Benigne zystische Raumforderungen des Hodens: Eine Übersicht

Zusammenfassung: Hodenzysten werden im Rahmen der skrotalen Sonographie zunehmend diagnostiziert. Grund hierfür ist u.a. die flächendeckende Verfügbarkeit moderner, hochauflösender Ultraschallgeräte. Differentialdiagnostisch und ätiologisch sind benigne und maligne Erkrankungen mit testikulärer Zystenbildung voneinander zu unterscheiden. Benigne Krankheitsbilder mit zystischen Raumforderungen des Hodens sind die tubuläre Ektasie des Rete testis, die zystische Dysplasie, Epidermoidzysten, einfache intraparenchymatöse Hodenzysten und Zysten der Tunica albuginea. Die testikuläre Dermoidzyste, die lange Zeit zu Unrecht als potentiell maligne angesehen wurde, ist ebenfalls als benigne zu klassifizieren. Bei Diagnose einer benignen zystischen Raumforderung des Hodens kann in den meisten Fällen eine organerhaltende operative Therapie oder ein abwartendes, überwachendes Procedere empfohlen werde

Pion, kaon, proton and anti-proton transverse momentum distributions from p+p and d+Au collisions at sNN=200\sqrt{s_{NN}} = 200 GeV

Identified mid-rapidity particle spectra of $\pi^{\pm}$, $K^{\pm}$, and $p(\bar{p})$ from 200 GeV p+p and d+Au collisions are reported. A time-of-flight detector based on multi-gap resistive plate chamber technology is used for particle identification. The particle-species dependence of the Cronin effect is observed to be significantly smaller than that at lower energies. The ratio of the nuclear modification factor ($R_{dAu}$) between protons $(p+\bar{p})$ and charged hadrons ($h$) in the transverse momentum range $1.2<{p_{T}}<3.0$ GeV/c is measured to be $1.19\pm0.05$(stat)$\pm0.03$(syst) in minimum-bias collisions and shows little centrality dependence. The yield ratio of $(p+\bar{p})/h$ in minimum-bias d+Au collisions is found to be a factor of 2 lower than that in Au+Au collisions, indicating that the Cronin effect alone is not enough to account for the relative baryon enhancement observed in heavy ion collisions at RHIC.Comment: 6 pages, 4 figures, 1 table. We extended the pion spectra from transverse momentum 1.8 GeV/c to 3. GeV/

Experimental and Theoretical Challenges in the Search for the Quark Gluon Plasma: The STAR Collaboration's Critical Assessment of the Evidence from RHIC Collisions

We review the most important experimental results from the first three years of nucleus-nucleus collision studies at RHIC, with emphasis on results from the STAR experiment, and we assess their interpretation and comparison to theory. The theory-experiment comparison suggests that central Au+Au collisions at RHIC produce dense, rapidly thermalizing matter characterized by: (1) initial energy densities above the critical values predicted by lattice QCD for establishment of a Quark-Gluon Plasma (QGP); (2) nearly ideal fluid flow, marked by constituent interactions of very short mean free path, established most probably at a stage preceding hadron formation; and (3) opacity to jets. Many of the observations are consistent with models incorporating QGP formation in the early collision stages, and have not found ready explanation in a hadronic framework. However, the measurements themselves do not yet establish unequivocal evidence for a transition to this new form of matter. The theoretical treatment of the collision evolution, despite impressive successes, invokes a suite of distinct models, degrees of freedom and assumptions of as yet unknown quantitative consequence. We pose a set of important open questions, and suggest additional measurements, at least some of which should be addressed in order to establish a compelling basis to conclude definitively that thermalized, deconfined quark-gluon matter has been produced at RHIC.Comment: 101 pages, 37 figures; revised version to Nucl. Phys.

Azimuthal anisotropy in Au+Au collisions at √s\u3csub\u3eNN\u3c/sub\u3e = 200 GeV

The results from the STAR Collaboration on directed flow (ν1), elliptic flow (ν2), and the fourth harmonic (ν4) in the anisotropic azimuthal distribution of particles from Au+Au collisions at √sNN=200GeV are summarized and compared with results from other experiments and theoretical models. Results for identified particles are presented and fit with a blast-wave model. Different anisotropic flow analysis methods are compared and nonflow effects are extracted from the data. For ν2, scaling with the number of constituent quarks and parton coalescence are discussed. For ν4, scaling with v22 and quark coalescence are discussed

Incident energy dependence of p\u3csub\u3et\u3c/sub\u3e correlations at relativistic energies

We present results for two-particle transverse momentum correlations, ⟨Δpt,iΔpt,j⟩, as a function of event centrality for Au+Au collisions at √sNN=20, 62, 130, and 200 GeV at the BNL Relativistic Heavy Ion Collider. We observe correlations decreasing with centrality that are similar at all four incident energies. The correlations multiplied by the multiplicity density increase with incident energy, and the centrality dependence may show evidence of processes such as thermalization, jet production, or the saturation of transverse flow. The square root of the correlations divided by the event-wise average transverse momentum per event shows little or no beam energy dependence and generally agrees with previous measurements made at the CERN Super Proton Synchrotron

Proton-Λ correlations in central Au+Au collisions at √s\u3csub\u3eNN\u3c/sub\u3e = 200 GeV

We report on p−Λ,p− ¯Λ¯ ,¯p¯−Λ, and ¯p¯− ¯Λ¯ correlation functions constructed in central Au-Au collisions at √sNN=200 GeV by the STAR experiment at RHIC. The proton and lambda source size is inferred from the p−Λ and p− ¯Λ¯; correlation functions. It is found to be smaller than the pion source size also measured by the STAR experiment at smaller transverse masses, in agreement with a scenario of a strong universal collective flow. The ¯p¯− Λ and p− ¯Λ¯ correlation functions, which are measured for the first time, exhibit a large anticorrelation. Annihilation channels and/or a negative real part of the spin-averaged scattering length must be included in the final-state interactions calculation to reproduce the measured correlation function

Transverse-momentum ptp_t correlations on (η,ϕ)(\eta,\phi) from mean-ptp_{t} fluctuations in Au-Au collisions at sNN=\sqrt{s_{NN}} = 200 GeV

We present first measurements of the pseudorapidity and azimuth $(\eta,\phi)$ bin-size dependence of event-wise mean transverse momentum $$ fluctuations for Au-Au collisions at $\sqrt{s_{NN}} = 200$ GeV. We invert that dependence to obtain $p_t$ autocorrelations on differences $(\eta_\Delta,\phi_\Delta)$ interpreted to represent velocity/temperature distributions on ($\eta,\phi$). The general form of the autocorrelations suggests that the basic correlation mechanism is parton fragmentation. The autocorrelations vary strongly with collision centrality, which suggests that fragmentation is strongly modified by a dissipative medium in the more central Au-Au collisions relative to peripheral or p-p collisions. \\Comment: 7 pages, 3 figure

Forward Neutral Pion Production in p + p and d + Au Collisions at √ sNN = 200 GeV

Measurements of the production of forward π0 mesons from p+p and d+Au collisions at √sNN=200  GeV are reported. The p+p yield generally agrees with next-to-leading order perturbative QCD calculations. The d+Au yield per binary collision is suppressed as η increases, decreasing to ∼30% of the p+p yield at ⟨η⟩=4.00, well below shadowing expectations. Exploratory measurements of azimuthal correlations of the forward π0 with charged hadrons at η≈0 show a recoil peak in p+p that is suppressed in d+Au at low pion energy. These observations are qualitatively consistent with a saturation picture of the low-x gluon structure of heavy nuclei

Transverse-momentum p\u3csub\u3et\u3c/sub\u3e correlations on (η,ϕ) from mean-p\u3csub\u3et\u3c/sub\u3e fluctuations in Au–Au collisions at √s\u3csub\u3eNN\u3c/sub\u3e = 200 GeV

We present first measurements of the pseudorapidity and azimuth (η, ϕ) binsize dependence of event-wise mean transverse-momentum ⟨pt⟩ fluctuations for Au–Au collisions at √sNN = 200 GeV. We invert that dependence to obtain pt autocorrelations on differences (η∆, ϕ∆) interpreted to represent velocity/temperature distributions on (η, ϕ). The general form of the autocorrelations suggests that the basic correlation mechanism is parton fragmentation. The autocorrelations vary rapidly with collision centrality, which suggests that fragmentation is strongly modified by a dissipative medium in the more central Au–Au collisions relative to peripheral or p–p collisions

Hadronization geometry from net-charge angular correlations on momentum subspace (η,ϕ\eta,\phi) in Au-Au collisions at sNN=130\sqrt{s_{NN}} = 130 GeV

We present the first measurements of charge-dependent correlations on angular difference variables $\eta_1 - \eta_2$ (pseudorapidity) and $\phi_1 - \phi_2$ (azimuth) for primary charged hadrons with transverse momentum $0.15 \leq p_t \leq 2$ GeV/$c$ and $|\eta| \leq 1.3$ from Au-Au collisions at $\sqrt{s_{NN}} = 130$ GeV. We observe correlation structures not predicted by theory but consistent with evolution of hadron emission geometry with increasing centrality from one-dimensional fragmentation of color strings along the beam direction to an at least two-dimensional hadronization geometry along the beam and azimuth directions of a hadron-opaque bulk medium.Comment: 8 pages, 4 figure