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Author |
HADES Collaboration (Agakishiev, G. et al); Diaz, J.; Gil, A. |
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Title |
Lambda-p femtoscopy in collisions of Ar + KCl at 1.76AGeV |
Type |
Journal Article |
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Year |
2010 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
82 |
Issue |
2 |
Pages |
021901 - 5pp |
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Abstract |
Results on Lambda p femtoscopy are reported at the lowest energy so far. At a beam energy of 1.76AGeV, the reaction Ar + KCl was studied with the High Acceptance Di-Electron Spectrometer ( HADES) at SIS18/GSI. A high-statistics and high-purity Lambda sample was collected, allowing for the investigation of Lambda p correlations at low relative momenta. The experimental correlation function is compared to corresponding model calculations allowing the determination of the space-time extent of the Lambda p emission source. The Lambda p source radius is found to be slightly smaller than the pp correlation radius for a similar collision system. The present Lambda p radius is significantly smaller than that found for Au + Au/Pb + Pb collisions in the AGS, SPS, and RHIC energy domains but larger than that observed for electroproduction from He. Taking into account all available data, we find the Lambda p source radius to increase almost linearly with the number of participants to the power of one-third. |
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Address |
[Finocchiaro, P.] Ist Nazl Fis Nucl, Lab Nazl Sud, I-95125 Catania, Italy, Email: kotte@fzd.de |
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Publisher |
Amer Physical Soc |
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English |
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ISSN |
0556-2813 |
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Conference |
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Notes |
ISI:000281017300001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
393 |
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Permanent link to this record |
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Author |
Belver, D.; Cabanelas, P.; Castro, E.; Garzon, J.A.; Gil, A.; Gonzalez-Diaz, D.; Koenig, W.; Traxler, M. |
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Title |
Performance of the Low-Jitter High-Gain/Bandwidth Front-End Electronics of the HADES tRPC Wall |
Type |
Journal Article |
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Year |
2010 |
Publication |
IEEE Transactions on Nuclear Science |
Abbreviated Journal |
IEEE Trans. Nucl. Sci. |
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Volume |
57 |
Issue |
5 |
Pages |
2848-2856 |
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Keywords |
Charge to width algorithm; fast amplifying and digitizing electronics; front-end electronics; HADES; time of flight; timing RPC |
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Abstract |
A front-end electronics (FEE) chain for accurate time measurements has been developed for the new Resistive Plate Chamber (RPC)-based Time-of-Flight (TOF) wall of the High Acceptance Di-Electron Spectrometer (HADES). The wall covers an area of around 8 m(2) divided in 6 sectors. In total, 1122 4-gap timing RPC cells are read-out by 2244 time and charge sensitive channels. The FEE chain consists of 2 custom-made boards: a 4-channel Daughter BOard(DBO) and a 32-channel MotherBOard (MBO). The DBO uses a fast 2 GHz amplifier feeding a dual high-speed discriminator. The time and charge information are encoded, respectively, in the leading edge and the width of an LVDS signal. Each MBO houses up to 8 DBOs providing them regulated voltage supply, threshold values via DACs, test signals and, additionally, routing out a signal proportional to the channel multiplicity needed for a 1st level trigger decision. The MBO delivers LVDS signals to a multi-purpose Trigger Readout Board (TRB) for data acquisition. The FEE allows achieving a system resolution around 75 ps fulfilling comfortably the requirements of the HADES upgrade [1]. The commissioning of the whole RPC wall is finished and the 6 sectors are already mounted in their final position in the HADES spectrometer and ready to take data during the beam-times foreseen for 2010. |
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Address |
[Belver, Daniel; Cabanelas, P.; Castro, E.; Garzon, J. A.] Univ Santiago Compostela, LabCAF, Santiago De Compostela 15782, Spain, Email: daniel.belver@usc.es |
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Ieee-Inst Electrical Electronics Engineers Inc |
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English |
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ISSN |
0018-9499 |
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Notes |
ISI:000283440400007 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
349 |
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Permanent link to this record |
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Author |
HADES Collaboration (Agakishiev, G. et al); Diaz, J.; Gil, A. |
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Title |
In-medium effects on K-0 mesons in relativistic heavy-ion collisions |
Type |
Journal Article |
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Year |
2010 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
82 |
Issue |
4 |
Pages |
044907 - 9pp |
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Keywords |
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Abstract |
We present the transverse momentum spectra and rapidity distributions of pi(-) and K-S(0) in Ar + KCl reactions at a beam kinetic energy of 1.756 A GeV measured with the High Acceptance Di-Electron Spectrometer (HADES). The reconstructed K-S(0) sample is characterized by good event statistics for a wide range in momentum and rapidity. We compare the experimental pi(-) and K-S(0) distributions to predictions by the Isospin Quantum Molecular Dynamics (IQMD) model. The model calculations show that K-S(0) at low transverse momenta constitute a particularly well-suited tool to investigate the kaon in-medium potential. Our K-S(0) data suggest a strong repulsive in-medium K-0 potential of about 40 MeV strength. |
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Address |
[Agakishiev, G.; Destefanis, M.; Gilardi, C.; Kirschner, D.; Kuehn, W.; Lange, J. S.; Metag, V.; Mishra, D.; Pechenov, V.; Pechenova, O.; Cavalcanti, T. Perez; Spataro, S.; Spruck, B.] Univ Giessen, Inst Phys 2, D-35392 Giessen, Germany, Email: laura.fabbietti@ph.tum.de |
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Publisher |
Amer Physical Soc |
Place of Publication |
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English |
Summary Language |
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Series Editor |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0556-2813 |
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Expedition |
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Conference |
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Notes |
ISI:000283648400009 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
334 |
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Permanent link to this record |
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Author |
HADES Collaboration (Agakishiev, G. et al); Diaz, J.; Gil, A. |
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Title |
Origin of the low-mass electron pair excess in light nucleus-nucleus collisions |
Type |
Journal Article |
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Year |
2010 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
690 |
Issue |
2 |
Pages |
118-122 |
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Keywords |
Virtual bremsstrahlung; Dileptons; Nucleon-nucleon collisions |
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Abstract |
We report measurements of electron pair production in elementary p + p and d + p reactions at 1.25 GeV/mu with the HADES spectrometer. For the first time, the electron pairs were reconstructed for n + p reactions by detecting the proton spectator from the deuteron breakup. We find that the yield of electron pairs with invariant mass Me+e- > 0.15 GeV/c(2) is about an order of magnitude larger in n + p reactions as compared to p + p. A comparison to model calculations demonstrates that the production mechanism is not sufficiently described yet. The electron pair spectra measured in C + C reactions are compatible with a superposition of elementary n + p and p + p collisions, leaving little room for additional electron pair sources in such light collision systems. |
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Address |
[Froehlich, I.; Galatyuk, T.; Goebel, K.; Lorenz, M.; Markert, J.; Michel, J.; Muentz, C.; Pachmayer, Y. C.; Stroebele, H.; Stroth, J.; Sturm, C.; Tarantola, A.; Teilab, K.] Goethe Univ Frankfurt, Inst Kernphys, D-60438 Frankfurt, Germany, Email: t.galatyuk@gsi.de |
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Publisher |
Elsevier Science Bv |
Place of Publication |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0370-2693 |
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Conference |
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Notes |
ISI:000279513800003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
413 |
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Permanent link to this record |
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Author |
HADES Collaboration (Agakishiev, G. et al); Diaz, J.; Gil, A. |
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Title |
Hyperon production in Ar plus KCl collisions at 1.76A GeV |
Type |
Journal Article |
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Year |
2011 |
Publication |
European Physical Journal A |
Abbreviated Journal |
Eur. Phys. J. A |
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Volume |
47 |
Issue |
2 |
Pages |
21 - 9pp |
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Keywords |
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Abstract |
We present transverse momentum spectra, rapidity distribution and multiplicity of Lambda-hyperons measured with the HADES spectrometer in the reaction Ar(1.76A GeV) + KCl. The yield of Xi(-) is calculated from our previously reported Xi(-)/(Lambda+Sigma(0)) ratio and compared to other strange particle multiplicities. Employing a strangeness balance equation the multiplicities of the yet unmeasured Sigma(+/-)-hyperons can be estimated. Finally a statistical hadronization model is used to fit the yields of pi(-), K+, K-s(0), K-, phi, Lambda and Xi(-). The resulting chemical freeze-out temperature of T = (76 +/- 2) MeV is compared to the measured slope parameters obtained from fits to the transverse mass distributions of the different particles. |
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Address |
[Agakishiev, G.; Belyaev, A.; Chernenko, S.; Fateev, O.; Lapidus, K.; Zanevsky, Y.] Joint Inst Nucl Res, Dubna 141980, Russia, Email: Lorenz@Physik.uni-frankfurt.de |
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Corporate Author |
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Thesis |
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Publisher |
Springer |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1434-6001 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
ISI:000288551700007 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
540 |
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Permanent link to this record |