Refine
Year of publication
- 2022 (421)
- 2023 (415)
- 2021 (385)
- 2019 (299)
- 2020 (273)
- 2017 (237)
- 2018 (224)
- 2024 (196)
- 2015 (185)
- 2016 (181)
- 2014 (133)
- 2012 (128)
- 2013 (113)
- 2011 (112)
- 2004 (107)
- 2005 (97)
- 2003 (90)
- 2010 (87)
- 2002 (85)
- 1999 (75)
- 2006 (69)
- 2009 (67)
- 2001 (65)
- 1998 (64)
- 2008 (64)
- 2007 (62)
- 1997 (55)
- 2000 (49)
- 1995 (34)
- 1996 (29)
- 1994 (23)
- 1993 (18)
- 1992 (17)
- 1986 (16)
- 1983 (14)
- 1984 (14)
- 1966 (13)
- 1990 (12)
- 1972 (11)
- 1981 (11)
- 1980 (10)
- 1987 (10)
- 1988 (10)
- 1962 (9)
- 1976 (9)
- 1991 (9)
- 1954 (8)
- 1965 (8)
- 1967 (8)
- 1974 (8)
- 1978 (8)
- 1982 (8)
- 1985 (8)
- 1989 (8)
- 1971 (7)
- 1977 (6)
- 1979 (6)
- 1956 (5)
- 1957 (5)
- 1958 (5)
- 1959 (5)
- 1973 (5)
- 1953 (4)
- 1960 (4)
- 1970 (4)
- 1975 (4)
- 1950 (3)
- 1952 (3)
- 1961 (3)
- 1964 (3)
- 1969 (3)
- 1947 (2)
- 1963 (2)
- 1968 (2)
- 1919 (1)
- 1921 (1)
- 1923 (1)
- 1926 (1)
- 1928 (1)
- 1949 (1)
- 1951 (1)
- 1955 (1)
Document Type
- Article (2040)
- Preprint (1436)
- Doctoral Thesis (597)
- Conference Proceeding (249)
- diplomthesis (100)
- Bachelor Thesis (75)
- Master's Thesis (61)
- Contribution to a Periodical (46)
- Diploma Thesis (34)
- Book (33)
Has Fulltext
- yes (4762) (remove)
Keywords
- Kollisionen schwerer Ionen (47)
- heavy ion collisions (44)
- LHC (27)
- Quark-Gluon-Plasma (25)
- Heavy Ion Experiments (21)
- BESIII (19)
- equation of state (19)
- quark-gluon plasma (19)
- Relativistic heavy-ion collisions (18)
- QCD (16)
Institute
- Physik (4762) (remove)
In the framework of RQMD we investigate antiproton observables in massive heavy ion collisions at AGS energies and compare to preliminary results of the E878 collaboration. We focus here on the considerable influence of the real part of an antinucleon nucleus optical potential on the ¯p momentum spectra. Pacs-numbers: 14.20 Dh, 25.70.-z
We study the thermodynamic properties of infinite nuclear matter with the Ultrarelativistic Quantum Molecular Dynamics (URQMD), a semiclassical transport model, running in a box with periodic boundary conditions. It appears that the energy density rises faster than T4 at high temperatures of T approx. 200 - 300 MeV. This indicates an increase in the number of degrees of freedom. Moreover, We have calculated direct photon production in Pb+Pb collisions at 160 GeV/u within this model. The direct photon slope from the microscopic calculation equals that from a hydrodynamical calculation without a phase transition in the equation of state of the photon source.
A study of secondary Drell-Yan production in nuclear collisions is presented for SPS energies. In addition to the lepton pairs produced in the initial collisions of the projectile and target nucleons, we consider the potentially high dilepton yield from hard valence antiquarks in produced mesons and antibaryons. We calculate the secondary Drell-Yan contributions taking the collision spectrum of hadrons from the microscopic model URQMD. The con- tributions from meson-baryon interactions, small in hadron-nucleus interac- tions, are found to be substantial in nucleus-nucleus collisions at low dilepton masses. Preresonance collisions of partons may further increase the yields.
We demonstrate that the creation of strange matter is conceivable in the midrapidity region of heavy ion collisions at Brookhaven RHIC and CERN LHC. A finite net-baryon density, abundant (anti)strangeness production, as well as strong net-baryon and net-strangeness fluctuations, provide suitable initial conditions for the formation of strangelets or metastable exotic multistrange ( baryonic) objects. Even at very high initial entropy per baryon SyAinit ¯ 500 and low initial baryon numbers of Ainit B ¯ 30 a quark-gluon-plasma droplet can immediately charge up with strangeness and accumulate net-baryon number. PACS numbers: 25.75.Dw, 12.38.Mh, 24.85.+
We calculate the evolution of quark-gluon-plasma droplets during the hadronization in a thermodynamical model. It is speculated that cooling as well as strangeness enrichment allow for the formation of strangelets even at very high initial entropy per baryon S/Ainit H 500 and low initial baryon numbers of Ainit B H 30. It is shown that the droplet with vanishing initial chemical potential of strange quarks and a very moderate chemical potential of up/down quarks immediately charges up with strangeness. Baryon densi- ties of H 2 0 and strange chemical potentials of µs > 350 MeV are reached if strangelets are stable. The importance of net baryon and net strangeness fluctuations for the possible strangelet formation at RHIC and LHC is em- phasized. Pacs-Classif.: 25.15.tr, 12.38.Mh, 24.85.tp
We present a RQMD calculation of antiproton yields and their momentum distribution in Ne + NaF collisions at 2 GeV/u. The antiprotons can be produced below threshold due to multi-step excitations for which meson-baryon interactions play a considerable role. In this system the annihilation probability for an initially produced antiproton is predicted to be about 65%.
Measured hadron yields from relativistic nuclear collisions can be equally well understood in two physically distinct models, namely a static thermal hadronic source vs. a time-dependent, nonequilibrium hadronization o a quark-gluon plasma droplet. Due to the time-dependent particle evapora- tion o the hadronic surface in the latter approach the hadron ratios change (by factors of <H 5) in time. Final particle yields reflect time averages over the actual thermodynamic properties of the system at a certain stage of the evolution. Calculated hadron, strangelet and (anti-)cluster yields as well as freeze-out times are presented for di erent systems. Due to strangeness distillation the system moves rapidly out of the T, µq plane into the µs-sector. Classif.: 25.75.Dw, 12.38.Mh, 24.85.+p
The deconfinement transition region between hadronic matter and quark-gluon plasma is studied for finite volumes. Assuming simple model equations of state and a first order phase transition, we find that fluctuations in finite volumes hinder a sharp separation between the two phases around the critical temperature, leading to a rounding of the phase transition. For reaction volumes expected in heavy ion experiments, the softening of the equation of state is reduced considerably. This is especially true when the requirement of exact color-singletness is included in the QGP equation of state.
Measured hadron yields from relativistic nuclear collisions can be equally well understood in two physically distinct models, namely a static thermal hadronic source versus a time-dependent, non-equilibrium hadronization off a quark gluon plasma droplet. Due to the time-dependent particle evaporation off the hadronic surface in the latter approach the hadron ratios change (by factors of / 5) in time. The overall particle yields then reflect time averages over the actual thermodynamic properties of the system at a certain stage of evolution.