18 research outputs found
Flow Fluctuations from Early-Time Correlations in Nuclear Collisions
We propose that flow fluctuations have the same origin as transverse momentum
fluctuations. The common source of these fluctuations is the spatially
inhomogeneous initial state that drives hydrodynamic flow. Longitudinal
correlations from an early Glasma stage followed by hydrodynamic flow
quantitatively account for many features of multiplicity and fluctuation
data. We develop a framework for studying flow and its fluctuations in this
picture. We then compute elliptic and triangular flow fluctuations, and study
their connections to the ridge
The Glasma and the Hard Ridge
Correlation measurements indicate that excess two particle correlations
extend over causally disconnected rapidity ranges. Although, this enhancement
is broad in relative rapidity , it is focused in a narrow
region in relative azimuthal angle . The resulting
structure looks like a ridge centered at . Similar ridge
structures are observed in correlations of particles associated with a jet
trigger (the hard ridge) and in correlations without a trigger (the soft
ridge). The long range rapidity behavior requires that the correlation
originates in the earliest stage of the collision, and probes properties of the
production mechanism. Glasma initial conditions as predicted by the theory of
Color Glass Condensate and provide a and early stage correlation that naturally
extends far in rapidity. We have previously shown that the soft ridge is a
consequence of particles forming from an initial Glasma phase that experience a
later stage transverse flow. We extend this work to study the ridge dependence
on the of the correlated pairs. We then determine the soft contribution
to the hard ridge.Comment: Proceeding of the APS meeting of the Division of Particles and Fields
2009, Detroit, Mi. Also see arXiv:0910.359
Long Range Correlations and the Soft Ridge in Relativistic Nuclear Collisions
Relativistic Heavy Ion Collider experiments exhibit correlations peaked in
relative azimuthal angle and extended in rapidity. Called the ridge, this peak
occurs both with and without a jet trigger. We argue that the untriggered ridge
arises when particles formed by flux tubes in an early glasma stage later
manifest transverse flow. Combining a blast wave model of flow fixed by
single-particle spectra with a simple description of the glasma, we find
excellent agreement with current data.Comment: revised text, results unchange
Two Particle Correlations And The Ridge In Relativistic Heavy Ion Collisions
Measurements at the Relativistic Heavy Ion Collider (RHIC) find an enhancement of two particle correlations in relativistic heavy ion collisions, not present in proton-proton collisions. Because the correlation structure is wide in relative pseudorapidity and narrow in relative azimuthal angle, it is known as the ridge. The most striking feature of the ridge is that it seems to extend to a long range in relative pseudorapidity where causality limits interaction. Similar ridge structures are observed in correlations of particles associated with and without a jet trigger. We argue that the untriggered ridge arises when particles formed in an early Glasma stage later manifest transverse flow. We extend this study to address the triggered ridge in the same context. Finally we address the effects of shear viscosity on our correlation formalism
Viscosity and the Soft Ridge at RHIC
Correlation studies exhibit a ridge-like feature in rapidity and azimuthal
angle, with and without a jet trigger. We ask whether the feature in
untriggered correlations can be a consequence of transverse flow and viscous
diffusion.Comment: Proc. Quark Matter 2008, Jaipur, Indi
Soft Contribution to the Hard Ridge in Relativistic Nuclear Collisions
Nuclear collisions exhibit long-range rapidity correlations not present in
proton-proton collisions. Because the correlation structure is wide in relative
pseudorapidity and narrow in relative azimuthal angle, it is known as the
ridge. Similar ridge structures are observed in correlations of particles
associated with a jet trigger (the hard ridge) as well as correlations without
a trigger (the soft ridge). Earlier we argued that the soft ridge arises when
particles formed in an early Glasma stage later manifest transverse flow. We
extend this study to address new soft ridge measurements. We then determine the
contribution of flow to the hard ridge.Comment: 16 pages, 9 figures, includes comparison to dat
Fluctuation and flow probes of early-time correlations in relativistic heavy ion collisions
Fluctuation and correlation observables are often measured using
multi-particle correlation methods and therefore mutually probe the origins of
genuine correlations present in multi-particle distribution functions. We
investigate the common influence of correlations arising from the spatially
inhomogeneous initial state on multiplicity and momentum fluctuations as well
as flow fluctuations. Although these observables reflect different aspects of
the initial state, taken together, they can constrain a correlation scale set
at the earliest moments of the collision. We calculate both the correlation
scale in an initial stage Glasma flux tube picture and the modification to
these correlations from later stage hydrodynamic flow and find quantitative
agreement with experimental measurements over a range of collision systems and
energies.Comment: Proceedings of the 28th Winter Workshop on Nuclear Dynamics, Dorado
del Mar, Puerto Rico, April 7-14, 201
A systemic transformation of an arts and sciences curriculum to nurture inclusive excellence of all students through course-based research experiences
IntroductionWe describe herein a large-scale, multidisciplinary course-based undergraduate research experience program (CRE) developed at Lawrence Technological University (LTU). In our program, all students enrolled in CRE classes participate in authentic research experiences within the framework of the curriculum, eliminating self-selection processes and other barriers to traditional extracurricular research experiences.MethodsSince 2014, we have designed and implemented more than 40 CRE courses in our College of Arts and Sciences involving more than 30 instructors from computer science, mathematics, physics, biology, chemistry, English composition, literature, philosophy, media communication, nursing, and psychology.ResultsAssessment survey data indicates that students who participate in CRE courses have an enhanced attitude towards research and discovery, as well as increased self-efficacy. This intervention is particularly relevant for non-traditional students, such as students who commute and/or have significant work or childcare commitments, who often experience limited access to research activities.DiscussionHerein we highlight the importance of a systemic institutional change that has made this intervention sustainable and likely to outlast the external funding phase. Systemic change can emerge from a combination of conditions, including: (1) developing a critical mass of CRE courses by providing instructors with both incentives and training; (2) developing general principles on which instructors can base their CRE activities; (3) securing and maintaining institutional support to promote policy changes towards a more inclusive institution; and (4) diversifying the range of the intervention, both in terms of initiatives and disciplines involved