Refine
Year of publication
Language
- English (64)
Has Fulltext
- yes (64)
Is part of the Bibliography
- no (64)
Keywords
- LHC (8)
- ALICE (3)
- ALICE experiment (3)
- pp collisions (3)
- Beauty production (2)
- Chemotherapy (2)
- Heavy Ions (2)
- Heavy-ion collisions (2)
- Radiotherapy (2)
- Single electrons (2)
Institute
- Physik (57)
- Frankfurt Institute for Advanced Studies (FIAS) (39)
- Informatik (39)
- Medizin (6)
- Sportwissenschaften (1)
The directed and elliptic flow of protons and charged pions has been observed from the semi-central collisions of a 158 GeV/nucleon Pb beam with a Pb target. The rapidity and transverse momentum dependence of the flow has been measured. The directed flow of the pions is opposite to that of the protons but both exhibit negative flow at low pt. The elliptic flow of both is fairly independent of rapidity but rises with pt. PACS numbers: 25.75.-q, 25.75.Ld
Using the NA49 main TPC, the central production of hyperons has been measured in CERN SPS Pb - Pb collisions at 158 GeV c-1. The preliminary ratio, studied at 2.0 < y < 2.6 and 1 < pT < 3 GeV c-1, equals ~ (13 ± 4)% (systematic error only). It is compatible, within errors, with the previously obtained ratios for central S + S [1], S + W [2], and S + Au [3] collisions. The fit to the transverse momentum distribution resulted in an inverse slope parameter T of 297 MeV. At this level of statistics we do not see any noticeable enhancement of hyperon production with the increased volume (and, possibly, degree of equilibration) of the system from S + S to Pb + Pb. This result is unexpected and counterintuitive, and should be further investigated. If confirmed, it will have a significant impact on our understanding of mechanisms leading to the enhanced strangeness production in heavy-ion collisions.
Preliminary data on phi production in central Pb + Pb collisions at 158 GeV per nucleon are presented, measured by the NA49 experiment in the hadronic decay channel phi - K+K-. At mid-rapidity, the kaons were separated from pions and protons by combining dE/dx and time-of-flight information; in the forward rapidity range only dE/dx identification was used to obtain the rapidity distribution and a rapidity-integrated mt-spectrum. The mid-rapidity yield obtained was dN/dy = 1.85 ± 0.3 per event; the total phi multiplicity was estimated to be 5.0 ± 0.7 per event. Comparison with published pp data shows a slight, but not very significant strangeness enhancement.
Lambda and Antilambda reconstruction in central Pb+Pb collisions using a time projection chamber
(1997)
The large acceptance time projection chambers of the NA49 experiment are used to record the trajectory of charged particles from Pb + Pb collisions at 158 GeV per nucleon. Neutral strange hadrons have been reconstructed from their charged decay products. To obtain distributions of Λ, and Ks0 in discrete bins of rapidity, y, and transverse momentum, pT, calculations have been performed to determine the acceptance of the detector and the efficiency of the reconstruction software as a function of both variables. The lifetime distributions obtained give values of cτ = 7.8 ± 0.6 cm for Λ and cτ = 2.5 ± 0.3 cm for Ks0, consistent with data book values.
Two-particle correlation functions of negative hadrons over wide phase space, and transverse mass spectra of negative hadrons and deuterons near mid-rapidity have been measured in central Pb+Pb collisions at 158 GeV per nucleon by the NA49 experiment at the CERN SPS. A novel Coulomb correction procedure for the negative two-particle correlations is employed making use of the measured oppositely charged particle correlation. Within an expanding source scenario these results are used to extract the dynamic characteristics of the hadronic source, resolving the ambiguities between the temperature and transverse expansion velocity of the source, that are unavoidable when single and two particle spectra are analysed separately. The source shape, the total duration of the source expansion, the duration of particle emission, the freeze-out temperature and the longitudinal and transverse expansion velocities are deduced.
We report measurements of Xi and Xi-bar hyperon absolute yields as a function of rapidity in 158 GeV/c Pb+Pb collisions. At midrapidity, dN/dy = 2.29 +/- 0.12 for Xi, and 0.52 +/- 0.05 for Xi-bar, leading to the ratio of Xi-bar/Xi = 0.23 +/- 0.03. Inverse slope parameters fitted to the measured transverse mass spectra are of the order of 300 MeV near mid-rapidity. The estimated total yield of Xi particles in Pb+Pb central interactions amounts to 7.4 +/- 1.0 per collision. Comparison to Xi production in properly scaled p+p reactions at the same energy reveals a dramatic enhancement (about one order of magnitude) of Xi production in Pb+Pb central collisions over elementary hadron interactions.
Background: Common warts (verrucae vulgares) are human papilloma virus (HPV) infections with a high incidence and prevalence, most often affecting hands and feet, being able to impair quality of life. About 30 different therapeutic regimens described in literature reveal a lack of a single striking strategy. Recent publications showed positive results of photodynamic therapy (PDT) with 5-aminolevulinic acid (5-ALA) in the treatment of HPV-induced skin diseases, especially warts, using visible light (VIS) to stimulate an absorption band of endogenously formed protoporphyrin IX. Additional experiences adding waterfiltered infrared A (wIRA) during 5-ALA-PDT revealed positive effects. Aim of the study: First prospective randomised controlled blind study including PDT and wIRA in the treatment of recalcitrant common hand and foot warts. Comparison of "5-ALA cream (ALA) vs. placebo cream (PLC)" and "irradiation with visible light and wIRA (VIS+wIRA) vs. irradiation with visible light alone (VIS)". Methods: Pre-treatment with keratolysis (salicylic acid) and curettage. PDT treatment: topical application of 5-ALA (Medac) in "unguentum emulsificans aquosum" vs. placebo; irradiation: combination of VIS and a large amount of wIRA (Hydrosun® radiator type 501, 4 mm water cuvette, waterfiltered spectrum 590-1400 nm, contact-free, typically painless) vs. VIS alone. Post-treatment with retinoic acid ointment. One to three therapy cycles every 3 weeks. Main variable of interest: "Percent change of total wart area of each patient over the time" (18 weeks). Global judgement by patient and by physician and subjective rating of feeling/pain (visual analogue scales). 80 patients with therapy-resistant common hand and foot warts were assigned randomly into one of the four therapy groups with comparable numbers of warts at comparable sites in all groups. Results: The individual total wart area decreased during 18 weeks in group 1 (ALA+VIS+wIRA) and in group 2 (PLC+VIS+wIRA) significantly more than in both groups without wIRA (group 3 (ALA+VIS) and 4 (PLC+VIS)): medians and interquartile ranges: -94% (-100%/-84%) vs. -99% (-100%/-71%) vs. -47% (-75%/0%) vs. -73% (-92%/-27%). After 18 weeks the two groups with wIRA differed remarkably from the two groups without wIRA: 42% vs. 7% completely cured patients; 72% vs. 34% vanished warts. Global judgement by patient and by physician and subjective rating of feeling was much better in the two groups with wIRA than in the two groups without wIRA. Conclusions: The above described complete treatment scheme of hand and foot warts (keratolysis, curettage, PDT treatment, irradiation with VIS+wIRA, retinoic acid ointment; three therapy cycles every 3 weeks) proved to be effective. Within this treatment scheme wIRA as non-invasive and painless treatment modality revealed to be an important, effective factor, while photodynamic therapy with 5-ALA in the described form did not contribute recognisably - neither alone (without wIRA) nor in combination with wIRA - to a clinical improvement. For future treatment of warts an even improved scheme is proposed: one treatment cycle (keratolysis, curettage, wIRA, without PDT) once a week for six to nine weeks. © 2004 Fuchs et al; licensee German Medical Science. This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original URL : http://www.egms.de/en/gms/volume2.shtml
We compare multiplicities as well as rapidity and transverse momentum distributions of protons, pions and kaons calculated within presently available transport approaches for heavy ion collisions around 1 AGeV. For this purpose, three reactions have been selected: Au+Au at 1 and 1.48 AGeV and Ni+Ni at 1.93 AGeV.
The first measurement of two-pion Bose–Einstein correlations in central Pb–Pb collisions at √sNN=2.76 TeV at the Large Hadron Collider is presented. We observe a growing trend with energy now not only for the longitudinal and the outward but also for the sideward pion source radius. The pion homogeneity volume and the decoupling time are significantly larger than those measured at RHIC.