Long-range Pseudorapidity Dihadron Correlations in D + Au Collisions at {u221A}SNN

Long-range Pseudorapidity Dihadron Correlations in D + Au Collisions at {u221A}SNN
Author:
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Total Pages: 7
Release: 2015
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Dihadron angular correlations in d + Au collisions at √sNN = 200 GeVare reported as a function of the measured zero-degree calorimeter neutral energy and the forward charged hadron multiplicity in the Au-beam direction. A finite correlated yield is observed at large relative pseudorapidity (? ?) on the near side (id est relative azimuth ? ? ̃0). This correlated yield as a function of ?? appears to scale with the dominant, primarily jet-related, away-side (? ? ̃?) yield. The Fourier coefficients of the ?? correlation, Vn = cosn ?? , have a strong ?? dependence. In addition, it is found that V1 is approximately inversely proportional to the mid-rapidity event multiplicity, while V2 is independent of it with similar magnitude in the forward (d-going) and backward (Au-going) directions.

Long-range Pseudorapidity Dihadron Correlations in D + Au Collisions at [arrow]"NN

Long-range Pseudorapidity Dihadron Correlations in D + Au Collisions at [arrow]
Author:
Publisher:
Total Pages: 7
Release: 2015
Genre:
ISBN:

Dihadron angular correlations in d + Au collisions at [arrow]"NN = 200 GeVare reported as a function of the measured zero-degree calorimeter neutral energy and the forward charged hadron multiplicity in the Au-beam direction. A finite correlated yield is observed at large relative pseudorapidity ([Delta][eta]) on the near side (i.e. relative azimuth [Delta][Phi] ~ 0). This correlated yield as a function of [Delta][eta] appears to scale with the dominant, primarily jet-related, away-side ([Delta][Phi] ~ [pi]) yield. The Fourier coefficients of the [Delta][Phi] correlation, Vn = cosn[Delta][Phi], have a strong [Delta][eta] dependence. In addition, it is found that V1 is approximately inversely proportional to the mid-rapidity event multiplicity, while V2 is independent of it with similar magnitude in the forward (d-going) and backward (Au-going) directions.

Long Range Rapidity Correlations and Jet Production in High Energy Nuclear Collisions

Long Range Rapidity Correlations and Jet Production in High Energy Nuclear Collisions
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Release: 2010
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The STAR Collaboration at RHIC presents a systematic study of high transverse momentum charged di-hadron correlations at small azimuthal pair separation [Delta][phi], in d+Au and central Au+Au collisions at √s{sub NN} = 200 GeV. Significant correlated yield for pairs with large longitudinal separation [Delta][eta] is observed in central Au+Au, in contrast to d+Au collisions. The associated yield distribution in [Delta][eta] x [delta][phi] 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 [Delta][phi] and depends only weakly on [Delta][eta], the 'ridge'. Using two systematically independent analyses, finite ridge yield is found to persist for trigger p{sub t} > 6 GeV/c, 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

Long-range Pseudorapidity Correlations at High Pt in [square Root]nn

Long-range Pseudorapidity Correlations at High Pt in [square Root]nn
Author: Martin John Michael Codrington
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Total Pages:
Release: 2012
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The Quark Gluon Plasma (QGP) is a form of matter in which quarks and gluons are deconfined, and was suggested to be formed in high-energy heavy-ion collisions. Since the discovery of high-pT hadron suppression in central Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC), and the related discovery of the quenching of the away-side jet in these collisions, the role of jets as key probes of the QGP was re-affirmed. The Solenoidal Tracker At RHIC (STAR) detector system, which is suited for jet studies because of its large solid-angle coverage, has produced a number of interesting jet measurements in recent years, including gamma-jet measurements, attempts at full heavy-ion jet reconstruction, and two-dimensional correlations. A long-range correlation in pseudorapidity (the "Ridge") was studied (with statistical significance) out to pT^trig.

A Study of Jets at the STAR Experiment at the Relativistic Heavy Ion Collider Via Two-particle Correlations

A Study of Jets at the STAR Experiment at the Relativistic Heavy Ion Collider Via Two-particle Correlations
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Jets have been studied in high energy heavy ion collisions by measuring the angular correlation between particles at high transverse momentum. Differences in the yield and shape of the angular correlations as a function of system size give information on the medium produced in the collision. Such modifications can be used to infer the presence of a Quark-Gluon Plasma phase, wherein parton degrees of freedom are manifest over nuclear rather than nucleonic scales. In the present work, two-particle correlations were studied in \(d+Au\) and \(Au+Au\) collisions at \(\sqrt{s_{NN}}\) = 200 GeV measured by the STAR experiment at RHIC. The technique was extended to include pseudo-rapidity, permitting jets to be characterised in two-dimensions, and enabling the jet shape to be studied in greater detail. Corrections were developed for the incomplete detector acceptance and finite two-track resolution. Both unidentified and identified particle correlations were studied, using charged tracks and neutral strange particles \(\Lambda, \overline{\Lambda}\), and \(K^0_{Short}\) reconstructed from their characteristic \(V\)0 decay topology. The focus of the analysis was the correlation peak centred at zero azimuthal separation, which is significantly enhanced in central \(Au+Au\) collisions compared to lighter systems. The modified peak was found to comprise a jet-like peak broadened in the pseudo-rapidity direction, sitting atop a long range pseudo-rapidity correlation. The former is suggestive of jet modification by the medium, and the latter may indicate a medium response to jets. Correlations with identified particles indicated the modified same side peak may in part be formed from particles originating from the underlying event.