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167 results on '"Belounnas A."'

1. Exploring time like tranistions in pp, πp and AA reactions with HADES

Author

Salabura Piotr, Adamczewski-Musch J., Arnoldi-Meadows B., Belounnas A., Belyaev A., Blanco A., Blume C., Böhmer M., Borisenko S, Chlad L., Chudoba P, Ciepał I., Dittert D., Dreyer J., Esmail W., Dürr M., Fabbietti L., Fateev S., Fonte P., Friese J., Fröhlich I., Förtsch J., Galatyuk T., Gernhäuser R., Golosov O., Golubeva M., Greifenhagen R., Guber F., Gumberidze M., Harabasz S., Hensch R., Höhne C., Holzmann R., Huck H., Ierusalimov A., Ivashkin A., Kämpfer B., Kampert K-H., Kardan B., Koenig I., Koenig W., Kornakov G., Kornas F., Kotte R., Kozela A., Kres I., Kuboś J., Kugler A., Kulesa P., Ladygin V., Lalik R., Lebedev A., Lebedev S., Linev S., Lopes L., Lorenz M., Lykasov G., Mahmoud T., Malige A., Markert J., Matulewicz T., Maurus S., Metag V., Michel J., Morozov S., Müntz C., Naumann L., Nowakowski K., Otto J.-H., Patel V., Pauly C., Pechenov V., Pechenova O., Petukhov O., Pfeifer D., Piasecki K., Pietraszko J., Prozorov A., Przygoda W., Pysz K., Ramstein B., Rathod N., Reshetin A., Ritman L., Rodriguez-Ramos P., Rost A., Salabura P., Scozzi F., Seck F., Selyuzhenkov I., Shabanov I., Singh US, Smyrski J., Spies S., Ströbele H., Stroth J., Stumm J., Svoboda O., Szala M., Tlusty P., Traxler M., Ungethüm C., Vazquez-Doce O., Wagner V., Weber A.A., Wendisch C., Wiebusch M.G., Wintz P., Wirth J., Zhilin A., and Zumbruch P.

Subjects
Physics, QC1-999
Abstract

Radiative transition of an excited baryon to a nucleon with emission of a virtual massive photon converting to dielectron pair (Dalitz decays) provides important information about baryon-photon coupling at low q2 in timelike region. A prominent enhancement in the respective electromagnetic transition Form Factors (etFF) at q2 near vector mesons ρ/ω poles has been predicted by various calculations reflecting strong baryon-vector meson couplings. The understanding of these couplings is also of primary importance for the interpretation of the emissivity of QCD matter studied in heavy ion collisions via dilepton emission. Dedicated measurements of baryon Dalitz decays in proton-proton and pion-proton scattering with HADES detector at GSI/FAIR are presented and discussed. The relevance of these studies for the interpretation of results obtained from heavy ion reactions is elucidated on the example of the HADES results.

Published
2020
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2. Time-Like Baryon Transitions studies with HADES

Author

Ramstein B., Adamczewski-Musch J., Arnold O., Arnoldi-Meadows B., Belounnas A., Belyaev A., Biernat J., Blanco A., Blume C., Böhmer M., Bordalo P., Chlad L., Chudoba P., Ciepał I., Deveaux C., Dittert D., Dreyer J., Fabbietti L., Fateev O., Fonte P., Franco C., Friese J., Fröhlich I., Galatyuk T., Garzón J. A., Gernhäuser R., Gillitzer A., Golubeva M., Greifenhagen R., Guber F., Gumberidze M., Harabasz S., Heinz T., Hennino T., Himmelreich M., Höhne C., Holzmann R., Ierusalimov A., Ivanov V., Ivashkin A., Kämpfer B., Kajetanowicz M., Kampert K-H., Karavicheva T., Kardan B., Khomyakov V., Koenig I., Koenig W., Korcyl G., Kornakov G., Kornas F., Kotte R., Kozela A., Kuboś J., Kugler A., Kunz T., Kurepin A., Kurilkin P., Kushpil V, Ladygin V., Lalik R., Lebedev A., Linev S., Liu M., Lopes L., Lorenz M., Lykasov G., Mahmoud T., Malakhov A., Markert J., Maurus S., Metag V., Michel J., Mihaylov D.M., Mikhaylov V., Morozov S., Müntz C., Naumann L., Nowakowski K., Parpottas Y., Patel V., Pauly C., Pechenov V., Pechenova O., Pereira A., Petousis V., Petukhov O., Pfeifer D., Pietraszko J., Przygoda W., Pysz K., Ramos S., Reshetin A., Ritman L., Rodriguez-Ramos P., Rost A., Sadovsky A., Salabura P., Scheib T., Schuldes H., Schwab E., Scozzi F., Seck F., Sellheim P., Selyuzhenkov I., Silva L., Smyrski J., Sobiella M., Spataro S., Spies S., Ströbele H., Stroth J., Strzempek P., Svoboda O., Szala M., Taranenko A., Tlusty P., Traxler M., Troyan A., Tsertos H., Wagner V., Wendisch C., Wiebusch M.G., Wintz P., Wirth J., Włoch B., Zhilin A., Zinchenko A., Zumbruch P., and Zuschke M.

Subjects
Physics, QC1-999
Abstract

The HADES collaboration uses the e+e− production as a probe of the resonance matter produced in collisions at incident energies of 1-3.5 GeV/nucleon at GSI. Elementary reactions provide useful references for these studies and give information on resonance Dalitz decays (R→Ne+e−). Such processes are sensitive to the structure of time-like electromagnetic baryon transitions in a kinematic range where (off-shell) vector mesons play a crucial role. Results obtained in proton-proton reactions and in a commissioning pion-beam experiment are reported and prospects for future pion beam experiments and for first hyperon Dalitz decay measurements are described. The connection with the investigations of medium effects to be continued with HADES in the next years at SIS18 and SIS100 is also discussed.

Published
2019
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3. Proton, deuteron and triton flow measurements in Au+Au collisions at $\sqrt{s_{NN}} = 2.4$ GeV

Author

HADES collaboration, Adamczewski-Musch, J., Arnold, O., Behnke, C., Belounnas, A., Berger-Chen, J. C., Blanco, A., Blume, C., Böhmer, M., Bordalo, P., Chlad, L., Ciepal, I., Deveaux, C., Dreyer, J., Epple, E., Fabbietti, L., Filip, P., Fonte, P., Franco, C., Friese, J., Fröhlich, I., Galatyuk, T., Garzón, J. A., Gernhäuser, R., Greifenhagen, R., Gumberidze, M., Harabasz, S., Heinz, T., Hennino, T., Hlavac, S., Höhne, C., Holzmann, R., Kämpfer, B., Kardan, B., Koenig, I., Koenig, W., Kohls, M., Kolb, B. W., Korcyl, G., Kornakov, G., Kornas, F., Kotte, R., Kugler, A., Kunz, T., Lalik, R., Lapidus, K., Lopes, L., Lorenz, M., Mahmoud, T., Maier, L., Malige, A., Mangiarotti, A., Markert, J., Matulewicz, T., Maurus, S., Metag, V., Michel, J., Mihaylov, D. M., Müntz, C., Münzer, R., Naumann, L., Nowakowski, K., Parpottas, Y., Pechenov, V., Pechenova, O., Piasecki, K., Pietraszko, J., Przygoda, W., Pysz, K., Ramos, S., Ramstein, B., Rathod, N., Rodriguez-Ramos, P., Rosier, P., Rost, A., Rustamov, A., Salabura, P., Scheib, T., Schuldes, H., Schwab, E., Scozzi, F., Seck, F., Sellheim, P., Selyuzhenkov, I., Siebenson, J., Silva, L., Singh, U., Smyrski, J., Sobolev, Yu. G., Spataro, S., Spies, S., Ströbele, H., Stroth, J., Sturm, C., Svoboda, O., Szala, M., Tlusty, P., Traxler, M., Tsertos, H., Wagner, V., Wendisch, C., Wiebusch, M. G., Wirth, J., Wójcik, D., and Zumbruch, P.

Subjects
Nuclear Experiment
Abstract

High precision measurements of flow coefficients $v_{n}$ ($n = 1 - 4$) for protons, deuterons and tritons relative to the first-order spectator plane have been performed in Au+Au collisions at $\sqrt{s_{NN}} = 2.4$ GeV with the High-Acceptance Di-Electron Spectrometer (HADES) at the SIS18/GSI. Flow coefficients are studied as a function of transverse momentum $p_{t}$ and rapidity $y_{cm}$ over a large region of phase space and for several classes of collision centrality. A clear mass hierarchy is found for the slope of $v_{1}$, $d v_{1}/d y^{\prime}|_{y^{\prime} = 0}$ where $y^{\prime}$ is the scaled rapidity, and for $v_{2}$ at mid-rapidity. Scaling with the number of nucleons is observed for the $p_{t}$ dependence of $v_{2}$ and $v_{4}$ at mid-rapidity, which is indicative for nuclear coalescence as the main process responsible for light nuclei formation. $v_{2}$ is found to scale with the initial eccentricity $\langle \epsilon_{2} \rangle$, while $v_{4}$ scales with $\langle \epsilon_{2} \rangle^{2}$ and $\langle \epsilon_{4} \rangle$. The multi-differential high-precision data on $v_{1}$, $v_{2}$, $v_{3}$, and $v_{4}$ provides important constraints on the equation-of-state of compressed baryonic matter., Comment: 21 pages, 18 figures, 4 tables; Figs. 11 updated; The manuscript has associated data in the HEPData repository: https://doi.org/10.17182/hepdata.152804

Published
2022
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4. Measurement of global polarization of {\Lambda} hyperons in few-GeV heavy-ion collisions

Author

Yassine, R. Abou, Adamczewski-Musch, J., Asal, C., Becker, M., Belounnas, A., Blanco, A., Blume, C., Chlad, L., Chudoba, P., Ciepal, I., Cordts, M., Dreyer, J., Esmail, W. A., Fabbietti, L., Floersheimer, H., Fonte, P., Friese, J., Fröhlich, I., Förtsch, J., Galatyuk, T., Gniazdowski, T, Greifenhagen, R., Grunwald, M., Gumberidze, M., Harabasz, S., Heinz, T., Höhne, C., Hojeij, F., Holzmann, R., Huck, H., Idzik, M., Kämpfer, B., Kampert, K-H., Kardan, B., Kedych, V., Koenig, I., Koenig, W., Kohls, M., Kolas, J., Kornakov, G., Kotte, R., Kres, I., Krueger, W., Kugler, A., Lalik, R., Lebedev, S., Linev, S., Linz, F., Lopes, L., Lorenz, M., Malige, A., Markert, J., Matulewicz, T., Maurus, S., Metag, V., Michel, J., Molenda, A., Müntz, C., Nabroth, M., Naumann, L., Nowakowski, K., Orliński, J., Otto, J. -H., Parschau, M., Pauly, C., Pechenov, V., Pechenova, O., Pfeifer, D., Piasecki, K., Pietraszko, J., Povar, T., Prozorov, A., Przygoda, W., Pysz, K., Ramstein, B., Rathod, N., Ritman, J., Rodriguez-Ramos, P., Rost, A., Rustamov, A., Salabura, P., Saraiva, J., Schild, N., Schwab, E., Scozzi, F., Seck, F., Selyuzhenkov, I., Singh, U., Skorpil, L., Smyrski, J., Spies, S., Stefaniak, M. S., Ströbele, H., Stroth, J., Sumara, K., Svoboda, O., Szala, M., Tlusty, P., Traxler, M., Wagner, V., Wasiluk, M., Weber, A. A., Wendisch, C., Wirth, J., Zbroszczyk, H. P., Zherebtsova, E., Zielinski, M., and Zumbruch, P.

Subjects
Nuclear Experiment
Abstract

The global polarization of {\Lambda} hyperons along the total orbital angular momentum of a relativistic heavy-ion collision is presented based on the high statistics data samples collected in Au+Au collisions at \sqrt{s_{NN}} = 2.4 GeV and Ag+Ag at 2.55 GeV with the High-Acceptance Di-Electron Spectrometer (HADES) at GSI, Darmstadt. This is the first measurement below the strangeness production threshold in nucleon-nucleon collisions. Results are reported as a function of the collision centrality as well as a function of the hyperon transverse momentum (p_T) and rapidity (y_{CM}) for the range of centrality 0--40%. We observe a strong centrality dependence of the polarization with an increasing signal towards peripheral collisions. For mid-central (20--40%) collisions the polarization magnitudes are (%) = 6.8 \pm 1.3 (stat.) \pm 2.1 (syst.) for Au+Au and (%) = 6.2 \pm 0.4 (stat.) \pm 0.6 (syst.) for Ag+Ag, which are the largest values observed so far. This observation thus provides a continuation of the increasing trend previously observed by STAR and contrasts expectations from recent theoretical calculations predicting a maximum in the region of collision energies about 3 GeV. The observed polarization is of a similar magnitude as predicted by 3D fluid dynamics and the UrQMD plus thermal vorticity model and significantly above results from the AMPT model., Comment: 8 pages, 4 figures

Published
2022
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5. Impact of the Coulomb field on charged-pion spectra in few-GeV heavy-ion collisions

Author

Adamczewski-Musch, J., Arnold, O., Behnke, C., Belounnas, A., Belyaev, A., Berger-Chen, J. C., Blanco, A., Blume, C., Böhmer, M., Bordalo, P., Chernenko, S., Chlad, L., Ciepał, I., Deveaux, C., Dreyer, J., Epple, E., Fabbietti, L., Fateev, O., Filip, P., Fonte, P., Franco, C., Friese, J., Fröhlich, I., Galatyuk, T., Garzon, J. A., Gernhäuser, R., Golubeva, M., Greifenhagen, R., Guber, F., Gumberidze, M., Harabasz, S., Heinz, T., Hennino, T., Hlavac, S., Höhne, C., Holzmann, R., Ierusalimov, A., Ivashkin, A., Kämpfer, B., Karavicheva, T., Kardan, B., Koenig, I., Koenig, W., Kohls, M., Kolb, B. W., Korcyl, G., Kornakov, G., Kornas, F., Kotte, R., Kugler, A., Kunz, T., Kurepin, A., Kurilkin, A., Kurilkin, P., Ladygin, V., Lalik, R., Lapidus, K., Lebedev, A., Linev, S., Lopes, L., Lorenz, M., Mahmoud, T., Maier, L., Malige, A., Mangiarotti, A., Markert, J., Matulewicz, T., Maurus, S., Metag, V., Michel, J., Mihaylov, D. M., Morozov, S., Müntz, C., Münzer, R., Nabroth, M., Naumann, L., Nowakowski, K., Parpottas, Y., Parschau, M., Pechenov, V., Pechenova, O., Petukhov, O., Piasecki, K., Pietraszko, J., Przygoda, W., Pysz, K., Ramos, S., Ramstein, B., Rathod, N., Reshetin, A., Rodriguez-Ramos, P., Rosier, P., Rost, A., Rustamov, A., Sadovsky, A., Salabura, P., Scheib, T., Schuldes, H., Schild, N., Schwab, E., Scozzi, F., Seck, F., Sellheim, P., Selyuzhenkov, I., Siebenson, J., Silva, L., Singh, U., Smyrski, J., Sobolev, Yu. G., Spataro, S., Spies, S., Ströbele, H., Stroth, J., Sturm, C., Sumara, K., Svoboda, O., Szala, M., Tlusty, P., Traxler, M., Tsertos, H., Usenko, E., Wagner, V., Wendisch, C., Wiebusch, M. G., Wirth, J., Zanevsky, Y., and Zumbruch, P.

Subjects
Nuclear Experiment
Abstract

In nuclear collisions the incident protons generate a Coulomb field which acts on produced charged particles. The impact of these interactions on charged pion transverse-mass and rapidity spectra, as well as on pion-pion momentum correlations is investigated in Au+Au collisions at $\sqrt{s_{NN}}$ = 2.4 GeV. We show that the low-mt part of the data ($m_t < 0.2$ GeV/c$^2$) can be well described with a Coulomb-modified Boltzmann distribution that also takes changes of the Coulomb field during the expansion of the fireball into account. The observed centrality dependence of the fitted mean Coulomb potential deviates strongly from a $A_{part}^{2/3}$ scaling, indicating that, next to the fireball, the non-interacting charged spectators have to be taken into account. For the most central collisions, the Coulomb modifications of the HBT source radii are found to be consistent with the potential extracted from the single-pion transverse-mass distributions. This finding suggests that the region of homogeneity obtained from two-pion correlations coincides with the region in which the pions freeze-out. Using the inferred mean-square radius of the charge distribution at freeze-out, we have deduced a baryon density, in fair agreement with values obtained from statistical hadronization model fits to the particle yields., Comment: 14 pages, 12 figures, to be published in EPJA

Published
2022
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6. Correlated pion-proton pair emission off hot and dense QCD matter

Author

Adamczewski-Musch, J., Arnold, O., Behnke, C., Belounnas, A., Belyaev, A., Berger-Chen, J. C., Blanco, A., Blume, C., B"ohmer, M., Bordalo, P., Chernenko, S., Chlad, L., Ciepal, I., Deveaux, C., Dreyer, J., Epple, E., Fabbietti, L., Fateev, O., Filip, P., Fonte, P., Franco, C., Friese, J., Fr"ohlich, I., Galatyuk, T., Garzon, J. A., Gernh"auser, R., Golubeva, M., Greifenhagen, R., Guber, F., Gumberidze, M., Harabasz, S., Heinz, T., Hennino, T., Hlavac, S., H"ohne, C., Holzmann, R., Ierusalimov, A., Ivashkin, A., K"ampfer, B., Karavicheva, T., Kardan, B., Koenig, I., Koenig, W., Kohls, M., Kolb, B. W., Korcyl, G., Kornakov, G., Kornas, F., Kotte, R., Kugler, A., Kunz, T., Kurepin, A., Kurilkin, A., Kurilkin, P., Ladygin, V., Lalik, R., Lapidus, K., Lebedev, A., Lopes, L., Lorenz, M., Mahmoud, T., Maier, L., Malige, A., Mangiarotti, A., Markert, J., Matulewicz, T., Maurus, S., Metag, V., Michel, J., Mihaylov, D. M., Morozov, S., M"untz, C., M"unzer, R., Naumann, L., Nowakowski, K., Parpottas, Y., Pechenov, V., Pechenova, O., Petukhov, O., Piasecki, K., Pietraszko, J., Przygoda, W., Pysz, K., Ramos, S., Ramstein, B., Rathod, N., Reshetin, A., Rodriguez-Ramos, P., Rosier, P., Rost, A., Sadovsky, A., Salabura, P., Scheib, T., Schuldes, H., Schwab, E., Scozzi, F., Seck, F., Sellheim, P., Selyuzhenkov, I., Siebenson, J., Silva, L., Singh, U., Smyrski, J., Sobolev, Yu. G., Spataro, S., Spies, S., Str"obele, H., Stroth, J., Sturm, C., Svoboda, O., Szala, M., Tlusty, P., Traxler, M., Tsertos, H., Usenko, E., Wagner, V., Wendisch, C., Wiebusch, M. G., Wirth, J., Wojcik, D., Zanevsky, Y., and Zumbruch, P.

Subjects
Nuclear Experiment
Abstract

In this letter we report the first multi-differential measurement of correlated pion-proton pairs from 2 billion Au+Au collisions at \sqrt{s_{NN}} = 2.42 GeV collected with HADES. In this energy regime the population of \Delta(1232) resonances plays an important role in the way energy is distributed between intrinsic excitation energy and kinetic energy of the hadrons in the fireball. The triple differential d3N/dM{\pi}pdpTdy distributions of correlated {\pi}p pairs have been determined by subtracting the {\pi}p combinatorial background using an iterative method. The invariant-mass distributions in the \Delta(1232) mass region show strong deviations from a Breit-Wigner function with vacuum width and mass. The yield of correlated pion-proton pairs exhibits a complex isospin, rapidity and transverse-momentum dependence. In the invariant mass range 1.1 < Minv (GeV/c2) < 1.4, the yield is found to be similar for {\pi}+p and {\pi}-p pairs, and to follow a power law ^{\alpha}, where is the mean number of participating nucleons. The exponent {\alpha} depends strongly on the pair transverse momentum (pT) while its pT-integrated and charge-averaged value is {\alpha} = 1.5 \pm 0.08stat \pm 0.2sys., Comment: 9 pages, 9 figures

Published
2020
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7. Directed, elliptic and higher order flow harmonics of protons, deuterons and tritons in Au+Au collisions at $\sqrt{s_{NN}} = 2.4$ GeV

Author

HADES collaboration, Adamczewski-Musch, J., Arnold, O., Behnke, C., Belounnas, A., Belyaev, A., Berger-Chen, J. C., Blanco, A., Blume, C., Böhmer, M., Bordalo, P., Chernenko, S., Chlad, L., Ciepal, I., Deveaux, C., Dreyer, J., Epple, E., Fabbietti, L., Fateev, O., Filip, P., Fonte, P., Franco, C., Friese, J., Fröhlich, I., Galatyuk, T., Garzón, J. A., Gernhäuser, R., Golosov, O., Golubeva, M., Greifenhagen, R., Guber, F., Gumberidze, M., Harabasz, S., Heinz, T., Hennino, T., Hlavac, S., Höhne, C., Holzmann, R., Ierusalimov, A., Ivashkin, A., Kämpfer, B., Karavicheva, T., Kardan, B., Koenig, I., Koenig, W., Kohls, M., Kolb, B. W., Korcyl, G., Kornakov, G., Kornas, F., Kotte, R., Kugler, A., Kunz, T., Kurepin, A., Kurilkin, A., Kurilkin, P., Ladygin, V., Lalik, R., Lapidus, K., Lebedev, A., Lopes, L., Lorenz, M., Mahmoud, T., Maier, L., Malige, A., Mamaev, M., Mangiarotti, A., Markert, J., Matulewicz, T., Maurus, S., Metag, V., Michel, J., Mihaylov, D. M., Morozov, S., Müntz, C., Münzer, R., Naumann, L., Nowakowski, K., Parpottas, Y., Pechenov, V., Pechenova, O., Petukhov, O., Piasecki, K., Pietraszko, J., Przygoda, W., Pysz, K., Ramos, S., Ramstein, B., Rathod, N., Reshetin, A., Rodriguez-Ramos, P., Rosier, P., Rost, A., Rustamov, A., Sadovsky, A., Salabura, P., Scheib, T., Schuldes, H., Schwab, E., Scozzi, F., Seck, F., Sellheim, P., Selyuzhenkov, I., Siebenson, J., Silva, L., Singh, U., Smyrski, J., Sobolev, Yu. G., Spataro, S., Spies, S., Ströbele, H., Stroth, J., Sturm, C., Svoboda, O., Szala, M., Tlusty, P., Traxler, M., Tsertos, H., Usenko, E., Wagner, V., Wendisch, C., Wiebusch, M. G., Wirth, J., Wójcik, D., Zanevsky, Y., and Zumbruch, P.

Subjects
Nuclear Experiment
Abstract

Flow coefficients $v_{n}$ of the orders $n = 1 - 6$ are measured with the High-Acceptance DiElectron Spectrometer (HADES) at GSI for protons, deuterons and tritons as a function of centrality, transverse momentum and rapidity in Au+Au collisions at $\sqrt{s_{NN}} = 2.4$ GeV. Combining the information from the flow coefficients of all orders allows to construct for the first time, at collision energies of a few GeV, a multi-differential picture of the angular emission pattern of these particles. It reflects the complicated interplay between the effect of the central fireball pressure on the emission of particles and their subsequent interaction with spectator matter. The high precision information on higher order flow coefficients is a major step forward in constraining the equation-of-state of dense baryonic matter., Comment: 6 pages, 5 figures; Figs. 2, 3 and 5 updated from re-analysis of data including UrQMD model predictions. Plotting error in Fig. 4 corrected; Accepted for publication in Phys. Rev. Lett

Published
2020
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8. Charged pion production in $\mathbf{Au+Au}$ collisions at $\mathbf{\sqrt{s_{NN}}}$ = 2.4$\mathbf{GeV}$

Author

Adamczewski-Musch, J., Arnold, O., Behnke, C., Belounnas, A., Belyaev, A., Berger-Chen, J. C., Biernat, J., Blanco, A., Blume, C., Boehmer, M., Bordalo, P., Chernenko, S., Chlad, L., Ciepal, I., Deveaux, C., Dreyer, J., Dybczak, A., Epple, E., Fabbietti, L., Fateev, O., Filip, P., Fonte, P., Franco, C., Friese, J., Froehlich, I., Galatyuk, T., Garzon, J. A., Gernhaeuser, R., Glaessel, S., Golubeva, M., Greifenhagen, R., Guber, F., Gumberidze, M., Harabasz, S., Heinz, T., Hennino, T., Hlavac, S., Höhne, C., Holzmann, R., Ierusalimov, A., Ivashkin, A., Kämpfer, B., Karavicheva, T., Kardan, B., Koenig, I., Koenig, W., Kohls, M., Kolb, B. W., Korcyl, G., Kornakov, G., Kornas, F., Kotte, R., Kugler, A., Kunz, T., Kurepin, A., Kurilkin, A., Kurilkin, P., Ladygin, V., Lalik, R., Lapidus, K., Lebedev, A., Lopes, L., Lorenz, M., Mahmoud, T., Maier, L., Malige, A., Mangiarotti, A., Markert, J., Matulewicz, T., Maurus, S., Metag, V., Michel, J., Mihaylov, D. M., Morozov, S., Muentz, C., Muenzer, R., Naumann, L., Nowakowski, K., Palka, M., Parpottas, Y., Pechenov, V., Pechenova, O., Petukhov, O., Piasecki, K., Pietraszko, J., Przygoda, W., Pysz, K., Ramos, S., Ramstein, B., Reshetin, A., Rodriguez-Ramos, P., Rathod, N., Rosier, P., Rost, A., Rustamov, A., Sadovsky, A., Salabura, P., Scheib, T., Schuldes, H., Schwab, E., Scozzi, F., Seck, F., Sellheim, P., Selyuzhenkov, I., Siebenson, J., Silva, L., Singh, U., Smyrski, J., Sobolev, Yu. G., Spataro, S., Spies, S., Stroebele, H., Stroth, J., Strzempek, P., Sturm, C., Svoboda, O., Szala, M., Tlusty, P., Traxler, M., Tsertos, H., Usenko, E., Wagner, V., Wendisch, C., Wiebusch, M. G., Wirth, J., Wojcik, D., Zanevsky, Y., and Zumbruch, P.

Subjects
Nuclear Experiment
Abstract

We present high-statistic data on charged pion emission from Au+Au collisions at $\sqrt{s_{\rm{NN}}}$ = 2.4 GeV (corresponding to $E_{beam}$ = 1.23 A GeV) in four centrality classes in the range 0 - 40$\%$ of the most central collisions. The data are analyzed as a function of transverse momentum, transverse mass, rapidity, and polar angle. Pion multiplicity per participating nucleon decreases moderately with increasing centrality. The polar angular distributions are found to be non-isotropic even for the most central event class. Our results on pion multiplicity fit well into the general trend of the world data, but undershoot by $2.5 \sigma$ data from the FOPI experiment measured at slightly lower beam energy. We compare our data to state-of-the-art transport model calculations (PHSD, IQMD, PHQMD, GiBUU and SMASH) and find substantial differences between the measurement and the results of these calculations., Comment: 17 pages, 19 figures, 4 tables

Published
2020
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9. Two-Pion production in the second resonance region in $\pi^- p$ collisions with HADES

Author

Adamczewski-Musch, J., Arnold, O., Atomssa, E. T., Behnke, C., Belounnas, A., Belyaev, A., Berger-Chen, J. C., Biernat, J., Blanco, A., Blume, C., Böhmer, M., Chernenko, S., Chlad, L., Chudoba, P., Ciepał, I., Deveaux, C., Dittert, D., Dreyer, J., Epple, E., Fabbietti, L., Fateev, O., Fonte, P., Franco, C., Friese, J., Fröhlich, I., Galatyuk, T., Garzón, J. A., Gernhäuser, R., Golubeva, M., Greifenhagen, R., Guber, F., Gumberidze, M., Harabasz, S., Heinz, T., Hennino, T., Höhne, C., Holzmann, R., Ierusalimov, A., Ivashkin, A., Kämpfer, B., Kardan, B., Koenig, I., Koenig, W., Kolb, B. W., Korcyl, G., Kornakov, G., Kornas, F., Kotte, R., Kuboś, J., Kugler, A., Kunz, T., Kurepin, A., Kurilkin, A., Kurilkin, P., Ladygin, V., Lalik, R., Lapidus, K., Lebedev, A., Linev, S., Lopes, L., Lorenz, M., Mahmoud, T., Maier, L., Malige, A., Markert, J., Maurus, S., Metag, V., Michel, J., Mihaylov, D. M., Mikhaylov, V., Morozov, S., Müntz, C., Münzer, R., Naumann, L., Nowakowski, K., Parpottas, Y., Pechenov, V., Pechenova, O., Petukhov, O., Pietraszko, J., Prozorov, A. P., Przygoda, W., Ramstein, B., Rathod, N., Reshetin, A., Rodriguez-Ramos, P., Rost, A., Sadovsky, A., Salabura, P., Scheib, T., Schmidt-Sommerfeld, K., Schuldes, H., Schwab, E., Scozzi, F., Seck, F., Sellheim, P., Siebenson, J., Silva, L., Sing, U., Smyrski, J., Spataro, S., Spies, S., Ströbele, H., Stroth, J., Strzempek, P., Sturm, C., Svoboda, O., Szala, M., Tlusty, P., Traxler, M., Tsertos, H., Ungethüm, C., Vazquez-Doce, O., Wagner, V., Wendisch, C., Wiebusch, M. G., Wirth, J., Wójcik, D., Zanevsky, Y., and Zumbruch, P.

Subjects
Nuclear Experiment
Abstract

Pion induced reactions provide unique opportunities for an unambiguous description of baryonic resonances and their coupling channels by means of a partial wave analysis. Using the secondary pion beam at SIS18, the two pion production in the second resonance region has been investigated to unravel the role of the $N(1520) \frac{3}{2}^-$ resonance in the intermediate $\rho$ production. Results on exclusive channels with one pion ($\pi^{-}p$) and two pions ($\pi^{+}\pi^{-}n$, $\pi^{0}\pi^{-}p$) in the final state measured in the $\pi^{-}-p$ reaction at four different pion beam momenta (0.650, 0.685, 0.733, and 0.786 GeV/c) are presented. The excitation function of the different partial waves and $\Delta\pi$, $N\sigma$ and $N\rho$ isobar configurations is obtained, using the Bonn-Gatchina partial wave analysis. The $N(1520) \frac{3}{2}^-$ resonance is found to dominate the $N\rho$ final state with the branching ratio $BR=12.2 \pm 1.9\%$.

Published
2020
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10. Proton number fluctuations in $\sqrt{s_{NN}}$ = 2.4 GeV Au+Au collisions studied with HADES

Author

Adamczewski-Musch, J., Arnold, O., Behnke, C., Belounnas, A., Belyaev, A., Berger-Chen, J. C., Biernat, J., Blanco, A., Blume, C., B"ohmer, M., Bordalo, P., Chernenko, S., Chlad, L., Deveaux, C., Dreyer, J., Dybczak, A., Epple, E., Fabbietti, L., Fateev, O., Filip, P., Fonte, P., Franco, C., Friese, J., Fr"ohlich, I., Galatyuk, T., Garzon, J. A., Gernh"auser, R., Golubeva, M., Greifenhagen, R., Guber, F., Gumberidze, M., Harabasz, S., Heinz, T., Hennino, T., Hlavac, S., H"ohne, C., Holzmann, R., Ierusalimov, A., Ivashkin, A., K"ampfer, B., Karavicheva, T., Kardan, B., Koenig, I., Koenig, W., Kohls, M., Kolb, B. W., Korcyl, G., Kornakov, G., Kornas, F., Kotte, R., Kugler, A., Kunz, T., Kurepin, A., Kurilkin, A., Kurilkin, P., Ladygin, V., Lalik, R., Lapidus, K., Lebedev, A., Lopes, L., Lorenz, M., Mahmoud, T., Maier, L., Mangiarotti, A., Markert, J., Matulewicz, T., Maurus, S., Metag, V., Michel, J., Mihaylov, D. M., Morozov, S., M"untz, C., M"unzer, R., Naumann, L., Nowakowski, K., Palka, M., Parpottas, Y., Pechenov, V., Pechenova, O., Petukhov, O., Piasecki, K., Pietraszko, J., Przygoda, W., Ramos, S., Ramstein, B., Reshetin, A., Rodriguez-Ramos, P., Rosier, P., Rost, A., Rustamov, A., Sadovsky, A., Salabura, P., Scheib, T., Schuldes, H., Schwab, E., Scozzi, F., Seck, F., Sellheim, P., Selyuzhenkov, I., Siebenson, J., Silva, L., Sobolev, Yu. G., Spataro, S., Spies, S., Str"obele, H., Stroth, J., Strzempek, P., Sturm, C., Svoboda, O., Szala, M., Tlusty, P., Traxler, M., Tsertos, H., Usenko, E., Wagner, V., Wendisch, C., Wiebusch, M. G., Wirth, J., Zanevsky, Y., and Zumbruch, P.

Subjects
Nuclear Experiment
Abstract

We present an analysis of proton number fluctuations in $\sqrt{s_{NN}}$ = 2.4 GeV Au+Au collisions measured with the High-Acceptance DiElectron Spectrometer (HADES) at GSI. With the help of extensive detector simulations done with IQMD transport model events including nuclear clusters, various nuisance effects influencing the observed proton cumulants have been investigated. Acceptance and efficiency corrections have been applied as a function of fine grained rapidity and transverse momentum bins, as well as considering local track density dependencies. Next, the effects of volume changes within particular centrality selections have been considered and beyond-leading-order corrections have been applied to the data. The efficiency and volume corrected proton number moments and cumulants Kn of orders n = 1, . . . , 4 have been obtained as a function of centrality and phase-space bin, as well as the corresponding correlators C_n . We find that the observed correlators show a power-law scaling with the mean number of protons, i.e. $C_n \propto ^n$, indicative of mostly long-range multi-particle correlations in momentum space. We also present a comparison of our results with Au+Au collision data obtained at RHIC at similar centralities, but higher $\sqrt{s_{NN}}$., Comment: 35 pages, 33 figures

Published
2020
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11. Identical pion intensity interferometry at sqrt(s_{NN})=2.4 GeV

Author

Adamczewski-Musch, J., Arnold, O., Behnke, C., Belounnas, A., Belyaev, A., Berger-Chen, J. C., Biernat, J., Blanco, A., Blume, C., Böhmer, M., Bordalo, P., Chernenko, S., Chlad, L., Deveaux, C., Dreyer, J., Dybczak, A., Epple, E., Fabbietti, L., Fateev, O., Filip, P., Fonte, P., Franco, C., Friese, J., Fröhlich, I., Galatyuk, T., Garzón, J. A., Gernhäuser, R., Golubeva, M., Greifenhagen, R., Guber, F., Gumberidze, M., Harabasz, S., Heinz, T., Hennino, T., Hlavac, S., Höhne, C., Holzmann, R., Ierusalimov, A., Ivashkin, A., Kämpfer, B., Karavicheva, T., Kardan, B., Koenig, I., Koenig, W., Kolb, B. W., Korcyl, G., Kornakov, G., Kornas, F., Kotte, R., Kugler, A., Kunz, T., Kurepin, A., Kurilkin, A., Kurilkin, P., Ladygin, V., Lalik, R., Lapidus, K., Lebedev, A., Lopes, L., Lorenz, M., Mahmoud, T., Maier, L., Mangiarotti, A., Markert, J., Matulewicz, T., Maurus, S., Metag, V., Michel, J., Mihaylov, D. M., Morozov, S., Müntz, C., Münzer, R., Naumann, L., Nowakowski, K., Palka, M., Parpottas, Y., Pechenov, V., Pechenova, O., Petukhov, O., Piasecki, K., Pietraszko, J., Przygoda, W., Ramos, S., Ramstein, B., Reshetin, A., Rodriguez-Ramos, P., Rosier, P., Rost, A., Sadovsky, A., Salabura, P., Scheib, T., Schuldes, H., Schwab, E., Scozzi, F., Seck, F., Sellheim, P., Selyuzhenkov, I., Siebenson, J., Silva, L., Sobolev, Yu. G., Spataro, S., Spies, S., Ströbele, H., Stroth, J., Strzempek, P., Sturm, C., Svoboda, O., Szala, M., Tlusty, P., Traxler, M., Tsertos, H., Usenko, E., Wagner, V., Wendisch, C., Wiebusch, M. G., Wirth, J., Wójcik, D., Zanevsky, Y., and Zumbruch, P.

Subjects
Nuclear Experiment
Abstract

High-statistics $\pi^-\pi^-$ and $\pi^+\pi^+$ femtoscopy data are presented for Au+Au collisions at $\sqrt{s_\mathrm{NN}}=2.4$ GeV, measured with HADES at SIS18/GSI. The experimental correlation functions allow the determination of the space-time extent of the corresponding emission sources via a comparison to models. The emission source, parametrized as three-dimensional Gaussian distribution, is studied in dependence on pair transverse momentum, azimuthal emission angle with respect to the reaction plane, collision centrality and beam energy. For all centralities and transverse momenta, a geometrical distribution of ellipsoidal shape is found in the plane perpendicular to the beam direction with the larger extension perpendicular to the reaction plane. For large transverse momenta, the corresponding eccentricity approaches the initial eccentricity. The eccentricity is smallest for most central collisions, where the shape is almost circular. The magnitude of the tilt angle of the emission ellipsoid in the reaction plane decreases with increasing centrality and increasing transverse momentum. All source radii increase with centrality, largely exhibiting a linear rise with the number of participants, irrespective of transverse momentum. A substantial charge-sign difference of the source radii is found, appearing most pronounced at low transverse momentum. The extracted source parameters are consistent with the extrapolation of their energy dependence down from higher energies., Comment: 20 pages, 19 figures, 7 tables. arXiv admin note: text overlap with arXiv:1811.06213

Published
2019
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12. Sub-threshold production of K^{0}_{s} mesons and {\Lambda} hyperons in Au(1.23A GeV)+Au

Author

HADES collaboration, Adamczewski-Musch, J., Arnold, O., Behnke, C., Belounnas, A., Belyaev, A., Berger-Chen, J. C., Biernat, J., Blanco, A., Blume, C., Böhmer, M., Bordalo, P., Chernenko, S., Chlad, L., Deveaux, C., Dreyer, J., Dybczak, A., Epple, E., Fabbietti, L., Fateev, O., Filip, P., Fonte, P., Franco, C., Friese, J., Fröhlich, I., Galatyuk, T., Garzon, J. A., Gernhäuser, R., Golubeva, M., Greifenhagen, R., Guber, F., Gumberidze, M., Harabasz, S., Heinz, T., Hennino, T., Hlavac, S., Höhne, C., Holzmann, R., Ierusalimov, A., Ivashkin, A., Kämpfer, B., Karavicheva, T., Kardan, B., Koenig, I., Koenig, W., Kolb, B. W., Korcyl, G., Kornakov, G., Kotte, R., Kugler, A., Kunz, T., Kurepin, A., Kurilkin, A., Kurilkin, P., Ladygin, V., Lalik, R., Lapidus, K., Lebedev, A., Lopes, L., Lorenz, M., Mahmoud, T., Maier, L., Mangiarotti, A., Markert, J., Maurus, S., Metag, V., Michel, J., Mihaylov, D. M., Morozov, S., Müntz, C., Münzer, R., Naumann, L., Nowakowski, K. N., Palka, M., Parpottas, Y., Pechenov, V., Pechenova, O., Petukhov, O., Pietraszko, J., Przygoda, W., Ramos, S., Ramstein, B., Reshetin, A., Rodriguez-Ramos, P., Rosier, P., Rost, A., Sadovsky, A., Salabura, P., Scheib, T., Schuldes, H., Schwab, E., Scozzi, F., Seck, F., Sellheim, P., Selyuzhenkov, I., Siebenson, J., Silva, L., Sobolev, Yu. G., Spataro, S., Ströbele, H., Stroth, J., Strzempek, P., Sturm, C., Svoboda, O., Szala, M., Tlusty, P., Traxler, M., Tsertos, H., Usenko, E., Wagner, V., Wendisch, C., Wiebusch, M. G., Wirth, J., Zanevsky, Y., Zumbruch, P., and Leifels, Y.

Subjects
Nuclear Experiment
Abstract

We present first data on sub-threshold production of K0 s mesons and {\Lambda} hyperons in Au+Au collisions at $\sqrt{s_{NN}}$ = 2.4 GeV. We observe an universal scaling of hadrons containing strangeness, independent of their corresponding production thresholds. Comparing the yields, their scaling, and the shapes of the rapidity and the pt spectra to state-of-the-art transport model (UrQMD, HSD, IQMD) predictions, we find that none of the latter can simultaneously describe all observables with reasonable \c{hi}2 values., Comment: 8 pages, 10 figures

Published
2018
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13. Strong absorption of hadrons with hidden and open strangeness in nuclear matter

Author

Adamczewski-Musch, J., Arnold, O., Atomssa, E. T., Behnke, C., Belounnas, A., Belyaev, A., Berger-Chen, J. C., Biernat, J., Blanco, A., Blume, C., Böhmer, M., Chernenko, S., Chlad, L., Chudoba, P., Ciepal, I., Deveaux, C., Dittert, D., Dreyer, J., Dybczak, A., Epple, E., Fabbietti, L., Fateev, O., Fonte, P., Franco, C., Friese, J., Fröhlich, I., Galatyuk, T., Garzon, J. A., Gernhäuser, R., Golubeva, M., Greifenhagen, R., Guber, F., Gumberidze, M., Harabasz, S., Heinz, T., Hennino, T., Höhne, C., Holzmann, R., Ierusalimov, A., Ivashkin, A., Kämpfer, B., Kardan, B., Koenig, I., Koenig, W., Kolb, B. W., Korcyl, G., Kornakov, G., Kornas, F., Kotte, R., Kubos, J., Kugler, A., Kunz, T., Kurepin, A., Kurilkin, A., Kurilkin, P., Ladygin, V., Lalik, R., Lapidus, K., Lebedev, A., Linev, S., Lopes, L., Lorenz, M., Mahmoud, T., Maier, L., Malige, A., Markert, J., Maurus, S., Metag, V., Michel, J., Mihaylov, D. M., Mikhaylov, V., Morozov, S., Müntz, C., Münzer, R., Naumann, L., Nowakowsk, K., Parpottas, Y., Pechenov, V., Pechenova, O., Petukhov, O., Pietraszko, J., Prozorov, A. P., Przygoda, W., Ramstein, B., Reshetin, A., Rodriguez-Ramos, P., Rost, A., Sadovsky, A., Salabura, P., Scheib, T., Schmidt-Sommerfeld, K., Schuldes, H., Schwab, E., Scozzi, F., Seck, F., Sellheim, P., Siebenson, J., Silva, L., Smyrski, J., Spataro, S., Spies, S., Ströbele, H., Stroth, J., Strzempek, P., Sturm, C., Svoboda, O., Szala, M., Tlusty, P., Traxler, M., Tsertos, H., Ungethüm, C., Doce, O. Vazquez, Wagner, V., Wendisch, C., Wiebusch, M. G., Wirth, J., Zanevsky, Y., and Zumbruch, P.

Subjects
Nuclear Experiment
Abstract

We present the first observation of K- and \phi absorption within nuclear matter by means of \pi- -induced reactions on C and W targets at an incident beam momentum of 1.7 GeV/c studied with HADES at SIS18/GSI. The double ratio (K-/K+)W / (K-/K+)C is found to be 0.319 \pm 0.009(stat)+0.014-0.012 (syst) indicating a larger absorption of K- in heavier targets as compared to lighter ones. The measured \phi/K- ratios in \pi-+C and \pi^- +W reactions within the HADES acceptance are found to be equal to $0.55 \pm 0.03(stat)+0.06-0.07$ (syst) and to $0.63 \pm 0.05(stat)-0.11+0.11$ (syst), respectively. The similar ratios measured in the two different reactions demonstrate for the first time experimentally that the dynamics of the \phi meson in nuclear medium is strongly coupled to the K- dynamics. The large difference in the \phi production off C and W nuclei is discussed in terms of a strong \phiN in-medium coupling., Comment: 6 pages, 3 figures

Published
2018
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14. Identical pion intensity interferometry in central Au+Au collisions at 1.23A GeV

Author

Adamczewski-Musch, J., Arnold, O., Behnke, C., Belounnas, A., Belyaev, A., Berger-Chen, J. C., Biernat, J., Blanco, A., Blume, C., Böhmer, M., Bordalo, P., Chernenko, S., Chlad, L., Deveaux, C., Dreyer, J., Dybczak, A., Epple, E., Fabbietti, L., Fateev, O., Filip, P., Fonte, P., Franco, C., Friese, J., Fröhlich, I., Galatyuk, T., Garzon, J. A., Gernhäuser, R., Golubeva, M., Greifenhagen, R., Guber, F., Gumberidze, M., Harabasz, S., Heinz, T., Hennino, T., Hlavac, S., Höhne, C., Holzmann, R., Ierusalimov, A., Ivashkin, A., Kämpfer, B., Karavicheva, T., Kardan, B., Koenig, I., Koenig, W., Kolb, B. W., Korcyl, G., Kornakov, G., Kotte, R., Kühn, W., Kugler, A., Kunz, T., Kurepin, A., Kurilkin, A., Kurilkin, P., Ladygin, V., Lalik, R., Lapidus, K., Lebedev, A., Lopes, L., Lorenz, M., Mahmoud, T., Maier, L., Mangiarotti, A., Markert, J., Matulewicz, T., Maurus, S., Metag, V., Michel, J., Mihaylov, D. M., Morozov, S., Müntz, C., Münzer, R., Naumann, L., Nowakowski, K. N., Palka, M., Parpottas, Y., Pechenov, V., Pechenova, O., Petukhov, O., Piasecki, K., Pietraszko, J., Przygoda, W., Ramos, S., Ramstein, B., Reshetin, A., Rodriguez-Ramos, P., Rosier, P., Rost, A., Sadovsky, A., Salabura, P., Scheib, T., Schuldes, H., Schwab, E., Scozzi, F., Seck, F., Sellheim, P., Siebenson, J., Silva, L., Sobolev, Yu. G., Spataro, S., Ströbele, H., Stroth, J., Strzempek, P., Sturm, C., Svoboda, O., Szala, M., Tlusty, P., Traxler, M., Tsertos, H., Usenko, E., Wagner, V., Wendisch, C., Wiebusch, M. G., Wirth, J., Wojcik, D., Zanevsky, Y., and Zumbruch, P.

Subjects
Nuclear Experiment
Abstract

We investigate identical pion HBT intensity interferometry for central Au+Au collisions at 1.23A GeV. High-statistics $\pi^-\pi^-$ and $\pi^+\pi^+$ data are measured with HADES at SIS18/GSI. The radius parameters, derived from the correlation function depending on relative momenta in the longitudinal-comoving system and parametrized as three-dimensional Gaussian distribution, are studied as function of transverse momentum. A substantial charge-sign difference of the source radii is found, particularly pronounced at low transverse momentum. The extracted Coulomb-corrected source parameters agree well with a smooth extrapolation of the center-of-mass energy dependence established at higher energies, extending the corresponding excitation functions down towards a very low energy. Our data would thus rather disfavour any strong energy dependence of the radius parameters in the low energy region., Comment: 7 pages, 5 figures, updated author and grant lists

Published
2018
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15. Centrality determination of Au+Au collisions at 1.23A GeV with HADES

Author

HADES collaboration, Adamczewski-Musch, J., Arnold, O., Behnke, C., Belounnas, A., Belyaev, A., Chernenko, S., Chlad, L., Deveaux, C., Dreyer, J., Dybczak, A., Epple, E., Fabbietti, L., Fateev, O., Filip, P., Fonte, P., Franco, C., Friese, J., Froehlich, I., Galatyuk, T., Garzon, J. A., Gernhaeuser, R., Golubeva, M., Greifenhagen, R., Guber, F., Gumberidze, M., Harabasz, S., Heinz, T., Hennino, T., Hlavac, S., Hoehne, C., Holzmann, R., Ierusalimov, A., Ivashkin, A., Kaempfer, B., Karavicheva, T., Kardan, B., Koenig, I., Koenig, W., Kolb, B. W., Korcyl, G., Kornakov, G., Kotte, R., Kuehn, W., Kugler, A., Kunz, T., Kurepin, A., Kurilkin, A., Kurilkin, P., Ladygin, V., Lalik, R., Lapidus, K., Lebedev, A., Lopes, L., Lorenz, M., Mahmoud, T., Maier, L., Mangiarotti, A., Markert, J., Maurus, S., Metag, V., Michel, J., Mihaylov, D. M., Morozov, S., Muentz, C., Muenzer, R., Naumann, L., Nowakowski, K. N., Palka, M., Parpottas, Y., Pechenov, V., Pechenova, O., Petukhov, O., Pietraszko, J., Przygoda, W., Ramos, S., Ramstein, B., Reshetin, A., Rodriguez-Ramos, P., Rosier, P., Rost, A., Sadovsky, A., Salabura, P., Scheib, T., Schuldes, H., Schwab, E., Scozzi, F., Seck, F., Sellheim, P., Siebenson, J., Silva, L., Sobolev, Yu. G., Spataro, S., Stroebele, H., Stroth, J., Strzempek, P., Sturm, C., Svoboda, O., Szala, M., Tlusty, P., Traxler, M., Tsertos, H., Usenko, E., Wagner, V., Wendisch, C., Wiebusch, M. G., Wirth, J., Zanevsky, Y., and Zumbruch, P.

Subjects
Nuclear Experiment
Abstract

The centrality determination for Au+Au collisions at 1.23A GeV, as measured with HADES at the GSI-SIS18, is described. In order to extract collision geometry related quantities, such as the average impact parameter or number of participating nucleons, a Glauber Monte Carlo approach is employed. For the application of this model to collisions at this relatively low centre-of-mass energy of $\sqrt{s_{\mathrm{NN}}} = 2.42$ GeV special investigations were performed. As a result a well defined procedure to determine centrality classes for ongoing analyses of heavy-ion data is established.

Published
2017
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16. Analysis of the exclusive final state npe$^+$e$^-$ in quasi-free np reaction

Author

Adamczewski-Musch, J., Arnold, O., Atomssa, E. T., Behnke, C., Belounnas, A., Belyaev, A., Berger-Chen, J. C., Biernat, J., Blanco, A., Blume, C., Böhmer, M., Bordalo, P., Chernenko, S., Chlad, L., Deveaux, C., Dreyer, J., Dybczak, A., Epple, E., Fabbietti, L., Fateev, O., Filip, P., Finocchiaro, P., Fonte, P., Franco, C., Friese, J., Fröhlich, I., Galatyuk, T., Garzón, J. A., Gernhäuser, R., Golubeva, M., Guber, F., Gumberidze, M., Harabasz, S., Heinz, T., Hennino, T., Hlavac, S., Höhne, C., Holzmann, R., Ierusalimov, A., Ivashkin, A., Kämpfer, B., Karavicheva, T., Kardan, B., Koenig, I., Koenig, W., Kolb, B. W., Korcyl, G., Kornakov, G., Kotte, R., Kühn, W., Kugler, A., Kunz, T., Kurepin, A., Kurilkin, A., Kurilkin, P., Ladygin, V., Lalik, R., Lapidus, K., Lebedev, A., Liu, T., Lopes, L., Lorenz, M., Mahmoud, T., Maier, L., Mangiarotti, A., Markert, J., Maurus, S., Metag, V., Michel, J., Morinière, E., Mihaylov, D. M., Morozov, S., Müntz, C., Münzer, R., Naumann, L., Nowakowski, K. N., Palka, M., Parpottas, Y., Pechenov, V., Pechenova, O., Petukhov, O., Pietraszko, J., Przygoda, W., Ramos, S., Ramstein, B., Reshetin, A., Rodriguez-Ramos, P., Rosier, P., Rost, A., Sadovsky, A., Salabura, P., Scheib, T., Schuldes, H., Schwab, E., Scozzi, F., Seck, F., Sellheim, P., Siebenson, J., Silva, L., Sobolev, Yu. G., Spataro, S., Ströbele, H., Stroth, J., Strzempek, P., Sturm, C., Svoboda, O., Tlusty, P., Traxler, M., Tsertos, H., Usenko, E., Wagner, V., Wendisch, C., Wiebusch, M. G., Wirth, J., Zanevsky, Y., Zumbruch, P., and Sarantsev, A. V.

Subjects
Nuclear Experiment, J.2
Abstract

We report on the investigation of dielectron production in tagged quasi-free neutron-proton collisions by using a deuteron beam of kinetic energy 1.25 GeV/u inpinging on a liquid hydrogen target. Our measurements with HADES confirm a significant excess of $e^+e^-$ pairs above the $\pi^{0}$ mass in the exclusive channel $dp \to npe^{+}e^{-}(p_{spect})$ as compared to the exclusive channel $ppe^{+}e^{-}$ measured in proton-proton collisions at the same energy. That excess points to different bremsstrahlung production mechanisms. Two models were evaluated for the role of the charged pion exchange between nucleons and double-$\Delta$ excitation combined with intermediate $\rho$-meson production. Differential cross sections as a function of the $e^+e^-$ invariant mass and of the angles of the virtual photon, proton and electrons provide valuable constraints and encourage further investigations on both experimental and theoretical side., Comment: 12 pages, 7 figures

Published
2017
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17. Deep sub-threshold {\phi} production and implications for the K+/K- freeze-out in Au+Au collisions

Author

Adamczewski-Musch, J., Arnold, O., Behnke, C., Belounnas, A., Belyaev, A., Berger-Chen, J. C., Biernat, J., Blanco, A., Blume, C., Böhmer, M., Bordalo, P., Chernenko, S., Chlad, L., Deveaux, C., Dreyer, J., Dybczak, A., Epple, E., Fabbietti, L., Fateev, O., Filip, P., Fonte, P., Franco, C., Friese, J., Fröhlich, I., Galatyuk, T., Garzon, J. A., Gernhäuser, R., Golubeva, M., Guber, F., Gumberidze, M., Harabasz, S., Heinz, T., Hennino, T., Hlavac, S., Höhne, C., Holzmann, R., Ierusalimov, A., Ivashkin, A., Kämpfer, B., Karavicheva, T., Kardan, B., Koenig, I., Koenig, W., Kolb, B. W., Korcy, G., Kornakov, G., Kotte, R., Kühn, W., Kugler, A., Kunz, T., Kurepin, A., Kurilkin, A., Kurilkin, P., Ladygin, V., Lalik, R., Lapidus, K., Lebedev, A., Lopes, L., Lorenz, M., Mahmoud, T., Maier, L., Mangiarotti, A., Markert, J., Maurus, S., Metag, V., Michel, J., Mihaylov, D. M., Morozov, S., Müntz, C., Münzer, R., Naumann, L., Nowakowski, K. N., Palka, M., Parpottas, Y., Pechenov, V., Pechenova, O., Petukhov, O., Pietraszko, J., Przygoda, W., Ramos, S., Ramstein, B., Reshetin, A., Rodriguez-Ramos, P., Rosier, P., Rost, A., Sadovsky, A., Salabura, P., Scheib, T., Schuldes, H., Schwab, E., Scozzi, F., Seck, F., Sellheim, P., Siebenson, J., Silva, L., Sobolev, Yu. G., Spataro, S., Ströbele, H., Stroth, J., Strzempek, P., Sturm, C., Svoboda, O., Szala, M., Tlusty, P., Traxler, M., Tsertos, H., Usenko, E., Wagner, V., Wendisch, C., Wiebusch, M. G., Wirth, J., Zanevsky, Y., and Zumbruch, P.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

We present data on charged kaons (K+-) and {\phi} mesons in Au(1.23A GeV)+Au collisions. It is the first simultaneous measurement of K and {\phi} mesons in central heavy-ion collisions below a kinetic beam energy of 10A GeV. The {\phi}/K- multiplicity ratio is found to be surprisingly high with a value of 0.52 +- 0.16 and shows no dependence on the centrality of the collision. Consequently, the different slopes of the K+ and K- transverse-mass spectra can be explained solely by feed- down, which substantially softens the spectra of K- mesons. Hence, in contrast to the commonly adapted argumentation in literature, the different slopes do not necessarily imply diverging freeze- out temperatures of K+ and K- mesons caused by different couplings to baryons., Comment: Corrected and updated version, 28 November 2017

Published
2017
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18. $\Delta$(1232) Dalitz decay in proton-proton collisions at T=1.25 GeV measured with HADES

Author

Adamczewski-Musch, J., Arnold, O., Atomssa, E. T., Behnke, C., Belounnas, A., Belyaev, A., Berger-Chen, J. C., Biernat, J., Blanco, A., Blume, C., Böhmer, M., Bordalo, P., Chernenko, S., Chlad, L., Deveaux, C., Dreyer, J., Dybczak, A., Epple, E., Fabbietti, L., Fateev, O., Filip, P., Finocchiaro, P., Fonte, P., Franco, C., Friese, J., Fröhlich, I., Galatyuk, T., Garzón, J. A., Gernhäuser, R., Golubeva, M., Guber, F., Gumberidze, M., Harabasz, S., Heinz, T., Hennino, T., Hlavac, S., Höhne, C., Holzmann, R., Ierusalimov, A., Ivashkin, A., Kämpfer, B., Karavicheva, T., Kardan, B., Koenig, I., Koenig, W., Kolb, B. W., Korcyl, G., Kornakov, G., Kotte, R., Kühn, W., Kugler, A., Kunz, T., Kurepin, A., Kurilkin, A., Kurilkin, P., Ladygin, V., Lalik, R., Lapidus, K., Lebedev, A., Liu, T., Lopes, L., Lorenz, M., Mahmoud, T., Maier, L., Mangiarotti, A., Markert, J., Maurus, S., Metag, V., Michel, J., Morinière, E., Mihaylov, D. M., Morozov, S., Müntz, C., Münzer, R., Naumann, L., Nowakowski, K. N., Palka, M., Parpottas, Y., Pechenov, V., Pechenova, O., Petukhov, O., Pietraszko, J., Przygoda, W., Ramos, S., Ramstein, B., Reshetin, A., Rodriguez-Ramos, P., Rosier, P., Rost, A., Sadovsky, A., Salabura, P., Scheib, T., Schuldes, H., Schwab, E., Scozzi, F., Seck, F., Sellheim, P., Siebenson, J., Silva, L., Sobolev, Yu. G., Spataro, S., Ströbele, H., Stroth, J., Strzempek, P., Sturm, C., Svoboda, O., Tlusty, P., Traxler, M., Tsertos, H., Usenko, E., Wagner, V., Wendisch, C., Wiebusch, M. G., Wirth, J., Zanevsky, Y., Zumbruch, P., and Sarantsev, A. V.

Subjects
Nuclear Experiment, J.2
Abstract

We report on the investigation of $\Delta$(1232) production and decay in proton-proton collisions at a kinetic energy of 1.25 GeV measured with HADES. Exclusive dilepton decay channels $ppe^{+}e^{-}$ and $ppe^{+}e^{-}\gamma$ have been studied and compared with the partial wave analysis of the hadronic $pp\pi^{0}$ channel. They allow to access both $\Delta^+ \to p\pi^0(e^+e^-\gamma)$ and $\Delta^+ \to pe^+e^-$ Dalitz decay channels. The perfect reconstruction of the well known $\pi^0$ Dalitz decay serves as a proof of the consistency of the analysis. The $\Delta$ Dalitz decay is identified for the first time and the sensitivity to N-$\Delta$ transition form factors is tested. The $\Delta$(1232) Dalitz decay branching ratio is also determined for the first time; our result is (4.19 $\pm$ 0.62 syst. $\pm$ 0.34 stat.) $\times $ 10$^{-5}$, albeit with some model dependence., Comment: 13 pages, 7 figures

Published
2017
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19. Measurement of global polarization of Λ hyperons in few-GeV heavy-ion collisions

Author

Abou Yassine, R., primary, Adamczewski-Musch, J., additional, Asal, C., additional, Becker, M., additional, Belounnas, A., additional, Blanco, A., additional, Blume, C., additional, Chlad, L., additional, Chudoba, P., additional, Ciepał, I., additional, Cordts, M., additional, Dreyer, J., additional, Esmail, W.A., additional, Fabbietti, L., additional, Floersheimer, H., additional, Fonte, P., additional, Friese, J., additional, Fröhlich, I., additional, Förtsch, J., additional, Galatyuk, T., additional, Gniazdowski, T., additional, Greifenhagen, R., additional, Grunwald, M., additional, Gumberidze, M., additional, Harabasz, S., additional, Heinz, T., additional, Höhne, C., additional, Hojeij, F., additional, Holzmann, R., additional, Huck, H., additional, Idzik, M., additional, Kämpfer, B., additional, Kampert, K-H., additional, Kardan, B., additional, Kedych, V., additional, Koenig, I., additional, Koenig, W., additional, Kohls, M., additional, Kolas, J., additional, Kornakov, G., additional, Kotte, R., additional, Kres, I., additional, Krueger, W., additional, Kugler, A., additional, Lalik, R., additional, Lebedev, S., additional, Linev, S., additional, Linz, F., additional, Lopes, L., additional, Lorenz, M., additional, Malige, A., additional, Markert, J., additional, Matulewicz, T., additional, Maurus, S., additional, Metag, V., additional, Michel, J., additional, Molenda, A., additional, Müntz, C., additional, Nabroth, M., additional, Naumann, L., additional, Nowakowski, K., additional, Orliński, J., additional, Otto, J.-H., additional, Parschau, M., additional, Pauly, C., additional, Pechenov, V., additional, Pechenova, O., additional, Pfeifer, D., additional, Piasecki, K., additional, Pietraszko, J., additional, Povar, T., additional, Prozorov, A., additional, Przygoda, W., additional, Pysz, K., additional, Ramstein, B., additional, Rathod, N., additional, Ritman, J., additional, Rodriguez-Ramos, P., additional, Rost, A., additional, Rustamov, A., additional, Salabura, P., additional, Saraiva, J., additional, Schild, N., additional, Schwab, E., additional, Scozzi, F., additional, Seck, F., additional, Selyuzhenkov, I., additional, Singh, U., additional, Skorpil, L., additional, Smyrski, J., additional, Spies, S., additional, Stefaniak, M.S., additional, Ströbele, H., additional, Stroth, J., additional, Sumara, K., additional, Svoboda, O., additional, Szala, M., additional, Tlusty, P., additional, Traxler, M., additional, Wagner, V., additional, Wasiluk, M., additional, Weber, A.A., additional, Wendisch, C., additional, Wirth, J., additional, Zbroszczyk, H.P., additional, Zherebtsova, E., additional, Zielinski, M., additional, and Zumbruch, P., additional

Published
2022
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20. Study of baryonic resonances and ρ meson production in the reaction pp → ppπ+π− at 3.5 GeV with HADES

Author

Belounnas Amel

Subjects
Physics, QC1-999
Abstract

We report on measurements of baryon resonance and ρ meson production in the exclusive pp → ppπ+π− channel at a beam kinetic energy of 3.5 GeV measured with the HADES experimental setup. The differential distributions are compared to Monte Carlo simulations based on a resonance model assuming an incoherent sum of contributions of various baryonic resonances with masses below 2 GeV and using inputs from one pion production measured in the same experiment. A very good description of the two pion production is achieved allowing for an estimate of the contribution of one and double baryon-resonance excitation. Using appropriate kinematical cuts the ρ meson signal could also be extracted.

Published
2019
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21. Analyse de facteurs de fiabilité d'actifs industriels de transport de gaz par apprentissage automatique supervisé

Author

Belounnas, Amel, Brissaud, Florent, Gregory, Jardon, and RAGUENET, Manon

Subjects
Asset management, [SPI] Engineering Sciences [physics], SHAP, Machine learning, Scikit-survival, XGBoost, Cox regression
Abstract

Ce travail vise à explorer deux algorithmes d'apprentissage automatique supervisé (XGBoost et Scikit-survival) avec la régression de survie de Cox pour modéliser la fiabilité d'actifs industriels. Ils sont tous les deux efficaces pour analyser les facteurs de fiabilité des actifs industriels de transport de gaz, mais n'ont pas la même performance.

Published
2022

22. Proton, deuteron and triton flow measurements in Au+Au collisions at sNN=2.4 GeV.

Author

Adamczewski-Musch, J., Arnold, O., Behnke, C., Belounnas, A., Berger-Chen, J. C., Blanco, A., Blume, C., Böhmer, M., Bordalo, P., Chlad, L., Ciepal, I., Deveaux, C., Dreyer, J., Epple, E., Fabbietti, L., Filip, P., Fonte, P., Franco, C., Friese, J., and Fröhlich, I.

Abstract

High-precision measurements of flow coefficients v n ( n = 1 - 4 ) for protons, deuterons and tritons relative to the first-order spectator plane have been performed in Au+Au collisions at s NN = 2.4 GeV with the High-Acceptance Di-Electron Spectrometer (HADES) at the SIS18/GSI. Flow coefficients are studied as a function of transverse momentum p t and rapidity y cm over a large region of phase-space and for several classes of collision centrality. A clear mass hierarchy, as expected by relativistic hydrodynamics, is found for the slope of v 1 , d v 1 / d y ′ | y ′ = 0 where y ′ is the scaled rapidity, and for v 2 at mid-rapidity. Scaling with the number of nucleons is observed for the p t dependence of v 2 and v 4 at mid-rapidity, which is indicative for nuclear coalescence as the main process responsible for light nuclei formation. v 2 is found to scale with the initial eccentricity ⟨ ϵ 2 ⟩ , while v 4 scales with ⟨ ϵ 2 ⟩ 2 and ⟨ ϵ 4 ⟩ . The multi-differential high-precision data on v 1 , v 2 , v 3 , and v 4 provides important constraints on the equation-of-state of compressed baryonic matter. [ABSTRACT FROM AUTHOR]

Published
2023
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24. Sub-threshold production of Ks0 mesons and Λ hyperons in Au+Au collisions at sNN=2.4 GeV

Author

J. Adamczewski-Musch, O. Arnold, C. Behnke, A. Belounnas, A. Belyaev, J.C. Berger-Chen, J. Biernat, A. Blanco, C. Blume, M. Böhmer, P. Bordalo, S. Chernenko, L. Chlad, C. Deveaux, J. Dreyer, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Filip, P. Fonte, C. Franco, J. Friese, I. Fröhlich, T. Galatyuk, J.A. Garzón, R. Gernhäuser, M. Golubeva, R. Greifenhagen, F. Guber, M. Gumberidze, S. Harabasz, T. Heinz, T. Hennino, S. Hlavac, C. Höhne, R. Holzmann, A. Ierusalimov, A. Ivashkin, B. Kämpfer, T. Karavicheva, B. Kardan, I. Koenig, W. Koenig, B.W. Kolb, G. Korcyl, G. Kornakov, R. Kotte, A. Kugler, T. Kunz, A. Kurepin, A. Kurilkin, P. Kurilkin, V. Ladygin, R. Lalik, K. Lapidus, A. Lebedev, L. Lopes, M. Lorenz, T. Mahmoud, L. Maier, A. Mangiarotti, J. Markert, S. Maurus, V. Metag, J. Michel, D.M. Mihaylov, S. Morozov, C. Müntz, R. Münzer, L. Naumann, K. Nowakowski, M. Palka, Y. Parpottas, V. Pechenov, O. Pechenova, O. Petukhov, J. Pietraszko, W. Przygoda, S. Ramos, B. Ramstein, A. Reshetin, P. Rodriguez-Ramos, P. Rosier, A. Rost, A. Sadovsky, P. Salabura, T. Scheib, H. Schuldes, E. Schwab, F. Scozzi, F. Seck, P. Sellheim, I. Selyuzhenkov, J. Siebenson, L. Silva, Yu.G. Sobolev, S. Spataro, S. Spies, H. Ströbele, J. Stroth, P. Strzempek, C. Sturm, O. Svoboda, M. Szala, P. Tlusty, M. Traxler, H. Tsertos, E. Usenko, V. Wagner, C. Wendisch, M.G. Wiebusch, J. Wirth, Y. Zanevsky, P. Zumbruch, and Y. Leifels

Subjects
Nuclear Theory, High Energy Physics::Experiment, Nuclear Experiment, lcsh:Physics, lcsh:QC1-999
Abstract

We present first data on sub-threshold production of Ks0 mesons and Λ hyperons in Au+Au collisions at sNN=2.4 GeV. We observe an universal 〈Apart〉 scaling of hadrons containing strangeness, independent of their corresponding production thresholds. Comparing the yields, their 〈Apart〉 scaling, and the shapes of the rapidity and the pt spectra to state-of-the-art transport model (UrQMD, HSD, IQMD) predictions, we find that none of them can simultaneously describe these observables with reasonable χ2 values.

Published
2019

26. Correlated pion-proton pair emission off hot and dense QCD matter

Author

Adamczewski-Musch, J., primary, Arnold, O., additional, Behnke, C., additional, Belounnas, A., additional, Belyaev, A., additional, Berger-Chen, J.C., additional, Blanco, A., additional, Blume, C., additional, Böhmer, M., additional, Bordalo, P., additional, Chernenko, S., additional, Chlad, L., additional, Ciepał, I., additional, Deveaux, C., additional, Dreyer, J., additional, Epple, E., additional, Fabbietti, L., additional, Fateev, O., additional, Filip, P., additional, Fonte, P., additional, Franco, C., additional, Friese, J., additional, Fröhlich, I., additional, Galatyuk, T., additional, Garzón, J.A., additional, Gernhäuser, R., additional, Golubeva, M., additional, Greifenhagen, R., additional, Guber, F., additional, Gumberidze, M., additional, Harabasz, S., additional, Heinz, T., additional, Hennino, T., additional, Hlavac, S., additional, Höhne, C., additional, Holzmann, R., additional, Ierusalimov, A., additional, Ivashkin, A., additional, Kämpfer, B., additional, Karavicheva, T., additional, Kardan, B., additional, Koenig, I., additional, Koenig, W., additional, Kohls, M., additional, Kolb, B.W., additional, Korcyl, G., additional, Kornakov, G., additional, Kornas, F., additional, Kotte, R., additional, Kugler, A., additional, Kunz, T., additional, Kurepin, A., additional, Kurilkin, A., additional, Kurilkin, P., additional, Ladygin, V., additional, Lalik, R., additional, Lapidus, K., additional, Lebedev, A., additional, Lopes, L., additional, Lorenz, M., additional, Mahmoud, T., additional, Maier, L., additional, Malige, A., additional, Mangiarotti, A., additional, Markert, J., additional, Matulewicz, T., additional, Maurus, S., additional, Metag, V., additional, Michel, J., additional, Mihaylov, D.M., additional, Morozov, S., additional, Müntz, C., additional, Münzer, R., additional, Naumann, L., additional, Nowakowski, K., additional, Parpottas, Y., additional, Pechenov, V., additional, Pechenova, O., additional, Petukhov, O., additional, Piasecki, K., additional, Pietraszko, J., additional, Przygoda, W., additional, Pysz, K., additional, Ramos, S., additional, Ramstein, B., additional, Rathod, N., additional, Reshetin, A., additional, Rodriguez-Ramos, P., additional, Rosier, P., additional, Rost, A., additional, Sadovsky, A., additional, Salabura, P., additional, Scheib, T., additional, Schuldes, H., additional, Schwab, E., additional, Scozzi, F., additional, Seck, F., additional, Sellheim, P., additional, Selyuzhenkov, I., additional, Siebenson, J., additional, Silva, L., additional, Singh, U., additional, Smyrski, J., additional, Sobolev, Yu.G., additional, Spataro, S., additional, Spies, S., additional, Ströbele, H., additional, Stroth, J., additional, Sturm, C., additional, Svoboda, O., additional, Szala, M., additional, Tlusty, P., additional, Traxler, M., additional, Tsertos, H., additional, Usenko, E., additional, Wagner, V., additional, Wendisch, C., additional, Wiebusch, M.G., additional, Wirth, J., additional, Wójcik, D., additional, Zanevsky, Y., additional, and Zumbruch, P., additional

Published
2021
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27. Directed, Elliptic, and Higher Order Flow Harmonics of Protons, Deuterons, and Tritons inAu+AuCollisions atsNN=2.4 GeV

Author

M. Lorenz, S. Spataro, A. Malige, Roman Gernhäuser, A. Kugler, J. Dreyer, I. Fröhlich, Alexander Belyaev, Tatiana Karavicheva, T. Hennino, C. Behnke, P. Tlusty, L. Chlad, C. Wendisch, T. Heinz, Kirill Lapidus, S. Spies, Yu. G. Sobolev, J. A. Garzón, C. Müntz, F. Seck, A. Blanco, P. Fonte, B. Kämpfer, I. Koenig, Laura Fabbietti, Ilya Selyuzhenkov, L. Lopes, P. Zumbruch, Eliane Epple, A. Ivashkin, R. Kotte, K. Pysz, T. Scheib, O. Pechenova, P. Bordalo, C. Deveaux, H. Ströbele, M. Gumberidze, J. Pietraszko, Fedor Guber, R. Greifenhagen, Andrey Reshetin, M. Mamaev, C. Sturm, Oliver Werner Arnold, N. Rathod, V. Wagner, R. H. Munzer, D. M. Mihaylov, P. Rosier, S. Maurus, Y. Parpottas, O. Svoboda, J. Stroth, L. Silva, J. Friese, F. Scozzi, J. Adamczewski-Musch, V. Pechenov, K. Nowakowski, Sergey V. Morozov, B. Kardan, O. Petukhov, Grzegorz Korcyl, T. Mahmoud, B. W. Kolb, R. Lalik, A. K. Kurilkin, Krzysztof Piasecki, T. Kunz, P. Sellheim, A. Rost, Udai Pratap Singh, Christoph Blume, P. Filip, Yu.V. Zanevsky, Witold Przygoda, C. Franco, M. B. Golubeva, P. Rodriguez-Ramos, W. Koenig, G. Kornakov, B. Ramstein, T. Matulewicz, D. Wójcik, S. P. Chernenko, Volker Metag, A. Sadovsky, J. Michel, A. Lebedev, J. Wirth, M. Szala, A. Belounnas, A. B. Kurepin, S. Harabasz, M. Traxler, Jerzy Smyrski, M. Böhmer, A. Mangiarotti, T. Galatyuk, Piotr Salabura, L. Naumann, L. Maier, P. K. Kurilkin, C. Höhne, M. G. Wiebusch, E. Usenko, H. Schuldes, Izabela Ciepał, J. C. Berger-Chen, R. Holzmann, J. Markert, S. Ramos, S. Hlavac, V. P. Ladygin, O. V. Fateev, O. Golosov, F. Kornas, M. Kohls, J. Siebenson, E. Schwab, A.P. Ierusalimov, A. Rustamov, and H. Tsertos

Subjects
Physics, Equation of state, Spectrometer, Nuclear Theory, Elliptic flow, General Physics and Astronomy, 01 natural sciences, 7. Clean energy, Baryon, Nuclear physics, Deuterium, Flow (mathematics), Harmonics, 0103 physical sciences, Rapidity, Nuclear Experiment, 010306 general physics
Abstract

Flow coefficients vn of the orders n=1-6 are measured with the High-Acceptance DiElectron Spectrometer (HADES) at GSI for protons, deuterons, and tritons as a function of centrality, transverse momentum, and rapidity in Au+Au collisions at sNN=2.4 GeV. Combining the information from the flow coefficients of all orders allows us to construct for the first time, at collision energies of a few GeV, a multidifferential picture of the angular emission pattern of these particles. It reflects the complicated interplay between the effect of the central fireball pressure on the emission of particles and their subsequent interaction with spectator matter. The high precision information on higher order flow coefficients is a major step forward in constraining the equation of state of dense baryonic matter.

Published
2020
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28. Proton-number fluctuations in sNN=2.4 GeV Au + Au collisions studied with the High-Acceptance DiElectron Spectrometer (HADES)

Author

H. Tsertos, N. Rathod, E. Schwab, J. Stroth, A. Sadovsky, Roman Gernhäuser, A. Kugler, A.P. Ierusalimov, L. Silva, Laura Fabbietti, S. Spies, G. Korcyl, Oliver Werner Arnold, W. Koenig, K. Nowakowski, Yu.V. Zanevsky, F. Scozzi, T. Galatyuk, J. Adamczewski-Musch, R. Lalik, A. Rustamov, V. P. Ladygin, F. Kornas, A. Lebedev, O. V. Fateev, A. Belounnas, M. Traxler, L. Chlad, P. Rodriguez-Ramos, B. W. Kolb, C. Sturm, P. Tlusty, Kirill Lapidus, V. Pechenov, Sergey V. Morozov, L. Lopes, F.F. Guber, L. Maier, A. K. Kurilkin, M. Szala, M. Böhmer, Yiannis Parpottas, E. Usenko, I. Koenig, A. Mangiarotti, Ilya Selyuzhenkov, B. Kämpfer, P. Filip, K. Pysz, T. Scheib, Alexey Kurepin, B. Kardan, O. Petukhov, J. A. Garzón, T. Hennino, A. Blanco, P. Fonte, H. Schuldes, M. Kohls, J. Siebenson, A. Rost, A. Ivashkin, B. Ramstein, S. Harabasz, C. Wendisch, M. Gumberidze, T. Matulewicz, R. Kotte, S. Spataro, Witold Przygoda, I. Fröhlich, P. Bordalo, O. Pechenova, Krzysztof Piasecki, T. Kunz, Izabela Ciepał, Jerzy Smyrski, T. Heinz, C. Höhne, J. C. Berger-Chen, J. Pietraszko, M. G. Wiebusch, Christoph Blume, M.B. Golubeva, Andrey Reshetin, V. Metag, H. Ströbele, Yu. G. Sobolev, R. H. Munzer, D. M. Mihaylov, C. Müntz, R. Holzmann, J. Markert, M. Lorenz, V. Wagner, P. Rosier, S. Maurus, Tatiana Karavicheva, S. Ramos, C. Behnke, P. K. Kurilkin, L. Naumann, Udai Pratap Singh, S. Hlavac, T. Mahmoud, A. Malige, D. Wójcik, P. Sellheim, S. P. Chernenko, P. Zumbruch, P. Salabura, J. Dreyer, Alexander Belyaev, J. Friese, J. Michel, J. Wirth, F. Seck, Eliane Epple, G. Kornakov, C. Franco, C. Deveaux, R. Greifenhagen, and O. Svoboda

Subjects
Physics, Proton, Spectrometer, 010308 nuclear & particles physics, Position and momentum space, 01 natural sciences, 7. Clean energy, Nuclear physics, Isospin, Phase space, 0103 physical sciences, Rapidity, Atomic number, Nuclear Experiment, 010306 general physics, Relativistic Heavy Ion Collider
Abstract

We present an analysis of proton-number fluctuations in sNN=2.4 GeV Au197+Au197 collisions measured with the High-Acceptance DiElectron Spectrometer (HADES) at GSI Helmholtzzentrum fur Schwerionenforschung, Darmstadt. With the help of extensive detector simulations done with Isospin Quantum Molecular Dynamics (IQMD) transport model events including nuclear clusters, various nuisance effects influencing the observed proton cumulants have been investigated. Acceptance and efficiency corrections have been applied as a function of fine-grained rapidity and transverse momentum bins, as well as considering local track density dependencies. Next, the effects of volume changes within particular centrality selections have been considered and beyond-leading-order corrections have been applied to the data. The efficiency and volume-corrected proton number moments and cumulants Kn of orders n=1, 2, 3, and 4 have been obtained as a function of centrality and phase-space bin, as well as the corresponding correlators Cn. We find that the observed correlators show a power-law scaling with the mean number of protons, i.e., Cn∞«N»n, indicative of mostly long-range multiparticle correlations in momentum space. We also present a comparison of our results with Au + Au collision data obtained at the Relativistic Heavy Ion Collider (RHIC) at similar centralities but higher √sNN.

Published
2020
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29. Two-pion production in the second resonance region in π−p collisions with the High-Acceptance Di-Electron Spectrometer (HADES)

Author

J. Stroth, Sergey V. Morozov, F.F. Guber, E. Schwab, B. Kämpfer, A. Sadovsky, Yiannis Parpottas, G. Korcyl, R. Lalik, O. V. Fateev, M. Böhmer, Alexey Kurepin, D. Dittert, A.P. Ierusalimov, W. Koenig, M. Gumberidze, C. Franco, H. Ströbele, V. Wagner, T. Mahmoud, A. Prozorov, P. Sellheim, S. Spataro, V. P. Ladygin, L. Silva, I. Fröhlich, H. Schuldes, Roman Gernhäuser, K. Nowakowski, J. Dreyer, A. Kugler, Alexander Belyaev, C. Müntz, C. Wendisch, Oliver Werner Arnold, T. Galatyuk, Yu.V. Zanevsky, J. Kuboś, C. Höhne, L. Lopes, T. Kunz, F. Kornas, M. G. Wiebusch, Izabela Ciepał, Piotr Salabura, C. Sturm, S. Spies, F. Scozzi, J. A. Garzón, E. T. Atomssa, L. Chlad, G. Kornakov, J. Adamczewski-Musch, L. Maier, Laura Fabbietti, J. Siebenson, B. Ramstein, P. Strzempek, M.B. Golubeva, P. Rodriguez-Ramos, P. Chudoba, J. Biernat, A. K. Kurilkin, S. Linev, A. Lebedev, B. W. Kolb, Andrey Reshetin, R. Holzmann, J. Markert, V. Metag, V. Pechenov, A. Rost, A. Belounnas, S. Maurus, T. Heinz, M. Traxler, R. H. Munzer, D. M. Mihaylov, M. Lorenz, B. Kardan, O. Petukhov, O. Vazquez-Doce, A. V. Sarantsev, C. Behnke, J. C. Berger-Chen, P. Tlusty, Kirill Lapidus, V. Mikhaylov, A. Malige, F. Seck, H. Tsertos, V. A. Nikonov, P. Zumbruch, I. Koenig, Eliane Epple, S. Harabasz, O. Pechenova, N. Rathod, J. Pietraszko, C. Deveaux, R. Greifenhagen, O. Svoboda, K. Schmidt-Sommerfeld, Udai Pratap Singh, Witold Przygoda, J. Friese, T. Scheib, C. Ungethüm, P. K. Kurilkin, L. Naumann, T. Hennino, D. Wójcik, M. Szala, A. Blanco, P. Fonte, A. Ivashkin, R. Kotte, Christoph Blume, Jerzy Smyrski, S. P. Chernenko, J. Michel, and J. Wirth

Subjects
Physics, Excitation function, Particle physics, 010308 nuclear & particles physics, Branching fraction, Partial wave analysis, Nuclear Theory, Resonance, Coupling (probability), 7. Clean energy, 01 natural sciences, Baryon, Pion, 0103 physical sciences, Production (computer science), Nuclear Experiment, 010306 general physics
Abstract

Pion induced reactions provide unique opportunities for an unambiguous description of baryonic resonances and their coupling channels by means of a partial wave analysis. Using the secondary pion beam at SIS18, the two pion production in the second resonance region has been investigated to unravel the role of the $N(1520) \frac{3}{2}^-$ resonance in the intermediate $\rho$ production. Results on exclusive channels with one pion ($\pi^{-}p$) and two pions ($\pi^{+}\pi^{-}n$, $\pi^{0}\pi^{-}p$) in the final state measured in the $\pi^{-}-p$ reaction at four different pion beam momenta (0.650, 0.685, 0.733, and 0.786 GeV/c) are presented. The excitation function of the different partial waves and $\Delta\pi$, $N\sigma$ and $N\rho$ isobar configurations is obtained, using the Bonn-Gatchina partial wave analysis. The $N(1520) \frac{3}{2}^-$ resonance is found to dominate the $N\rho$ final state with the branching ratio $BR=12.2 \pm 1.9\%$.

Published
2020
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30. Correlated pion-proton pair emission off hot and dense QCD matter

Author

Adamczewski-Musch, J., Arnold, O., Behnke, C., Belounnas, A., Belyaev, A., Berger-Chen, J. C., Blanco, A., Blume, C., Böhmer, M., Bordalo, P., Chernenko, S., Chlad, L., Ciepal, I., Deveaux, C., Dreyer, J., Epple, E., Fabbietti, L., Fateev, O., Filip, P., Fonte, P., Franco, C., Friese, J., Fröhlich, I., Galatyuk, T., Garzon, J. A., Gernhäuser, R., Golubeva, M., Greifenhagen, R., Guber, F., Gumberidze, M., Harabasz, S., Heinz, T., Hennino, T., Hlavac, S., Höhne, C., Holzmann, R., Ierusalimov, A., Ivashkin, A., Kämpfer, B., Karavicheva, T., Kardan, B., Koenig, I., Koenig, W., Kohls, M., Kolb, B. W., Korcyl, G., Kornakov, G., Kornas, F., Kotte, R., Kugler, A., Kunz, T., Kurepin, A., Kurilkin, A., Kurilkin, P., Ladygin, V., Lalik, R., Lapidus, K., Lebedev, A., Lopes, L., Lorenz, M., Mahmoud, T., Maier, L., Malige, A., Mangiarotti, A., Markert, J., Matulewicz, T., Maurus, S., Metag, V., Michel, J., Mihaylov, D. M., Morozov, S., Müntz, C., Münzer, R., Naumann, L., Nowakowski, K., Parpottas, Y., Pechenov, V., Pechenova, O., Petukhov, O., Piasecki, K., Pietraszko, J., Przygoda, W., Pysz, K., Ramos, S., Ramstein, B., Rathod, N., Reshetin, A., Rodriguez-Ramos, P., Rosier, P., Rost, A., Sadovsky, A., Salabura, P., Scheib, T., Schuldes, H., Schwab, E., Scozzi, F., Seck, F., Sellheim, P., Selyuzhenkov, I., Siebenson, J., Silva, L., Singh, U., Smyrski, J., Sobolev, Y. G., Spataro, S., Spies, S., Ströbele, H., Stroth, J., Sturm, C., Svoboda, O., Szala, M., Tlusty, P., Traxler, M., Tsertos, H., Usenko, E., Wagner, V., Wendisch, C., Wiebusch, M. G., Wirth, J., Wojcik, D., Zanevsky, Y., Zumbruch, P., Adamczewski-Musch, J., Arnold, O., Behnke, C., Belounnas, A., Belyaev, A., Berger-Chen, J. C., Blanco, A., Blume, C., Böhmer, M., Bordalo, P., Chernenko, S., Chlad, L., Ciepal, I., Deveaux, C., Dreyer, J., Epple, E., Fabbietti, L., Fateev, O., Filip, P., Fonte, P., Franco, C., Friese, J., Fröhlich, I., Galatyuk, T., Garzon, J. A., Gernhäuser, R., Golubeva, M., Greifenhagen, R., Guber, F., Gumberidze, M., Harabasz, S., Heinz, T., Hennino, T., Hlavac, S., Höhne, C., Holzmann, R., Ierusalimov, A., Ivashkin, A., Kämpfer, B., Karavicheva, T., Kardan, B., Koenig, I., Koenig, W., Kohls, M., Kolb, B. W., Korcyl, G., Kornakov, G., Kornas, F., Kotte, R., Kugler, A., Kunz, T., Kurepin, A., Kurilkin, A., Kurilkin, P., Ladygin, V., Lalik, R., Lapidus, K., Lebedev, A., Lopes, L., Lorenz, M., Mahmoud, T., Maier, L., Malige, A., Mangiarotti, A., Markert, J., Matulewicz, T., Maurus, S., Metag, V., Michel, J., Mihaylov, D. M., Morozov, S., Müntz, C., Münzer, R., Naumann, L., Nowakowski, K., Parpottas, Y., Pechenov, V., Pechenova, O., Petukhov, O., Piasecki, K., Pietraszko, J., Przygoda, W., Pysz, K., Ramos, S., Ramstein, B., Rathod, N., Reshetin, A., Rodriguez-Ramos, P., Rosier, P., Rost, A., Sadovsky, A., Salabura, P., Scheib, T., Schuldes, H., Schwab, E., Scozzi, F., Seck, F., Sellheim, P., Selyuzhenkov, I., Siebenson, J., Silva, L., Singh, U., Smyrski, J., Sobolev, Y. G., Spataro, S., Spies, S., Ströbele, H., Stroth, J., Sturm, C., Svoboda, O., Szala, M., Tlusty, P., Traxler, M., Tsertos, H., Usenko, E., Wagner, V., Wendisch, C., Wiebusch, M. G., Wirth, J., Wojcik, D., Zanevsky, Y., and Zumbruch, P.

Abstract

In this letter we report the first multi-differential measurement of correlated pion-proton pairs from 2 billion Au+Au collisions at \sqrt{s_{NN}} = 2.42 GeV collected with HADES. In this energy regime the population of \Delta(1232) resonances plays an important role in the way energy is distributed between intrinsic excitation energy and kinetic energy of the hadrons in the fireball. The triple differential d3N/dM{\pi}pdpTdy distributions of correlated {\pi}p pairs have been determined by subtracting the {\pi}p combinatorial background using an iterative method. The invariant-mass distributions in the \Delta(1232) mass region show strong deviations from a Breit-Wigner function with vacuum width and mass. The yield of correlated pion-proton pairs exhibits a complex isospin, rapidity and transverse-momentum dependence. In the invariant mass range 1.1 < Minv (GeV/c2) < 1.4, the yield is found to be similar for {\pi}+p and {\pi}-p pairs, and to follow a power law ^{\alpha}, where is the mean number of participating nucleons. The exponent {\alpha} depends strongly on the pair transverse momentum (pT) while its pT-integrated and charge-averaged value is {\alpha} = 1.5 \pm 0.08stat \pm 0.2sys.

Published
2021

32. Identical pion intensity interferometry at $$\sqrt{s_{\mathrm{NN}}}=2.4~\hbox {GeV}$$

Author

Adamczewski-Musch, J., primary, Arnold, O., additional, Behnke, C., additional, Belounnas, A., additional, Belyaev, A., additional, Berger-Chen, J. C., additional, Biernat, J., additional, Blanco, A., additional, Blume, C., additional, Böhmer, M., additional, Bordalo, P., additional, Chernenko, S., additional, Chlad, L., additional, Deveaux, C., additional, Dreyer, J., additional, Dybczak, A., additional, Epple, E., additional, Fabbietti, L., additional, Fateev, O., additional, Filip, P., additional, Fonte, P., additional, Franco, C., additional, Friese, J., additional, Fröhlich, I., additional, Galatyuk, T., additional, Garzón, J. A., additional, Gernhäuser, R., additional, Golubeva, M., additional, Greifenhagen, R., additional, Guber, F., additional, Gumberidze, M., additional, Harabasz, S., additional, Heinz, T., additional, Hennino, T., additional, Hlavac, S., additional, Höhne, C., additional, Holzmann, R., additional, Ierusalimov, A., additional, Ivashkin, A., additional, Kämpfer, B., additional, Karavicheva, T., additional, Kardan, B., additional, Koenig, I., additional, Koenig, W., additional, Kolb, B. W., additional, Korcyl, G., additional, Kornakov, G., additional, Kornas, F., additional, Kotte, R., additional, Kugler, A., additional, Kunz, T., additional, Kurepin, A., additional, Kurilkin, A., additional, Kurilkin, P., additional, Ladygin, V., additional, Lalik, R., additional, Lapidus, K., additional, Lebedev, A., additional, Lopes, L., additional, Lorenz, M., additional, Mahmoud, T., additional, Maier, L., additional, Mangiarotti, A., additional, Markert, J., additional, Matulewicz, T., additional, Maurus, S., additional, Metag, V., additional, Michel, J., additional, Mihaylov, D. M., additional, Morozov, S., additional, Müntz, C., additional, Münzer, R., additional, Naumann, L., additional, Nowakowski, K., additional, Palka, M., additional, Parpottas, Y., additional, Pechenov, V., additional, Pechenova, O., additional, Petukhov, O., additional, Piasecki, K., additional, Pietraszko, J., additional, Przygoda, W., additional, Ramos, S., additional, Ramstein, B., additional, Reshetin, A., additional, Rodriguez-Ramos, P., additional, Rosier, P., additional, Rost, A., additional, Sadovsky, A., additional, Salabura, P., additional, Scheib, T., additional, Schuldes, H., additional, Schwab, E., additional, Scozzi, F., additional, Seck, F., additional, Sellheim, P., additional, Selyuzhenkov, I., additional, Siebenson, J., additional, Silva, L., additional, Sobolev, Yu. G., additional, Spataro, S., additional, Spies, S., additional, Ströbele, H., additional, Stroth, J., additional, Strzempek, P., additional, Sturm, C., additional, Svoboda, O., additional, Szala, M., additional, Tlusty, P., additional, Traxler, M., additional, Tsertos, H., additional, Usenko, E., additional, Wagner, V., additional, Wendisch, C., additional, Wiebusch, M. G., additional, Wirth, J., additional, Wójcik, D., additional, Zanevsky, Y., additional, and Zumbruch, P., additional

Published
2020
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33. Proton-number fluctuations in sNN =2.4 GeV Au + Au collisions studied with the High-Acceptance DiElectron Spectrometer (HADES) PROTON-NUMBER FLUCTUATIONS in sNN =2.4 GeV Au + Au ... J. ADAMCZEWSKI-MUSCH et al

Author

Adamczewski-Musch, J., Arnold, O., Behnke, C., Belounnas, A., Belyaev, A., Berger-Chen, J. C., Blanco, A., Blume, C., Bohmer, M., Bordalo, P., Chernenko, S., Chlad, L., Ciepal, I., Deveaux, C., Dreyer, J., Epple, E., Fabbietti, L., Fateev, O., Filip, P., Fonte, P., Franco, C., Friese, J., Frohlich, I., Galatyuk, T., Garzon, J. A., Gernhauser, R., Golubeva, M., Greifenhagen, R., Guber, F., Gumberidze, M., Harabasz, S., Heinz, T., Hennino, T., Hlavac, S., Hohne, C., Holzmann, R., Ierusalimov, A., Ivashkin, A., Kampfer, B., Karavicheva, T., Kardan, B., Koenig, I., Koenig, W., Kohls, M., Kolb, B. W., Korcyl, G., Kornakov, G., Kornas, F., Kotte, R., Kugler, A., Kunz, T., Kurepin, A., Kurilkin, A., Kurilkin, P., Ladygin, V., Lalik, R., Lapidus, K., Lebedev, A., Lopes, L., Lorenz, M., Mahmoud, T., Maier, L., Malige, A., Mangiarotti, A., Markert, J., Matulewicz, T., Maurus, S., Metag, V., Michel, J., Mihaylov, D. M., Morozov, S., Muntz, C., Munzer, R., Naumann, L., Nowakowski, K., Parpottas, Y., Pechenov, V., Pechenova, O., Petukhov, O., Piasecki, K., Pietraszko, J., Przygoda, W., Pysz, K., Ramos, S., Ramstein, B., Rathod, N., Reshetin, A., Rodriguez-Ramos, P., Rosier, P., Rost, A., Rustamov, A., Sadovsky, A., Salabura, P., Scheib, T., Schuldes, H., Schwab, E., Scozzi, F., Seck, F., Sellheim, P., Selyuzhenkov, I., Siebenson, J., Silva, L., Singh, U., Smyrski, J., Sobolev, Y. G., Spataro, S., Spies, S., Strobele, H., Stroth, J., Sturm, C., Svoboda, O., Szala, M., Tlusty, P., Traxler, M., Tsertos, H., Usenko, E., Wagner, V., Wendisch, C., Wiebusch, M. G., Wirth, J., Wojcik, D., Zanevsky, Y., and Zumbruch, P.

Published
2020

34. Identical pion intensity interferometry at $\sqrt{s_{\mathrm{NN}}}=2.4~\hbox {GeV}$: HADES collaboration

Author

Christoph Blume, Marek Palka, O. V. Fateev, I. Koenig, S. Harabasz, F. Seck, Ilya Selyuzhenkov, P. Tlusty, P. Strzempek, C. Franco, A. Dybczak, J. C. Berger-Chen, J. Biernat, Tatiana Karavicheva, C. Behnke, C. Wendisch, J. Dreyer, B. W. Kolb, Alexander Belyaev, B. Ramstein, L. Silva, A. Blanco, P. Fonte, S. Spataro, T. Matulewicz, S. Hlavac, Laura Fabbietti, A. Ivashkin, R. Kotte, K. Nowakowski, C. Deveaux, R. Greifenhagen, I. Fröhlich, C. Höhne, M. G. Wiebusch, T. Heinz, A. Sadovsky, O. Svoboda, P. Zumbruch, P. Salabura, H. Tsertos, E. Usenko, L. Chlad, M. Lorenz, Andrey Reshetin, L. Lopes, J. Siebenson, Joachim Stroth, Roman Gernhäuser, E. Epple, S. Maurus, A. Kugler, G. Kornakov, H. Schuldes, R. H. Munzer, D. M. Mihaylov, J. Friese, A. Rost, T. Galatyuk, F. Kornas, F. Scozzi, J. Adamczewski-Musch, E. Schwab, L. Naumann, R. Holzmann, P. Rosier, L. Maier, J. Markert, Krzysztof Piasecki, T. Kunz, S. Ramos, B. Kämpfer, S. Spies, J. A. Garzón, Witold Przygoda, G. Korcyl, R. Lalik, A.P. Ierusalimov, M. Gumberidze, T. Scheib, C. Sturm, T. Hennino, B. Kardan, M. Böhmer, A. Mangiarotti, Sergey V. Morozov, O. Petukhov, Fedor Guber, Oliver Werner Arnold, V. P. Ladygin, Yu.V. Zanevsky, S. P. Chernenko, Volker Metag, J. Michel, J. Wirth, M. B. Golubeva, P. Rodriguez-Ramos, Yu. G. Sobolev, M. Szala, C. Müntz, A. K. Kurilkin, O. Pechenova, J. Pietraszko, P. Filip, K. Lapidus, V. Pechenov, P. Bordalo, D. Wójcik, Y. Parpottas, A. Lebedev, A. Belounnas, A. B. Kurepin, M. Traxler, W. Koenig, H. Ströbele, V. Wagner, T. Mahmoud, P. Sellheim, P. K. Kurilkin, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and HADES

Subjects
Nuclear and High Energy Physics, dimension: 3, media_common.quotation_subject, interferometer, transverse momentum: low, Extrapolation, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, beam: energy, energy dependence, Nuclear physics, Pion, 0103 physical sciences, Perpendicular, correlation function, Eccentricity (behavior), 010306 general physics, Nuclear Experiment, impact parameter, media_common, pi pi, Physics, energy: high, 010308 nuclear & particles physics, Plane (geometry), Transverse plane, Correlation function (statistical mechanics), 2.4 GeV-cms/nucleon, HADES, space-time, Impact parameter
Abstract

High-statistics $$\pi ^-\pi ^-$$π-π- and $$\pi ^+\pi ^+$$π+π+ femtoscopy data are presented for Au + Au collisions at $$\sqrt{s_\mathrm{NN}} = 2.4~\hbox {GeV}$$sNN=2.4GeV, measured with HADES at SIS18/GSI. The experimental correlation functions allow the determination of the space-time extent of the corresponding emission sources via a comparison to models. The emission source, parametrized as three-dimensional Gaussian distribution, is studied in dependence on pair transverse momentum, azimuthal emission angle with respect to the reaction plane, collision centrality and beam energy. For all centralities and transverse momenta, a geometrical distribution of ellipsoidal shape is found in the plane perpendicular to the beam direction with the larger extension perpendicular to the reaction plane. For large transverse momenta, the corresponding eccentricity approaches the initial eccentricity. The eccentricity is smallest for most central collisions, where the shape is almost circular. The magnitude of the tilt angle of the emission ellipsoid in the reaction plane decreases with increasing centrality and increasing transverse momentum. All source radii increase with centrality, largely exhibiting a linear rise with the cube root of the number of participants. A substantial charge-sign difference of the source radii is found, appearing most pronounced at low transverse momentum. The extracted source parameters are consistent with the extrapolation of their energy dependence down from higher energies.

Published
2020
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35. Proton number fluctuations in sqrt(s_NN)= 2.4 GeV Au+Au collisions studied with HADES

Author

Adamczewski-Musch, J., Arnold, O., Behnke, C., Belounnas, A., Belyaev, A., Berger-Chen, J. C., Biernat, J., Blanco, A., Blume, C., B\\'ohmer, M., Bordalo, P., Chernenko, S., Chlad, L., Deveaux, C., Dreyer, J., Dybczak, A., Epple, E., Fabbietti, L., Fateev, O., Filip, P., Fonte, P., Franco, C., Friese, J., Fr\\'ohlich, I., Galatyuk, T., Garzon, J. A., Gernh\\'auser, R., Golubeva, M., Greifenhagen, R., Guber, F., Gumberidze, M., Harabasz, S., Heinz, T., Hennino, T., Hlavac, S., H\\'ohne, C., Holzmann, R., Ierusalimov, A., Ivashkin, A., K\\'ampfer, B., Karavicheva, T., Kardan, B., Koenig, I., Koenig, W., Kohls, M., Kolb, B. W., Korcyl, G., Kornakov, G., Kornas, F., Kotte, R., Kugler, A., Kunz, T., Kurepin, A., Kurilkin, A., Kurilkin, P., Ladygin, V., Lalik, R., Lapidus, K., Lebedev, A., Lopes, L., Lorenz, M., Mahmoud, T., Maier, L., Mangiarotti, A., Markert, J., Matulewicz, T., Maurus, S., Metag, V., Michel, J., Mihaylov, D. M., Morozov, S., M\\'untz, C., M\\'unzer, R., Naumann, L., Nowakowski, K., Palka, M., Parpottas, Y., Pechenov, V., Pechenova, O., Petukhov, O., Piasecki, K., Pietraszko, J., Przygoda, W., Ramos, S., Ramstein, B., Reshetin, A., Rodriguez-Ramos, P., Rosier, P., Rost, A., Rustamov, A., Sadovsky, A., Salabura, P., Scheib, T., Schuldes, H., Schwab, E., Scozzi, F., Seck, F., Sellheim, P., Selyuzhenkov, I., Siebenson, J., Silva, L., Sobolev, Yu. G., Spataro, S., Spies, S., Str\\'obele, H., Stroth, J., Strzempek, P., Sturm, C., Svoboda, O., Szala, M., Tlusty, P., Traxler, M., Tsertos, H., Usenko, E., Wagner, V., Wendisch, C., Wiebusch, M. G., Wirth, J., Zanevsky, Y., and Zumbruch, P.

Subjects
FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

We present an analysis of proton number fluctuations in $\sqrt{s_{NN}}$ = 2.4 GeV Au+Au collisions measured with the High-Acceptance DiElectron Spectrometer (HADES) at GSI. With the help of extensive detector simulations done with IQMD transport model events including nuclear clusters, various nuisance effects influencing the observed proton cumulants have been investigated. Acceptance and efficiency corrections have been applied as a function of fine grained rapidity and transverse momentum bins, as well as considering local track density dependencies. Next, the effects of volume changes within particular centrality selections have been considered and beyond-leading-order corrections have been applied to the data. The efficiency and volume corrected proton number moments and cumulants Kn of orders n = 1, . . . , 4 have been obtained as a function of centrality and phase-space bin, as well as the corresponding correlators C_n . We find that the observed correlators show a power-law scaling with the mean number of protons, i.e. $C_n \propto ^n$, indicative of mostly long-range multi-particle correlations in momentum space. We also present a comparison of our results with Au+Au collision data obtained at RHIC at similar centralities, but higher $\sqrt{s_{NN}}$., Comment: 35 pages, 33 figures

Published
2020

36. Correlated pion-proton pair emission off hot and dense QCD matter

Author

S. Spataro, I. Fröhlich, A. K. Kurilkin, R. Holzmann, J. Markert, S. Ramos, C. Franco, V. P. Ladygin, L. Lopes, H. Ströbele, V. Wagner, P. Filip, C. Wendisch, Joachim Stroth, Tatiana Karavicheva, C. Behnke, E. Usenko, O. Pechenova, O. V. Fateev, M. Böhmer, A. Mangiarotti, E. Schwab, P. Bordalo, L. Fabbietti, S. Harabasz, J. Pietraszko, A.P. Ierusalimov, Witold Przygoda, C. Deveaux, F. Kornas, C. Sturm, Y. Parpottas, H. Schuldes, R. Greifenhagen, L. Silva, O. Svoboda, K. Pysz, T. Scheib, T. Galatyuk, A. Lebedev, C. Höhne, M. G. Wiebusch, F. Scozzi, K. Nowakowski, A. Belounnas, A. B. Kurepin, M. Traxler, T. Heinz, Yu. G. Sobolev, J. Adamczewski-Musch, J. Dreyer, Alexander Belyaev, L. Naumann, H. Tsertos, B. W. Kolb, C. Müntz, J. Friese, Izabela Ciepał, P. Zumbruch, P. Salabura, M. Lorenz, W. Koenig, B. Kämpfer, Sergey V. Morozov, P. K. Kurilkin, V. Pechenov, Yu.V. Zanevsky, G. Kornakov, M. B. Golubeva, P. Rodriguez-Ramos, A. Malige, G. Korcyl, R. Lalik, E. Epple, P. Rosier, L. Maier, S. Hlavac, J. A. Garzón, Udai Pratap Singh, J. C. Berger-Chen, F. Seck, M. Kohls, J. Siebenson, S. Maurus, M. Gumberidze, Roman Gernhäuser, A. Kugler, I. Koenig, Ilya Selyuzhenkov, S. Spies, L. Chlad, N. Rathod, B. Kardan, O. Petukhov, Fedor Guber, Oliver Werner Arnold, B. Ramstein, T. Matulewicz, A. Sadovsky, A. Blanco, P. Fonte, A. Ivashkin, R. Kotte, Christoph Blume, M. Szala, T. Mahmoud, P. Sellheim, A. Rost, Jerzy Smyrski, K. Lapidus, T. Hennino, D. Wójcik, S. P. Chernenko, Volker Metag, J. Michel, J. Wirth, Krzysztof Piasecki, T. Kunz, P. Tlusty, Andrey Reshetin, R. H. Munzer, D. M. Mihaylov, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
energy [excited state], Proton, Freezeout, transverse momentum dependence, 01 natural sciences, energy [hadron], Invariant mass, heavy-ion reactions, Nuclear Experiment (nucl-ex), Nuclear Experiment, mass [Delta(1232)], Physics, Baryonic resonances, Heavy-ion reactions, education.field_of_study, fireball, Breit-Wigner, hadron: energy, pi p: correlation, kinetic [energy], ddc, Isospin, Nucleon, Nuclear and High Energy Physics, 2.42 GeV-cms/nucleon, QC1-999, Population, correlation [pi p], FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], transverse momentum, Kinetic energy, Nuclear physics, isospin, Pion, 0103 physical sciences, Delta(1232): mass, matter [quantum chromodynamics], ddc:530, 010306 general physics, education, quantum chromodynamics: matter, energy: kinetic, 010308 nuclear & particles physics, background, excited state: energy, rapidity, HADES, freezeout, Energy (signal processing)
Abstract

In this letter we report the first multi-differential measurement of correlated pion-proton pairs from 2 billion Au+Au collisions at \sqrt{s_{NN}} = 2.42 GeV collected with HADES. In this energy regime the population of \Delta(1232) resonances plays an important role in the way energy is distributed between intrinsic excitation energy and kinetic energy of the hadrons in the fireball. The triple differential d3N/dM{\pi}pdpTdy distributions of correlated {\pi}p pairs have been determined by subtracting the {\pi}p combinatorial background using an iterative method. The invariant-mass distributions in the \Delta(1232) mass region show strong deviations from a Breit-Wigner function with vacuum width and mass. The yield of correlated pion-proton pairs exhibits a complex isospin, rapidity and transverse-momentum dependence. In the invariant mass range 1.1 < Minv (GeV/c2) < 1.4, the yield is found to be similar for {\pi}+p and {\pi}-p pairs, and to follow a power law ^{\alpha}, where is the mean number of participating nucleons. The exponent {\alpha} depends strongly on the pair transverse momentum (pT) while its pT-integrated and charge-averaged value is {\alpha} = 1.5 \pm 0.08stat \pm 0.2sys., Comment: 9 pages, 9 figures

Published
2020
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37. Identical pion intensity interferometry at √sNN=2.4GeV : HADES collaboration

Author

Adamczewski-Musch, J., Arnold, O., Behnke, C., Belounnas, A., Belyaev, A., Berger-Chen, J. C., Biernat, J., Blanco, A., Blume, C., Bohmer, M., Bordalo, P., Chernenko, S., Chlad, L., Deveaux, C., Dreyer, J., Dybczak, A., Epple, E., Fabbietti, L., Fateev, O., Filip, P., Fonte, P., Franco, C., Friese, J., Frohlich, I., Galatyuk, T., Garzon, J. A., Gernhauser, R., Golubeva, M., Greifenhagen, R., Guber, F., Gumberidze, M., Harabasz, S., Heinz, T., Hennino, T., Hlavac, S., Hohne, C., Holzmann, R., Ierusalimov, A., Ivashkin, A., Kampfer, B., Karavicheva, T., Kardan, B., Koenig, I., Koenig, W., Kolb, B. W., Korcyl, G., Kornakov, G., Kornas, F., Kotte, R., Kugler, A., Kunz, T., Kurepin, A., Kurilkin, A., Kurilkin, P., Ladygin, V., Lalik, R., Lapidus, K., Lebedev, A., Lopes, L., Lorenz, M., Mahmoud, T., Maier, L., Mangiarotti, A., Markert, J., Matulewicz, T., Maurus, S., Metag, V., Michel, J., Mihaylov, D. M., Morozov, S., Muntz, C., Munzer, R., Naumann, L., Nowakowski, K., Palka, M., Parpottas, Y., Pechenov, V., Pechenova, O., Petukhov, O., Piasecki, K., Pietraszko, J., Przygoda, W., Ramos, S., Ramstein, B., Reshetin, A., Rodriguez-Ramos, P., Rosier, P., Rost, A., Sadovsky, A., Salabura, P., Scheib, T., Schuldes, H., Schwab, E., Scozzi, F., Seck, F., Sellheim, P., Selyuzhenkov, I., Siebenson, J., Silva, L., Sobolev, Y. G., Spataro, S., Spies, S., Strobele, H., Stroth, J., Strzempek, P., Sturm, C., Svoboda, O., Szala, M., Tlusty, P., Traxler, M., Tsertos, H., Usenko, E., Wagner, V., Wendisch, C., Wiebusch, M. G., Wirth, J., Wojcik, D., Zanevsky, Y., and Zumbruch, P.

Published
2020

38. Charged-pion production in Au + Au collisions at $\sqrt{^{s}NN}=2.4$ GeV

Author

Adamczewski-Musch, J., Arnold, O., Behnke, C., Belounnas, A., Belyaev, A., Berger-Chen, J. C., Blanco, A., Blume, C., Böhmer, M., Bordalo, P., Chernenko, S., Chlad, L., Ciepał, Izabela, Deveaux, C., Dreyer, J., Epple, E., Fabbietti, L., Fateev, O., Filip, P., Fonte, P., Franco, C., Friese, J., Fröhlich, I., Galatyuk, T., Garzón, J. A., Gernhäuser, R., Gläßel, S., Golubeva, M., Greifenhagen, R., Guber, F., Gumberidze, M., Harabasz, Szymon, Heinz, T., Hennino, T., Hlavac, S., Höhne, C., Holzmann, R., Ierusalimov, A., Ivashkin, A., Kämpfer, B., Karavicheva, T., Kardan, B., Koenig, I., Koenig, W., Kohls, M., Kolb, B. W., Korcyl, Grzegorz, Kornakov, G., Kornas, F., Kotte, R., Kugler, A., Kunz, T., Kurepin, A., Kurilkin, A., Kurilkin, P., Ladygin, V., Lalik, Rafał, Lapidus, K., Lebedev, A., Lopes, L., Lorenz, M., Mahmoud, T., Maier, L., Malige, Akshay, Mangiarotti, A., Markert, J., Matulewicz, T., Maurus, S., Metag, V., Michel, J., Mihaylov, D. M., Morozov, S., Müntz, C., Münzer, R., Naumann, L., Nowakowski, Krzysztof, Parpottas, Y., Pechenov, V., Pechenova, O., Petukhov, O., Piasecki, K., Pietraszko, J., Przygoda, Witold, Pysz, K., Ramos, S., Ramstein, B., Rathod, Narendra, Reshetin, A., Rodriguez-Ramos, P., Rosier, P., Rost, A., Rustamov, A., Sadovsky, A., Salabura, Piotr, Scheib, T., Schuldes, H., Schwab, E., Scozzi, F., Seck, F., Sellheim, P., Selyuzhenkov, I., Siebenson, J., Silva, L., Singh, Udai, Smyrski, Jerzy, Sobolev, Yu. G., Spataro, S., Spies, S., Ströbele, H., Stroth, J., Sturm, C., Svoboda, O., Szala, M., Tlusty, P., Traxler, M., Tsertos, H., Usenko, E., Wagner, V., Wendisch, C., Wiebusch, M. G., Wirth, J., Wójcik, D., Zanevsky, Y., and Zumbruch, P.

Published
2020

39. Charged-pion production in Au+ Au collisions at √sNN=2.4GeV : HADES Collaboration

Author

Adamczewski-Musch, J., Arnold, O., Behnke, C., Belounnas, A., Belyaev, A., Berger-Chen, J. C., Blanco, A., Blume, C., Bohmer, M., Bordalo, P., Chernenko, S., Chlad, L., Ciepal, I., Deveaux, C., Dreyer, J., Epple, E., Fabbietti, L., Fateev, O., Filip, P., Fonte, P., Franco, C., Friese, J., Frohlich, I., Galatyuk, T., Garzon, J. A., Gernhauser, R., Glassel, S., Golubeva, M., Greifenhagen, R., Guber, F., Gumberidze, M., Harabasz, S., Heinz, T., Hennino, T., Hlavac, S., Hohne, C., Holzmann, R., Ierusalimov, A., Ivashkin, A., Kampfer, B., Karavicheva, T., Kardan, B., Koenig, I., Koenig, W., Kohls, M., Kolb, B. W., Korcyl, G., Kornakov, G., Kornas, F., Kotte, R., Kugler, A., Kunz, T., Kurepin, A., Kurilkin, A., Kurilkin, P., Ladygin, V., Lalik, R., Lapidus, K., Lebedev, A., Lopes, L., Lorenz, M., Mahmoud, T., Maier, L., Malige, A., Mangiarotti, A., Markert, J., Matulewicz, T., Maurus, S., Metag, V., Michel, J., Mihaylov, D. M., Morozov, S., Muntz, C., Munzer, R., Naumann, L., Nowakowski, K., Parpottas, Y., Pechenov, V., Pechenova, O., Petukhov, O., Piasecki, K., Pietraszko, J., Przygoda, W., Pysz, K., Ramos, S., Ramstein, B., Rathod, N., Reshetin, A., Rodriguez-Ramos, P., Rosier, P., Rost, A., Rustamov, A., Sadovsky, A., Salabura, P., Scheib, T., Schuldes, H., Schwab, E., Scozzi, F., Seck, F., Sellheim, P., Selyuzhenkov, I., Siebenson, J., Silva, L., Singh, U., Smyrski, J., Sobolev, Y. G., Spataro, S., Spies, S., Strobele, H., Stroth, J., Sturm, C., Svoboda, O., Szala, M., Tlusty, P., Traxler, M., Tsertos, H., Usenko, E., Wagner, V., Wendisch, C., Wiebusch, M. G., Wirth, J., Wojcik, D., Zanevsky, Y., and Zumbruch, P.

Published
2020

40. Two-pion production in the second resonance region in π-p collisions with the High-Acceptance Di-Electron Spectrometer (HADES)

Author

Adamczewski-Musch, J., Arnold, O., Atomssa, E. T., Behnke, C., Belounnas, A., Belyaev, A., Berger-Chen, J. C., Biernat, Jacek, Blanco, A., Blume, C., Böhmer, M., Chernenko, S., Chlad, L., Chudoba, P., Ciepał, Izabela, Deveaux, C., Dittert, D., Dreyer, J., Epple, E., Fabbietti, L., Fateev, O., Fonte, P., Franco, C., Friese, J., Fröhlich, I., Galatyuk, T., Garzón, J. A., Gernhäuser, R., Golubeva, M., Greifenhagen, R., Guber, F., Gumberidze, M., Harabasz, Szymon, Heinz, T., Hennino, T., Höhne, C., Holzmann, R., Ierusalimov, A., Ivashkin, A., Kämpfer, B., Kardan, B., Koenig, I., Koenig, W., Kolb, B. W., Korcyl, Grzegorz, Kornakov, G., Kornas, F., Kotte, R., Kuboś, J., Kugler, A., Kunz, T., Kurepin, A., Kurilkin, A., Kurilkin, P., Ladygin, V., Lalik, Rafał, Lapidus, K., Lebedev, A., Linev, S., Lopes, L., Lorenz, M., Mahmoud, T., Maier, L., Malige, Akshay, Markert, J., Maurus, S., Metag, V., Michel, J., Mihaylov, D. M., Mikhaylov, V., Morozov, S., Müntz, C., Münzer, R., Naumann, L., Nowakowski, Krzysztof, Parpottas, Y., Pechenov, V., Pechenova, O., Petukhov, O., Pietraszko, J., Prozorov, AP, Przygoda, Witold, Ramstein, B., Rathod, Narendra, Reshetin, A., Rodriguez-Ramos, P., Rost, A., Sadovsky, A., Salabura, Piotr, Scheib, T., Schmidt-Sommerfeld, K., Schuldes, H., Schwab, E., Scozzi, F., Seck, F., Sellheim, P., Siebenson, J., Silva, L., Singh, Udai, Smyrski, Jerzy, Spataro, S., Spies, S., Ströbele, H., Stroth, J., Strzempek, Paweł, Sturm, C., Svoboda, O., Szala, M., Tlusty, P., Traxler, M., Tsertos, H., Ungethüm, C., Vazquez-Doce, O., Wagner, V., Wendisch, C., Wiebusch, M. G., Wirth, J., Wójcik, D., Zanevsky, Y., Zumbruch, P., Sarantsev, A. V., Nikonov, V. A., Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and HADES

Subjects
N(1520), baryon resonance, Nuclear Theory, partial wave analysis, production: two-pion, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], HADES, beam: momentum, High Energy Physics::Experiment, pi: beam, branching ratio, Nuclear Experiment, Nucleon-Nucleon Interaction, pi- p: scattering, Few-Body Systems, experimental results
Abstract

International audience; Pion-induced reactions provide unique opportunities for an unambiguous description of baryonic resonances and their coupling channels by means of a partial-wave analysis. Using the secondary pion beam at SIS18, the two-pion production in the second resonance region has been investigated to unravel the role of the N(1520)32− resonance in the intermediate ρ-meson production. Results on exclusive channels with one pion (π−p) and two pions (π+π−n, π0π−p) in the final state measured in the π−-p reaction at four different pion beam momenta (0.650, 0.685, 0.733, and 0.786 GeV/c) are presented. The excitation function of the different partial waves and Δπ, Nσ, and Nρ isobar configurations is obtained, using the Bonn-Gatchina partial-wave analysis. The N(1520)32− resonance is found to dominate the Nρ final state with the branching ratio BR=12.2%±1.9%.

Published
2020
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41. Charged pion production in Au+Au collisions at sqrt(s_NN) = 2.4 GeV

Author

Adamczewski-Musch, J., Arnold, O., Behnke, C., Belounnas, A., Belyaev, A., Berger-Chen, J. C., Biernat, J., Blanco, A., Blume, C., Boehmer, M., Bordalo, P., Chernenko, S., Chlad, L., Ciepal, I., Deveaux, C., Dreyer, J., Dybczak, A., Epple, E., Fabbietti, L., Fateev, O., Filip, P., Fonte, P., Franco, C., Friese, J., Froehlich, I., Galatyuk, T., Garzon, J. A., Gernhaeuser, R., Glaessel, S., Golubeva, M., Greifenhagen, R., Guber, F., Gumberidze, M., Harabasz, S., Heinz, T., Hennino, T., Hlavac, S., Höhne, C., Holzmann, R., Ierusalimov, A., Ivashkin, A., Kämpfer, B., Karavicheva, T., Kardan, B., Koenig, I., Koenig, W., Kohls, M., Kolb, B. W., Korcyl, G., Kornakov, G., Kornas, F., Kotte, R., Kugler, A., Kunz, T., Kurepin, A., Kurilkin, A., Kurilkin, P., Ladygin, V., Lalik, R., Lapidus, K., Lebedev, A., Lopes, L., Lorenz, M., Mahmoud, T., Maier, L., Malige, A., Mangiarotti, A., Markert, J., Matulewicz, T., Maurus, S., Metag, V., Michel, J., Mihaylov, D. M., Morozov, S., Muentz, C., Muenzer, R., Naumann, L., Nowakowski, K., Palka, M., Parpottas, Y., Pechenov, V., Pechenova, O., Petukhov, O., Piasecki, K., Pietraszko, J., Przygoda, W., Pysz, K., Ramos, S., Ramstein, B., Reshetin, A., Rodriguez-Ramos, P., Rathod, N., Rosier, P., Rost, A., Rustamov, A., Sadovsky, A., Salabura, P., Scheib, T., Schuldes, H., Schwab, E., Scozzi, F., Seck, F., Sellheim, P., Selyuzhenkov, I., Siebenson, J., Silva, L., Singh, U., Smyrski, J., Sobolev, Y. G., Spataro, S., Spies, S., Stroebele, H., Stroth, J., Strzempek, P., Sturm, C., Svoboda, O., Szala, M., Tlusty, P., Traxler, M., Tsertos, H., Usenko, E., Wagner, V., Wendisch, C., Wiebusch, M. G., Wirth, J., Wojcik, D., Zanevsky, Y., and Zumbruch, P.

Subjects
Nuclear Experiment
Abstract

We present high-statistic data on charged pion emission from Au+Au collisions at sqrt(s_NN) = 2.4 GeV (corresponding to E_beam = 1.23 A GeV) in four centrality classes in the range 0 - 40% of the most central collisions. The data are analyzed as a function of transverse momentum, transverse mass, rapidity, and polar angle. Pion multiplicity per participating nucleon decreases moderately with increasing centrality. The polar angular distributions are found to be non-isotropic even for the most central event class. Our results on pion multiplicity fit well into the general trend of the world data, but undershoot by 2.5σ data from the FOPI experiment measured at slightly lower beam energy. We compare our data to state-of-the-art transport model calculations (PHSD, IQMD, PHQMD, GiBUU and SMASH) and find substantial differences between the measurement and the results of these calculations.

Published
2020

43. Directed, elliptic and higher order flow harmonics of protons, deuterons and tritons in Au+Au collisions at sqrt(s_NN)=2.4 GeV

Author

Adamczewski-Musch, J., Arnold, O., Behnke, C., Belounnas, A., Belyaev, A., Berger-Chen, J. C., Blanco, A., Blume, C., Böhmer, M., Bordalo, P., Chernenko, S., Chlad, L., Ciepal, I., Deveaux, C., Dreyer, J., Epple, E., Fabbietti, L., Fateev, O., Filip, P., Fonte, P., Franco, C., Friese, J., Fröhlich, I., Galatyuk, T., Garzón, J. A., Gernhäuser, R., Golosov, O., Golubeva, M., Greifenhagen, R., Guber, F., Gumberidze, M., Harabasz, S., Heinz, T., Hennino, T., Hlavac, S., Höhne, C., Holzmann, R., Ierusalimov, A., Ivashkin, A., Kämpfer, B., Karavicheva, T., Kardan, B., Koenig, I., Koenig, W., Kohls, M., Kolb, B. W., Korcyl, G., Kornakov, G., Kornas, F., Kotte, R., Kugler, A., Kunz, T., Kurepin, A., Kurilkin, A., Kurilkin, P., Ladygin, V., Lalik, R., Lapidus, K., Lebedev, A., Lopes, L., Lorenz, M., Mahmoud, T., Maier, L., Malige, A., Mamaev, M., Mangiarotti, A., Markert, J., Matulewicz, T., Maurus, S., Metag, V., Michel, J., Mihaylov, D. M., Morozov, S., Müntz, C., Münzer, R., Naumann, L., Nowakowski, K., Parpottas, Y., Pechenov, V., Pechenova, O., Petukhov, O., Piasecki, K., Pietraszko, J., Przygoda, W., Pysz, K., Ramos, S., Ramstein, B., Rathod, N., Reshetin, A., Rodriguez-Ramos, P., Rosier, P., Rost, A., Rustamov, A., Sadovsky, A., Salabura, P., Scheib, T., Schuldes, H., Schwab, E., Scozzi, F., Seck, F., Sellheim, P., Selyuzhenkov, I., Siebenson, J., Silva, L., Singh, U., Smyrski, J., Sobolev, Y. G., Spataro, S., Spies, S., Ströbele, H., Stroth, J., Sturm, C., Svoboda, O., Szala, M., Tlusty, P., Traxler, M., Tsertos, H., Usenko, E., Wagner, V., Wendisch, C., Wiebusch, M. G., Wirth, J., Wójcik, D., Zanevsky, Y., and Zumbruch, P.

Subjects
Nuclear Experiment
Abstract

Flow coefficients v_{n} of the orders n=1-6 are measured with the High-Acceptance DiElectron Spectrometer (HADES) at GSI for protons, deuterons, and tritons as a function of centrality, transverse momentum, and rapidity in Au+Au collisions at sqrt[s_{NN}]=2.4 GeV. Combining the information from the flow coefficients of all orders allows us to construct for the first time, at collision energies of a few GeV, a multidifferential picture of the angular emission pattern of these particles. It reflects the complicated interplay between the effect of the central fireball pressure on the emission of particles and their subsequent interaction with spectator matter. The high precision information on higher order flow coefficients is a major step forward in constraining the equation of state of dense baryonic matter.

Published
2020

44. Directed, Elliptic, and Higher Order Flow Harmonics of Protons, Deuterons, and Tritons in $\mathrm{Au}+\mathrm{Au}$ Collisions at $\sqrt{{s}_{NN}}=2.4\text{ }\text{ }\mathrm{GeV}$

Author

Adamczewski-Musch, J., Arnold, O., Behnke, C., Belounnas, A., Belyaev, A., Berger-Chen, J.C., Blanco, A., Blume, C., Böhmer, M., Bordalo, P., Chernenko, S., Chlad, L., Ciepal, I., Deveaux, C., Dreyer, J., Epple, E., Fabbietti, L., Fateev, O., Filip, P., Fonte, P., Franco, C., Friese, J., Fröhlich, I., Galatyuk, T., Garzón, J.A., Gernhäuser, R., Golosov, O., Golubeva, M., Greifenhagen, R., Guber, F., Gumberidze, M., Harabasz, S., Heinz, T., Hennino, T., Hlavac, S., Höhne, C., Holzmann, R., Ierusalimov, A., Ivashkin, A., Kämpfer, B., Karavicheva, T., Kardan, B., Koenig, I., Koenig, W., Kohls, M., Kolb, B.W., Korcyl, G., Kornakov, G., Kornas, F., Kotte, R., Kugler, A., Kunz, T., Kurepin, A., Kurilkin, A., Kurilkin, P., Ladygin, V., Lalik, R., Lapidus, K., Lebedev, A., Lopes, L., Lorenz, M., Mahmoud, T., Maier, L., Malige, A., Mamaev, M., Mangiarotti, A., Markert, J., Matulewicz, T., Maurus, S., Metag, V., Michel, J., Mihaylov, D.M., Morozov, S., Müntz, C., Münzer, R., Naumann, L., Nowakowski, K., Parpottas, Y., Pechenov, V., Pechenova, O., Petukhov, O., Piasecki, K., Pietraszko, J., Przygoda, W., Pysz, K., Ramos, S., Ramstein, B., Rathod, N., Reshetin, A., Rodriguez-Ramos, P., Rosier, P., Rost, A., Rustamov, A., Sadovsky, A., Salabura, P., Scheib, T., Schuldes, H., Schwab, E., Scozzi, F., Seck, F., Sellheim, P., Selyuzhenkov, I., Siebenson, J., Silva, L., Singh, U., Smyrski, J., Sobolev, Yu. G., Spataro, S., Spies, S., Ströbele, H., Stroth, J., Sturm, C., Svoboda, O., Szala, M., Tlusty, P., Traxler, M., Tsertos, H., Usenko, E., Wagner, V., Wendisch, C., Wiebusch, M.G., Wirth, J., Wójcik, D., Zanevsky, Y., Zumbruch, P., Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and HADES

Subjects
flow: higher-order, deuteron, heavy ion: scattering, elliptic flow, Nuclear Theory, transverse momentum, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 2.4 GeV-cms/nucleon, rapidity, HADES, spectrometer, Nuclear Experiment, Nuclear Physics, fluid, experimental results
Abstract

International audience; Flow coefficients vn of the orders n=1–6 are measured with the High-Acceptance DiElectron Spectrometer (HADES) at GSI for protons, deuterons, and tritons as a function of centrality, transverse momentum, and rapidity in Au+Au collisions at sNN=2.4 GeV. Combining the information from the flow coefficients of all orders allows us to construct for the first time, at collision energies of a few GeV, a multidifferential picture of the angular emission pattern of these particles. It reflects the complicated interplay between the effect of the central fireball pressure on the emission of particles and their subsequent interaction with spectator matter. The high precision information on higher order flow coefficients is a major step forward in constraining the equation of state of dense baryonic matter.

Published
2020
Full Text
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45. Charged-pion production in $\mathbf {Au+Au}$ collisions at $\sqrt{\mathbf {s}_{\mathbf {NN}}} = 2.4~{\mathbf {GeV}}$: HADES Collaboration

Author

Adamczewski-Musch, J., Arnold, O., Behnke, C., Belounnas, A., Belyaev, A., Berger-Chen, J.C., Blanco, A., Blume, C., Böhmer, M., Bordalo, P., Chernenko, S., Chlad, L., Ciepał, I., Deveaux, C., Dreyer, J., Epple, E., Fabbietti, L., Fateev, O., Filip, P., Fonte, P., Franco, C., Friese, J., Fröhlich, I., Galatyuk, T., Garzón, J.A., Gernhäuser, R., Gläßel, S., Golubeva, M., Greifenhagen, R., Guber, F., Gumberidze, M., Harabasz, S., Heinz, T., Hennino, T., Hlavac, S., Höhne, C., Holzmann, R., Ierusalimov, A., Ivashkin, A., Kämpfer, B., Karavicheva, T., Kardan, B., Koenig, I., Koenig, W., Kohls, M., Kolb, B.W., Korcyl, G., Kornakov, G., Kornas, F., Kotte, R., Kugler, A., Kunz, T., Kurepin, A., Kurilkin, A., Kurilkin, P., Ladygin, V., Lalik, R., Lapidus, K., Lebedev, A., Lopes, L., Lorenz, M., Mahmoud, T., Maier, L., Malige, A., Mangiarotti, A., Markert, J., Matulewicz, T., Maurus, S., Metag, V., Michel, J., Mihaylov, D.M., Morozov, S., Müntz, C., Münzer, R., Naumann, L., Nowakowski, K., Parpottas, Y., Pechenov, V., Pechenova, O., Petukhov, O., Piasecki, K., Pietraszko, J., Przygoda, W., Pysz, K., Ramos, S., Ramstein, B., Rathod, N., Reshetin, A., Rodriguez-Ramos, P., Rosier, P., Rost, A., Rustamov, A., Sadovsky, A., Salabura, P., Scheib, T., Schuldes, H., Schwab, E., Scozzi, F., Seck, F., Sellheim, P., Selyuzhenkov, I., Siebenson, J., Silva, L., Singh, U., Smyrski, J., Sobolev, Yu. G., Spataro, S., Spies, S., Ströbele, H., Stroth, J., Sturm, C., Svoboda, O., Szala, M., Tlusty, P., Traxler, M., Tsertos, H., Usenko, E., Wagner, V., Wendisch, C., Wiebusch, M.G., Wirth, J., Wójcik, D., Zanevsky, Y., Zumbruch, P., Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and HADES

Subjects
pi: multiplicity, mass: transverse, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], pi: production, transverse momentum, beam: energy, 2.4 GeV-cms/nucleon, rapidity, HADES, transport theory, angular distribution, Nuclear Experiment, impact parameter
Abstract

The European physical journal / A 56(10), 259 (2020). doi:10.1140/epja/s10050-020-00237-2, We present high-statistic data on charged-pion emission from Au + Au collisions at $\sqrt{s_{\mathrm{NN}}} = 2.4~\hbox {GeV}$ (corresponding to $E_{beam} = 1.23~\hbox {A GeV}$) in four centrality classes in the range 0–40% of the most central collisions. The data are analyzed as a function of transverse momentum, transverse mass, rapidity, and polar angle. Pion multiplicity per participating nucleon decreases moderately with increasing centrality. The polar angular distributions are found to be non-isotropic even for the most central event class. Our results on pion multiplicity fit well into the general trend of the available world data, but undershoot by $2.5~\sigma $ data from the FOPI experiment measured at slightly lower beam energy. We compare our data to state-of-the-art transport model calculations (PHSD, IQMD, PHQMD, GiBUU and SMASH) and find substantial differences between the measurement and the results of these calculations., Published by Springer, Heidelberg

Published
2020
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46. Proton-number fluctuations in $\sqrt {s_{NN}}$ =2.4 GeV Au + Au collisions studied with the High-Acceptance DiElectron Spectrometer (HADES)

Author

Adamczewski-Musch, J., Arnold, O., Behnke, C., Belounnas, A., Belyaev, A., Berger-Chen, J. C., Blanco, A., Blume, C., Böhmer, M., Bordalo, P., Chernenko, S., Chlad, L., Ciepał, Izabela, Deveaux, C., Dreyer, J., Epple, E., Fabbietti, L., Fateev, O., Filip, P., Fonte, P., Franco, C., Friese, J., Fröhlich, I., Galatyuk, T., Garzón, J. A., Gernhäuser, R., Golubeva, M., Greifenhagen, R., Guber, F., Gumberidze, M., Harabasz, Szymon, Heinz, T., Hennino, T., Hlavac, S., Höhne, C., Holzmann, R., Ierusalimov, A., Ivashkin, A., Kämpfer, B., Karavicheva, T., Kardan, B., Koenig, I., Koenig, W., Kohls, M., Kolb, B. W., Korcyl, Grzegorz, Kornakov, G., Kornas, F., Kotte, R., Kugler, A., Kunz, T., Kurepin, A., Kurilkin, A., Kurilkin, P., Ladygin, V., Lalik, Rafał, Lapidus, K., Lebedev, A., Lopes, L., Lorenz, M., Mahmoud, T., Maier, L., Malige, Akshay, Mangiarotti, A., Markert, J., Matulewicz, T., Maurus, S., Metag, V., Michel, J., Mihaylov, D. M., Morozov, S., Müntz, C., Münzer, R., Naumann, L., Nowakowski, Krzysztof, Parpottas, Y., Pechenov, V., Pechenova, O., Petukhov, O., Piasecki, K., Pietraszko, J., Przygoda, Witold, Pysz, K., Ramos, S., Ramstein, B., Rathod, Narendra, Reshetin, A., Rodriguez-Ramos, P., Rosier, P., Rost, A., Rustamov, A., Sadovsky, A., Salabura, Piotr, Scheib, T., Schuldes, H., Schwab, E., Scozzi, F., Seck, F., Sellheim, P., Selyuzhenkov, I., Siebenson, J., Silva, L., Singh, Udai, Smyrski, Jerzy, Sobolev, Yu. G., Spataro, S., Spies, S., Ströbele, H., Stroth, J., Sturm, C., Svoboda, O., Szala, M., Tlusty, P., Traxler, M., Tsertos, H., Usenko, E., Wagner, V., Wendisch, C., Wiebusch, M. G., Wirth, J., Wójcik, D., Zanevsky, Y., Zumbruch, P., Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and HADES

Subjects
fluctuation, correction: efficiency, transverse momentum, Relativistic Nuclear Collisions, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], long-range, phase space, 2.4 GeV-cms/nucleon, HADES, transport theory, spectrometer, correlation function, Nuclear Experiment, Brookhaven RHIC Coll, experimental results, acceptance
Abstract

International audience; We present an analysis of proton-number fluctuations in sNN=2.4 GeV Au197+Au197 collisions measured with the High-Acceptance DiElectron Spectrometer (HADES) at GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt. With the help of extensive detector simulations done with Isospin Quantum Molecular Dynamics (IQMD) transport model events including nuclear clusters, various nuisance effects influencing the observed proton cumulants have been investigated. Acceptance and efficiency corrections have been applied as a function of fine-grained rapidity and transverse momentum bins, as well as considering local track density dependencies. Next, the effects of volume changes within particular centrality selections have been considered and beyond-leading-order corrections have been applied to the data. The efficiency and volume-corrected proton number moments and cumulants Kn of orders n=1, 2, 3, and 4 have been obtained as a function of centrality and phase-space bin, as well as the corresponding correlators Cn. We find that the observed correlators show a power-law scaling with the mean number of protons, i.e., Cn∝〈N〉n, indicative of mostly long-range multiparticle correlations in momentum space. We also present a comparison of our results with Au + Au collision data obtained at the Relativistic Heavy Ion Collider (RHIC) at similar centralities but higher sNN.

Published
2020
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47. Sub-threshold production of K mesons and Λ hyperons in Au+Au collisions at GeV

Author

Adamczewski-Musch, J., Arnold, O., Behnke, C., Belounnas, A., Belyaev, A., Berger-Chen, J.C., Biernat, J., Blanco, A., Blume, C., Böhmer, M., Bordalo, P., Chernenko, S., Chlad, L., Deveaux, C., Dreyer, J., Dybczak, A., Epple, E., Fabbietti, L., Fateev, O., Filip, P., Fonte, P., Franco, C., Friese, J., Fröhlich, I., Galatyuk, T., Garzón, J.A., Gernhäuser, R., Golubeva, M., Greifenhagen, R., Guber, F., Gumberidze, M., Harabasz, S., Heinz, T., Hennino, T., Hlavac, S., Höhne, C., Holzmann, R., Ierusalimov, A., Ivashkin, A., Kämpfer, B., Karavicheva, T., Kardan, B., Koenig, I., Koenig, W., Kolb, B.W., Korcyl, G., Kornakov, G., Kotte, R., Kugler, A., Kunz, T., Kurepin, A., Kurilkin, A., Kurilkin, P., Ladygin, V., Lalik, R., Lapidus, K., Lebedev, A., Lopes, L., Lorenz, M., Mahmoud, T., Maier, L., Mangiarotti, A., Markert, J., Maurus, S., Metag, V., Michel, J., Mihaylov, D.M., Morozov, S., Müntz, C., Münzer, R., Naumann, L., Nowakowski, K., Palka, M., Parpottas, Y., Pechenov, V., Pechenova, O., Petukhov, O., Pietraszko, J., Przygoda, W., Ramos, S., Ramstein, B., Reshetin, A., Rodriguez-Ramos, P., Rosier, P., Rost, A., Sadovsky, A., Salabura, P., Scheib, T., Schuldes, H., Schwab, E., Scozzi, F., Seck, F., Sellheim, P., Selyuzhenkov, I., Siebenson, J., Silva, L., Sobolev, Yu.G., Spataro, S., Spies, S., Ströbele, H., Stroth, J., Strzempek, P., Sturm, C., Svoboda, O., Szala, M., Tlusty, P., Traxler, M., Tsertos, H., Usenko, E., Wagner, V., Wendisch, C., Wiebusch, M.G., Wirth, J., Zanevsky, Y., Zumbruch, P., and Leifels, Y.

Abstract

We present first data on sub-threshold production of Ks0 mesons and Λ hyperons in Au+Au collisions at sNN=2.4 GeV. We observe an universal 〈Apart〉 scaling of hadrons containing strangeness, independent of their corresponding production thresholds. Comparing the yields, their 〈Apart〉 scaling, and the shapes of the rapidity and the pt spectra to state-of-the-art transport model (UrQMD, HSD, IQMD) predictions, we find that none of them can simultaneously describe these observables with reasonable χ2 values.

Published
2019

48. Identical pion intensity interferometry at $$\sqrt{s_{\mathrm{NN}}}=2.4~\hbox {GeV}$$

Author

Adamczewski-Musch, J., Arnold, O., Behnke, C., Belounnas, A., Belyaev, A., Berger-Chen, J. C., Biernat, J., Blanco, A., Blume, C., Böhmer, M., Bordalo, P., Chernenko, S., Chlad, L., Deveaux, C., Dreyer, J., Dybczak, A., Epple, E., Fabbietti, L., Fateev, O., Filip, P., Fonte, P., Franco, C., Friese, J., Fröhlich, I., Galatyuk, T., Garzón, J. A., Gernhäuser, R., Golubeva, M., Greifenhagen, R., Guber, F., Gumberidze, M., Harabasz, S., Heinz, T., Hennino, T., Hlavac, S., Höhne, C., Holzmann, R., Ierusalimov, A., Ivashkin, A., Kämpfer, B., Karavicheva, T., Kardan, B., Koenig, I., Koenig, W., Kolb, B. W., Korcyl, G., Kornakov, G., Kornas, F., Kotte, R., Kugler, A., Kunz, T., Kurepin, A., Kurilkin, A., Kurilkin, P., Ladygin, V., Lalik, R., Lapidus, K., Lebedev, A., Lopes, L., Lorenz, M., Mahmoud, T., Maier, L., Mangiarotti, A., Markert, J., Matulewicz, T., Maurus, S., Metag, V., Michel, J., Mihaylov, D. M., Morozov, S., Müntz, C., Münzer, R., Naumann, L., Nowakowski, K., Palka, M., Parpottas, Y., Pechenov, V., Pechenova, O., Petukhov, O., Piasecki, K., Pietraszko, J., Przygoda, W., Ramos, S., Ramstein, B., Reshetin, A., Rodriguez-Ramos, P., Rosier, P., Rost, A., Sadovsky, A., Salabura, P., Scheib, T., Schuldes, H., Schwab, E., Scozzi, F., Seck, F., Sellheim, P., Selyuzhenkov, I., Siebenson, J., Silva, L., Sobolev, Yu. G., Spataro, S., Spies, S., Ströbele, H., Stroth, J., Strzempek, P., Sturm, C., Svoboda, O., Szala, M., Tlusty, P., Traxler, M., Tsertos, H., Usenko, E., Wagner, V., Wendisch, C., Wiebusch, M. G., Wirth, J., Wójcik, D., Zanevsky, Y., and Zumbruch, P.

Subjects
ddc
Published
2019

49. Etude de résonances baryoniques dans le canal pp->ppπ⁺π⁻ à une énergie de faisceau de 3.5 GeV avec le détecteur HADES

Author

Belounnas, Amel, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Saclay, and Béatrice Ramstein

Subjects
GSI, Résonances baryoniques, Baryonic resonances, HADES detector, Hadronic physics, Physique hadronique, Détecteur HADES, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Simulation
Abstract

The subject of this thesis is the analysis of the pp->ppπ⁺π⁻ reaction measured at a beam energy of 3.5 GeV with the High Acceptance Di-Electron Spectrometer (HADES) at GSI. The aim is to provide additional information on the production of a pion and a kaon measured by HADES for the excitation of a resonance as well as new results for the production of two resonances and the ρ meson production. Such information is important, in particular, for the interpretation of the di-electron spectra measured by the HADES collaboration. The extraction of the signal for pp->ppπ⁺π⁻ production is based on the detection of one proton, one π⁺ and one π⁻ in the HADES detector and the calculation of the missing mass. Statistical errors are negligible and systematic errors are mainly due to the efficiency corrections which are based on simulations and to normalization. A simple model based on PLUTO event generator was built for the interpretation of the data, by including three main types of contributions: the production of one resonance decaying into pπ⁺π⁻ and the excitation of two resonances, decaying respectively into pπ⁺ and pπ⁻ and the direct ρ production. A fitting procedure is developed, using as constraint the information obtained for the single resonance excitation from one pion and one kaon production data. The contribution of the ρ meson was also extracted after applying necessary kinematical cuts. Among all the identified contributions, the main ones are the double Δ(1232) excitation and the N(1520) excitation. A Lagrangian model was developed for these two contributions, the calculations give a similar result to the simple model and predict a negligible interferences effect. Finally, the confrontation of the experimental results to the predictions of existing theoretical models shows the necessity to take into account these new data for the description of mesons and di-electron production in nuclear collisions above 1.5 GeV/nucleus.; Le sujet de cette thèse est l’analyse de la réaction pp->ppπ⁺π⁻ mesurée à une énergie de faisceau de 3,5 GeV avec le spectromètre HADES à GSI. L’objectif est d’apporter des informations complémentaires à la production d'un pion et d'un kaon mesurés par HADES pour l'excitation d'une résonance ainsi que des résultats tout nouveaux pour la production de deux résonances et pour la production du méson ρ. Ces informations sont particulièrement importantes pour l'interprétation des spectres de di-électrons également mesurés par la collaboration HADES. L'extraction du signal pour la production de pp->ppπ⁺π⁻ est basée sur la détection d'un proton, un π⁺ et un π⁻ dans le détecteur HADES et sur le calcul de la masse manquante. Les erreurs statistiques sont négligeables et les erreurs systématiques sont principalement dues aux corrections d’efficacité basées sur des simulations et à la normalisation. Un modèle simple basé sur le générateur d’évènements PLUTO a été construit pour l'interprétation des données en incluant trois types de contributions: la production d’une résonance décroissant en pπ⁺π⁻ et l’excitation de deux résonances décroissant respectivement en pπ⁺ et pπ⁻ et la production directe du méson ρ. Une procédure de fit est développée en utilisant comme contraintes pour l'excitation baryonique simple les résultats obtenus pour la production d'un pion et d'un kaon. La contribution du méson ρ a été également extraite après l’application des coupures cinématiques nécessaires et le rôle des résonances baryoniques dans cette production est discuté. Parmi toutes les contributions identifiées, les principales sont la double excitation de Δ(1232) et la simple excitation de N(1520). Un modèle de Lagrangien a été mis au point pour ces deux contributions, les calculs donnent un résultat assez proche du modèle simple et prédisent un effet des interférences très faible. Finalement, la confrontation des résultats expérimentaux aux prédictions de modèles théoriques existants montre la nécessité de prendre en compte ces nouvelles données pour la description de la production de mésons et de di-électrons dans les collisions nucléaires au-delà de 1.5 GeV/nucléon.

Published
2019

50. Study of baryonic resonances in the channel pp->ppπ⁺π⁻ at 3.5 GeV beam energy with the HADES detector

Author

Belounnas, Amel, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Saclay, and Béatrice Ramstein

Subjects
GSI, Résonances baryoniques, Baryonic resonances, HADES detector, Hadronic physics, Physique hadronique, Détecteur HADES, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Simulation
Abstract

The subject of this thesis is the analysis of the pp->ppπ⁺π⁻ reaction measured at a beam energy of 3.5 GeV with the High Acceptance Di-Electron Spectrometer (HADES) at GSI. The aim is to provide additional information on the production of a pion and a kaon measured by HADES for the excitation of a resonance as well as new results for the production of two resonances and the ρ meson production. Such information is important, in particular, for the interpretation of the di-electron spectra measured by the HADES collaboration. The extraction of the signal for pp->ppπ⁺π⁻ production is based on the detection of one proton, one π⁺ and one π⁻ in the HADES detector and the calculation of the missing mass. Statistical errors are negligible and systematic errors are mainly due to the efficiency corrections which are based on simulations and to normalization. A simple model based on PLUTO event generator was built for the interpretation of the data, by including three main types of contributions: the production of one resonance decaying into pπ⁺π⁻ and the excitation of two resonances, decaying respectively into pπ⁺ and pπ⁻ and the direct ρ production. A fitting procedure is developed, using as constraint the information obtained for the single resonance excitation from one pion and one kaon production data. The contribution of the ρ meson was also extracted after applying necessary kinematical cuts. Among all the identified contributions, the main ones are the double Δ(1232) excitation and the N(1520) excitation. A Lagrangian model was developed for these two contributions, the calculations give a similar result to the simple model and predict a negligible interferences effect. Finally, the confrontation of the experimental results to the predictions of existing theoretical models shows the necessity to take into account these new data for the description of mesons and di-electron production in nuclear collisions above 1.5 GeV/nucleus.; Le sujet de cette thèse est l’analyse de la réaction pp->ppπ⁺π⁻ mesurée à une énergie de faisceau de 3,5 GeV avec le spectromètre HADES à GSI. L’objectif est d’apporter des informations complémentaires à la production d'un pion et d'un kaon mesurés par HADES pour l'excitation d'une résonance ainsi que des résultats tout nouveaux pour la production de deux résonances et pour la production du méson ρ. Ces informations sont particulièrement importantes pour l'interprétation des spectres de di-électrons également mesurés par la collaboration HADES. L'extraction du signal pour la production de pp->ppπ⁺π⁻ est basée sur la détection d'un proton, un π⁺ et un π⁻ dans le détecteur HADES et sur le calcul de la masse manquante. Les erreurs statistiques sont négligeables et les erreurs systématiques sont principalement dues aux corrections d’efficacité basées sur des simulations et à la normalisation. Un modèle simple basé sur le générateur d’évènements PLUTO a été construit pour l'interprétation des données en incluant trois types de contributions: la production d’une résonance décroissant en pπ⁺π⁻ et l’excitation de deux résonances décroissant respectivement en pπ⁺ et pπ⁻ et la production directe du méson ρ. Une procédure de fit est développée en utilisant comme contraintes pour l'excitation baryonique simple les résultats obtenus pour la production d'un pion et d'un kaon. La contribution du méson ρ a été également extraite après l’application des coupures cinématiques nécessaires et le rôle des résonances baryoniques dans cette production est discuté. Parmi toutes les contributions identifiées, les principales sont la double excitation de Δ(1232) et la simple excitation de N(1520). Un modèle de Lagrangien a été mis au point pour ces deux contributions, les calculs donnent un résultat assez proche du modèle simple et prédisent un effet des interférences très faible. Finalement, la confrontation des résultats expérimentaux aux prédictions de modèles théoriques existants montre la nécessité de prendre en compte ces nouvelles données pour la description de la production de mésons et de di-électrons dans les collisions nucléaires au-delà de 1.5 GeV/nucléon.

Published
2019

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