
Jet modifications [ref] , compared to a baseline obtained in proton-proton collisions, have been studied extensively for over a decade at RHIC and LHC [ref] .
Sensitivity of jet quenching to the initial state in heavy-ion collisions · Introduction · 0.99
-
In the initial stage of the collision, hard scatterings between partons in the incoming nuclei produce high transverse momentum () partons that fragment into jets of hadrons with a clear back-to-back di-jet signature [ref] .
Azimuthal di-hadron correlations in d+Au and Au+Au collisions at $\sqrt{s_{NN}}=200$ GeV from STAR · Introduction · 0.96
Discussion
Disagree with the review, or know something it missed? Leave a comment, highlight any passage above to comment on it, or challenge this review formally.