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Author  |
HADES Collaboration (Agakishiev, G. et al); Diaz, J.; Gil, A. |
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Title |
Study of the quasi-free np -> np pi(+)pi(-) reaction with a deuterium beam at 1.25 GeV/nucleon |
Type |
Journal Article |
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Year |
2015 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
750 |
Issue |
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Pages |
184-193 |
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Keywords |
Two-pion production; np collisions; Resonance excitations |
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Abstract |
The tagged quasi-free np -> np pi(+)pi(-) reaction has been studied experimentally with the High Acceptance Di-Electron Spectrometer (HADES) at GSI at a deuteron incident beam energy of 1.25 GeV/nucleon (root S similar to 2.42 GeV/c for the quasi-free collision). For the first time, differential distributions of solid statistics for pi(+)pi(-) production in np collisions have been collected in the region corresponding to the large transverse momenta of the secondary particles. The invariant mass and angular distributions for the np -> np pi(+)pi(-) reaction are compared with different models. This comparison confirms the dominance of the t-channel with Delta Delta contribution. It also validates the changes previously introduced in the Valencia model to describe two-pion production data in other isospin channels, although some deviations are observed, especially for the pi(+)pi(-) invariant mass spectrum. The extracted total cross section is also in much better agreement with this model. Our new measurement puts useful constraints for the existence of the conjectured dibaryon resonance at mass M similar to 2.38 GeV and with width Gamma similar to 70 MeV. (C) 2015 The Authors. Published by Elsevier B.V. |
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Address |
[Finocchiaro, P.] Ist Nazl Fis Nucl, Lab Nazl Sud, I-95125 Catania, Italy, Email: akurilkin@jinr.ru; |
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Publisher |
Elsevier Science Bv |
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English |
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Series Volume |
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ISSN |
0370-2693 |
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Conference |
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Notes |
WOS:000364250600031 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2469 |
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Author |
HADES Collaboration (Agakishiev, G. et al); Diaz, J.; Gil, A. |
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Title |
Deep sub-threshold K*(892)(0) production in collisions of Ar + KCl at 1.76A GeV |
Type |
Journal Article |
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Year |
2013 |
Publication |
European Physical Journal A |
Abbreviated Journal |
Eur. Phys. J. A |
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Volume |
49 |
Issue |
3 |
Pages |
34 - 7pp |
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Keywords |
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Abstract |
Results on the deep sub-threshold production of the short-lived hadronic resonance K*(892)(0) are reported for collisions of Ar + KCl at 1.76 A GeV beam energy, studied with the High Acceptance Di-Electron Spectrometer (HADES) at SIS18/GSI. The K*(892)(0) production probability per central collision of P-K*0 = (4.4 +/- 1.1 +/- 0.5) x 10(-4) and the K*(892)(0)/K-0 ratio of P-K*0/P-K0 = (1.9 +/- 0.5 +/- 0.3) x 10(-2) are determined at the lowest energy so far (i.e. deep below the threshold for the corresponding production in nucleon-nucleon collisions, root s(NN)-root s(thr) = -340MeV). The K*(0)/K-0 ratio is compared with results of other experiments and with the predictions of the UrQMD transport approach and of the statistical hadronization model. The experimental K*(0) yield and the K-*0/K-0 ratio are overestimated by the transport model by factors of about five and two, respectively. In a chemically equilibrated medium the ratio corresponds to a temperature of the thermalized system being systematically lower than the value determined by the yields of the stable and long-lived hadrons produced in Ar + KCl collisions. From the present measurement, we conclude that sub-threshold K* production either cannot be considered to proceed in a system being in thermal equilibrium or these short-lived resonances appear undersaturated, for example as a result of the rescattering of the decay particles in the ambient hadronic medium. |
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Address |
Inst Nazl Fis Nucl, Lab Nazl Sud, I-95125 Catania, Italy, Email: kotte@hzdr.de |
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Publisher |
Springer |
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English |
Summary Language |
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Original Title |
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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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Expedition |
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Conference |
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Notes |
WOS:000317855000006 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1426 |
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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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Thesis |
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Publisher |
Springer |
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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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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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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Author |
HADES Collaboration (Agakishiev, G. et al); Diaz, J.; Gil, A. |
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Title |
pp and pi pi intensity interferometry in collisions of Ar+KCl 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 |
5 |
Pages |
63 - 8pp |
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Keywords |
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Abstract |
Results on pp, pi(+) pi(+), and pi-pi-intensity interferometry are reported for collisions of Ar+KCl at 1.76A GeV beam energy, studied with the High Acceptance Di-Electron Spectrometer (HADES) at SIS18/GSI. The experimental correlation functions as a function of the relative momentum are compared to model calculations allowing the determination of the space-time extent of the corresponding emission sources. The pp source radii are found significantly larger than the pp emission radius. The present radii do well complement the beam-energy dependences of Gaussian source radii of the collision system of size A + A similar or equal to 40 + 40. The pp source radius at fixed beam energy is found to increase linearly with the cube root of the number of participants. From this trend, a lower limit of the pp correlation radius is deduced. |
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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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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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Area |
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Expedition |
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Conference |
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Notes |
ISI:000291659900005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
658 |
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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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Keywords |
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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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Corporate Author |
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Thesis |
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Publisher |
Amer Physical Soc |
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 |
0556-2813 |
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: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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