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Correlations and Fluctuations: Status and Perspectives

Description: We will provide an overview of the physics which can be addressed by studying fluctuations and correlations in heavy ion collisions. Observables, which have been discussed in the literature will be briefly reviewed and put in context with experiment and information from Lattice QCD. Special attention will be given to the QCD critical point and the first order co-existence region.
Date: April 15, 2008
Creator: Koch, Volker & Koch, Volker
Partner: UNT Libraries Government Documents Department

Hadronic Correlations and Fluctuations

Description: We will provide a review of some of the physics which can be addressed by studying fluctuations and correlations in heavy ion collisions. We will discuss Lattice QCD results on fluctuations and correlations and will put them into context with observables which have been measured in heavy-ion collisions. Special attention will be given to the QCD critical point and the first order co-existence region, and we will discuss how the measurement of fluctuations and correlations can help in an experimental search for non-trivial structures in the QCD phase diagram.
Date: October 9, 2008
Creator: Koch, Volker
Partner: UNT Libraries Government Documents Department

Exposing the non-collectivity in elliptic flow

Description: We show that backward-forward elliptic asymmetry correlations provide an experimentally accessible observable which distinguishes between collective and non-collective contributions to the observed elliptic asymmetry v2 in relativistic heavy ion collisions. The measurement of this observable will reveal the momentum scale at which collective expansion seizes and where the elliptic asymmetry is dominated by (semi)-hard processes. In addition, the knowledge of the actual magnitude of the collective component of the elliptic asymmetry will be essential for the extraction of the viscosity of the matter created in these collisions.
Date: February 13, 2009
Creator: Liao, Jinfeng & Koch, Volker
Partner: UNT Libraries Government Documents Department

Exact Relativistic Ideal Hydrodynamical Solutions in (1+3)D with Longitudinal and Transverse Flows

Description: A new method for solving relativistic ideal hydrodynamics in (1+3)D is developed. Longitudinal and transverse radial flows are explicitly embedded into the ansatz for velocity field and the hydrodynamic equations are reduced to a single equation for the transverse velocity field only, which is analytically more tractable as compared with the full hydrodynamic equations. As an application we use the method to find analytically all possible solutions whose transverse velocity fields have power dependence on proper time and transverse radius. Possible application to the Relativistic Heavy Ion Collisions and possible generalizations of the method are discussed.
Date: May 20, 2009
Creator: Liao, Jinfeng & Koch, Volker
Partner: UNT Libraries Government Documents Department

Crossover transition in bag-like models

Description: We formulate a simple model for a gas of extended hadrons at zero chemical potential by taking inspiration from the compressible bag model. We show that a crossover transition qualitatively similar to lattice QCD can be reproduced by such a system by including some appropriate additional dynamics. Under certain conditions, at high temperature, the system consist of a finite number of infinitely extended bags,which occupy the entire space. In this situation the system behaves as an ideal gas of quarks and gluons.
Date: March 13, 2009
Creator: Ferroni, Lorenzo & Koch, Volker
Partner: UNT Libraries Government Documents Department

Cherenkov Radiation from Jets in Heavy-ion Collisions

Description: The possibility of Cherenkov-like gluon bremsstrahlung in dense matter is studied. We point out that the occurrence of Cherenkov radiation in dense matter is sensitive to the presence of partonic bound states. This is illustrated by a calculation of the dispersion relation of a massless particle in a simple model in which it couples to two different massive resonance states. We further argue that detailed spectroscopy of jet correlations can directly probe the index of refraction of this matter, which in turn will provide information about the mass scale of these partonic bound states.
Date: July 26, 2005
Creator: Koch, Volker; Majumder, Abhijit & Wang, Xin-Nian
Partner: UNT Libraries Government Documents Department

Baryon-strangeness correlations: a diagnostic of stronglyinteracting matter

Description: The correlation between baryon number and strangeness elucidates the nature of strongly interacting matter. This diagnostic can be extracted theoretically from lattice QCD calculations and experimentally from event-by-event fluctuations. The analysis of present lattice results above the critical temperature severely limits the presence of q{bar q} bound states, thus supporting a picture of independent (quasi)quarks. Details may be found in [1].
Date: October 7, 2005
Creator: Koch, Volker; Majumder, Abhijit & Randrup, Jorgen
Partner: UNT Libraries Government Documents Department

Event by event fluctuations in heavy ion collisions

Description: The authors discuss the physics underlying event-by-event fluctuations in relativistic heavy ion collisions. We will argue that the fluctuations of the ratio of positively over negatively charged particles may serve as a unique signature for the Quark Gluon Plasma.
Date: January 1, 2001
Creator: Koch, Volker
Partner: UNT Libraries Government Documents Department

The {phi} mean free path in hot hadronic matter

Description: We calculate the {phi} meson collision rate and mean free path in a hot hadronic gas. The Hidden Local Symmetry model is used to take into account interactions of {phi} mesons with pseudoscalar ({pi}, K) and vector mesons ({rho}, {omega}, K*, {phi}). In contrast to previous calculations we find a significantly small mean free path (around 1 fm at T=200MeV). This implies that {phi} mesons produced after hadronization in relativistic heavy ion collisions will not leave the collision region without scattering. The consequences of these findings to the analysis of {phi} yields are discussed.
Date: February 20, 2002
Creator: Alvarez-Ruso, Luis & Koch, Volker
Partner: UNT Libraries Government Documents Department

Strangeness at SIS energies

Description: In this contribution the authors discuss the physics of strange hadrons in low energy ({approx_equal} 1-2 AGeV) heavy ion collision. In this energy range the relevant strange particle are the kaons and anti-kaons. The most interesting aspect concerning these particles are so called in-medium modifications. They will attempt to review the current status of understanding of these in medium modifications. In addition they briefly discuss other issues related with kaon production, such as the nuclear equation of state and chemical equilibrium.
Date: September 28, 2005
Creator: Koch, Volker
Partner: UNT Libraries Government Documents Department

DUSEL-related Science at LBNL -- Program and Opportunities

Description: The National Science Foundation is advancing the design of a Deep Underground Science and Engineering Laboratory (DUSEL) at the former Homestake mine in South Dakota. UC Berkeley and LBNL are leading the design effort for the facility and coordinating the definition and integration of the suite of experiments to be coupled to the facility design in the creation of an MREFC (Major Research Equipment and Facility Construction) proposal. The State of South Dakota has marshaled $120M to prepare the site and begin a modest science program at the 4850 ft level. The first physics experiment is anticipated to begin installation in 2009. The current timetable calls for the MREFC Preliminary Design to be assembled by 2010 to be presented to the National Science Board in 2011. This, in turn, indicates that the earliest DUSEL construction start would be FY2013. The MREFC is estimated (before the inclusion of the long baseline neutrino components) at $500--600M, roughly divided evenly between the experimental program and support for the facility. Construction was estimated at 6--8 years. The DOE and NSF are establishing a Joint Oversight Group (JOG) to coordinate the experimental programs and participation in DUSEL. It is anticipated that the JOG would mirror the similar function for the NSF and DOE participation in the LHC, and that DOE-HEP, DOE-NP, and NSF will all participate in the JOG. In parallel with the NSF efforts, DOE-HEP plans to develop a long baseline neutrino program with neutrino beams created at FNAL and aimed at DUSEL. In the P5 report the focus of the program is to pursue CP violation in the lepton sector. The same detectors can also be used for nucleon decay experiments. DOE has indicated that FNAL would be the ''lead lab'' for the long baseline neutrino program and be charged with designing and ...
Date: August 1, 2009
Creator: Bauer, Christian; Detweiler, Jason; Freedman, Stuart; Gilchriese, Murdock; Kadel, Richard; Koch, Volker et al.
Partner: UNT Libraries Government Documents Department

Phi meson propagation in a hot hadronic gas

Description: The Hidden Local Symmetry Lagrangian is used to study the interactions of phi mesons with other pseudoscalar and vector mesons in a hadronic gas at finite temperature. We have found a significantly small phi mean free path (less than 2.4 fm at T > 170 MeV) due to large collision rates with rho mesons, kaons and predominantly K* in spite of their heavy mass. This implies that phi mesons produced after hadronization in relativistic heavy ion collisions will not leave the hadronic system without scattering. The effect of these interactions on the time evolution of the phi density in the expanding hadronic fireball is investigated.
Date: February 20, 2002
Creator: Alvarez-Ruso, Luis & Koch, Volker
Partner: UNT Libraries Government Documents Department